Results Of Sentinel Lymph Node Biopsy Research Articles

Abstract PO4-23-02: Blue Dye-Only for Sentinel Lymph Node Biopsy After Neoadjuvant Chemotherapy in Patients with Initially Node-positive Breast Cancer

Abstract Importance: Randomized trials evaluated the false negative rate (FNR) of sentinel lymph node biopsy (SLNB) in initially node-positive (cN1/2) breast cancer (BC) patients who downstaged after neoadjuvant chemotherapy (NAC): the studies were negative, as they found FNR above 10%. However, the FNR was adequate when the lymph node was marked with a clip before NAC or at least 3 lymph nodes were removed. SLNB using a combination of blue dye and a radiotracer (Technetium-99) was encouraged to facilitate identification and maximize SLNB results in this scenario. However, radiotracer is unavailable in many services around the world, particularly in low- and middle-income countries (LMIC), but the feasibility and the recurrence rates of SNLB with the use of blue dye-only, in previous cN1/2 patients, are unknown. Objective: The aim of this study was to evaluate the feasibility, proportion of patients undergoing SLNB without axillary dissection (AD) and mean number of resected sentinel nodes (SN), and recurrence rates (axillary recurrence [AR], ipsilateral breast recurrence [IBR], new contralateral primary, disease-free survival [DFS] and overall survival [OS]) of SNLB with the use of blue dye-only in initially node-positive BC (cN1/2). Design, Setting, and Participants: From 2013 to 2023, a cohort of patients undergoing NAC was evaluated at a public institution in Brazil (Hospital Geral de Fortaleza - HGF). Radiotracer and clips were not available. Patients with prior cN1/2 were identified and evaluated. AD was not recommended in cases of negative histopathological results for lymph node metastases after SLNB using blue dye-only. Inflammatory, cN0 and cN3 BC patients were excluded. Results: Among 119 cN1/2 BC patients treated with NAC, 100 (84%) cases underwent SLNB with blue dye-only and 70 (59%) had SLNB alone. The median of SN were 3.1 and 55 (78%) cases had 3 or more SN. No events related to blue dye occurred. The median age of these 70 patients was 49 (25-84) years, and most cases were T2 (n=40/57.1%), followed by T3 (n=18/25.7%), T4 (n=6/8.6%) and T1 (n=6/8.6%), while N1 predominated in axillary status (n=64/91.4%). Regarding breast cancer subtype, there were 19 (27.1%) hormone receptor-positive/HER2-negative, 16 (22.9%) hormone receptor-negative/HER2-positive, 21 (30%) hormone receptor-positive/HER2-positive and 14 (20%) triple-negative cases. 55 (79%) patients received regimens containing anthracyclines and taxanes. Anti-HER2 therapy was used in all cases, but pertuzumab associated with trastuzumab were available in only 8 patients (8/37). Breast-conserving surgery was performed in 40 (57%) cases while total mastectomy in 30 (43%). Patients with hormone-positive BC received endocrine therapy. Adjuvant radiotherapy was made in all cases, except one who underwent mastectomy. After 36 months of median follow-up, no axillary recurrences were observed. One patient had a new primary in the contralateral breast. Three patients had distant disease and two died. Conclusions: This cohort found that the use of SLNB with blue dye-only in Initially cN1/2 BC patients who achieved complete response after NAC is feasible, with very low axillary recurrence rates, like previous reports in the literature that used a combination of tracers. These data reinforce the need for further studies in this scenario, as it maintains the possibility of avoiding AD in places with difficult access to oncological treatment, especially in LMIC. Figure 1 - Flowchart cN: Clinical node stage; BC: Breast cancer; NAC: Neoadjuvant chemotherapy; SNLB: Sentinel lymph node biopsy; AD: Axillary dissection; SN: Sentinel node Table 1 - Demographic Characteristics Citation Format: Francisco Pimentel Cavalcante, Felipe Zerwes, Alessandra Souza, Patricia Ziegelmann, Ryane Alcantara, Amanda Cardoso, Andre Mattar, Eduardo Millen, Antonio Frasson. Blue Dye-Only for Sentinel Lymph Node Biopsy After Neoadjuvant Chemotherapy in Patients with Initially Node-positive Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-23-02.

Impact of obesity on sentinel lymph node biopsy outcomes and survival in breast cancer patients: A single-center retrospective study.

Sentinel lymph node biopsy (SLNB) is a common choice for axillary surgery in patients with early-stage breast cancer (BC) who have clinically negative lymph nodes. Most research indicates that obesity is a prognostic factor for BC patients, but studies assessing its association with the rate of positive sentinel lymph nodes (SLN) and the prognosis of patients with early BC undergoing SLNB are limited. Between 2013 and 2016, 7062 early-stage BC patients from the Shanghai Cancer Center of Fudan University were included. Based on the Chinese Body Mass Index (BMI) classification standards, the patients were divided into three groups as follows: normal weight, overweight, and obese. Propensity score matching analysis was used to balance the baseline characteristics of the participants. Logistic regression analysis was used to determine the association between obesity and positive SLN rate. Cox regression analysis was used to investigate whether obesity was an independent prognostic factor for early-stage BC patients who had undergone SLNB. No significant association was observed between obesity and positive SLN rate in early-stage BC patients who had undergone SLNB. However, multivariate analysis revealed that compared to patients with normal BMI, the overall survival (hazard ratio (HR) 2.240, 95% confidence interval (CI) 1.27-3.95, p = 0.005) and disease-free survival (HR 1.750, 95% CI 1.16-2.62, p = 0.007) were poorer in patients with high BMI. Obesity is an independent prognostic factor for early-stage BC patients who undergo SLNB; however, it does not affect the positive SLN rate.

Tailoring postoperative management through sentinel lymph node biopsy in low- and intermediate-risk endometrial cancer - the SENTRY clinical trial.

While total hysterectomy and bilateral salpingo-oophorectomy without lymph node staging are standard for low- and intermediate-risk endometrial cancer, certain histopathologic factors revealed after surgery can necessitate additional interventions. Our study assessed the influence of sentinel lymph node biopsy on postoperative decision-making. In the SENTRY trial (July 2021 - February 2023), we enrolled patients with International Federation of Gynaecology and Obstetrics (FIGO) stage IA-IB low-grade endometrioid endometrial cancer. Laparoscopic sentinel lymph node mapping using indocyanine green was performed alongside total hysterectomy with bilateral salpingo-oophorectomy. Subsequent management changes based on sentinel lymph node biopsy results were evaluated. The trial was registered at ClinicalTrials.gov (NCT04972682). Of the 100 enrolled participants, a bilateral detection rate of 91% was observed with a median detection time of 10 min (interquartile range 8-13 min). Sentinel lymph node metastases were found in 8% (N = 8) of participants. Postoperative FIGO staging increased in 15% (N = 15) and decreased in 5% (N = 5) of patients. Sentinel lymph node biopsy results altered the adjuvant treatment plan for 20% (N = 20): external beam radiotherapy was omitted in 12% (N = 12) while 6% (N = 6) had external beam radiotherapy +/- systemic chemotherapy added due to sentinel lymph node metastases. In 2% (N = 2), the external beam radiotherapy field was expanded with the paraaortic region. No intraoperative complications were reported and no 30-day major morbidity and mortality occurred. Throughout a median follow-up of 14 (95% CI 12-15 months, neither patient-reported lymphedema nor pelvic recurrence surfaced in the cohort. Sentinel lymph node biopsy using indocyanine green is a safe procedure and allows tailoring adjuvant therapy in presumed low- and intermediate-risk endometrial cancer. It assists in avoiding external beam radiotherapy overtreatment and introducing additional modalities when necessary.

SURGICAL TREATMENT OF ADVANCED PALMOPLANTAR MELANOMA

Aim:
 Palmoplantar melanoma is a rare and aggressive subtype of malignant melanoma. Not like other subtypes, sunlight is not the primary etiologic factor. We aim to expand the knowledge on this rare and neglected malignant melanoma subtype and add our findings to the literature. 
 Materials and Methods:
 Malignant Melanoma patients admitted to our hospital between 2008 and 2020 were retrospectively analyzed. Twenty-seven patients with plantar and one with palmar melanoma were identified and included in our study. Data about gender, age at the diagnosis, histopathological features, sentinel lymph node localization, performed surgeries, sentinel lymph node biopsy (SLNB) and regional lymph node dissection results, recurrence, survival time, primary tumor localization, and systemic metastases were collected. 
 Results:
 26 plantar and one palmar melanoma patients were operated on in this period. Six patients died during follow-up. Twenty-three patients were treated with wide excisions, and four were treated with amputations. The defect was reconstructed with a skin graft in all cases with excisions. In 6 patients with suspicious lymph nodes in the preoperative imaging, lymph node dissection was added to the treatment. Other patients had sentinel lymph node biopsies and continued with dissection if a metastatic node was encountered. 
 Conclusion:
 Our findings are congruent with the current literature. Skin grafting may enhance the success of palmoplantar melanoma follow-up and demands attention.

Risk factors for sentinel lymph node metastasis in Korean acral and non-acral melanoma patients.

Breslow thickness, ulceration, and mitotic rate are well-known prognostic factors for sentinel lymph node (SLN) metastasis in cutaneous melanoma. We investigated risk factors, including especially the degree of pigmentation, for SLN metastasis in Korean melanoma patients. We enrolled 158, composed of Korean 107 acral and 51 non-acral melanoma patients who underwent SLN biopsy. Clinicopathologic features such as Breslow thickness, ulceration, mitotic rate, and the degree of pigmentation were evaluated. The recurrence-free survival (RFS) rate and date of recurrence were determined. Fifty-four patients (34.2%) had a positive SLN biopsy result. In a multivariate analysis, Breslow thickness (odds ratio [OR] 1.93; 95% confidence interval [CI], 1.12-3.47; p = .022) and heavy pigmentation (OR 13.14; 95% CI, 2.96-95.20, p = .002) were associated with SLN metastasis. Positive SLN patients had a higher rate of loco-regional and/or distant recurrence (hazard ratio 6.32; 95% CI, 3.39-11.79; p < .001). Heavy pigmentation was associated with poor RFS. Heavy pigmentation is an independent predictor of SLN metastasis in both acral and non-acral melanoma. Our results suggest the need for in-depth SLN evaluation of cutaneous melanoma patients with heavy pigmentation and provide clinicians with important information for determining patient prognosis.

Fine-needle aspiration biopsy of axillary lymph nodes: Areliable diagnostic tool for breast cancer staging.

Pathologic evaluation of sentinel lymph node biopsy (SLNB) samples is crucial for axillary staging in patients newly diagnosed with breast cancer. Patients with pathologic evidence of nodal metastasis scheduled for upfront surgery typically also undergo axillary lymph node dissection (ALND). Although SLNB is the gold standard method for detecting nodal metastasis, axillary lymph node fine-needle aspiration biopsy (FNAB) utility has not been thoroughly explored. Ultrasound-guided axillary lymph node FNAB samples along with concurrent ipsilateral breast tissue samples were searched and reviewed. The control group included histologic findings of axillary dissection or intraoperative SLNB results. A total of 354 axillary lymph node FNAB samples with matched histology were included. Of these, 187 (52.8%) were positive for metastatic carcinoma of breast origin; 143 (40.4%) were negative for metastasis; 12 (3.4%) showed atypical cells; six (1.7%) were suspicious for metastasis; and six (1.7%) were nondiagnostic because of a lack of lymphoid tissue and malignant cells. Of the 143 negative FNAB samples, 22 (15.4%) were positive on either intraoperative SLNB or ALND. When only the positive and negative FNAB samples were accounted for (n=330; 93.2%), overall diagnostic sensitivity and specificity were 89.4% and 99.2%, respectively. Although axillary SLNB is the standard procedure for detecting nodal metastasis of breast origin, axillary lymph node FNAB appears to be a suitable alternative in a significant proportion of patients. A standard SLNB should be performed in cases of negative axillary lymph node FNAB findings, particularly nodes with abnormal imaging findings.

266 Malignant Melanoma: Highlighting Delays in the Pathway from Biopsy to WLE (Wide Local Excision) + SLNB (Sentinel Lymph Node Biopsy)

Abstract Aim To highlight delays in the malignant melanoma (MM) pathway for patients undergoing a Wide Local Excision (WLE) and Sentinel Lymph Node Biopsy (SLNB). Aiming to evaluate if Trust standards are met, to provide a 31-day clock from time of clinic discussion for WLE and SLNB, to date of operation. In particular, comparing pre- (2019) and post-COVID (2022) waiting times. Method Retrospective data collection of patients with a MM diagnosis AJCC (American Joint Committee on Cancer) 1B-2C requiring WLE and SLNB, who were operated on between January-December 2019 and January-October 2022. All operations were performed at the Royal Victoria Infirmary, Newcastle. The following parameters were collected: AJCC grade; SLNB site and result; date of: initial biopsy, biopsy result, skin cancer multidisciplinary meeting (MDT), clinic discussion, and operation. Exclusion criteria: AJCC 1A and 3, incomplete original biopsy (i.e. initial 2-week wait clock had not stopped), incomplete documentation of clinic discussion date, extreme delays (3 patients &amp;gt;140 days, due to acute illness and initially declining operation). Results The average time from clinic discussion to operation was 35 days in 2019, compared to 53 days in 2022 (p-value &amp;lt;0.05). 56% (n = 79) of 2019 patients underwent their operation within the 31-day target, compared to 13% (n = 14) of 2022 patients, p&amp;lt;0.05. This statistically significant difference was irrespective of AJCC grade and SLNB site. Conclusions Statistically significant decrease in the percentage of patients meeting the 31-day target in 2022, compared to 2019. Delays were affected by an increase in number of MM referrals and limited capacity for operating.

Sentinel lymph node biopsy after nipple-sparing mastectomy in early postoperative period: Is it feasible?

Axillary lymph node status is one of the most important prognostic factors for breast cancer. Sentinel lymph node biopsy (SLNB) after mastectomy is highly controversial. There is not enough data about SLNB in the early period after nipple-sparing mastectomy (NSM). This study investigated the feasibility of SLNB in the early postoperative period of NSM. Patients who were operated on for breast cancer in Acibadem Maslak Hospital between 2009 and 2018 were searched retrospectively. Results of SLNB as the second session in patients whose final pathology report revealed breast carcinoma after contralateral/bilateral prophylactic mastectomy and mastectomy for benign lesions were evaluated. In the early period (median 14 days) after NSM, SLNB was performed by intradermal radioisotope injection in five patients with occult breast cancer in contralateral/bilateral prophylactic mastectomy and in one patient with preoperatively suspicious mass which yielded breast cancer at final pathology. In five (80%) patients, SLNB was performed, whereas in one patient axillary lymph node dissection (ALND) was performed due to the undetectability of SLN. In one patient, micrometastasis was observed, whereas no metastasis was observed in other patients including the one who underwent ALND. No complication due to SLNB was detected. No recurrence and distant metastasis were detected in a mean follow-up of 42.82 (19-70) months. While SLNB did not change the treatment of patients with contralateral occult carcinoma, other patients had hormonal therapy due to negative SLNB. SLNB in the early postoperative period of NSM can be performed by intradermal radioisotope injection. However, further studies are needed to determine the feasibility of SLNB in the early postoperative period of NSM.

Axillary Lymph Nodes in Breast Cancer Patients After COVID-19 Vaccine.

One of the side effects of vaccines used to end the COVID-19 epidemic is non-specifically enlarged axillary lymph nodes. Such lymphadenopathy detected during clinical examination of breast cancer patients may require additional imaging or interventional procedures that should not normally be performed. This study has been designed to estimate the incidence of palpable enlarged axillary lymph node in breast cancer patients who had received COVID-19 vaccination in the past 3months in the same arm as compared to those without vaccination. Breast cancer patients admitted to M.U. Medical Faculty Breast polyclinic between January 2021 and March 2022 were screened, and clinical staging was performed after thorough clinical examination. Among these patients with suspected enlarged axillary lymph node and those undergoing sentinel lymph node biopsy (SLNB), they were divided into two groups as vaccinated and unvaccinated. Age, menopausal status, tumor size, tumor location, surgery, pathology results, hormonal receptor status, and SLNB results were statistically compared with groups. There was no significant difference between groups in terms of age, menopause, tumor size, tumor location, surgery, pathological results, and hormone receptor status. The SLNB being reported as reactive only was 89.1% in the vaccinated group and 73.2% in the non-vaccinated group which was statistically significant different. Reactive lymph nodes were commonly found with an excess of 16% in patients who had received COVID-19 vaccination in the past 3months. This required caution and additional examination of the axillary lymph nodes in this period.

Improving Selection for Sentinel Lymph Node Biopsy Among Patients With Melanoma

Refining eligibility guidelines may identify more appropriate patients to undergo useful medical procedures. To improve cost-effectiveness in selecting patients with melanoma for sentinel lymph node biopsy (SLNB). This hybrid prognostic study/decision analytical model was conducted among patients with melanoma who were eligible for SLNB at 2 melanoma centers from Australia and the US from 2000 to 2014. Participants consisted of 2 cohorts of patients with melanoma undergoing SLNB and a cohort of eligible patients without SLNB. Individualized probabilities of SLNB positivity generated by a patient-centered methodology (PCM) were compared with those generated by conventional multiple logistic regression analysis investigating 12 prognostic factors. Prognostic accuracy was assessed by the area under the receiver operating characteristic curve (AUROC) for each methodology and by matched-pair analyses. Triaging appropriate patients to undergo SLNB. Total number of SLNBs performed (giving total cost) vs number of SLNB-positive outcomes (a measure of effectiveness) was evaluated. Improved cost-effectiveness through judicious patient selection was interpreted as increased numbers of SLNB-positive outcomes achieved, decreased numbers of SLNBs performed, or both outcomes simultaneously. Among 7331 patients with melanoma, SLNB outcomes were assessed in 3640 Australian patients (2212 males [60.8%]; 2447 aged >50 years [67.2%]) and 1342 US patients (774 males [57.7%]; 885 aged >50 years [66.0%]); 2349 patients eligible for SLNB who did not undergo the procedure were included in the simulation. PCM-generated probabilities achieved an AUROC of 0.803 in predicting SLNB positivity in the Australian cohort and 0.826 in the US cohort, higher than corresponding AUROCs generated by conventional logistic regression analysis. In simulation, adopting many SLNB-positive probabilities as minimally acceptable patient-selection criteria resulted in fewer procedures performed or increased the expected numbers of positive SLNBs. A minimally acceptable PCM-generated probability of 8.7% elicited the same number of SLNBs as historically performed (3640 SLNBs), with 1066 positive SLNBs (29.3%), constituting an improvement of 287 additional positive SLNBs compared with 779 actual positive SLNBs (36.8% improvement). In contrast, adopting a 23.7% PCM-generated minimum cutoff probability resulted in performing 1825 SLNBs, or 1815 fewer SLNBs than the actual experience (49.9%). It resulted in the same expected number of positive results (779 SLNBs), for a 42.7% positivity rate. This prognostic study/decision analytical model found that the PCM approach outperformed conventional multiple logistic regression analysis in predicting which patients would have positive results on SLNB. These findings suggest that systematically producing and exploiting more accurate SLNB-positivity probabilities could improve the selection of patients with melanoma for SLNB compared with using established guidelines, thus improving the cost-effectiveness of the selection process. Eligibility guidelines to undergo SLNB should include a context-tailored minimum cutoff probability.

Association of Complex Lymphatic Drainage in Head and Neck Cutaneous Melanoma With Sentinel Lymph Node Biopsy Outcomes

Although sentinel lymph node biopsy (SLNB) is a vital staging tool, its application in head and neck melanoma (HNM) is complicated by a higher false-negative rate (FNR) compared with other regions. This may be due to the complex lymphatic drainage in the head and neck. To compare the accuracy, prognostic value, and long-term outcomes of SLNB in HNM with melanoma from the trunk and limb, focusing on the lymphatic drainage pattern. This cohort observational study at a single UK University cancer center included all patients with primary cutaneous melanoma undergoing SLNB between 2010 to 2020. Data analysis was conducted during December 2022. Primary cutaneous melanoma undergoing SLNB between 2010 to 2020. This cohort study compared the FNR (defined as the ratio between false-negative results and the sum of false-negative and true-positive results) and false omission rate (defined as the ratio between false-negative results and the sum of false-negative and true-negative results) for SLNB stratified by 3 body regions (HNM, limb, and trunk). Kaplan-Meier survival analysis was used to compare recurrence-free survival (RFS) and melanoma-specific survival (MSS). Comparative analysis of detected lymph nodes on lymphoscintigraphy (LSG) and SLNB was performed by quantifying lymphatic drainage patterns by number of nodes and lymph node basins. Multivariable Cox proportional hazards regression identified independent risk factors. Overall, 1080 patients were included (552 [51.1%] men, 528 [48.9%] women; median age at diagnosis 59.8 years), with a median (IQR) follow-up 4.8 (IQR, 2.7-7.2) years. Head and neck melanoma had a higher median age at diagnosis (66.2 years) and higher Breslow thickness (2.2 mm). The FNR was highest in HNM (34.5% vs 14.8% trunk or 10.4% limb, respectively). Similarly, the false omission rate was 7.8% in HNM compared with 5.7% trunk or 3.0% limbs. The MSS was no different (HR, 0.81; 95% CI, 0.43-1.53), but RFS was lower in HNM (HR, 0.55; 95% CI, 0.36-0.85). On LSG, patients with HNM had the highest proportion of multiple hotspots (28.6% with ≥3 hotspots vs 23.2% trunk and 7.2% limbs). The RFS was lower for patients with HNM with 3 or more affected lymph nodes found on LSG than those with fewer than 3 affected lymph nodes (HR, 0.37; 95% CI, 0.18-0.77). Cox regression analysis showed head and neck location to be an independent risk factor for RFS (HR, 1.60; 95% CI, 1.01-2.50), but not for MSS (HR, 0.80; 95% CI, 0.35-1.71). This cohort study found higher rates of complex lymphatic drainage, FNR, and regional recurrence in HNM compared with other body sites on long-term follow-up. We advocate considering surveillance imaging for HNM for high-risk melanomas irrespective of sentinel lymph node status.

Abstract P3-05-56: The clinical impact of preoperatively needle-aspiration biopsy for axillary lymph nodes in T1-T2 breast cancer patients with axillary lymph node metastasis

Abstract Introduction: More than half of the results of axillary lymph node dissection followed by metastasis in sentinel lymph node(SLN) biopsy are negative. For deescalating axillary surgery, it is necessary to predict the non-SLN metastasis state, where metastasis was confirmed in the SLN biopsy. Method: Breast cancer patients with T1 and T2 stage were retrospectively reviewed from January 2008 to December 2016. A total of 818 patients underwent surgery as the primary treatment and the result of SLN biopsy was positive for metastasis. Patients who skipped SLN biopsy procedure and were proven metastatic axillary lymph nodes by needle-aspiration biopsy (NAB) were excluded. SLN was defined as lymph nodes detected by the dual method with hot-uptake by radioisotope and dyed by blue dye, or lymph nodes with palpable or suspected metastatic findings during SLN biopsy. Clinicopathological factors including and extra-nodal invasiveness were analyzed. Result: The median follow-up period was 73 months. Non-SLN metastasis was significantly seen in patients with older than 50 years, positive node metastases by preoperative NAB, high T stage, and extra-nodal invasion. In subgroup analysis, patients who underwent total mastectomy had the similar patterns of the increased risk of having non-SLN. Poor overall survival was observed in the patients with the presence of non-SLN metastasis. Conclusion: We confirmed predictive factors with a high probability of non-SLN metastasis. Axillary lymph node dissection cannot be overlooked in the patients proven the metastatic result of preoperative NAB. Citation Format: Jee Hyun Ahn, Suk Jun Lee, Jieon Go, Hyung Seok Park, Jee Ye Kim, Seung Il Kim, Byeong Woo Park, Seho Park. The clinical impact of preoperatively needle-aspiration biopsy for axillary lymph nodes in T1-T2 breast cancer patients with axillary lymph node metastasis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-56.

Representativeness of initial skin biopsies showing pure desmoplastic melanoma: implications for management

Desmoplastic melanoma (DM) is an uncommon subtype of melanoma with distinct clinicopathological features. It is classified into pure desmoplastic melanoma (PDM) when the proportion of desmoplastic melanoma is ≥90% of the dermally-invasive component, and mixed desmoplastic melanoma (MDM) when the proportion of desmoplastic melanoma is <90%. Studies have reported a lower sentinel lymph node biopsy (SLNB)-positivity rate in PDM compared to MDM and non-DM. As a result, some have recommended not performing SLNB in PDM patients. When PDM is identified in a partial biopsy of a melanoma, there is a risk that sampling bias may under-recognise MDM, but to the best of our knowledge this has not been previously assessed or quantified. The aim of this study was to assess the concordance of the proportion of desmoplastic melanoma in an initial partial biopsy of PDM with the proportion in the entire tumour following complete excision, in patients with cutaneous melanoma. A secondary aim was to determine how frequently this potentially resulted in a patient not receiving a SLNB. Seventy-eight cases of cutaneous melanoma were identified from the Melanoma Institute Australia (MIA) database and 23 cases from the Memorial Sloan Kettering Cancer Centre (MSKCC), where an initial biopsy contained PDM and a subsequent wide excision had residual invasive melanoma. Clinicopathological features were analysed in all patients, including whether a SLNB was performed, the results of SLNB, and any subsequent recurrence. Ninety percent (91/101) of cases were still classified as PDM in the complete wide excision specimen while 10% (10/101) of cases were reclassified as MDM, which was a significant change in classification of final desmoplastic melanoma subtype (p<0.001). The proportion of desmoplastic melanoma was also significantly different between the initial and excisional biopsies (p=0.004). Forty-eight (48/101) patients had a SLNB, of which two (4.5%) were positive for metastatic melanoma; both cases were PDM in the excision specimen. Of the 10 cases demonstrating MDM in the excision specimen, the initial biopsy was a punch biopsy in six cases, shave biopsy in two cases and subcutaneous tissue was sampled in two patients (one punch biopsy, one incisional biopsy). Four of these 10 patients underwent SLNB which was negative in all cases. Twenty-two patients developed recurrence in the follow-up period (median 30 months, range 1-192 months), three with MDM in their excision specimen. One patient did not have a SLNB and developed regional lymph node recurrence. In this study there was a 10% risk that the percentage of desmoplastic melanoma in an initial biopsy of PDM was not representative of the entire lesion, resulting in reclassification as MDM in the excision specimen. If a SLNB is not performed in such cases, a positive SLNB may be missed (one patient in our study) which could impact treatment options for the patient. We recommend caution in not offering a SLNB in the setting of an initial biopsy of PDM if the biopsy is small compared with the overall lesion. If a SLNB is not procured at the time of wide excision in such cases, the SLNs should still be mapped by lymphoscintigraphy to facilitate careful follow up and to enable earlier detection and treatment of nodal disease.

Alternatives and reduced need for sentinel lymph node biopsy (SLNB) staging for melanoma

Sentinel lymph node biopsy (SLNB) has been introduced in the 1990s to identify patients who might benefit from completion lymph node dissection. Neither SLNB nor CLND improved survival, but SLNB staging did provide the best staging, above Breslow thickness and ulceration. The SLN status and SLN tumour burden were used in all trials until date looking at modern adjuvant systemic therapy with immune checkpoint inhibition (ICI) or targeted therapies (TT). Adjuvant ICI and TT are shifting towards stage II melanoma. The question is whether there is still role for SLNB in melanoma, in this day and age, and if so, how does the future look for SLNB staging? The SLN status and SLN tumour burden might be useful for a consultation to discuss the number needed to treat in a risk/benefit discussion. For stage IIB/C patients, it seems likely, however, that patients will forego a nuclear scan followed by the risk of surgical intervention and morbidity associated with SLNB if they opt to receive adjuvant therapy regardless of the SLNB result. For stage I/IIA, it is still required to detect high-risk patients who might benefit from adjuvant therapy. However, biomarkers are emerging, such as gene expression profilers (GEP), immunohistological signatures and liquid biopsies with ctDNA. There still is a role for SLNB staging in melanoma today, but we expect that the availability of therapeutic option independent of SLNB status as well as emergence of validated biomarkers to predict risk will reduce the need for SLNB staging in the upcoming decade to the point it will no longer be used.

The Integrated 31-Gene Expression Profile Test (i31-GEP) for Cutaneous Melanoma Outperforms the CP-GEP at Identifying Patients who can Forego Sentinel Lymph Node Biopsy when Applying NCCN Guidelines

Introduction: Eighty-eight percent of patients who receive a sentinel lymph node biopsy (SLNB) receive a negative result. Current guidelines suggest avoiding SLNB if the risk of positivity is &lt;5%. A low threshold for performing SLNB indicates worry about missing positive nodes but results in many unnecessary biopsies. The integrated 31-gene expression profile (i31-GEP) test combines the 31-GEP with Breslow thickness, age, ulceration, and mitotic rate using a validated neural network algorithm to identify patients with &lt;5% risk by reporting a precise, individualized likelihood score. Using logistic regression, a separate GEP (8 genes plus Breslow thickness and age; CP-GEP) also aims to identify patients who can forego SLNB by binning patients into low- and high-risk categories. This study compared the i31-GEP for SLNB with the CP-GEP to identify patients who can safely forego SLNB. Methods: This study evaluated the genes, gene pathways, and relative contribution of the two gene signatures relative to clinical and pathologic factors and further analyzed patients with T1b-T2 tumors from previously published studies in U.S. cohorts for the i31-GEP (n=763) and CP-GEP (n=153). A ratio of true-to-false-negative i31-GEP for SLNB and CP-GEP test results was compared to the guideline-established ratio of 19 negatives to one missed positive (19:1) if foregoing SLNB using a 5% risk threshold. Results: The i31-GEP had a 30:1 true-to-false-negative ratio, compared to 15:1 using CP-GEP. In T1b tumors, the i31-GEP ratio increased to 35:1 compared to 14:1 using CP-GEP. Limitations: Retrospective design, which could lead to bias. Patients included in both analyses were primarily from institutional surgical centers, and referral bias may not make the result generalizable. Conclusion: Only the i31-GEP provided benefit over guideline-established care for identifying patients with low risk of SLN positivity.

Identification of the lymph node metastasis-related automated breast volume scanning features for predicting axillary lymph node tumor burden of invasive breast cancer via a clinical prediction model.

Breast cancer has become the malignant tumor with the highest incidence in women. Axillary lymph node dissection (ALND) is an effective method of maintaining regional control; however, it is associated with a significant risk of complications. Meanwhile, whether the patients need ALND or not is according to sentinel lymph node biopsy (SLNB). However, the false-negative results of SLNB had been reported. Automated breast volume scanning (ABVS) is a routine examination in breast cancer. A real-world cohort consisting of 245 breast cancer patients who underwent ABVS examination were enrolled, including 251 tumor lesions. The ABVS manifestations were analyzed with the SLNB results, and the ALND results for selecting the lymph node metastasis were related to ABVS features. Finally, a nomogram was used to construct a breast cancer axillary lymph node tumor burden prediction model. Breast cancer patients with a molecular subtype of luminal B type, a maximum lesion diameter of ≥5 cm, tumor invasion of the Cooper’s ligament, and tumor invasion of the nipple had heavy lymph node tumor burden. Molecular classification, tumor size, and Cooper’s ligament status were used to construct a clinical prediction model of axillary lymph node tumor burden. The consistency indexes (or AUC) of the training cohort and the validation cohort were 0.743 and 0.711, respectively, which was close to SLNB (0.768). The best cutoff value of the ABVS nomogram was 81.146 points. After combination with ABVS features and SLNB, the AUC of the prediction model was 0.889, and the best cutoff value was 178.965 points. The calibration curve showed that the constructed nomogram clinical prediction model and the real results were highly consistent. The clinical prediction model constructed using molecular classification, tumor size, and Cooper’s ligament status can effectively predict the probability of heavy axillary lymph node tumor burden, which can be the significant supplement to the SLNB. Therefore, this model may be used for individual decision-making in the diagnosis and treatments of breast cancer.

ASO Visual Abstract: How Often Do Sentinel Lymph Node Biopsy Results Affect Adjuvant Therapy Decisions Among Postmenopausal Women with Early-Stage HR+/HER2- Breast Cancer in the Post-RxPONDER Era?

ASO Visual Abstract: How Often Do Sentinel Lymph Node Biopsy Results Affect Adjuvant Therapy Decisions Among Postmenopausal Women with Early-Stage HR+/HER2- Breast Cancer in the Post-RxPONDER Era?

How Often Do Sentinel Lymph Node Biopsy Results Affect Adjuvant Therapy Decisions Among Postmenopausal Women with Early-Stage HR+/HER2- Breast Cancer in the Post-RxPONDER Era?

The RxPONDER trial reported no benefit to chemotherapy among postmenopausal patients with HR+/HER2- tumors, one to three positive nodes, and low recurrence scores, questioning the role of axillary staging in this population. Here, we evaluate the impact of sentinel lymph node biopsy (SLNB) results on adjuvant therapy decisions in postmenopausal women with HR+/HER2- breast cancer. Postmenopausal women with cT1-2N0, HR+/HER2- breast cancer treated with lumpectomy and SLNB from 2012 to 2018 were identified. Receipt of nodal irradiation, indication for axillary lymph node dissection (ALND) and chemotherapy, and partial breast irradiation (PBI) eligibility were reviewed with pre- and post-SLNB results. A total of 1786 women were identified: median age 62 years, 84% with pT1 tumors, and 16% with pT2-3 tumors. Of those, 85% (n = 1525) remained pN0, 14% (n = 244) were pN1, and 1% (n = 17) were pN2-3. A total of 20 (1%) patients had > 2 positive SLNs, necessitating ALND. Pre-SLNB, 1478 women were considered PBI eligible; post-SLNB, 227 (13%) converted to PBI ineligible. In total, 58 patients with positive nodes received nodal irradiation, representing 3% of the entire cohort and 22% of pN+ patients. Overall, 1401 patients had an Oncotype DX recurrence score available, including 1273 patients with pN0 stage and 128 with pN1, with 173 (14%) and 16 (13%), respectively, having a recurrence score > 25, warranting chemotherapy. While few cN0 postmenopausal women with HR+/HER2- tumors had nodal pathology that warranted ALND, receipt of nodal irradiation, or indicated need for chemotherapy, in 13%, SLNB would have an impact on consideration for PBI. Among patients eligible for PBI, findings from SLNB may help refine selection among postmenopausal women with this tumor profile.

Investigate the accuracy and economic value of the upstaging prediction model for ductal carcinoma in situ.

e12577 Background: The current study aims to define the “high-risk upstaging model” in ductal carcinoma in situ (DCIS) and investigate its accuracy in order to suggest the most precise application of sentinel lymph node biopsy (SLNB). Methods: PubMed, EMBASE, and Cochrane library databases were searched. Prospective and retrospective cohort studies that evaluated the pathological outcomes of SLNB and the upstaging rate in women with DCIS were included. We analyzed factors that potentially indicate nodal involvement risk and combine the significant ones into “high-risk upstaging model”. Consecutively, we conducted a retrospective study by applying our model and NCCN guideline model into DCIS patients extracted from hospital database. Both the excess treatment rate and incomplete treatment rate of SLNB were analyzed. The diagnostic performance of the model in predicting upstaging risk was evaluated with receiver operating characteristic (ROC) curve. Results: We retrieved 43 prospective and 69 retrospective studies including 44,001 DCIS patients. The upstaging rate was significantly higher in patients with estrogen receptor-negative status, palpable mass, tumor size &gt; 2 cm on imaging, and high-nuclear grade and those who received a preoperative diagnosis through core needle biopsy. We then collected 168 DCIS patients who entered in Shuang-Ho hospital from February 2017 to August 2021. Ninety-six patients who didn’t upstage in final pathology have received extra SLNB and two patients who upstaged in final pathology did not receive SLNB in primary surgery. The areas under the ROC curve of the model developed by multivariable logistic regression for predicting upstaging risk in the NCCN guideline group and “high-risk upstaging model” group were 0.642 and 0.706, the sensitivity at 66.0% and 83.0%, and the specificities at 62.5% and 49.2%, respectively. Conclusions: “High-risk upstaging model” shows higher areas under the ROC curve and sensitivity as well compared with current NCCN guideline. Our prediction model can provide surgeons with a more accurate and specific indications of SLNB in DCIS.

Abstract P1-01-06: Predictor of sentinel node positivity in screen-detected invasive breast cancer

Abstract Introduction: Sentinel lymph node biopsy represents the standard of care for staging axilla in breast cancer patients who are clinically node negative. ACOSOG Z11 trial results questioned the importance of low burden nodal disease. Results from the SOUND trial on omission of axillary surgery in selected patients with early stage breast cancer are still awaited. Breast screening programs aim to detect cancers at an early stage and are expected to have low burden of nodal disease. The aim of our study was to determine predictors of sentinel node biopsy positivity in invasive breast cancers detected on screening mammography. Methods: This retrospective study included patients with node negative invasive breast cancer detected on screening mammogram performed between April 2018 and March 2020 and subsequently underwent curative surgery including sentinel node biopsy at breast care unit of Castle Hill Hospital, Cottingham, U.K. We looked at patient’s clinical, radiological and pre-operative pathological features and correlated them with histological results of sentinel node biopsy. Statistical analysis of the data was performed using SPSS version 22 and p-value of 0.05 was considered significant. Results: We identified 304 patients who met inclusion criteria. The mean age of these patients was 62.71 ± 7.2 years (range 47-78 years). Majority (88%) of women were postmenopausal. Overall, the sentinel node positivity rate was 11.76%. Women over the age of 55 years were less likely to be node positive compared to younger women (9.9% vs 22%, p=0.016). Tumours less than 10mm in size had node positive rate of 5.5% compared to tumour larger than 21mm (25%, p = 0.000). In comparison to grade 2and grade 3 tumours, grade 1 tumours had lower node positivity rate, (5% vs 14.4%) but the difference did not reach statistical significance (p= 0.073). All women with tubular and mucinous histological subtypes (n=13) were node negative. All women with grade 1 tumours less than 10mm in size (n=48) had a negative sentinel node biopsy compared to women with grade 2 tumors more than 20mm (9/32=28% positivity rate) and p-value of 0.000. There was no association between oestrogen, progesterone and HER2 receptor status with sentinel lymph node positivity rate. Conclusion: In selected screen detected patients including those above the age of 55 years, having grade 1 cancer, and less than 10 mm size on pre-treatment imaging, there might be scope for omission of axillary surgery. Citation Format: Raouef Ahmed Bichoo, Mohammed Bilal Elahi, Dorin Dumitru, Naila Bint Ihsan, Eiman Khalifa, Masuma Sarker, Tapan K Mahapatra, Brendan Paul Wooler, Peter Kneeshaw, Kartikae Grover. Predictor of sentinel node positivity in screen-detected invasive breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-01-06.