Routine Sentinel Lymph Node Biopsy Research Articles

Characteristics and risk factors of axillary lymph node metastasis of microinvasive breast cancer.

To select patients who would benefit most from sentinel lymph node biopsy (SLNB) by investigating the characteristics and risk factors of axillary lymph node metastasis (ALNM) in microinvasive breast cancer (MIBC). This retrospective study included 1688 patients with MIBC who underwent breast surgery with axillary staging at the Asan Medical Center from 1995 to 2020. Most patients underwent SLNB alone (83.5%). Seventy (4.1%) patients were node-positive, and the majority had positive lymph nodes < 10mm, with micro-metastases occurring frequently (n = 37; 55%). Node-positive patients underwent total mastectomy and axillary lymph node dissection (ALND) more than breast-conserving surgery (BCS) and SLNB compared with node-negative patients (p < 0.001). In the multivariate analysis, independent predictors of ALNM included young age [odds ratio (OR) 0.959; 95% confidence interval (CI) 0.927-0.993; p = 0.019], ALND (OR 11.486; 95% CI 5.767-22.877; p < 0.001), number of lymph nodes harvested (≥ 5) (OR 3.184; 95% CI 1.555-6.522; p < 0.001), lymphovascular invasion (OR 6.831; 95% CI 2.386-19.557; p < 0.001), presence of multiple microinvasion foci (OR 2.771; 95% CI 1.329-5.779; p = 0.007), prominent lymph nodes in preoperative imaging (OR 2.675; 95% CI 1.362-5.253; p = 0.004), and hormone receptor positivity (OR 2.491; 95% CI 1.230-5.046; p = 0.011). Low ALNM rate (4.1%) suggests that routine SLNB for patients with MIBC is unnecessary butcan be valuable for patients with specific risk factors. Ongoing trials for omitting SLNB in early breast cancer, and further subanalyses focusing on rare populations with MIBC are necessary.

Management of acral lentiginous melanoma: current updates and future directions.

Acral lentiginous melanoma is a rare subtype of melanoma generally associated with poor outcomes, even when diagnosed at an early stage. The tumor genetic profile remains poorly understood, but it is known to have a suppressed immune environment compared to that of non-acral cutaneous melanomas, which limits therapy options. There is significant attention on the development of novel therapeutic approaches, although studies are limited due to disease rarity. For local disease, wide local excision remains the standard of care. Due to frequent under-staging on preoperative biopsy, wider margins and routine sentinel lymph node biopsy may be considered if morbidity would not be increased. For advanced disease, anti-PD1 monotherapy or combination therapy with anti-PD1 and anti-CTLA4 agents have been used as first-line treatment modalities. Anti-PD1 and anti-CTLA4 combination therapies have been shown to be particularly beneficial for patients with BRAF-mutant acral lentiginous melanoma. Other systemic combination regimens and targeted therapy options may be considered, although large studies with consistent results are lacking. Regional and intralesional therapies have shown promise for cutaneous melanomas, but studies generally have not reported results for specific histologic subtypes, especially for acral melanoma. Overall, the unique histologic and genetic characteristics of acral lentiginous melanoma make therapy options significantly more challenging. Furthermore, studies are limited, and data reporting has been inconsistent. However, more prospective studies are emerging, and alternative therapy pathways specific to acral lentiginous melanoma are being investigated. As further evidence is discovered, reliable treatment guidelines may be developed.

Luminal A Versus B After Choosing Wisely: Does Lymph Node Surgery Affect Oncologic Outcomes?

In 2016, the Choosing Wisely campaign recommended against routine sentinel lymph node biopsy (SLNB) in women ≥ 70 years old diagnosed with early-stage hormone receptor positive (HR+), HER2 negative (HER2-) breast cancer. No distinction is made between luminal A and luminal B phenotypes, despite luminal B being considered more aggressive. This study evaluates the effect of SLNB on oncologic outcomes in HER2- luminal B versus luminal A breast cancer. We performed an IRB-approved, single institution, retrospective cohort study from 2010 to 2020 of women aged ≥ 70 years with clinically node negative, HR+ breast cancer undergoing definitive surgical treatment. Luminal status was defined by gene expression panel testing, Ki67%, and/or pathologic grading. Primary endpoints included locoregional recurrence (LRR), disease free survival (DFS), and overall survival (OS). SLNB did not correlate with significant differences in LRR in luminal A (p = 0.92) or luminal B (p = 0.96) disease. SLNB correlated with improved DFS (p < 0.01) and OS (p < 0.001) in luminal A disease, but not in luminal B disease (DFS p = 0.73; OS p = 0.36). On multivariate analysis, age (HR = 1.17; p < 0.01) and tumor size (HR = 1.03; p < 0.05) were associated with DFS, while SLNB was not (p = 0.71). Luminal status (HR = 0.52, p < 0.05), age (HR = 1.15, p < 0.01), and comorbidities (HR = 1.35, p < 0.05) were associated with OS, but not SLNB (p = 0.71). Our results suggest that SLNB may be safely omitted in patients aged ≥ 70 years with luminal B disease given similar LRR in luminal A disease. Our findings suggest that DFS and OS are driven by tumor biology, patient age, and comorbidities rather than receipt of SLNB.

Use of sentinel lymph node biopsy in elderly patients with breast cancer – 10-year experience from a Swiss university hospital

BackgroundThe Choosing Wisely initiative recommended the omission of routine sentinel lymph node biopsy (SLNB) in patients ≥ 70 years of age, with clinically node-negative, early stage, hormone receptor (HR) positive and human epidermal growth factor receptor 2 (Her2) negative breast cancer in August 2016. Here, we assess the adherence to this recommendation in a Swiss university hospital.MethodsWe conducted a retrospective single center cohort study from a prospectively maintained database. Patients ≥ 18 years of age with node-negative breast cancer were treated between 05/2011 and 03/2022. The primary outcome was the percentage of patients in the Choosing Wisely target group who underwent SLNB before and after the initiative went live. Statistical significance was tested using chi-squared test for categorical and Wilcoxon rank-sum tests for continuous variables.ResultsIn total, 586 patients met the inclusion criteria with a median follow-up of 2.7 years. Of these, 163 were ≥ 70 years of age and 79 were eligible for treatment according to the Choosing Wisely recommendations. There was a trend toward a higher rate of SLNB (92.7% vs. 75.0%, p = 0.07) after the Choosing Wisely recommendations were published. In patients ≥ 70 years with invasive disease, fewer received adjuvant radiotherapy after omission of SLNB (6.2% vs. 64.0%, p < 0.001), without differences concerning adjuvant systemic therapy. Both short-term and long-term complication rates after SLNB were low, without differences between elderly patients and those < 70 years.ConclusionsChoosing Wisely recommendations did not result in a decreased use of SLNB in the elderly at a Swiss university hospital.

Long-term oncologic outcomes after omitting axillary surgery in older women with early stage, node-negative breast cancer: A systematic review and meta-analysis.

525 Background: In 2016, Choosing Wisely recommended the omission of routine sentinel lymph node biopsy (SLNB) in early stage, clinically node-negative, hormone receptor-positive, Her2-negative breast cancer in women ≥70 years old, although data supporting this was limited. Our study aimed to examine the long-term impact of omitting axillary staging in elderly women undergoing surgery for early stage, clinically node-negative breast cancer. Methods: A systematic review and meta-analysis was conducted. Medline (Ovid) and Embase were searched for published papers and abstracts using a systematic search strategy. Randomized and observational studies comparing women aged ≥70 years of age with early-stage, clinically node-negative breast cancer undergoing surgery for breast cancer with and without axillary staging, were included. Included studies reported at least one of the following outcomes: axillary recurrence (primary outcome), disease-free survival (DFS), breast cancer-specific survival (BCSS), and overall survival. Risk ratios (RR) were calculated as summary estimates for all outcomes. A weighted pooled mean difference and 95% CI was calculated using a random-effects inverse variance meta-analysis for each outcome. Heterogeneity was calculated using I2 statistics, and explored using meta-regression. The Newcastle-Ottawa Scale was used to assess the methodological quality of eligible trials, based on the selection of patients, comparability of cohorts, and the methods of outcome assessment. Results: Nine studies were eligible for meta-analysis, including data for 48,523 patients. For the primary outcome of axillary recurrence, data for 3,591 patients was meta-analyzed. Axillary staging was found to reduce the risk of axillary recurrence compared to no axillary staging, although this was not statistically significant (RR 0.59, 95% CI: 0.26 to 1.35, I2= 46.6%, p = 0.21). For overall mortality, data for 14,981 patients was meta-analyzed, and a statistically significant protective effect of axillary staging on overall mortality was demonstrated (RR 0.55, 95% CI: 0.33 to 0.90, I2= 78.1%, p= 0.003). No significant differences were observed in DFS (RR 1.02, 95% CI: 0.51 to 2.07, I2 = 0.0%, p = 0.37) and BCSS (RR 0.96, 95% CI: 0.57 to 1.62, I2 = 0.0%, p = 0.78). Conclusions: Omission of axillary surgery to stage the axilla may be associated with a higher risk of overall mortality in older women with early-stage breast cancer compared to those who undergo axillary surgery. Omission of axillary surgery in this patient population should be carefully tailored to the individual patient, taking into consideration co-morbidity, life expectancy, and formal measures of frailty. Randomized trials are required to further explore the oncologic safety of omitting axillary staging in women aged 70 years or older undergoing breast cancer surgery.

Clinical utility of sentinel lymph node biopsy in women ≥ 70 years with early breast cancer.

e12512 Background: Sentinel lymph node biopsy (SLNB) has traditionally been used to stage the axilla in early breast cancer (EBC) to guide adjuvant treatment recommendations. Following advances in genomic testing and tumor biology understanding, its role may be less critical especially in selected groups of women. The aim was to evaluate clinical utility of SLNB in adjuvant treatment recommendations for women ≥ 70 years with EBC in a tertiary unit in the United Kingdom. Methods: Retrospective cohort study of women ≥ 70 years with cT1-2N0 EBC undergoing primary surgery and SLNB between 01/2018-12/2022. Simple descriptive statistics and non-parametric tests were performed, including cost analysis of the SLNB procedure. Results: A total of 528 patients were included. The median age was 75 (IQR 72-79) years. Most cancers were invasive ductal (84.7%), grade 2 (66.9%), hormone receptor (HR) positive/HER2 negative (84.4%) with a median tumor size of 17 (IQR 4-50) mm. SLNB was positive in 64 (12.1%) patients. Of these 64 patients, 13 (20.3%) had completion ALND and 39 (60.9%) had adjuvant locoregional nodal radiotherapy (RT) including levels 1 &amp; 2 of the axilla; adjuvant RT to levels 3 &amp; 4 after ALND was given to 5/13. As per ACOSOG Z0011 criteria, 2/13 could have been spared ALND and 31/39 axillary RT. The multidisciplinary team (MDT) recommended adjuvant chemotherapy (AC) in 72 (13.6%) patients and 45 received it. Of those with a positive SLNB (n = 64), AC was recommended in 15, and received by 11. Recommendation for AC was significantly associated with age (p = 0.006), tumor grade (p &lt; 0.0001), size (p = 0.001), receptor status (p &lt; 0.0001) and positive SLNB status (p = 0.02) but not with comorbidities (p = 0.06). A subgroup analysis of 294 patients with cT1N0, HR+/HER2- EBC, representing a more favorable prognosis group, was performed. Here, 31/294 (10.5%) patients had positive SLNB, of whom 5 underwent ALND and 16 regional nodal RT, where 2/5 could have been spared ALND and 13/16 axillary RT as per ACOSOG Z0011 criteria. AC was recommended in 11/294 (3.7%) women and 9 received it. AC was not recommended in 20/31 (64.5%) cases, despite a positive SLNB. MDT recommendation for AC was associated with SLNB status (p = 0.02), grade 3 (p = 0.002) and multifocal disease (p = 0.02), while AC receipt was only associated with grade 3 (p = 0.017) and multifocal disease (p = 0.009) but not SLNB status (p = 0.058). Given an average cost of $6504.95 / £5359.38 per SLNB procedure in this unit, avoiding routine SLNB in the subgroup population may have potentially saved $1,912,493.95 / £1,575,657.72 in this 5 year period. Conclusions: Only a small proportion of women ≥ 70 years with EBC had positive SLNB that may influence adjuvant treatment recommendations, especially with favorable prognosis tumors. In such cases, where clinical morbidity and financial burden of SLNB may outweigh the benefits, a nuanced discussion for opting in SLNB rather than routine performance should be considered.

Evaluating the Necessity for Routine Sentinel Lymph Node Biopsy in Postmenopausal Patients Being Treated for Clinically Node Negative Breast Cancer the Era of RxPONDER

IntroductionTraditionally, sentinel lymph node biopsy (SLNB) was performed to inform adjuvant chemotherapy prescription and prognosis in breast cancer. Following RxPONDER, the OncotypeDX Recurrence Score (RS) guides adjuvant chemotherapy prescription for all postmenopausal patients with estrogen receptor positive, human epidermal growth factor receptor-2 negative (ER+/HER2−) breast cancer with 0 to 3 positive lymph nodes (0-3 + LN). AimsTo establish the oncological safety of omitting SLNB in postmenopausal patients with ER+/HER2− breast cancer indicated to undergo SLNB and to evaluate the primary determinants of chemotherapy prescription for these patients. Patients and MethodsA retrospective cohort study was undertaken. Cox regression and Kaplan-Meier analyses were performed. Data analytics was performed using SPSS v26.0. ResultsFive hundred and seventy five consecutive patients were included (mean age: 66.5 years, range: 45-96). The median follow-up was 97.2 months (range: 3.0-181.6). Of the 575 patients, just 12 patients had positive SLNB (SLNB+) (2.1%). Using Kaplan-Meier analyses, SLNB+ failed to impact recurrence (P = .766) or mortality (P = .310). However, using Cox regression analyses, SLNB+ independently predicted poorer disease-free survival (hazard ratio: 1.001, 95% confidence interval (95% CI): 1.000-1.001, P = .029). Logistic regression analysis identified RS as the sole predictor of chemotherapy prescription (odds ratio: 1.171, 95% CI: 1.097-1.250, P < .001). ConclusionOmitting SLNB may be safe and justifiable in postmenopausal patients with ER+/HER2− breast cancer with clinically negative axillae. Following RxPONDER, RS is the most important guide of chemotherapy use in these patients and SLNB may be less important than previously perceived. Prospective, randomized clinical trials are required to fully establish the oncological safety of omitting SLNB in this setting.

Omission of axillary sentinel lymph node biopsy in early invasive breast cancer

Local treatment of the axilla in clinically node-negative (cN0) early breast cancer patients with routine sentinel lymph node biopsy (SLNB) is debated after publication of ACOSOG Z0011 data in 2010. Currently, prospective randomized surgical trials investigating the omission of SLNB in upfront breast-conserving surgery (BCS) and in the neoadjuvant setting, respectively. Several prospective randomized trials (SOUND, INSEMA, BOOG 2013–08, and NAUTILUS) with axillary observation alone versus SLNB in cN0 patients and primary BCS have primary objectives to evaluate oncologic safety when omitting SLNB. The Italian SOUND trial was the earliest to open in 2012 and has completed accrual in 2017. First oncologic outcome data are expected soon for SOUND and at the end of 2024 for INSEMA. Improvements in systemic treatments for breast cancer have increased the rates of pathologic complete response (pCR) in patients receiving neoadjuvant systemic therapy (NAST), offering the opportunity to de-escalate surgery in patients who have a pCR. Two prospective single-arm trials (EUBREAST-01, ASICS) include only patients with the highest likelihood of having a pCR after NAST (triple-negative or HER2-positive breast cancer) and type of surgery will be defined according to the response to NAST rather than on the classical T and N status. The ongoing trials will hopefully help us to understand whether we might take the best therapeutic decisions without the pathologic evaluation of nodal status.

Abstract IA019: Surgery for DCIS: If, what and when

Abstract DCIS is traditionally viewed as a surgical problem managed in a comparable way to invasive breast cancer, by breast conservation or mastectomy, to prevent the evolution of intraductal to invasive disease. The need for surgery has been challenged by retrospective case series demonstrating that progression from DCIS to invasive disease is variable, increases with time, but may be modified by endocrine therapy. This data has led to the innovative trials currently under way of active monitoring compared with surgery – the “if” of whether surgery is needed. What surgery to perform requires pathology confirmation of the diagnosis, awareness of the heterogeneity of DCIS (and the potential for sampling to miss invasive disease) together with imaging by mammography, ultrasound and/or MRI. Clinical impressions, imaging and pathology findings direct treatment options. Surgery comprises lumpectomy versus simple, skin sparing or nipple sparing mastectomy (with consideration for reconstruction) potentially partnered with axillary node surgery, at least for those undergoing mastectomy. When (and how) to perform surgical and allied techniques is undergoing change. The required surgical margins of 2mm (for pure DCIS) at the time of conservation to reduce local recurrence remains challenging, with technologies such as optical coherence tomography demonstrating promise for intraoperative determination of adequate margins. Rather than routine sentinel lymph node biopsy, with the attendant risks of lymphedema, iron oxide/dextran coated particles injected prior to surgery, rapidly migrate to and lodge in the axillary nodes and provide an option for delayed axillary surgery if invasive disease is identified. Neoadjuvant approaches to DCIS, targeting the estrogen receptor or HER2, to downstage the extent of surgery are less favored than for invasive breast cancers, but DCIS may be the residue left after neoadjuvant treatment for invasive disease. However, adjuvant endocrine therapy and adjuvant radiotherapy may each have an impact on reducing the chance of re-occurrence of DCIS or development of invasive cancer. Currently, surgery remains the primary treatment for DCIS. If surgery is performed, what is done and when surgery takes place varies with the nature, the extent of the DCIS and is influenced by patient preference. Citation Format: Alastair M. Thompson, Elizabeth Bonefas, Stacey Carter, Ivan marin, Huma Javaid, Jessica Montalvan. Surgery for DCIS: If, what and when [abstract]. In: Proceedings of the AACR Special Conference on Rethinking DCIS: An Opportunity for Prevention?; 2022 Sep 8-11; Philadelphia, PA. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_1): Abstract nr IA019.

Sentinel lymph node biopsy in women over 70: Evaluation of rates of axillary staging and impact on adjuvant therapy in elderly women

BackgroundThe 2016 Society of Surgical Oncology Choosing Wisely guidelines recommended against routine sentinel lymph node biopsy in women ≥70 years old with favorable, early-stage breast cancer, as sentinel lymph node biopsy does not decrease recurrence or mortality in these patients. This study’s objective was to evaluate the use of sentinel lymph node biopsy and its effect on management in elderly patients. MethodsA retrospective analysis of female patients ≥70 years old with stage I–II, clinically node-negative, hormone-receptor positive, HER2-negative disease undergoing upfront breast cancer surgery between 2017 and 2019. Primary outcome was rate of sentinel lymph node biopsy. Secondary outcome was effect of sentinel lymph node biopsy on adjuvant therapy. ResultsIn total, 142 patients were included. Median age was 76 (interquartile range 73–81), and 71.8% underwent lumpectomy. On final pathology, 57.7% had invasive ductal carcinoma, and median tumor size was 15 mm (interquartile range 10–24.3). A total of 118 patients (83.1%) underwent sentinel lymph node biopsy; of these, 27 (22.9%) were positive for N1mi (7 patients) or N1a disease (20 patients). On multivariate regression analysis, patients undergoing sentinel lymph node biopsy were more likely to be younger (odds ratio 0.87, 95% confidence interval 0.78–0.95). The major risk factor for sentinel lymph node biopsy positivity was lymphovascular invasion (odds ratio 13.4, 95% confidence interval 4.57–40.1). Patients with sentinel lymph node biopsy positivity were more likely to receive local adjuvant radiation therapy (odds ratio 4.66, 95% confidence interval 1.49–16.8) and tended to receive more adjuvant regional radiation therapy (75.0% if sentinel lymph node biopsy positive compared with 15.3% if sentinel lymph node biopsy negative, P < .001). ConclusionDespite the 2016 Choosing Wisely guidelines, more than 80% of patients ≥70 years old underwent sentinel lymph node biopsy at our institution. If sentinel lymph node biopsy was positive, this is associated with over 4-fold higher rates of adjuvant radiation therapy.

A novel support vector machine to predict sentinel lymph node status in elderly patients with breast cancer.

1560 Background: Routine sentinel lymph node biopsy in older breast cancer patients with favorable tumor biology is not recommended. However, cases must be evaluated on an individual basis to avoid under or over-treatment. Many nomograms have been developed to calculate the risk of nodal positivity, but machine learning (ML) is a novel tool that may improve the accuracy of nodal prediction. In this study, we developed a support vector machine (SVM) model to delineate factors indicative of sentinel lymph node positivity and refine individualized nodal risk assessment for this heterogeneous patient population. Methods: We conducted a single-institution comprehensive retrospective review of patients 70 years or older diagnosed with unilateral stage I–III primary breast cancer from January 2005 to January 2016. Patient data was partitioned into training and testing sets. A SVM model was developed to predict lymph node status using patients’ demographics, tumor stage, genetic profile, and imaging data. Primary outcome was model performance determined by area under the curve (AUC). Secondary outcomes were accuracy, sensitivity and specificity. Permutation feature importance (PFI) analysis and accumulated local effect (ALE) plots were used to evaluate significant predictors identified by the SVM. Results: We identified 1706 consecutive patients who met the study criteria with a mean age of 76±4.5 years. The plurality of patients were Caucasian (82%), had ER+ (86%), PR+ (70%), HER2- (87%) stage I (72%) breast cancer. Sixteen percent of patients (n = 271) had a positive sentinel lymph node biopsy. The SVM model demonstrated good discriminatory performance for predicting sentinel lymph node positivity with mean AUC of 0.70 (95%CI, 0.62-0.77), mean accuracy of 84% (95%CI, 80-88%), mean sensitivity of 61% (95%CI, 57-66%), and mean specificity of 62% (95%CI, 52-73%). PFI and ALE identified higher disease stage, younger age, family history of breast cancer, margin status, estrogen and progesterone receptor positivity as independently associated with high risk of sentinel lymph node positivity. Conclusions: The proposed ML model accurately identified sentinel lymph node status in older patients with breast cancer. This model holds promise for counselling patients as to the potential risk for node positive disease which may impact surgical and adjuvant therapy recommendations.

127P Sentinel lymph node biopsy in older patients with breast cancer: Which subset can be omitted?

Current breast cancer surgical treatment includes axillary staging using sentinel lymph node biopsy (SLNB) for those with clinically and radiological negative axillae. Morbidity is associated with axillary surgery in those aged 70 and above. There is a move towards de-escalation of treatment if it does not confer survival benefit. The Society of Surgical Oncology Choosing Wisely Initiative hypothesize that routine SLNB can be omitted in patients aged 70 and above with early stage ER+ HER2- invasive breast cancers.

The role of routine sentinel lymph node biopsy in elderly patients with breast cancer

Recent guidelines from the Society of Surgical Oncology recommended against the routine use of sentinel lymph biopsy (SLN) in women over the age of 70 years with pT1 ER-positive breast cancer. The aim of this study was to evaluate the use of axillary staging with SLN in patients aged older than 70 with early-stage breast cancer. A retrospective review identified all women over 70 years of age with a new diagnosis of invasive breast cancer who proceeded to therapeutic surgery between 2011 and 2020 at St. Vincent's Hospital, Dublin. All patients proceeded to therapeutic surgery. All patients had an axillary ultrasound at diagnosis. Clinicopathological data was assessed. Final pathological stage for patients who received axillary staging with SLN were assessed. Of 1360 women aged over 70 at time of diagnosis during the study period, 474 patients (mean age of 80 years) underwent a wide local excision and SLN. Of these, 217 (46%) had a final pathological stage of pT1 and a tumour that was ER positive. Within this group 79% had a negative SLNB (pN0). The rate of SLN positivity was higher in those with pT2 disease at 34% (p=0.005). Axillary staging with SLN is still routinely employed for patients older than age 70 who proceed to surgery for treatment of their breast cancer with a >20% positivity rate, even in those with pT1 disease. Efforts to reduce SLNB use in this cohort should incorporate both assessments of patient frailty and tumour parameters that allow estimates of sentinel node positivity.

AB007. SOH22ABS130. The role of routine sentinel lymph node biopsy in elderly patients with breast cancer

Background: Recent guidelines from the Society of Surgical Oncology recommended against the routine use of sentinel lymph biopsy (SLN) in women over the age of 70 years with pT1 ER-positive breast cancer. The aim of this study was to evaluate the use of axillary staging with SLN in patients aged older than 70 with early-stage breast cancer.

Cost-effectiveness of Choosing Wisely guidelines for axillary observation in women older than age 70 years with hormone receptor-positive, clinically node-negative, operable breast tumors.

The Society for Surgical Oncology's Choosing Wisely guidelines recommend against sentinel lymph node biopsy (SLNB) in favor of observation in this population. Recent analyses reveal that this has not been widely adopted. The purpose of this cost-effectiveness analysis is to compare the costs and benefits associated with observation or SLNB in women >70 years old with hormone receptor-positive, clinically node-negative, operable breast cancer. A decision tree with Markov modeling was created to compare treatment strategies using long-term follow-up data from clinical trials in this population. Costs were estimated from published literature and publicly available databases. Breast cancer-specific health-state utilities were derived from the literature and expert opinion. One-way, 2-way, and probabilistic sensitivity analyses were conducted. A structural sensitivity analysis was performed to assess the effect of functional status and anxiety from nonevaluation of the axilla on cost-effectiveness. Costs and benefits, measured in life-years (LYs) and quality-adjusted life-years (QALYs), were tabulated across 10, 15, and 20 years and compared using incremental cost-effectiveness ratios (ICERs). SLNB is not cost-effective from the payer or societal perspectives with ICERs of $138,374/LY and $131,900/LY, respectively. When QALYs were considered, SLNB provided fewer QALYs (SLNB, 10.33 QALYs; observation, 10.53 QALYs) at a higher cost (SLNB, $15,845; observation, $4020). Structural sensitivity analysis revealed that SLNB was cost-effective in certain patients with significant anxiety related to axillary observation (ICER, $39,417/QALY). Routine SLNB in this population is not cost-effective. The cost-effectiveness of SLNB, however, is dependent on individual patient factors, including functional status as well as patient preference.

Abstract PD7-08: Less is not necessarily more: A propensity matched national analysis on effect and outcome of sentinel lymph node biopsy omission

Abstract Background: Routine sentinel lymph node biopsy (SLNB) has been recommended against by Choosing Wisely© Foundation due to its low value in clinical node negative, hormone receptor positive breast cancer patients age≥70 years old. We used the National Cancer Database (NCDB) to examine the effect of SLNB omission and outcomes in this population. We hypothesized that SLNB would be beneficial in this population.Methods: The National Cancer Database was queried for women diagnosed with primary unilateral invasive clinical stage T1N0M0 hormone receptor positive, HER-2 negative breast cancer from 2012-2017. Patients age ≥ 70 years old with Charlson Score ≥1 who underwent partial mastectomy and received hormonal therapy were included in the study cohort. Patients received neoadjuvant therapy or underwent upfront axillary lymph node dissection (ALND) were excluded. A 1:3 propensity match with replacement was performed to compare SLNB omission vs. SLNB group controlling age, race, comorbidities, insurance and facility. Overall survival was analyzed using stratified multivariable Cox proportional hazard regression analysis.Results: Of 14,150 patients, 1,928 (13.6%) omitted SLNB and 12,222 (86.4%) underwent SLNB, including 1,545/12,222 (12.6%) who proceeded to ALND. Central portion tumor location (OR=1.77, P=0.001), clinical T1c (OR= 2.49, P&amp;lt;0.001) and lymph-vascular invasion (OR=7.46, P&amp;lt;0.001) were significant associated with positive pathological lymph node involvement in SLNB group. Among the 1,397 patients of positive nodal status with SLNB, 87.7% received radiation therapy and 19.3% received chemotherapy. Propensity matching reduced bias between the groups, generating 1,903 SLNB omission and 5,703 SLNB patients for analysis. After match, the SLNB omission group was less likely to receive chemotherapy (1.1% vs. 3.0%, p&amp;lt;0.001) or radiation therapy (28.9% vs. 60.8%, p&amp;lt;0.001). Omitting SLNB was associated with inferior overall survival (3-year 83.7% vs. 90.6%, 5-year 66.4% vs. 76.1%, p&amp;lt;0.001). Omitting SLNB was also associated with inferior survival in multivariate cox regression (HR=1.64, p&amp;lt;0.001). Chemotherapy (OR=0.51, p=0.020) and radiation therapy (OR=0.85, P=0.007) were associated with superior overall survival.Conclusions: SLNB remains to be of importance in cT1N0M0 HR+HER2- patients of age 70 years. Pathologic staging affects decisions on adjuvant treatment and SLNB omission is associated with inferior survival. In this population, SLNB might need to be re-implemented, especially in patients with high likelihood of nodal involvement. Citation Format: Lifen Cao, Megan E Miller, Luke D Rothermel, Alberto J Montero, Christopher W Towe, Robert Shenk. Less is not necessarily more: A propensity matched national analysis on effect and outcome of sentinel lymph node biopsy omission [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 PD7-08.

Evaluating axillary management and re-excision rates of Ductal Carcinoma in Situ (DCIS) at a London district general hospital

Background: Ductal carcinoma in situ (DCIS) is a premalignant breast lesion without metastatic potential. Since the implementation of the national breast cancer screening programme in the UK, the incidence of DCIS has increased; now representing 12% of all breast cancers, with more than 7000 new cases per year in the UK. Under National Institute for Health and Care Excellence (NICE) guidelines [NG101] 2018, it is clear that routine sentinel lymph node biopsy is not recommended for DCIS when managed with breast conserving surgery.

Evaluating the Clinical Utility of Routine Sentinel Lymph Node Biopsy and the Value of Adjuvant Chemotherapy in Elderly Patients Diagnosed With Oestrogen Receptor Positive, Clinically Node Negative Breast Cancer.

Background:Sentinel lymph node biopsy (SLNB) provides staging information and guides adjuvant therapy in early breast cancer (EBC). Routine SLNB in oncogeriatricians with low-risk EBC remains controversial.Aims:To evaluate axillary management in elderly patients diagnosed with oestrogen receptor positive (ER+), clinically lymph node negative (cLN−) EBC, and to assess whether SLNB affects further axillary management or adjuvant chemotherapy (ACTX) decision making.Methods:Female patients aged > 65 years, diagnosed with ER+, human epidermal growth factor receptor-2 negative (HER2−), and cLN− breast cancer (BC), who underwent surgery and SLNB were included. Clinicopathological predictors of ACTX and completion axillary lymph node dissection (CALND) were determined. Kaplan-Meier analyses assessed survival outcomes.Results:A total of 253 patients were included (median age: 72 years, range: 66-90), all underwent SLNB; 50 (19.8%) had lymphatic metastasis on SLNB (SLNB+). Of these, 19 proceeded to CALND (38.0%), 10 (52.6%) of whom had further axillary disease (ALND+). 20 of the 50 SLNB+ patients received ACTX (40.0%) as did 31 of the 203 SLNB− patients (15.2%) (P < .001). Oncotype DX (ODX) testing was utilized in 82 cases (32.8%). Younger age (P < .001), SLNB+ (P < .001) and ODX score (P = .003) were all associated with ACTX prescription. ODX > 25 (OR: 4.37, 95% CI: 1.38-13.80, P = .012) independently predicted receiving ACTX. Receiving ACTX and proceeding to CALND did not improve disease-free (P = .485 and P = .345) or overall survival (P = .981 and P = .646).Conclusions:Routine SNLB may not be necessary in elderly patients diagnosed with ER+, cLN− EBC. Future oncogeriatric practice is likely to see genomic testing guiding ACTX prescription in this group.

Management of Deep Margin Involvement and or Perineural Invasion in Cutaneous Squamous Cell Carcinoma in the Head and Neck in a Single Unit: 12 Years’ Experience

INTRODUCTION: The eighth edition of American Joint Committee on Cancer guidelines separated cutaneous squamous cell carcinoma in the head and neck (cHNSCCs) into its own entity within head and neck malignancies with the aim of improving tumor risk stratification. The lack of precise prognostic estimates for cHNSCCs prevents clear guidance on the clinical approach to cHNSCCs resulting in heterogeneity of management. OBJECTIVE: Detailed review of the historical management of cHNSCCs in a single tertiary skin cancer center with the aim of creating a treatment algorithm that provides guidance in selecting the appropriate workup and treatment while minimizing unnecessary treatment and resulting morbidity. METHODS: Retrospective review of our institutional pathology database from January 2007 to December 2019 of all recorded head and neck cutaneous lesions excised by St Helens & Knowsley Teaching Hospitals NHS Foundation Trust Plastic Surgery Department. Primary outcomes include recurrence rates and cHNSCC-related mortality. RESULTS: A total of 442 lesions of cHNSCCs from 216 patients excised from the head and neck region were excised during the study period and 164 cHNSCCs had deep margin involvement ± perineural invasion. Median age was 78 years (49–98 years). Median follow-up was 23 months (0–153 months), 9 patients (4%) were lost to follow-up. Seven patients (3%) died before their first 3-monthly follow-up appointment was due. Thirty-nine patients (18%) were immunosuppressed, 10 were solid organ transplant recipients. One hundred thirteen patients (52%) were deceased at the time of review, 25 (22%) died directly or from complications of cHNSCCs. Out of 164 cHNSCCS, majority had deep margin involvement (77%, n = 126), 21% (n = 35) had both deep margin and perineural involvement. Only 5 patients (3%) had cHNSCCs with features of perineural invasion but adequate margins. Forty-five patients (27.4%) in the positive cohort (deep margin involvement ± perineural invasion) went on to develop local, regional, or distant recurrence with a median disease-free interval of 7.7 months (0.5–58 months). Overall recurrence rate was 14.5% (n = 64/442) with a false-negative rate of 6.8% (n = 19/278), The scalp was the most common primary tumor site to recur (45%), followed by the ear (27%) and face (23%). Fifty percent of primary tumors that recurred were moderately differentiated compared with 19% which were poorly differentiated. CONCLUSIONS: Our study demonstrates increased recurrence risk of both scalp and ear cHNSCCs, which warrant calls for more aggressive surgical measures, that is, primary excision with a wide margin down to periosteum with flap reconstruction with adjuvant radiotherapy. Routine sentinel lymph node biopsy in high-risk cHNSCCs could play a role in locoregional control.

Gaps in Online Breast Cancer Treatment Information for Older Women

For women older than 70years with early-stage breast cancer, the routine use of sentinel lymph node biopsy (SLNB) and adjuvant radiotherapy offers no overall survival benefit and may be perceived as undesirable by many women. National guidelines allow possible omission of these practices for older women. This study aimed to assess the availability of web-based educational materials targeting older women and their age-specific treatment recommendations. The study systematically assessed the websites of the top 25 "Best Hospitals for Cancer" ranked by the U.S. News & World Report, as well as the websites of four prominent national cancer organizations. Websites for the leading cancer hospitals and national cancer organizations contain extremely limited information directed toward older patients with breast cancer. Both SLNB and adjuvant radiotherapy are described as treatments "typically," "most often," or "usually" used in combination with breast-conserving surgery without circumstances noted for possible omission. Specifically, no hospital website and only one national organization in this study included information on the recommendation to avoid routine SLNB. Only two hospitals and two national organizations included information suggesting possible omission of adjuvant radiotherapy for patients older than 70years. The absence of online material for older patients with breast cancer represents a gap potentially contributing to overtreatment by framing SLNB and adjuvant radiotherapy as necessary. Informational resources available to women aged 70years or older may aid in informed physician-patient communication and decision-making, which may reduce SLNB and adjuvant radiotherapy for patients who might opt out of these procedures if fully informed about them.