Role Of Adjuvant Radiotherapy Research Articles

The role of adjuvant radiation in stage II–III endometrial stromal sarcoma

The role of adjuvant radiation in stage II–III endometrial stromal sarcoma

Evidence for Radiation Therapy in Stage III Locoregionally Advanced Cutaneous Melanoma in the Post-Immunotherapy Era: A Literature Review.

In the landscape of Stage III locoregionally advanced cutaneous melanoma treatment, the post-immunotherapy era has sparked a number of questions on the management of the nodal basin. However, much of the available literature is not focused on radiation therapy as an adjuvant therapy. This literature review aims to illuminate the evidence surrounding radiation therapy's potential to mitigate regional recurrences in the adjuvant setting for melanoma. Additionally, it seeks to identify adjunct systemic therapy options and explore the synergy between systemic therapy and radiation. Despite strides in surgical techniques and systemic therapies, controlling regional Stage III melanoma remains a formidable clinical hurdle. While historical data strongly suggest the efficacy of adjuvant radiation therapy in reducing regional recurrence risk, its evaluation predates the advent of MAPK pathway inhibitors and robust immunotherapy options. Notably, clinical trials have yet to definitively demonstrate a survival advantage with adjuvant radiation therapy. Additional research should focus on refining the definition of high risk for regional recurrence through gene expression profiling or tumor immune profiling scores and elucidate the optimal role of adjuvant radiation therapy in patients treated with neoadjuvant systemic therapy.

1383: The Role of Adjuvant Radiotherapy in Patients with Vulvar Cancer: A Monocentric Experience

1383: The Role of Adjuvant Radiotherapy in Patients with Vulvar Cancer: A Monocentric Experience

Giant retroperitoneal liposarcoma with multiple organ involvement: a case report and literature review

BackgroundRetroperitoneal liposarcoma (RPLPS) is a relatively rare disease. Liposarcomas vary in size, but sizeable RPLPS larger than 30 cm in diameter are very rare, and their diagnosis and treatment present significant challenges.Case presentationWe report a 58-year-old male patient who was admitted to the hospital with an increased abdominal circumference and was later diagnosed with a giant RPLPS. The liposarcoma was found to adhere to the right kidney and the entire ureter, invading the ascending colon. The patient underwent complete combined surgical resection. The tumor was removed intact, measured 55.0 cm × 30.0 cm × 18.0 cm, and weighed 19.8 kg. Histopathologic analysis revealed well-differentiated liposarcoma (WDLPS). The patient was successfully discharged from the hospital and followed up for 6 months with no signs of recurrence.ConclusionRPLPS is a rare tumor with atypical clinical presentation. Surgery remains the most effective method of treatment for retroperitoneal sarcomas, with complete removal if there is local invasion. Preoperative examination, including three-dimensional (3D) reconstruction, is essential for surgical success. The role of adjuvant radiotherapy or chemotherapy remains controversial. However, clinicians should not rule them out as viable options.

Outcomes of adjuvant lymph node field radiotherapy and immunotherapy for stage III melanoma

PurposeWith the promising results of immunotherapy in patients with stage III melanoma, the role of adjuvant radiotherapy after resection and complete lymph-node dissection must be reassessed. We evaluate the outcomes and safety of adjuvant radiotherapy and immunotherapy compared to immunotherapy only in patients with resected stage III melanoma. Patients and methodsThis retrospective and single institution study included patients treated for a stage III melanoma with complete lymph-node dissection and adjuvant immunotherapy from January 2019 to December 2022. The radiotherapy associated with immunotherapy group was defined by completion of immunotherapy and adjuvant radiotherapy in the lymph-node dissection area. The primary endpoint was disease-free survival. The secondary endpoints were locoregional progression, incidence of adverse events grade 3 or above and disease-free survival rate in patients with high risk of locoregional recurrence. ResultsThirty-three patients were included. Among them, twelve received adjuvant lymph-node field radiotherapy. The median duration of follow-up was 17months (range: 8–45months). Patients receiving radiotherapy and immunotherapy had a significantly higher disease stage and more frequent extracapsular extension. At 12months, the disease-free survival rate was 66.7% for the patients receiving immunotherapy alone (95% CI: 42.5–82.5%) and 83.3% for those receiving radiotherapy and immunotherapy (95% CI: 48.2–95.6%; P=0.131). The locoregional progression rate was 24% in patients receiving immunotherapy and 8% in patients receiving immunotherapy and radiotherapy (P=0.379). After adjuvant treatment, 6% of patients developed grade 3 or above immunotherapy-related events and none developed grade 3 or above radiation-related adverse events. ConclusionIn patients with stage III melanoma, adjuvant lymph-node field radiotherapy combined with immunotherapy seems to be associated with longer disease-free survival, with acceptable tolerance. However, these results need to be confirmed by long-term and prospective studies.

Surgery for Infrarenal Retroperitoneal Node Metastases from Colon Cancer.

Treatment of retroperitoneal lymph node metastases (RPN) from colon cancer (CC) is a therapeutic challenge. Available evidence supporting a curative approach is weak and uncertainties remain concerning the extent of the dissection, the optimal timing for surgery, and the role of adjuvant radiotherapy. We report the outcomes of a curative intent strategy in a recent monocentric series of patients. We did a retrospective review of all curative intent surgical treatment of RPN from CC performed consecutively in a French university hospital from June 2015 to April 2021. Demographics, clinicopathological, and molecular characteristics were evaluated. We describe recurrence-free and overall survival and factors related to recurrence. Records from 18 patients were reviewed. The median age was 69years. Most of the patients were male (55%), ASA 1-2 (94%), had a left-sided primary colon cancer (73%), and had metachronous RPN (62%). Thirteen patients (72%) experienced recurrence. Recurrence was often limited to RPN (27%) or liver (22%). Four patients underwent a second surgery for RPN recurrence. Median disease-free and overall survival were 22months and 50months after RPN surgery. We did not find any factor associated with recurrence. Short-term recurrence (< 6months) was associated with shorter overall survival (0.031). The current results suggest that RPN resection is feasible and associated with long survival in selected patients. Further studies evaluating the benefit of curative strategies including radical surgery for patients with potentially resectable RPN are warranted.

Retroperitoneal leiomyosarcoma; Demographics, clinicopathological, survival analysis, role of adjuvant radiation and genomic analysis.

e23327 Background: Retroperitoneal leiomyosarcoma (RPL) is an exceedingly rare malignancy and is the second most common subtype of leiomyosarcomas. Most of the information concerning this rare disease is limited to case studies and few literature studies. The study's objectives were to assess the demographics, pathological factors, survival outcomes, genomic landscape and potential for targeted therapy. Methods: Data of retroperitoneal leiomyosarcoma were obtained from the Surveillance, Epidemiology, and End Results (SEER) database, with cases diagnosed between 2000 and 2020 used for this study and the Cancer Genome Atlas containing sequencing information for 27 cases of RPL. Results: A total of 1406 cases were extracted with mean age of diagnosis of 62.1 years. Of these, RPL had a higher incidence in women (71.5%), more cases affected Whites (58.7%). Histologically, in patients with known grading, most patients’ i.e. 62.35% were grade 3, G3 (poorly differentiated). Nearly all (99.9%) patients presented with a tumor size ≥4.1 cm. Local lymph nodes metastasis were positive in 76.0% of cases when lymph node status was reported. In known cases of distant metastases, the most common site was liver (8.9%). The main treatment modality was surgery only (26.7%, hazard ratio, HR 1.17, p-value &lt; 0.001), followed by the standard of care (surgery and radiation) (18.4%, HR 1.03, p-value &lt; 0.001), and radiation only (18.4%). Five-year overall survival was 40% and 5-year cause-specific survival was 64%. The highest 5-year survival was observed in patients undergoing surgery and radiation (57%), and in combination therapy (chemotherapy, surgery, and radiation) the 5-year survival was 39%. Genetic analysis found the most common mutations included TP53 (51.9%), RB1 (25.9%), and ATRX (14.8%). When accounting for deep deletions and rearrangements, total frequency of the alterations was higher such that TP53 (63.0%), RB1 (51.9%), and ATRX (18.5%). Potentially actionable alterations were rare but included activating alterations in FGFR1, PIK3CA and ESR1, as well as deep deletions of BRCA1. Conclusions: Retroperitoneal leiomyosarcoma is a very rare tumor where surgery and radiation has been the conventional therapy. Our study indicates there are genetic alterations in the majority of retroperitoneal leiomyosarcoma. To further understand the pathogenesis and survival factors, patients with RPL should be enrolled into national and international registries.

Abstract PO4-22-05: Changes in Treatment Recommendation for Patients with Ductal Carcinoma In Situ Using a 7-Gene Predictive Biosignature: Analysis of the PREDICT Australia Study

Abstract Background: The role of adjuvant radiotherapy (RT) following breast-conserving surgery (BCS) for women with ductal carcinoma in situ (DCIS) remains controversial. Although there is Level 1 evidence supporting the use of RT to reduce the risk of local recurrence, prognostic and predictive tools are needed to better stratify the individual risks and benefits of RT. The 7-gene predictive DCIS biosignature provides a validated score (DS) for women receiving BCS that assesses 10-year risk of DCIS recurrence and development of invasive breast cancer with and without adjuvant RT. We established a registry to evaluate the decision impact of the 7-gene predictive biosignature on DCIS treatment recommendations in an Australian setting. Methods: The PREDICT study is a prospective, multi-institutional registry for patients who received DCISionRT testing as part of their routine care. The registry includes females 26 and older who are diagnosed with DCIS and are candidates for BCS and eligible for RT. Treating physicians completed treatment recommendation forms before and after receiving test reports to capture surgical, radiation and hormonal treatment (HT) recommendations and patient preferences. Results: This planned interim analysis was performed in 483 patients with complete data treated at 43 clinical sites in Australia. The median age of patients was 61 years, 19% were 50 or younger, nuclear grade was high in 51%, and tumor size was 2.5 cm or greater in 15%. Overall, RT recommendation (yes/no) was changed for 41% of women and HT recommendation was changed for 9% after testing with a net reduction in recommended RT of 14% (66% pre-assay to 52% post-assay p&amp;lt; 0.001). Of patients recommended to receive RT pre-test, 42% were recommended to not receive RT post-test and of the patients recommended to not receive RT pre-test, 40% were recommended to receive RT post-test. The post-test RT recommendation rate increased with increasing DS score (&amp;lt; 2, 2-4, &amp;gt;4), with 9% of patients recommended RT for DS&amp;lt; 2, 62% for DS 2-4, and 100% for DS 4-10. The use of the test resulted in different RT recommendations than with clinicopathology alone, where RT recommendations were changed for 49%, 37%, and 34% for women of age&amp;lt; 50 yrs, with Grade 3 DCIS, or with DCIS &amp;gt; 2.5 cm, respectively. Collectively, this suggests that physicians had a high confidence in the test results when making their final treatment recommendations with the test results. Conclusions: This analysis demonstrates that the use of the 7-gene predictive biosignature resulted in significant changes in recommendations to add or omit RT in this study of 483 women. The integration of DCISionRT into the clinical decision-making processes has a substantial impact on recommendations to personalize care and prevent over- or under-treatment. Table 1: Impact of DCISionRT on Adjuvant Radiation Recommendations by Clinicopathologic Features Citation Format: Yvonne Zissiadis, Bruce Mann, David Speakman, Christobel Saunders, Marcus Dreosti, Christopher Pyke, Daniel De Viana, Melissa Bochner, James French, Sally Baron-Hay, Karuna Mittal, Steven Shivers, Troy Bremer. Changes in Treatment Recommendation for Patients with Ductal Carcinoma In Situ Using a 7-Gene Predictive Biosignature: Analysis of the PREDICT Australia Study [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 PO4-22-05.

The Role of Neoadjuvant and Adjuvant Chemotherapy in Pancreatic Cancer.

Pancreatic cancer is an aggressive malignancy. Recurrences are very high despite high-quality surgery necessitating adjuvant therapy. The evolution of adjuvant therapy took several decades and gradually evolved from single-agent chemotherapy to multi-agent chemotherapy. The two important agents that are active in pancreatic cancer are 5-fluorouracil and gemcitabine, and with several combinations showing better results in the subsequent trials, the most recent trial PRODIGE 24 shows a median survival of 54.4months. The role of neoadjuvant therapy is still evolving in resectable cancers. The role of adjuvant radiotherapy is not well defined due to controversial results from historical trials.

Primary Mucinous Carcinoma of the Axillary Skin: A Case Report &amp; The Role of Adjuvant Tamoxifen

Primary mucinous carcinoma of the skin (PMCS) is a rare cancer. It is indolent and progresses slowly but can recur locally, damaging the structure. The majority of mucinous carcinoma that occurs in the skin are metastatic lesions originating from various sites. In terms of morphology, PMCS is almost indistinguishable from secondary metastatic deposits. We reported a case of a 44-year-old male with left axillary skin PMCS that had spread to axillary lymph nodes. The pathologic diagnosis was challenging but was facilitated by expert pathologists from different centers. A multidisciplinary meeting concluded that the best managementapproach was to include a wide local excision and axillary clearance followed by adjuvant tamoxifen. The role of adjuvant radiotherapy was discussed but was declined by the patient. The patient is well now with no recurrence, 22 months since the diagnosis.

The Role of Adjuvant Radiotherapy in the Treatment of Breast Cancer.

The role of postmastectomy radiotherapy and regional nodal irradiation after radical mastectomy is defined in high-risk patients with locally advanced tumors, positive margins, and unfavorable biology. The benefit of postmastectomy radiotherapy in intermediate-risk patients (T3N0 tumors) remains a matter of controversy. It has been demonstrated that radiotherapy after breast-conserving surgery lowers the locoregional recurrence rate compared with surgery alone and improves the overall survival rate. In patients with four or more positive lymph nodes or extracapsular extension, regional lymph node irradiation is indicated regardless of the surgery type (breast-conserving surgery or mastectomy). Despite the consensus that patients with more than three positive lymph nodes should be treated with radiotherapy, there is controversy regarding the recommendations for patients with one to three involved lymph nodes. In patients with N0 disease with negative findings on axillary surgery, there is a trend to administer regional lymph node irradiation in patients with a high risk of recurrence. In patients treated with neoadjuvant systemic therapy and mastectomy, adjuvant radiotherapy should be administered in cases of clinical stage III and/or ≥ypN1. In patients treated with neoadjuvant systemic therapy and breast-conserving surgery, postoperative radiotherapy is indicated irrespective of pathological response.

Extraskeletal osteosarcoma misdiagnosed as metastatic breast cancer: A case report

IntroductionExtraskeletal osteosarcomas are rare tumors with poor overall survival and a high propensity for recurrence. It frequently arises in the lower extremities and has been reported to metastasize commonly in the lungs. Controversy exists as to whether it should be treated as a soft tissue sarcoma or an osteosarcoma. Various adjuvant treatment approaches have also been studied with conflicting results. Case reportWe present a 73-year-old female with a painless, gradually enlarging right upper arm mass for 2 months. She previously underwent a left mastectomy 5 years ago for a stage II breast cancer. Preoperative imaging showed a resectable, heterogenous right upper arm mass. She subsequently underwent radical excision with frozen section revealing spindle cell neoplasm. Final histopathology was consistent with extraskeletal osteosarcoma. The patient remains disease-free as of most recent follow-up. DiscussionThere are several proposed mechanisms for extraskeletal osteosarcomas. Based on the history and location of the tumor, we initially thought that this was metastatic breast cancer. Preoperative imaging determines resectability and surgical approach. Radical surgery is frequently performed which largely depends on the site of the tumor. Complete primary resection with adequate margins remains to be the treatment of choice to prevent recurrence or metastasis. The role of adjuvant radiotherapy or chemotherapy is still to be established. ConclusionThis case highlights the various treatment options and the need for further research on its clinical behavior and potential targeted therapies.

Multivariate analysis of prognostic factors in patients with lip squamous cell carcinoma after surgery

BackgroundLip squamous cell carcinoma (LSCC) was one of the most common cancer types of head and neck tumors. This study aimed to find more predictors of the prognosis in postoperative LSCC patients.MethodsA total of 147 LSCC patients between June 2012 and June 2018 were collected from two tertiary care institutions. There were 21 clinicopathological factors included and analyzed in our study. The univariate and multivariate Cox regression analyses were performed to find the independent prognostic factors for predicting progression-free survival (PFS) and overall survival (OS) in postoperative LSCC patients. The role of adjuvant radiotherapy in various subgroups was displayed by Kaplan–Meier plots.ResultsThe 1-, 3-, and 5-year PFS of postoperative LSCC patients were 88.4%, 70.1%, and 57.8%, respectively. Similarly, the 1-, 3-, and 5-year OS of postoperative LSCC patients were 94.6%, 76.9%, and 69.4%, respectively. The results suggested that postoperative LSCC patients with age at diagnosis ≥ 70 years, grade with moderate or poor differentiate, the American Joint Committee on Cancer (AJCC) stage IV, higher systemic immune-inflammation index (SII), surgical margin < 5, and age-adjusted Charlson Comorbidity Index (ACCI) ≥ 5 tend to have a poorer PFS (all P < 0.05). Besides, postoperative LSCC patients with age at diagnosis ≥ 70 years, AJCC stage IV, higher GPS, higher SII, and ACCI ≥ 5 tend to have a worse OS (all P < 0.05). Additionally, postoperative patients with LSCC in the subgroup of ACCI < 5 and AJCC III–IV stage was more likely to benefit from adjuvant radiotherapy, but not for the other subgroups.ConclusionWe identified a series of significant immune-inflammation-related and comorbidity-related clinicopathological factors associated with the prognosis of postoperative LSCC patients by local data from two tertiary care institutions in China, which can be helpful for patients and surgeons to pay more attention to nutrition, inflammation, and complications and finally obtained a better prognosis.

Efficacy and safety of adjuvant radiation therapy in localized adrenocortical carcinoma.

Adrenocortical carcinoma (ACC) is rare and have high rates of recurrence and mortality. The role of adjuvant radiation therapy (RT) in localized ACC was controversial. We conducted a retrospective study in our center between 2015 and 2021 to evaluate the efficacy and safety of adjuvant RT in localized ACC. Overall survival (OS) and disease-free survival (DFS) were estimated using the Kaplan-Meier method. Cox proportional hazards regression models were used to estimate the independent risk factors. Adverse events associated with RT were documented according to the toxicity criteria of the radiation therapy oncology group (RTOG) and the common terminology criteria for adverse events (CTCAE v5.0). Of 105 patients with localized ACC, 46 (43.8%) received adjuvant RT after surgery. The median radiation dose was 45.0Gy (range:30.0-50.4) and median follow up time was 36.5 (IQR: 19.7-51.8) months. In comparison to the no adjuvant RT group, patients with adjuvant RT had better 3-year OS (87.9% vs 79.5%, P=0.039), especially for patients with ENSAT I/II stage (P=0.004). Adjuvant RT also improved the median DFS time from 16.5months (95%CI, 12.0-20.9) to 34.6months (95%CI, 16.1-53.0). Toxicity of RT was generally mild and moderate with six grade 3 events. Postoperative adjuvant RT significantly improved OS and DFS compared with the use of surgery alone in resected ACC patients. Although this retrospective study on RT in localized ACC indicates that RT is effective in ACC, its findings need to be prospectively confirmed.

Analysis of demographics and the impact of adjuvant radiotherapy on a nationwide cohort of patients with high-grade spinal meningiomas.

Although typically benign, 5% of spinal meningiomas (SMs) present with higher-grade features (World Health Organization grades 2 and 3). High-grade SMs are poorly studied and the role of adjuvant radiotherapy in their management remains controversial. We hence aimed to study the demographic characteristics of this rare tumor and investigate the outcomes associated with the use of surgery with adjuvant therapy in contrast to surgery alone. The National Cancer Database was queried for patients with SMs from 2004 to 2017. Basic statistics were used to identify differences between low- and high-grade tumors in terms of baseline characteristics. Surgery with and without adjuvant radiotherapy were compared after (1:1) propensity-score matching. Kaplan-Meier survival analysis was conducted to study overall survival. All analyses were performed on R. A total of 13184 patients diagnosed with SMs were included, of whom only 5% (n = 669) had high-grade SMs. Patients with high-grade SMs presented at a younger median age (57 years [IQR: 44-68] versus 65 years [54-75]; P < .001) and were more commonly males (33% vs 20%; P < .001). After propensity-score matching, survival analysis revealed similar overall survival outcomes in patients with high-grade SM undergoing both surgery and radiotherapy as compared to those only receiving surgery (P = .19). This study reveals major demographic differences between high- and low-grade SMs. There were no benefits associated with the use of adjuvant radiotherapy. However, due to confounding, overall survival outcomes between patients receiving surgery alone and those receiving surgery with adjuvant radiotherapy are not causally interpretable.

Adjuvant Radiation Therapy for Salivary Duct and Epithelial Myoepithelial Salivary Carcinoma

Salivary gland cancers are rare in general and salivary duct carcinoma and epithelial myoepithelial carcinomas are rare subtypes. This topic discussion will review the characteristics of these uncommon cancers. Additionally, it will briefly discuss available guidelines for salivary cancers and summarize author opinions on the role of adjuvant radiation therapy for these cases.

ASO Visual Abstract: Patterns of Recurrence after Poor Response to Neoadjuvant Chemotherapy in Gastric Cancer and the Role for Adjuvant Radiation.

ASO Visual Abstract: Patterns of Recurrence after Poor Response to Neoadjuvant Chemotherapy in Gastric Cancer and the Role for Adjuvant Radiation.

Is there role of adjuvant radiotherapy after complete resection of locally advanced nonsmall cell lung cancer?

This review aims to provide a timely and relevant overview of the role of postoperative radiotherapy (PORT) in completely resected stage IIIA-N2 nonsmall cell lung cancer (NSCLC). Given the controversy surrounding the use of PORT and the emergence of advanced radiation techniques and therapies, this review provides valuable insight into current and potential treatment strategies. The Lung ART and PORT-C trials have provided valuable insights into the efficacy of PORT in stage IIIA-N2 NSCLC. While the results have been mixed, studies have shown that advanced radiation techniques, such as intensity-modulated radiotherapy (IMRT) and proton therapy, can reduce cardiopulmonary toxicities associated with PORT. Molecular targeted therapies and immunotherapies have also shown potential in improving NSCLC treatment outcomes. The role of radiotherapy becomes smaller and smaller in new era. However, it is too early to abolish radiotherapy for all the patients after complete resection of locally advanced NSCLC. Nowadays, it is recommended to adopt individualized treatment approaches guided by multidisciplinary team consultations. The integration of IMRT, proton therapy, and emerging therapies offers the potential to enhance treatment efficacy while minimizing toxicity. Further research is needed to optimize the use of PORT and explore the method to identify the patients who can really benefit from PORT.

Role of Adjuvant Radiotherapy in Patients with Cervical Cancer Undergoing Radical Hysterectomy.

The benefit of adjuvant radiotherapy (RT) after radical hysterectomy in patients with cervical cancer remains controversial. The aim of this study was to determine adjuvant RT's impact on survival in accordance with Sedlis criteria. Patients with early-stage cervical cancer undergoing radical hysterectomy between 2005 and 2022 at a single tertiary care institution were included. A multivariate analysis was performed to determinate if RT was an independent prognostic factor for recurrence or death. We also analysed whether there was a statistically significant difference in overall survival (OS) between patients who met only one or two Sedlis criteria, depending on whether they received adjuvant RT or not. 121 patients were included in this retrospective study, of whom 48 (39.7%) received adjuvant RT due to the presence of unfavourable pathological findings. In multivariate analysis, RT was not found to be a statistically significant prognostic factor for OS (p = 0.584) or disease-free survival (DFS) (p = 0.559). When comparing patients who met one or two Sedlis criteria, there were no statistically significant differences in OS between RT and no adjuvant treatment in either group. Since the selection of patients with cervical cancer eligible for surgery is becoming more accurate, adjuvant RT might not be necessary for patients with intermediate risk factors.

Adjuvant Radiation Therapy Improves Local Control in the Treatment of Adnexal Carcinoma

Adnexal carcinoma (AC) is a rare subset of cutaneous malignancies derived from skin adnexa. There are limited data on the role of adjuvant radiation therapy (RT). This study investigates outcomes associated with adjuvant RT at our high-volume referral center. Using an institutional pathology database we identified 45 patients with locoregionally-confined AC treated between 2001-2020 with curative intent surgery and RT at initial diagnosis or at the time of locoregionally-confined recurrence. Clinicopathologic variables were described and time to relapse events were assessed by the Kaplan-Meier method. Median age was 64 yrs (IQR 57-71). Primary tumors were in the head and neck (H&N, n = 36, 80%), trunk/extremities (n = 8, 18%) or unknown (n = 1). The most common histologic subtypes were: sebaceous-14 (31%), microcystic adnexal carcinoma-9 (20%), eccrine-6 (13%), and trichilemmal-5 (11%). Twenty-two (50% of known primaries) had PNI. All patients had primary tumor excision. Six had clinically evident lymphadenopathy (13%), all of whom had lymph node dissection (LND). Five patients without evidence of nodal disease (13%) had sentinel lymph node biopsy (SLNB) with one having SLN+ disease. Thirty patients (67%) received adjuvant locoregional RT at initial diagnosis with the following targets: 21 (30%) primary only, 4 (13%) nodal only, and 5 (17%) both. Of those receiving nodal RT, 7 (78%) had LN+ LND with 2 of those receiving concurrent platinum-based chemoradiation. Sixteen were treated at recurrence with the following targets: 4 (25%) primary only (1 having had prior adjuvant nodal RT), 4 (25%) nodal only, and 8 (50%) both. Across the full cohort, median RT dose was 60 Gy in 30 fractions. Median follow-up from initial surgical resection was 60 months (IQR 30-160). 5-year LC, NC, DFS and DSS were 71%, 86%, 66%, and 91% respectively. The only evaluated factor associated with better outcome was adjuvant primary site RT (5-yr LC 83% vs. 56%, p = 0.01 and 5-yr DFS 83% vs. 46%, p = 0.0003). All 15 patients with local recurrence (LR) had salvage surgery with median subsequent follow-up of 75 months (IQR 2-94). Overall, 5 patients receiving adjuvant primary site RT at any time (initial or salvage) developed subsequent local recurrence (13%). Of the 8 patients who developed nodal recurrence (NR) during follow-up, 1 received adjuvant nodal RT at initial diagnosis. Six of 7 who did not receive prior RT then received adjuvant nodal RT after LND and only 1 developed subsequent NR. AC is a rare skin cancer with a primarily locoregional recurrence pattern. In our experience, adjuvant RT was associated with improved LC which, depending on the tumor location, may help prevent morbid or cosmetically-impactful salvage surgery. Patients with AC would benefit from radiation oncology referral to discuss adjuvant treatment.