PURPOSE: To provide recommendations on the best strategies for the management and on the best timing and treatment (surgical and radiotherapeutic) of the axilla for patients with early-stage breast cancer.METHODS: Ontario Health (Cancer Care Ontario) and ASCO convened a Working Group and Expert Panel to develop evidence-based recommendations informed by a systematic review of the literature.RESULTS: This guideline endorsed two recommendations of the ASCO 2017 guideline for the use of sentinel lymph node biopsy in patients with early-stage breast cancer and expanded on that guideline with recommendations for radiotherapy interventions, timing of staging after neoadjuvant chemotherapy (NAC), and mapping modalities. Overall, the ASCO 2017 guideline, seven high-quality systematic reviews, 54 unique studies, and 65 corollary trials formed the evidentiary basis of this guideline.RECOMMENDATIONS: Recommendations are issued for each of the objectives of this guideline: (1) To determine which patients with early-stage breast cancer require axillary staging, (2) to determine whether any further axillary treatment is indicated for women with early-stage breast cancer who did not receive NAC and are sentinel lymph node–negative at diagnosis, (3) to determine which axillary strategy is indicated for women with early-stage breast cancer who did not receive NAC and are pathologically sentinel lymph node–positive at diagnosis (after a clinically node-negative presentation), (4) to determine what axillary treatment is indicated and what the best timing of axillary treatment for women with early-stage breast cancer is when NAC is used, and (5) to determine which are the best methods for identifying sentinel nodes. Additional information is available at www.asco.org/breast-cancer-guidelines .

ASCO Guidelines provide recommendations with comprehensive review and analyses of the relevant literature for each recommendation, following the guideline development process as outlined in the ASCO Guidelines Methodology Manual . ASCO Guidelines follow the ASCO Conflict of Interest Policy for Clinical Practice Guidelines . Clinical Practice Guidelines and other guidance (“Guidance”) provided by ASCO is not a comprehensive or definitive guide to treatment options. It is intended for voluntary use by clinicians and should be used in conjunction with independent professional judgment. Guidance may not be applicable to all patients, interventions, diseases or stages of diseases. Guidance is based on review and analysis of relevant literature, and is not intended as a statement of the standard of care. ASCO does not endorse third-party drugs, devices, services, or therapies and assumes no responsibility for any harm arising from or related to the use of this information. See complete disclaimer in Appendix 1 and 2 (online only) for more. PURPOSE: To update the ASCO evidence-based recommendations on the use of sentinel lymph node biopsy (SLNB) in patients with early-stage breast cancer treated with initial surgery. METHODS: ASCO convened an Expert Panel to develop updated recommendations based on a systematic literature review (January 2016-May 2024). RESULTS: Eleven randomized clinical trials (14 publications), eight meta-analyses and/or systematic reviews, and one prospective cohort study met the inclusion criteria for this systematic review. Expert Panel members used available evidence and informal consensus to develop practice recommendations. RECOMMENDATIONS: Clinicians should not recommend routine SLNB in select patients who are postmenopausal and ≥50 years of age and with negative findings on preoperative axillary ultrasound for grade 1-2, small (≤2 cm), hormone receptor–positive, human epidermal growth factor receptor 2–negative breast cancer and who undergo breast-conserving therapy. Clinicians may offer postmastectomy radiation (RT) with regional nodal irradiation (RNI) and omit axillary lymph node dissection (ALND) in patients with clinically node-negative invasive breast cancer ≤5 cm who receive mastectomy and have one to two positive sentinel nodes. Clinicians may offer SLNB in patients who have cT3-T4c or multicentric tumors (clinically node-negative) or ductal carcinoma in situ treated with mastectomy, and in patients who are obese, male, or pregnant, or who have had prior breast or axillary surgery. Clinicians should not recommend ALND for patients with early-stage breast cancer who do not have nodal metastases, and clinicians should not recommend ALND for patients with early-stage breast cancer who have one or two sentinel lymph node metastases and will receive breast-conserving surgery and whole-breast RT with or without RNI. Additional information is available at www.asco.org/breast-cancer-guidelines . This guideline has been endorsed by the American Society for Radiation Oncology (ASTRO).

Delayed recurrences, common in breast cancer, are well explained by the concept of tumour dormancy. Numerous publications describe clinical times to disease recurrence or death, using mathematical approaches to infer mechanisms responsible for delayed recurrences. However, most of the clinical literature discussing tumour dormancy uses data from over a half century ago and much has since changed. This review explores how current breast cancer treatment could change our understanding of the biology of breast cancer tumour dormancy, and summarizes relevant experimental models to date. Current knowledge gaps are highlighted and potential areas of future research are identified.

Background and Purpose: Adjuvant whole-breast irradiation after breast-conserving surgery, typically delivered over several weeks, is the traditional standard of care for low-risk breast cancer. More recently, hypofractionated, partial-breast irradiation has increasingly become established. Neoadjuvant single-fraction radiotherapy (RT) is an uncommon approach wherein the unresected lesion is irradiated preoperatively in a single fraction. We developed the SIGNAL (Stereotactic Image-Guided Neoadjuvant Ablative Radiation Then Lumpectomy) trial, a prospective single-arm trial to test our hypothesis that, for low-risk carcinoma of the breast, the preoperative single-fraction approach would be feasible and safe. Methods: Patients presenting with early-stage (T < 3 cm), estrogen-positive, clinically node-negative invasive carcinoma of the breast with tumours at least 2 cm away from skin and chest wall were enrolled. All patients received prone breast magnetic resonance imaging (MRI) and prone computed tomography simulation. Treatable patients received a single 21 Gy fraction of external-beam rt (as volumetric-modulated arc therapy) to the primary lesion in the breast, followed by definitive surgery 1 week later. The primary endpoints at 3 weeks, 6 months, and 1 year were toxicity and cosmesis (that is, safety) and feasibility (defined as the proportion of mri-appropriate patients receiving RT). Results: Of 52 patients accrued, 27 were successfully treated. The initial dosimetric constraints resulted in a feasibility failure, because only 57% of eligible patients were successfully treated. Revised dosimetric constraints were developed, after which 100% of patients meeting mri criteria were treated according to protocol. At 3 weeks, 6 months, and 1 year after the operation, toxicity, patient- and physician-rated cosmesis, and quality of life were not significantly different from baseline. Conclusions: The SIGNAL trial presents a feasible method of implementing single-dose preoperative rt in early-stage breast cancer. This pilot study did not identify any significant toxicity and demonstrated excellent cosmetic and quality-of-life outcomes. Future randomized multi-arm studies are required to corroborate these findings.

BACKGROUND: Studies examining treatment delay and survival after surgical treatment of colon cancer have varied in quality and outcome, with little evidence available regarding the safety of longer surgical treatment wait times. OBJECTIVE: Our study examined the effect of surgical treatment wait times on survival for patients with stage I to III colon cancer. DESIGN: A subset cohort analysis was performed using data from a prospectively maintained database. SETTINGS: The study was conducted at a tertiary referral center. PATIENTS: Data on all of the patients undergoing elective surgery for stage I to III colon cancer from 2006 to 2015 were collected from a prospectively maintained clinical and administrative database. MAIN OUTCOME MEASURES: We examined the impact of prolonged wait time to surgery on disease-free and overall survival. Patients were divided into 2 groups based on a treatment wait time of ≤30 or >30 days and were compared using a Cox proportional hazards model. A subgroup analysis was performed using alternative treatment delay cutoffs of 60 and 90 days. RESULTS: There were 908 patients with stage I to III colon cancer treated over the study period, with a median treatment wait time of 38 days (interquartile range, 21–61 days); 368 patients were treated within 30 days, and 540 were treated beyond 30 days from diagnosis. In adjusted multivariate analysis, a treatment delay of >30 days was not associated with decreased disease-free survival (HR = 0.89 (95% CI, 0.61–1.3); p = 0.52) or overall survival (HR = 0.82 (95% CI, 0.63–1.1); p = 0.16). Likewise, subgroup analysis using alternative treatment delay cutoffs of 60 and 90 days did not demonstrate an adverse effect on survival. LIMITATIONS: This study was limited by retrospective analysis. CONCLUSIONS: Despite longer median treatment wait times from diagnosis to surgery, with the majority of patients exceeding 30 days and many experiencing delays of 2 to 3 months, no adverse impact on survival was observed. Patients who require additional consultations or investigations preoperatively may safely have their surgery moderately delayed to minimize their perioperative risk without any evidence that this will compromise treatment outcomes. See Video Abstract at http://links.lww.com/DCR/A397.