Purpose: To update the ASCO clinical practice guideline on adjuvant endocrine therapy on the basis of emerging data on the optimal duration of treatment, particularly adjuvant tamoxifen. Methods: ASCO convened the Update Committee and conducted a systematic review of randomized clinical trials from January 2009 to June 2013 and analyzed three historical trials. Guideline recommendations were based on the Update Committee's review of the evidence. Outcomes of interest included survival, disease recurrence, and adverse events. Results: This guideline update reflects emerging data on duration of tamoxifen treatment. There have been five studies of tamoxifen treatment beyond 5 years of therapy. The two largest studies with longest reported follow-up show a breast cancer survival advantage with 10-year durations of tamoxifen use. In addition to modest gains in survival, extended therapy with tamoxifen for 10 years compared with 5 years was associated with lower risks of breast cancer recurrence and contralateral breast cancer. Recommendations: Previous ASCO guidelines recommended treatment of women who have hormone receptor–positive breast cancer and are premenopausal with 5 years of tamoxifen, and those who are postmenopausal a minimum of 5 years of adjuvant therapy with an aromatase inhibitor or tamoxifen followed by an aromatase inhibitor (in sequence). If women are pre- or perimenopausal and have received 5 years of adjuvant tamoxifen, they should be offered 10 years total duration of tamoxifen. If women are postmenopausal and have received 5 years of adjuvant tamoxifen, they should be offered the choice of continuing tamoxifen or switching to an aromatase inhibitor for 10 years total adjuvant endocrine therapy.

Purpose: To determine the long-term prognosis in each phenotypic subset of breast cancer related to residual cancer burden (RCB) after neoadjuvant chemotherapy alone, or with concurrent human epidermal growth factor receptor 2 (HER2)–targeted treatment. Methods: We conducted a pathologic review to measure the continuous RCB index (wherein pathologic complete response has RCB = 0; residual disease is categorized into three predefined classes of RCB index [RCB-I, RCB-II, and RCB-III]), and yp-stage of residual disease. Patients were prospectively observed for survival. Three patient cohorts received paclitaxel (T) followed by fluorouracil, doxorubicin, and cyclophosphamide (T/FAC): original development cohort (T/FAC-1), validation cohort (T/FAC-2), and independent validation cohort (T/FAC-3). Another validation cohort received FAC chemotherapy only, and a fifth cohort received concurrent trastuzumab (H) with sequential paclitaxel and fluorouracil, epirubicin, and cyclophosphamide (FEC; H+T/FEC). Phenotypic subsets were defined by hormone receptor (HR) and HER2 status at diagnosis, classified as HR-positive/HER2-negative, HER2-positive (HR-negative/HER2-positive or HR-positive/HER2-positive), or triple receptor–negative. Relapse-free survival estimates were determined from Kaplan-Meier analysis and compared using the log-rank test. Results: Five cohorts (T/FAC-1 [n = 219], T/FAC-2 [n = 262], T/FAC-3 [n = 342], FAC [n = 132], and H+T/FEC [n = 203]) had median event-free follow-up of 13.5, 9.1, 6.8, 16.4, and 7.1 years, respectively. Continuous RCB index was prognostic within each phenotypic subset, independent of other clinical-pathologic variables. RCB classes stratified prognostic risk overall, within each phenotypic subset, and within yp-stage categories. Estimates of 10-year relapse-free survival rates in the four RCB classes (pathologic complete response, RCB-I, RCB-II, and RCB-III) were 86%, 81%, 55%, and 23% for triple receptor–negative; 83%, 97%, 74%, and 52% for HR-positive/HER2-negative in the combined T/FAC cohorts; and 95%, 77%, 47%, and 21% in the H+T/FEC cohort. Conclusion: RCB was prognostic for long-term survival after neoadjuvant chemotherapy in all three phenotypic subsets of breast cancer. Our institutional findings should be externally validated.

Purpose: To update the ASCO clinical practice guideline on adjuvant endocrine therapy based on emerging data about the optimal duration of aromatase inhibitor (AI) treatment. Methods: ASCO conducted a systematic review of randomized clinical trials from 2012 to 2018. Guideline recommendations were based on the Panel’s review of the evidence from six trials. Results: The six included studies of AI treatment beyond 5 years of therapy demonstrated that extension of AI treatment was not associated with an overall survival advantage but was significantly associated with lower risks of breast cancer recurrence and contralateral breast cancer compared with placebo. Bone-related toxic effects were more common with extended AI treatment. Recommendations: The Panel recommends that women with node-positive breast cancer receive extended therapy, including an AI, for up to a total of 10 years of adjuvant endocrine treatment. Many women with node-negative breast cancer should consider extended therapy for up to a total of 10 years of adjuvant endocrine treatment based on considerations of recurrence risk using established prognostic factors. The Panel noted that the benefits in absolute risk of reduction were modest and that, for lower-risk node-negative or limited node-positive cancers, an individualized approach to treatment duration that is based on considerations of risk reduction and tolerability was appropriate. A substantial portion of the benefit for extended adjuvant AI therapy was derived from prevention of second breast cancers. Shared decision making between clinicians and patients is appropriate for decisions about extended adjuvant endocrine treatment, including discussions about the absolute benefits in the reduction of breast cancer recurrence, the prevention of second breast cancers, and the impact of adverse effects of treatment. Additional information can be found at www.asco.org/breast-cancer-guidelines .

Purpose: Concerns exist regarding breast cancer patients' access to breast reconstruction, which provides important psychosocial benefits. Patients and Methods: Using the MarketScan database, a claims-based data set of US patients with employment-based insurance, we identified 20,560 women undergoing mastectomy for breast cancer from 1998 to 2007. We evaluated time trends using the Cochran-Armitage test and correlated reconstruction use with plastic-surgery workforce density and other treatments using multivariable regression. Results: Median age of our sample was 51 years. Reconstruction use increased from 46% in 1998 to 63% in 2007 (P < .001), with increased use of implants and decreased use of autologous techniques over time (P < .001). Receipt of bilateral mastectomy also increased: from 3% in 1998 to 18% in 2007 (P < .001). Patients receiving bilateral mastectomy were more likely to receive reconstruction (odds ratio [OR], 2.3; P < .001) and patients receiving radiation were less likely to receive reconstruction (OR, 0.44; P < .001). Rates of reconstruction receipt varied dramatically by geographic region, with associations with plastic surgeon density in each state and county-level income. Autologous techniques were more often used in patients who received both reconstruction and radiation (OR, 1.8; P < .001) and less frequently used in patients with capitated insurance (OR, 0.7; P < .001), patients undergoing bilateral mastectomy (OR, 0.5; P < .001), or patients in the highest income quartile (OR, 0.7; P = .006). Delayed reconstruction was performed in 21% of patients who underwent reconstruction. Conclusion: Breast reconstruction has increased over time, but it has wide geographic variability. Receipt of other treatments correlates with the use of and approaches toward reconstruction. Further research and interventions are needed to ensure equitable access to this important component of multidisciplinary treatment of breast cancer.

Purpose: ACOSOG Z0011 established that axillary lymph node dissection (ALND) is unnecessary in patients with breast cancer with one to two positive sentinel lymph nodes (SLNs) who undergo lumpectomy, radiotherapy (RT), and systemic therapy. We sought to ascertain RT coverage of the regional nodes in that trial. Methods: We evaluated case report forms completed 18 months after enrollment. From 2012 to 2013, we collected all available detailed RT records for central review. Results: Among 605 patients with completed case report forms, 89% received whole-breast RT. Of these, 89 (15%) were recorded as also receiving treatment to the supraclavicular region. Detailed RT records were obtained for 228 patients, of whom 185 (81.1%) received tangent-only treatment. Among 142 with sufficient records to evaluate tangent height, high tangents (cranial tangent border ≤ 2 cm from humeral head) were used in 50% of patients (33 of 66) randomly assigned to ALND and 52.6% (40 of 76) randomly assigned to SLND. Of the 228 patients with records reviewed, 43 (18.9%) received directed regional nodal RT using ≥ three fields: 22 in the ALND arm and 21 in the SLND arm. Those receiving directed nodal RT had greater nodal involvement (P < .001) than those who did not. Overall, there was no significant difference between treatment arms in the use of protocol-prohibited nodal fields. Conclusion: Most patients treated in Z0011 received tangential RT alone, and some received no RT at all. Some patients received directed nodal irradiation via a third field. Further research is necessary to determine the optimal RT approach in patients with low-volume axillary disease treated with SLND alone.

Purpose: To update the ASCO adjuvant endocrine therapy guideline based on emerging data concerning the benefits and risks of ovarian suppression in addition to standard adjuvant therapy in premenopausal women with estrogen receptor–positive breast cancer. Methods: ASCO convened an Update Panel and conducted a systematic review of randomized clinical trials investigating ovarian suppression. Results: Two trials investigating the addition of ovarian suppression to tamoxifen did not show an overall clinical benefit for ovarian suppression. Nonetheless, the addition of ovarian suppression to standard adjuvant therapy with tamoxifen or with an aromatase inhibitor improved disease-free survival and improved freedom from breast cancer and distant recurrence compared with tamoxifen alone among the subset of patients who were at sufficient risk for recurrence such that adjuvant chemotherapy was warranted. Compared with tamoxifen alone, ovarian suppression was associated with a substantial increase in menopausal symptoms, sexual dysfunction, and diminished quality of life. Recommendations: The Panel recommends that higher-risk patients should receive ovarian suppression in addition to adjuvant endocrine therapy, whereas lower-risk patients should not. Women with stage II or III breast cancers who would ordinarily be advised to receive adjuvant chemotherapy should receive ovarian suppression with endocrine therapy. The panel recommends that some women with stage I or II breast cancers at higher risk of recurrence who might consider chemotherapy may also be offered ovarian suppression with endocrine therapy. Women with stage I breast cancers not warranting chemotherapy should not receive ovarian suppression, nor should women with node-negative cancers 1 cm or less. Ovarian suppression may be administered with either tamoxifen or an aromatase inhibitor. Additional information is available at www.asco.org/guidelines/endocrinebreast and www.asco.org/guidelineswiki .