Faculty Bibliography

BACKGROUND AND PURPOSE: We evaluated the effect of post-mastectomy radiation (PMRT) in 1-3 positive lymph nodes (LN) in patients who received uniform modern systemic therapy. MATERIALS AND METHODS: Cohort study using individual data collected for 1,649 node-positive women who received doxorubicin/cyclophosphamide with sequential docetaxel in 2000-2003 on the control arm of BCIRG-005. All women underwent mastectomy or lumpectomy and axillary LN dissection. PMRT was given at investigator's discretion. RESULTS: A total of 523 women with 1-3 positive LN underwent mastectomy and 39% (206/523) received PMRT. With a median follow-up of 10years, PMRT improved loco-regional control (LRC) from 91% to 98% (p=0.001) but had no effect on overall survival (OS) (84% vs. 86%, p=0.9). On multivariate analysis, PMRT improved local control (LC) (hazard ratio, 0.14; 95% CI, 0.03-0.62; p=0.01) and LRC (hazard ratio, 0.15; 95% CI, 0.04-0.50; p=0.002). PMRT did not significantly impact OS on multivariate analysis (hazard ratio, 0.91; 95% CI, 0.55-1.51; p=0.7). Results remained consistent with the use of propensity score analysis. CONCLUSIONS: In this cohort of patients with N1 disease treated with modern systemic therapy, PMRT improves LRC but has no effect on OS. The rates of OS were excellent, irrespective of adjuvant radiation.

Background/Objective: In a time when clinicians are attempting to identify a cohort of patients with ductal carcinoma in situ (DCIS) who will benefit most from post-lumpectomy radiation therapy (RT), tools have been developed to quantify patients' risk for in-breast recurrence. These tools have not yet been integrated into standard use. At our institution, the recommendation for RT after lumpectomy for DCIS is guided by established clinicopathologic factors and reviewed by a multi-disciplinary group. The purpose of this study was to compare the clinicopathologic characteristics and outcomes of postlumpectomy DCIS patients with and without RT at our institution. Methods: The Institutional Breast Cancer Database was queried for all women who were diagnosed with DCIS from 2010-2016. Variables included age, method of presentation, risk factors, tumor and treatment characteristics, and ipsilateral breast tumor recurrence (IBTR). Statistical analyses included Pearson's Chi Square and Fisher's Exact Tests. Results: Of 480 women with pure DCIS and no prior history of breast cancer, 350 (73%) underwent lumpectomy. The median follow-up was 4 years, and median age was 60 years. Two hundred thirty-six (67%) women underwent RT following lumpectomy. Compared to women who did not undergo RT, these women were younger (p=0.003), had larger tumor size (p=0.0008), higher grade (p=0.0006), and comedo features (p=0.03). Women who underwent post-lumpectomy RT had an IBTR rate of 2% vs. 4% (p=0.32) with no RT. The 10 patients with early IBTR in both groups were younger (median age 54 years), and all had intermediate- or high-grade DCIS. Of the 114 patients who did not undergo adjuvant RT, 70 (61%) met the RTOG 9804 criteria for omission of adjuvant RT. Of the 44 patients who did not receive adjuvant RT and did not meet RTOG 9804 criteria, 20 declined RT, and 24 were not referred. Conclusions: Within a relatively short follow-up period, we found a very low overall rate (3%) of IBTR for our patients who underwent lumpectomy for DCIS. These results are consistent with previously published trials on post-lumpectomy RT in DCIS. RT at our institution is recommended based on wellestablished clinicopathologic factors and multidisciplinary care. Considering the low recurrence rates, we recommend continuing the current trend of using published criteria and multidisciplinary review. It remains to be seen to what extent the newly developed recurrence tools, such as Oncotype DX Breast DCIS ScoreTM, will improve upon these short-term recurrence rates