Postmastectomy radiation therapy for T3N0: A SEER analysis

Abstract

Background There is conflicting evidence regarding the benefit of post-mastectomy radiation therapy (PMRT) for pathologic stage T3N0M0 breast cancers. We analyzed data from the Surveillance, Epidemiology, and End Results (SEER) database to investigate the benefit of PMRT in these patients. Methods We queried the SEER database for T3N0M0 breast cancer patients diagnosed from 2000–2010 who underwent modified radical mastectomy. We excluded males, patients with unknown radiation timing/type, other primary tumors, or survival <6 months. 2525 patients were included in this analysis. We performed univariate and multivariate statistical analysis using Chi-squared tests, log rank test, and Cox proportional hazards regression. Primary endpoints were overall survival (OS) and breast cancer-specific survival (CSS). Results Of the 2525 patients identified, 1063 received PMRT. The median follow-up was 56 months (range: 6–131). On univariate analysis, PMRT improved OS (76.5% vs. 61.8%, p<0.01) and CSS (85.0% vs. 82.4%, p<0.01) at 8 years. The use of PMRT remained significant on multivariate analysis: PMRT improved OS (HR 0.63, p<0.001) and CSS (HR 0.77, p=0.045). Low tumor grade (p<0.01) and marital status "married" (p=0.01) also predicted for improved CSS on multivariate analysis. Conclusion(s) PMRT was associated with significant improvements in both CSS and OS in patients with T3N0M0 breast cancers treated with modified radical mastectomy from 2000 to 2010. PMRT should be strongly considered in T3N0M0 patients.

Postmastectomy radiation therapy in T3 node-negative breast cancer

“…Our data are in contrast to an updated SEER analysis of T3N0M0 from the years 2000e2010 by Johnson et al [14]. This study included 2525 patients and noted an improvement in breast cancer-specific survival in patients undergoing PMRT (85.0 versus 82.4%, P < 0.01).…”

The role of postmastectomy radiotherapy in women with pathologic T3N0M0 breast cancer

“…Because approximately 33% of patients treated with PMRT also received RNI in addition to chest wall RT, we also were able to examine the role of RNI in patients with pT3N0 breast cancer. 9 Several additional single institutional studies also have found a benefit for PMRT. Previous prospective and retrospective studies also have shown that PMRT improves OS in women with pT3N0 breast cancer.…”

“…1 Although the overall incidence of breast cancer is high, the number of large primary breast malignancies without lymph node involvement is small because the risk of lymph node disease generally increases with tumor size. [5][6][7][8][9][10][11] Therefore, very few patients with T3N0 disease have received treatment as part of a randomized trial examining postmastectomy radiotherapy (PMRT). [5][6][7][8][9][10][11] Therefore, very few patients with T3N0 disease have received treatment as part of a randomized trial examining postmastectomy radiotherapy (PMRT).…”

“…[2][3][4] In fact, the majority of series published to date have estimated that only 1% to 4% of all breast cancers are >5 cm and lymph node negative (pT3N0). [5][6][7]9,10,[12][13][14] Current National Comprehensive Cancer Network guidelines state that RT to the chest wall, with or without regional lymph node irradiation (RNI), should be considered for patients with pT3N0 breast cancer. Thus, the question of whether PMRT is warranted in this subgroup of patients remains controversial because previous retrospective studies have found differing results, and randomized trials demonstrating the overall survival (OS) benefit of PMRT included only a small number of patients with pT3N0 breast cancer.…”

The role of postmastectomy radiotherapy in patients with stage II breast cancer

“…Multiple additional studies have been conducted using the Surveillance, Epidemiology, and End Results database, with mixed results. The most recent analysis demonstrated improvements in both cancer‐specific survival and overall survival with PMRT …”