The effect of postmastectomy radiotherapy in node-positive triple-negative breast cancer

Abstract

Background The value of postmastectomy radiotherapy (PMRT) for pathological node-positive triple-negative breast cancers (TNBC) remains debatable. The aim of this population-based retrospective study was to evaluate the effect of PMRT on survival outcomes in this population. Methods Patients diagnosed with stage T1-4N1-N3M0 TNBC between 2010 and 2014 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. We used univariate and multivariate Cox regression hazards method to determine the independent prognostic factors associated with 3-year breast cancer-specific survival (BCSS). The effect of PMRT on 3-year BCSS was analyzed after stratification by pathological staging of groups. Results Of the 4398 patients included in this study, 2649 (60.2%) received PMRT. Younger age, black ethnicity, and advanced tumor (T) and nodal (N) stage were the independent predictors associated with PMRT receipt (all P < 0.05). Patients who received PMRT showed better 3-year BCSS (OR = 0.720, 95% CI = 0.642–0.808, P < 0.001) than those that did not. The effect of PMRT on 3-year BCSS was analyzed after stratification by pathological staging of groups. The results showed that PMRT was associated with better 3-year BCSS in patients with stage T3–4N1 (P = 0.042), T1-4N2 (P < 0.001), and T1-4N3 (P < 0.001), while comparable 3-year BCSS was found between the PMRT and non-PMRT cohorts with T1–2N1 disease (P = 0.191). Conclusions Radiotherapy achieved better 3-year BCSS in TNBC patients with stage T3–4N1 and T1-4N2–3 disease. However, no survival benefit was found with the addition of PMRT in patients with T1–2N1 TNBC.

Effect of postmastectomy radiotherapy on T1-2N1M0 triple-negative breast cancer

“…Accordingly, we not only divided the subgroup analysis according to the clinicopathological characteristics but also performed subgroup analysis by crossing tumor size with the number of positive LNs, which proved that only BCSS in T2 patients with three positive LNs could benefit from PMRT. Zhang et al studied the effect of PMRT on the survival of T1-4N1-N3M0 patients, and the results showed that there was no difference in BCSS between PMRT and non-PMRT cohort in the T1-2N1 subgroup (P = 0.191) [24], which was consistent with our results, but they did not conduct further stratified analysis. Another study included 675 T1-2N1M0 TNBC patients and subgroup analysis was performed based on the number of positive lymph nodes.…”

Effect of postmastectomy radiotherapy on T1-2N1M0 triple-negative breast cancer

“…Tumor size and number of axillary lymph node metastases have been proved to be closely related to recurrence and prognosis of breast cancer [20,21].In our study, tumor size and number of positive LNs were associated with BCSS.The effect of PMRT mainly depends on the comprehensive consideration of tumor size and the number of positive LNs [22], and secondly, it is related to other high-risk factors such as young age and positive vascular tumor thrombus.Accordingly, we not only divided the subgroup analysis according to the clinicopathological characteristics, but also performed subgroup analysis by crossed tumor size with number of positive LNs, which proved that only BCSS in T2 patients with three positive LNs could bene t from PMRT.Zhang et al studied the effect of PMRT on the survival of T1-4N1-N3M0 patients, and the results showed that there was no difference in BCSS between PMRT and non-PMRT cohort in the T1-2N1 subgroup (P = 0.191) [23], which was consistent with our results, but they did not conduct further strati ed analysis.Another study included 675 T1-2N1M0 TNBC patients and subgroup analysis was performed based on the number of positive lymph nodes. After a median followup of 37 months, PMRT was independently associated with increased OS, but there was no improvement in BCSS in any subgroup [24].The reason why they are inconsistent with our conclusion may be due to their shorter follow-up time and fewer cases.…”

Abscopal Effects in Metastatic Cancer: Is a Predictive Approach Possible to Improve Individual Outcomes?

“…Unfortunately, no more details of this case were reported [168]. A separate study regarding patients with TNBC, performed post-mastectomy RT and reported a beneficial impact on 3-year breast cancer-specific survival which was dependent on the pathological stage of the patients [169].…”