The Role of Post-Mastectomy Radiotherapy in T1-2N1 Breast Cancer Patients: Propensity Score Matched Analysis

This study aimed to evaluate the role of post-mastectomy radiotherapy (PMRT) in T1-2N1 breast cancer. Between 2006 and 2014, a total of 504 patients with T1-2N1 breast cancer were analyzed. PMRT was administered to 71 patients, and 1:2 propensity score matching (PSM) was performed between the PMRT and non-PMRT groups. Loco-regional control (LRC), disease-free survival (DFS), and overall survival (OS) rates were compared according to PMRT status. Thirteen and one loco-regional recurrences were observed in the PMRT and non-PMRT groups, respectively. Before PSM, the 8-year LRC, DFS, and OS rates in the non-PMRT and PMRT groups were 98.5% and 96.5% (p = 0.426), 89.7% and 91.2% (p = 0.700), and 91.5% and 92.1% (p = 0.679), respectively. Corresponding rates were 95.6% and 96.5% (p = 0.365), 84.1% and 91.2% (p = 0.185), and 88.4% and 92.1% (p = 0.276), respectively, after PSM. Multivariate analysis showed that three lymph node metastases were prognostic for LRC and DFS rates and LVI for OS rate. Arm lymphedema developed in 32.4% of patients who received PMRT, which was significantly higher than the non-PMRT group (p < 0.001). Contributions of PMRT for improvement of treatments outcomes in T1-2N1 breast cancer patients were not evident, while the incidence of arm lymphedema significantly increased after PMRT. Further prospective trials are required to re-evaluate the role of PMRT.

Efficacy of post‑mastectomy radiotherapy in patients with T1‑2N1 breast cancer aged ≤35 years or with a positive HER‑2 status

Post-mastectomy radiotherapy (PMRT) is highly recommended for patients with breast cancer with one to three positive nodes; however, there remains some controversy regarding its use. The present retrospective study aimed to explore which patients may be able to avoid PMRT and its associated side effects. A total of 728 patients with T1-2N1 breast cancer who were treated with or without PMRT were included in the present study. The results suggested that PMRT significantly decreased the locoregional recurrence rate (LRR) [hazard ratio (HR)=5.602, 95% confidence interval (CI)=3.139-9.998, P<0.01; 3-year LRR: 4 vs. 17%] and improved overall survival (OS) (HR=0.651, 95% CI=0.437-0.971, P=0.03; 3-year OS: 91 vs. 87%) for patients with T1-2N1 breast cancer. By contrast, PMRT had no significant effect on the distant metastasis (DM) rate (HR=0.691, 95% CI=0.468-1.019, P=0.06; 3-year DM: 10 vs. 15%). Further stratified analysis revealed that PMRT did not reduce the LRR and DM, or improve OS in patients aged ≤35 years or in those with a positive human epidermal growth factor receptor-2 (HER-2) status. The analysis of 438 patients treated with PMRT revealed that patients aged ≤35 years or those with a positive HER-2 status were more likely to experience local recurrence even following PMRT. Thus, the benefits of using PMRT in patients with T1-2N1 breast cancer who are aged ≤35 years or in those with a positive HER-2 status need to be carefully considered. Further studies are required to confirm whether this patient group may be exempted from PMRT.

Is the prognosis of T1-2N1 colon cancer the same as that of T1-2N0 colon cancer after curative surgery?

Objectives: The prognoses of T1-2N0 and T1-2N1 colon cancer after curative surgery remain unclear. This study compared the prognoses of patients with T1-2N0 and T1-2N1 colon cancer after curative surgery.Materials and methods: We retrospectively evaluated 307 consecutive patients with T1-2N0/1 colon cancer who underwent radical surgery at our hospital between January 2010 and December 2016. There were 266 patients with T1-2N0 colon cancer and 41 patients with T1-2N1 colon cancer. After excluding patients with <12 retrieved lymph nodes, 179 patients with T1-2N0 and 32 with T1-2N1 colon cancer were included in the cohort.Results: Overall survival and disease-free survival did not differ between the T1-2N0 and T1-2N1 groups (p = 0.498 and p = 0.681, respectively). Overall survival and disease-free survival were not significantly different between the T1-2N1 + no chemotherapy and T1-2N1 + chemotherapy groups (p = 0.740 and p = 0.765, respectively). Additionally, overall survival and disease-free survival did not differ between the T1-2N0, T1-2N1 + no chemotherapy, and T1-2N1 + chemotherapy groups (p = 0.757 and p = 0.877, respectively), even after excluding patients with <12 retrieved lymph nodes.Conclusions: T1-2N1 has a prognosis as good as that of T1-2N0 colon cancer after curative surgery. Moreover, further research is needed to investigate the efficacy of adjuvant FOLFOX chemotherapy in T1-2N1.

Practical Model to Optimize the Strategy of Adjuvant Postmastectomy Radiotherapy in T1-2N1 Breast Cancer With Modern Systemic Therapy

Purpose

The effect of adjuvant irradiation after mastectomy in early-stage breast cancer patients remains controversial. The present study aims to explore the clinical benefit obtained from adjuvant radiotherapy among post-mastectomy pT1-2N1 breast cancer patients who received adjuvant modern systemic therapy.

Methods

Medical records of consecutive patients with pT1-2N1 breast cancer who received mastectomy in our institution between January 2009 and December 2016 were retrospectively reviewed. High-risk features consist of patient age, number of positive lymph nodes, T stage, and Ki67 index, which were developed previously at our institution using early-stage breast cancer patients after mastectomy without adjuvant radiotherapy. Differences of survival and local recurrence were compared between no-postmastectomy radiotherapy (PMRT) and PMRT group according to number of risk factors. The time-to-event curves were calculated by the Kaplan–Meier methods and compared by the log-rank test. Propensity score matching (PSM) was performed to reduce the imbalances in patient characteristics.

Results

A total of 548 patients were enrolled (no-PMRT: 259 and PMRT: 289). After a median follow-up of 69 months, the 5-year rate of DFS, BCSS, and LRR in the overall cohort was 90.2%, 97.4%, and 3.6%, respectively. PMRT did not significantly improve DFS, BCSS, and LRRFS in the whole cohort. Patients were divided into low-risk (with no or one risk factor) and high-risk (with two or more risk factors) groups. According to the univariable and multivariable analysis, high-risk group (HR = 1.81, 95% CI 1.11–2.98, p = 0.02) was demonstrated as an independent risk factor for DFS. For the high-risk group, PMRT significantly improved DFS from 81.4% to 91.9% and BCSS from 95.5% to 98.6% and decreased the 5-year rate of LRR from 5.6% to 1.4%, respectively (p < 0.01, p = 0.05, and p = 0.06). However, no survival benefit from PMRT was observed in the low-risk group in terms of DFS, BCSS, and LRR (p = 0.45, p = 0.51, and p = 0.99, respectively). In multivariate analysis, PMRT remained an independent prognostic factor for DFS (HR = 0.50, 95% CI 0.24–1.00, p = 0.05) in the high-risk group. After PSM analysis, the survival benefit of PMRT was sustained in high-risk patients.

Conclusion

PMRT significantly improved DFS in high-risk pT1-2N1 breast cancer patients, but not in low-risk patients. Independent validation of our scoring system is recommended.

Adjuvant regional nodal irradiation did not improve outcomes in T1-2N1 breast cancer after breast-conserving surgery: A propensity score matching analysis of BIG02/98 and BCIRG005 trials

Aim

To determine whether the addition of regional nodal irradiation (RNI) to whole-breast irradiation (WBI) would improve outcomes over WBI alone in T1-2N1 breast cancer after breast-conserving surgery (BCS) and adjuvant systematic therapy.

Methods

Data were obtained from two randomized controlled trials (NCT00174655 and NCT00312208). Univariate and multivariate Cox-regression analysis were performed to investigate predictors for overall survival and disease-free survival. A 1:1 propensity score matching (PSM) analysis was applied to eliminate selection bias.

Results

With median follow-up 80 months (range: 3–155 months), the 5-year local regional recurrence in the WBI group was 2% vs. 5% (p = 0.28) in the WBI + supraclavicular radiotherapy, and the rate of 5-year distant metastasis in the WBI group was 7% vs. 13% in the WBI + supraclavicular radiotherapy (p = 0.0748); In addition, the 5-year local regional recurrence in the WBI group was 3% vs. 9% (p = 0.19) in the WBI + internal mammary irradiation (IMI); However, the rate of 5-year distant metastasis in the in the WBI group was significantly lower than that in the WBI + IMI (8% vs. 24%, p = 0.036). After PSM, cox-regression analysis indicated that neither RNI nor IMI in combination with WBI in T1-2N1 breast cancer was associated with an improved overall survival and disease-free survival when compared to WBI alone.

Conclusion

The addition of RNI to WBI in T1-2N1 breast cancer after BCS and adjuvant systematic therapy did not improve outcomes in comparison with WBI alone. Further studies are still needed to identify patients who would most benefit from RNI in this patient population.

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The addition of RNI to WBI in unselected T1-2N1 breast cancer after BCS and adjuvant systematic therapy does not significantly improve outcomes in comparison with WBI alone.

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Early stage (pT1-2N1) breast cancer after BCS represents a diverse population.

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An individualized risk analysis based on clinical-genomic models is recommended to identify patients who would benefits or omit from RNI in further prospective studies.