Analysis of Breast Cancer Patients with T1-2 Tumors and 1-3 Positive Lymph Nodes Treated with or without Postmastectomy Radiation Therapy

Postmastectomy radiotherapy in patients with T1-2N1 breast cancer: a single center experience and a meta-analysis

PURPOSE

Postmastectomy radiotherapy (PMRT) in patients with T1-2N1 breast cancer is still controversial. This study was to evaluate the survival prognosis of T1-2N1 patients with or without PMRT.

PATIENTS AND METHODS

From January 2006 to May 2017, 2606 female breast cancer patients underwent mastectomy in our medical center, among whom 402 patients of T1-2N1 stage with or without PMRT were finally analyzed. The median follow-up duration was 59.5 months. The primary endpoint was overall survival (OS). The secondary endpoint was disease-free survival (DFS).

RESULTS

In the study of our center, no statistically significant difference was observed between the T1-2N1 PMRT and non-PMRT subgroups for the 5-year OS (94.4% vs 95.4%, p = 0.667) and DFS (90.1% vs. 91.1%, p = 0.798). By the date of the last follow-up, 8.96% (n = 36) of the patients experienced any recurrence. Univariate analysis revealed that PMRT was not a prognostic factor for either OS (p = 0.667) or DFS (p = 0.798) in T1-2N1 patients. We then did a meta-analysis on the current treatment patterns, in which 2606 PMRT and 4281 non-PMRT T1-2N1 breast cancer patients with mastectomy were included. The meta-analysis showed that PMRT didn't improve the OS of the patients (HR = 0.85, p = 0.11), but patients with PMRT had better DFS than those in the non-PMRT group (HR = 0.62, p < 0.001).

CONCLUSION

PMRT did not affect the survival of T1-2N1 breast cancer patients who underwent mastectomy, suggesting that radiotherapy may be safely omitted for them.

Postoperative Radiotherapy Contributes to the Survival Benefit of Breast-Conserving Therapy over Mastectomy

Purpose

A survival benefit of breast-conserving therapy (BCT) over mastectomy has been shown in recent studies. This study aimed to explore differences in recurrence patterns between BCT and mastectomy and clarify the contribution of radiotherapy (RT) to the survival benefit of BCT.

Methods

Consecutive patients with pT1-2/pN0-1/M0 breast cancer between 2009 and 2015 in our institution were retrospectively reviewed and compared in matched cohorts using 1 : 1 propensity score matching (PSM).

Results

A total of 2370 patients were enrolled with a median follow-up of 75 (3-148) months. In the cohort without regional nodal irradiation (RNI), WBI was associated with significantly increased 10-year relapse-free survival (RFS), distant metastasis-free survival (DMFS), and regional recurrence-free survival (RRFS) compared with mastectomy alone. There were 419 pairs in the cohort without RNI and 87 pairs in the cohort with RNI after PSM. In the PSM cohort, improved 10-year RFS (95.4% vs. 82.7%, p < 0.05), DMFS (97.4% vs. 84.1%, p < 0.05), and RRFS (99.1% vs. 95.5%, p < 0.05) were observed in WBI compared with mastectomy alone. Regarding the first recurrence event, WBI demonstrated a significantly lower cumulative rate of distant metastases than mastectomy alone. There was no significant difference in survival outcomes between WBI plus RNI and PMRT before and after the PSM. In patients without RNI, mastectomy alone was significantly associated with unfavorable RFS (HR = 2.3, 95% CI 1.2-4.5, p < 0.05) and DMFS (HR = 2.5, 95% CI 1.1-5.8, p < 0.05).

Conclusion

This study found the benefit of RFS and DMFS in BCT patients compared with those treated with mastectomy without RNI but not in those treated with RNI. We hypothesized that RT played an important role in reducing the risk of regional recurrence and distant metastases.

Suggestion for the omission of post-mastectomy chest wall radiation therapy in patients who underwent skin-sparing/nipple-sparing mastectomy

AIM

Both skin-sparing mastectomy (SSM) and nipple-sparing mastectomy (NSM) have been widely adopted. Although postmastectomy radiation therapy (PMRT) can improve clinical outcomes, it can worsen cosmesis following reconstruction. Therefore, identifying risk factors of ipsilateral breast tumor recurrence (IBTR) could help de-escalate PMRT after NSM/SSM in patients with pT1-2 disease.

METHODS

We retrospectively reviewed patients treated with SSM (N = 400) and NSM (N = 156) in patients with pT1-2N0-1 disease between 2009 and 2016. Seventy-four patients received PMRT with 50-50.4 Gy in 25-28 fractions. The Cox proportional hazards model was used to analyze the prognostic factors of IBTR.

RESULTS

With a median follow-up of 66.2 months, 17 IBTR events were observed, with 5-year IBTR-free rate of 97.2%. Although only one IBTR was observed after PMRT, there was no statistical difference in the 5-year IBTR-free rate (PMRT vs. no PMRT, 98.6% vs. 97.0%, p = 0.360). Multivariable analyses demonstrated that age ≤45 years and lymphovascular invasion (LVI) were adverse features of IBTR. The low-risk group (0 risk factor) showed a better 5-year IBTR-free rate than the high-risk group (≥1 risk factor) (100.0% vs. 95.8%, p = 0.003). In the high-risk group, PMRT slightly improved 5-year IBTR-free rate compared with no PMRT (98.6% vs. 95.2%, p = 0.166). In addition, PMRT increased 5-year cumulative incidence of reconstruction failure (10.0% vs. 2.8%, p = 0.001).

CONCLUSION

We identified risk factors (age and LVI) related to IBTR following upfront SSM/NSM with pT1-2 disease. As a hypothesis-generating study, de-escalation of PMRT by omitting chest wall irradiation in selective patients could improve reconstruction-related complications without compromising oncologic outcomes.

Optimizing Breast Reconstruction through Integration of Plastic Surgery and Radiation Oncology

Post-mastectomy radiation therapy (PMRT) is an important adjunct to improve oncologic outcomes and survival in select breast cancer patients at increased risk for local recurrence. As recommendations for PMRT broaden, an increasing number of patients will have it included as part of their breast cancer treatment plan.