Main Session
Sep
28
PQA 04 - Breast Cancer, Patient Reported Outcomes/QoL/Survivorship, Functional Radiation Medicine, Hematologic Malignancies, Palliative Care, and International/Global Oncology
2805 - Recurrence Patterns in Triple-Negative Breast Cancer Following Breast-Conserving Surgery with Radiotherapy Compared to Mastectomy
Presenter(s)
Swarupa Mitra, MD, MBA, MBBS - Rajiv Gandhi Cancer Institute & Research Centre, Delhi, Delhi
S. Mitra1, R. Singh2, A. Priyadarshini1, S. Rana1, N. Kakkar1, V. Immanuel1, T. Kumar1, A. Sarma1, A. R. Chaudhoory1, A. K. Anand V1, and R. B. Nair1; 1Fortis Memorial Research Institute, Gurgaon, India, 2Fortis Memorial Research Institute, Gurugram, India
Purpose/Objective(s):
The optimal surgical approach for triple-negative breast cancer (TNBC) remains controversial, particularly with respect to local recurrence and survival outcomes following breast-conserving therapy (BCT: breast-conserving surgery plus radiotherapy) versus mastectomy (MRM). We compared recurrence patterns and survival outcomes between BCT and MRM in TNBC patients.Materials/Methods:
We retrospectively analysed 100 TNBC patients treated between 2008 – 2021 receiving BCT (n = 61) or MRM (n = 39, with or without adjuvant RT). Clinicopathologic variables included tumour size, grade, nodal burden, extracapsular extension (ENE), lymphovascular invasion (LVI), neoadjuvant chemotherapy (NACT) response, and initial stage. Treatment variables included axillary surgery type (SLNB vs ANLD levels I – III), radiotherapy fractionation (Hypofractionated vs. conventional), and use of Regional nodal irradiation (RNI). Survival outcomes were estimated using Kaplan-Meier methods and compared with log-rank testing. Multivariable Cox regression evaluated independent prognostic factors. Recurrence sites were categorized as local, regional, or distant.Results:
Patients with MRM had more adverse features, including larger tumors, higher grade, LVI, and ENE. BCT patients received whole-breast RT, predominantly hypofractionated, with RNI in 70%. In MRM group, 74% received RT and 82% had RNI, commonly to the supraclavicular basin. With a median follow-up of 98 months, locoregional recurrence occurred in 5 patients (7.6%), all in the BCT group, mainly in patients with limited axillary surgery without nodal irradiation; no locoregional recurrences occurred in MRM. Distant metastases occurred in 3 patients, all in BCT group. Kaplan-Meier analysis showed no significant differences in OS or PFS between BCT and MRM. On multivariable analysis, surgery type was not independently associated with OS or PFS. Biological factors, including nodal burden, ENE, LVI, and NACT response, were dominant predictors of recurrence and survival. Axillary radiotherapy was associated with a significantly increased hazard of death in MRM patients (HR 4.65, 95% CI 1.18 - 18.39; p = 0.029), with a similar but non-significant trend for PFS. Interaction analyses demonstrated borderline statistical significance for both OS and PFS, suggesting that impact of axillary radiotherapy on survival outcomes may differ according to surgery type. Treatment-related toxicities were infrequent and comparable between groups.Conclusion:
In TNBC, breast-conserving therapy and mastectomy achieved comparable long-term survival despite baseline differences. Locoregional recurrence was rare and influenced more by tumor biology and adequacy of nodal treatment than by surgical approach alone. These findings support individualized integration of axillary surgery and RNI rather than escalation of surgical extent.