Pattern of local recurrence and metastasis in carcinoma breast according to molecular subtype in patients treated with definitive intent

Background: Despite the advances in breast cancer treatment, it has a higher rate of mortality. The response of treatment varies significantly; this could be due to the various subtypes that determine the course of the disease. In this study, we evaluated patients who were treated definitively and had developed organ-specific metastasis and local recurrence according to biological subtype. Materials and Methods: Out of 856 patients who were diagnosed to have carcinoma breast from the year January 2015 to January 2020, 468 patients were treated definitively, out of which 55 patients developed recurrent or metastatic disease after completion of treatment. Results: The most frequent subgroup for relapse was triple-negative breast cancer (TNBC) 23 (41.8%). Twenty-two (40%) had multiple metastases at the time of first distant recurrence. The most common site of distant recurrence was bone 28 patients (50.9%) with maximum incidence in Luminal B subgroup (23.6%), followed by liver metastasis 23 patients (41.81%) with the highest incidence seen among TNBC (18%), followed by lung 19 (34.5%) patients with maximum incidence in TNBC (16.3%) followed by brain 5 (9%) patients. Locoregional recurrence was observed in 13 patients, out of which 8 (61.5%) patients had TNBC molecular subgroup. Conclusion: Our results demonstrate an association between molecular subtype and pattern of recurrence.