The impact of the total size of lesions in multifocal/multicentric breast cancer on survival.

e12030 Background: Multifocal/multicentric(MF/MC) may be observed in 20% of patients with breast cancer.According to AJCCstaging system, the T stage of a tumor is determined based on the size of the largest lesion in the breast; however, some data suggest that considering the total size of the lesions is more valuable.We investigated and compared the prognostic value of determining the T stage according to the total size of lesions and according to the size of the largest lesion alone in patients with MF/MC breast cancer. Methods: The pathology reports of patients with breast cancer who were monitored at Hacettepe University 2003 and 2014 were reviewed. The T stage of MF/MC tumors was determined according to the largest lesion size (Tfirst ) and the sum of the longest diameters of the lesions (Tlast ). The impact of both T stages on DFS and OS was evaluated. Results: MF/MC tumors were diagnosed in 323 of 3890 patients with breast cancer (8.3%). When the T stage was determined by summing the sizes of the lesions, the T stage of 67 (20.7%) and 63 (19.5%) patients advanced from T1 to T2 and T2 to T3, respectively. Thus, the T stage in a total of 130 patients with MF/MC (40.2%) increased (32 patients from AJCC stage I to II and 13 patients from stage II to III). AJCC stage changed in a total of 45 patients (14%). In patients with unifocal and MF/MC tumors, the 10-year OS was 75% and 74%, respectively (p = 0.965) and the 10-year DFS was 66% and 61%,respectively (p = 0.817). It was observed that the DFS curves of the patients with MF/MC tumors whose T stage advanced from phase I to II according to Tfirst and Tlast (n = 32) overlapped with the survival curves of the patients with unifocal tumors whose was stage I, particularly in the first 3 years. The 3-year DFS was found to be 97.2% in patients with unifocal tumors of stage 1, 91.6% in patients with stage 2, and 100% in patients whose multifocal stage advanced from I to II according to Tlast . The independent predictors of DFS were found to be Tfirst , hormone receptor positivity, and lymph node involvement. There was no significant relationship between Tlast and DFS. Conclusions: It was observed that the T stage obtained by summing lesion sizes in patients with MF/MC breast cancer is not superior to the classic staging in terms of prognosis.