The influence of obesity on the recurrence of cancer in HER-2 positive breast cancer patients related to adjuvant trastuzumab treatment

Purpose: trastuzumab, a humanized monoclonal antibody, was shown to prolong survival in female her-2 positive early stage breast cancer patients. we examined whether obesity had an influence on the recurrences of her-2 positive patients, as related to adjuvant trastuzumab treatment, retrospectively. materials and methods: among her-2 positive 170 patients, 129 had accessible data, and with 114, recorded weight / height measurements were statistically analyzed. results: of these, the body mass index (bmi) was <30 kg/m2 in 68 (60%), and ≥30 kg/m2 in 46 (40%). recurrence-free survival (rfs) was 8.8 ± 6.5 and 78.09 ± 12.43 months in the groups with low and high bmi, respectively (p=0.32). recurrences were found in 7 of 95 (7.4%) receiving trastuzumab and 13 of 34 patients (38.2%) not receiving. the difference was significant (p<0.001). we detected that 53 patients have a carcinoma insitu on the pathological report (32 patients were bmi<30 kg/ m2 group and 21 patients were bmi ≥ 30 kg/m2 group). cox regression analysis showed that only presence of carcinoma in situ was significant for pfs, in the population of the study, hr 0.44 (95% ci 1.05-34.28, p=0.044). there was a significant relationship favoring trastuzumab treatment between size of tumor (p=0.04) and hormone receptor positivity with rfs (p =0.002). moreover, in the hormone receptor negative group, the risk of recurrence was 7.6 folds in the absence of trastuzumab treatment. median follow-up was 24 months (range 3-257) and recurrence was found in 20 patients (15.5 %). five patients died during follow-up. presence of carcinoma-in-situ and use of trastuzumab had influenced rfs in the population of the study. rate of hormone receptor negativity was higher and rfs was longer in obese patients than non-obese patients; however, the difference was not significant (p =0.659). conclusion: trastuzumab is effective in breast cancer patients to prevent the recurrence, particularly in hormone receptor negative patients.