Obesity is an independent prognostic factor of decreased pathological complete response to neoadjuvant chemotherapy in breast cancer patients.
OBJECTIVE
The relation between higher body mass index (BMI) and pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) in breast cancer (BC) is a controversial issue according to the data of Western and Asian patients. The aim of this study is to evaluate BMI and pCR to NAC and discuss the importance of pCR outcomes in Turkish BC patients as a bridging country between Europe and Asia.


METHODS
Of the 4423 BC patients diagnosed between the years 1994 and 2015 in Hacettepe University Cancer Institute, 295 female patients with stage II and III BC were enrolled in the study. Three different group divisions were done according to patients' BMI as normal or underweight (N/U) patients (BMI <25 kg/m2), overweight (OW) patients (BMI = 25-29.9 kg/m2) and obese (OB) patients (BMI ≥30 kg/m2). BC subtypes were defined as luminal-like (ER/PR-positive and HER2-negative), HER2/luminal (ER/PR-positive and HER2-positive), HER2-type (ER/PR-negative and HER2-positive), and triple-negative (TNBC; ER/PR- and HER2-negative). The analysis of overall survival (OS) and recurrence-free survival (RFS) was performed according to Kaplan-Meier method. The Log-rank test was used to compare the subgroup analysis and logistic regression analysis to determine the independent prognostic factors.


RESULTS
In this study, a total number of 93 (31.5%) patients were N/U, 107 (36.3%) patients were OW and 95 (32.2%) patients were OB. Among groups, except for the age, no baseline clinicopathological differences were found. In 70 (23.7%) patients, pCR was achieved. pCR rates in N/U, OW and OB were 31.2%, 22.4%, and 17.9% respectively, showing a considerable trend towards significance (P = 0.09 in chi-square test). In the multivariate logistic regression analysis, obesity was an independent adverse prognostic feature on pCR to NAC compared to N/U patients (OR, 0.34; 95% CI, 0.13 to 0.85, P = 0.02). The recurrence rates were slightly increased with the increase of BMI (N/U = 24.7%, OW = 29.0% and OB = 40%; P = 0.06 respectively). Median RFS was significantly higher in N/U group compared to OB patients (150 vs. 76 months respectively, P = 0.03) and was also higher in pCR group compared to non-pCR patients (151 vs. 77 months P = 0.004). Median OS was significantly higher in N/U patients compared to OB patients (N/U = not reached, OW = 211 and OB = 114 months; P = 0.01) and was also higher in pCR group compared to non-pCR patients (not reached vs. 211 months P = 0.04). In Cox regression analysis; pCR, histopathological grade and TNBC were found as independent prognostic factors on OS (HR, 0.29; 95% CI, 0.11 to 0.79, P = 0.015, HR, 2.09; 95% CI, 1.14 to 3.83, P = 0.017, HR, 1.95; 95% CI, 1.01 to 3.77, P = 0.046, respectively).


CONCLUSIONS
It was observed that obesity was an important independent prognostic factor which has an adverse effect on pCR. Moreover it causes decreasing RFS and OS in BC patients who had received NAC. The probability of inefficient treatment in obese patients should be considered.
Diskapi Yildirim Beyazit Education and Training Hospital, Department of Medical Oncology, Ankara, Turkey.
Fatih
F
Karatas
Ankara Numune Education and Training Hospital, Department of Medical Oncology, Ankara, Turkey.
Gokmen Umut
GU
Erdem
Diskapi Yildirim Beyazit Education and Training Hospital, Department of Medical Oncology, Ankara, Turkey.
Suleyman
S
Sahin
Gazi University Faculty of Medicine, Department of Medical Oncology, Ankara, Turkey.
Aydin
A
Aytekin
Hacettepe University Faculty of Medicine, Department of Preventive Oncology, Ankara, Turkey.
Deniz
D
Yuce
Hacettepe University Faculty of Medicine, Department of Radiology, Ankara, Turkey.
Ali R
AR
Sever
Hacettepe University Faculty of Medicine, Department of Medical Oncology, Ankara, Turkey.
Taner
T
Babacan
Hacettepe University Faculty of Medicine, Department of Medical Oncology, Ankara, Turkey.
Ozturk
O
Ates
Hacettepe University Faculty of Medicine, Department of Medical Oncology, Ankara, Turkey.
Yavuz
Y
Ozisik
Hacettepe University Faculty of Medicine, Department of Medical Oncology, Ankara, Turkey. Electronic address: altundag66@yahoo.com.
Kadri
K
Altundag
D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000150:complications / Q000188:drug therapy* / Q000473:pathology; D017024:Chemotherapy, Adjuvant / Q000401:mortality; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008875:Middle Aged; D015999:Multivariate Analysis; D020360:Neoadjuvant Therapy / Q000401:mortality*; D009364:Neoplasm Recurrence, Local / Q000401:mortality; D009367:Neoplasm Staging; D009765:Obesity / Q000150:complications*; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome; D014421:Turkey
Body mass index; Breast cancer; Neoadjuvant chemotherapy; Pathological complete response; Survival