Insulin-like growth factor-1, metabolic abnormalities, and pathological complete remission rate in HER2-positive breast cancer patients receiving neoadjuvant therapy.

HER2-positive breast cancer (BC) achieving pathological complete remission (pCR) after neoadjuvant therapy (NAT) had a superior disease outcome. Dysmetabolism and stimulation of insulin-like growth factor 1 (IGF-1)-axis would increase BC risk, but we are lacking data for their association with pCR in HER2-positive+ BC. We aim to evaluate the pCR predictive value of above factors in HER2-positive BC patients receiving NAT. HER2-positive BC patients receiving NAT ± trastuzumab were retrospectively included between January 2013 and December 2016. Data were compared between baseline at biopsy and surgery. Median value of IGF-1 expression was used as cutoff value to classify patients into low or high group. pCR was defined as no residual invasive carcinoma in breast and axilla. Overall, 101 patients were included. Metabolic syndrome was diagnosed in 29 (28.71%) with an average of 1.71±1.51 metabolic disorders at baseline, significantly increased after NAT (2.12±1.54, <0.001). Lipid metabolism factors, including triglycerides, TC, HDL-C and LDL-C significantly worsened after NAT (all <0.05). Average post-NAT IGF-1 was 196.14±86.03 ng/mL (vs preNAT 186.41±75.03 ng/mL, =0.182). pCR was achieved in 29 (28.71%) patients. pCR rate was 40.00% and 17.65% for those with low or high preIGF-1 level (=0.013). Multivariate analysis found that low IGF-1 expression, but not any other metabolic variable, was significantly associated with higher pCR rate in whole population (OR: 3.83, 95%CI: 1.32-11.11, =0.014) or in patients receiving NAT + trastuzumab (OR: 3.93, 95%CI: 1.13-13.63, =0.031). With a median follow-up of 29.03 (range: 10.42-56.98) months, IGF-1 level was not associated with overall survival (=0.328) or disease-free survival (=0.288). Low IGF-1 level was related with higher pCR rate in HER2-positive BC patients receiving NAT, which deserves further clinical evaluation.