The effect of HER2 expression on cisplatin-based chemotherapy in advanced non-small cell lung cancer patients.

Introduction: The prognostic value of HER2 expression in patients with advanced non-small cell lung cancer remains controversial. The relationship between HER2 expression, and platinum resistance and patient survival, was investigated.

Methods: Seventy-three consecutive patients (median age, 61 years) with stage IIIB and IV non-small cell lung cancer, admitted between February 2004 and December 2006, were included in this study. Sixty-one patients received gemcitabine, given as two 1250 mg/m2 doses on days 1 and 8 and, cisplatin, given as a 75 mg/m2 dose on day 8. Twelve patients received vinorelbine, given as two 25 mg/m2 doses on day 1 and 8, and cisplatin, given as a 75 mg/m2 dose on day 1. Both treatment paradigms were repeated on a 21-day cycle. Tumor response was evaluated by comparing tumor size on computerized tomography scans before and after three cycles of chemotherapy. HER2 status was examined by immunohistochemical analysis of paraffin-embedded specimens.

Results: HER2 was positive in 21 of 73 patients (28.8%). Of the 21 patients with HER2 positivity, 13 (61.9%) responded to chemotherapy with either a complete response, partial remission, or evidence of stable disease. Of 52 HER2-negative patients, 48 (92.3%) exhibited a response to chemotherapy. The difference in response to therapy between HER2-positive and -negative patients was statistically significant (p = 0.003). The median overall survival duration for all patients was 13 months. Median overall survival time was 14 months for HER2-negative patients and 10 months for HER2-positive patients (log-rank p = 0.007).

Conclusion: Non-small cell lung cancer patients with high expression of HER2 exhibited resistance to cisplatin-based chemotherapies that are the standard treatment for this disease. Our results indicate that HER2 status may be a predictive and prognostic factor for cisplatin- based therapy response and disease survival.