Measurement of chemoresistance markers in patients with stage iii non–small cell lung cancer: a novel approach for patient selection

Background The long-term survival of patients with stage III non–small cell lung cancer treated with a combination of chemotherapy and radiation is 10% to 20%. Survival could potentially be increased and toxicity limited if one could identify patients most likely to respond to a particular treatment regimen. This project prospectively evaluated a panel of potential immunohistochemical markers of chemoresistance in a population of patients with pathology-confirmed stage III non–small cell lung cancer in order to determine the prognostic value of each marker in relation to response to chemotherapy or survival. Methods Immunohistochemical staining was performed on histologically positive mediastinal nodal specimens obtained from 59 patients (mean age, 62 years; range, 41 to 79 years) without evidence of distant metastatic disease treated with navelbine-based chemotherapy and external beam radiation therapy between 1996 and 2001. Included were markers for apoptosis (p53, bcl-2), drug efflux/degradation (MDR, GST-π), growth factors (EGFr, Her2-neu), and mismatch repair (hMLH1, hMSH2). After chemotherapy, patients underwent radiologic evaluation for response measured by standard criteria. Results After a median 41 months of follow-up (range, 17 to 55 months), 43 patients had recurrent disease and 38 of these patients were dead of cancer (median cancer-free survival of 10 months and overall survival of 18 months). Patients who demonstrated a complete or partial response (n = 38) had a significantly improved survival (p = 0.002) compared with those with stable or progressive cancer (n = 21). Multivariable Cox step-wise regression analysis of marker expression associated overexpression of p53 and low expression of hMSH2 with poor treatment response and cancer death. Conclusions These preliminary data suggest that marker expression may allow the separation of patients into low- and high-risk groups with respect to survival after combined navelbine-based chemotherapy and XRT. This could represent a novel method of selecting patients for a particular treatment regimen if these data are reproduced in a larger prospective trial.