We examine whether induction chemotherapy response predicts thoracic radiotherapy response in locally advanced or oligometastatic non–small cell lung cancer.
Between January 2001 to August 2010, 25 consecutive patients were identified who received systemic dose chemotherapy followed by definitive thoracic radiotherapy alone. All patients had measurable disease after chemotherapy that was evaluable for response to radiotherapy. Response to each modality was scored by RECIST as stable disease (SD), progressive disease (PD), partial response (PR), or complete response (CR).
Patients had adenocarcinoma (n=13), squamous cell carcinoma (n=8), or other histologies (n=4). They had stage IIIA (n=6), IIIB (n=14), and IV (n=5) disease. Patients received 2 to 6 cycles (median 4) of platinum-based chemotherapy followed by radiotherapy (median 66.6/1.8 Gy [range 50 to 84 Gy]). Median time between chemotherapy end and radiotherapy start was 6.7 weeks (range, 1.6 to 53.4 wk). Twelve patients responded to chemotherapy (all were PRs) and 13 did not (SD+PD). Fifteen patients responded to radiotherapy (7 CR, 8 PR) and 10 did not (SD+PD). Of the 12 patients who responded to chemotherapy, 8 also responded to radiotherapy (4 CR, 4 PR). Of the 13 chemotherapy nonresponders, 7 responded to radiotherapy (3 CR, 4 PR). χ2 analysis did not find any association between chemotherapy and radiotherapy response (P=0.513). Regression analysis also failed to identify any correlation between chemotherapy and radiotherapy response (r 2=0.008).
This study suggests that response to chemotherapy does not predict response to radiotherapy in locally advanced or oligometastatic non–small cell lung cancer. Lack of response to chemotherapy, therefore, should not preclude treatment with definitive radiotherapy.
Perelman Center for Advanced Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA
Supported by Department of Radiation Oncology at the University of Pennsylvania School of Medicine. The department had a role in study design, the collection, analysis, and interpretation of data, the writing of the report, and the decision to submit the article for publication.
T.L.E. reports personal fees from Genentech, Lilly, and Celgene outside the submitted work. J.P.S. reports grants from Verastem, Merck, Boehringer Ingelheim, and Medimmune outside the submitted work. The remaining authors declare no conflicts of interest.
Reprints: Ramesh Rengan, MD, PhD, Department of Radiation Oncology, University of Washington, 1959 NE Pacific St, P.O. Box 356043, Seattle, WA 98195. E-mail: firstname.lastname@example.org.