Optimal duration of chemotherapy (CT) for advanced non-small cell lung cancer (NSCLC) in the first- and second-line settings

Abstract

e19037 Background: No difference in efficacy has been observed between 3 or 4 vs 6 cycles of 1st line CT in patients (pts) with advanced NSCLC. Although longer treatment may improve progression-free survival, this must be weighed against increased toxicity and potential for worse quality of life. There are no prospective, randomized data on the optimal duration of 2nd line CT. The aims of this retrospective study were to (i) confirm the lack of impact of treatment duration on response rate in 1st line NSCLC and (ii) investigate the impact of treatment duration in the 2nd line setting. Methods: Eligible pts had received at least 4 cycles of 1st line (n=95) or 2nd line (n=55) CT for stage IIIB/IV NSCLC in clinical trials of the ATOM group, Udine, Italy, or the National Cancer Institute, Genoa, Italy and achieved stable disease or responded to treatment; trials included one in the elderly, and the addition of biological agents to CT. Response was assessed according to RECIST after alternate CT cycles and tumor dimensions recorded. The proportion of pts achieving a complete or partial response, as well as its timing and any subsequent tumor shrinkage, were analyzed by treatment line. Results: In the 1st line setting, 48 of 95 pts responded; they did so after 2 (29 pts, 61%), 4 (15 pts, 31%) and 6 cycles (4 pts, 8%). In these pts, 16 (55%) and 9 (41%) pts who had responded by the 2nd and 4th cycle respectively and continued on treatment showed further tumor shrinkage; the median further reduction in tumor size was 16% (range 1–52%) and 6% (range 1–11%), respectively. In the 2nd line setting, 12 of 55 pts responded; they did so after 2 (3 pts, 25%), 4 (7 pts, 58%), and 6 cycles (2 pts, 17%). One and two pts who had responded by the 2nd and 4th cycle respectively and continued on treatment showed further tumor shrinkage of 25%, 5% and 24%, respectively. Conclusions: Approximately 90% of CT-naive pts who responded did so by the 4th cycle; most such pts achieved only minor tumor reduction with further CT and did so at the likely expense of increased toxicity. In the 2nd line setting the achievement of response appeared slower. These results support the discontinuation of 1st CT after 4 cycles and suggest the same is true for 2nd line CT. No significant financial relationships to disclose.