Are chemotherapy response rates related to treatment-induced survival prolongations in patients with advanced cancer?

Purpose: Patients with incurable cancer are faced with difficult decisions regarding whether to take chemotherapy in an attempt to preserve the quality and/or prolong the quantity of their lives. The average prolongation in survival with chemotherapy compared with best supportive care has not been well described. Methods: We performed a literature search using PUBMED combined with expert inquiry to identify trials comparing cytotoxic chemotherapy with best supportive care. Twenty-five randomized, controlled clinical trials comparing cytotoxic chemotherapy with best supportive care were identified. Sixteen trials (64%) were in patients with non-small-cell lung cancer (NSCLC). Data were extracted and analyzed. Results: Sufficient data for statistical modeling were available for NSCLC trials. The mean sample size of the NSCLC trials was 175 patients. Response rates in the treatment arms for NSCLC ranged from 7% to 42%. A relationship between response rate and survival was observed for NSCLC. The estimated relationship for NSCLC suggested that each 3.3% increase in response rate correlated, on average, with a 1-week increase in median survival, and each 2% increase in response rate correlated, on average, with a 1% increase in 1-year survival. The mean increase in 1-year survival for trials of agents with at least a 20% response rate in NSCLC was 16%. Formulas are provided to help estimate how a given response rate may effect median and 1-year survival relative to best supportive care alone for NSCLC. Conclusion: We found a relationship between response rate and both median and 1-year survival in NSCLC. This information may help oncologists estimate how an NSCLC chemotherapy regimen with a given response rate can, on average, impact survival relative to supportive care alone.