Comparison of different adjuvant therapies for 9 resectable cancer types.

Purpose: The objective of this study was to compare the clinical benefit across adjuvant therapies for cancer treatment, including adjuvant imatinib, and to quantify the results using the number-needed-to-treat (NNT) approach. Method: We reviewed studies meeting the following criteria: 1) US and European randomized clinical trial populations consisting of patients with cancer who underwent surgical resection of the primary tumor and were considered cancer free; 2) comparators were either placebo or no treatment; and 3) recurrence-free survival (RFS) and overall survival (OS) rates were reported and showed benefit with the experimental treatment. The NNT was calculated as the inverse of the difference in event rate between the study groups in each trial. Results: We identified 26 adjuvant treatment trials in 9 cancer types. With longer follow-up (3 years vs 1 year), 62.5% of treatments compared with placebo showed a decreased RFS NNT, including imatinib (7 vs 4). The largest relative decrease in RFS NNT over time was 91% (with trastuzumab or cyclophosphamide therapy). Approximately 25% of the treatments resulted in an increase in RFS NNT over time. The RFS NNT for imatinib was lower than that for all other treatments at 3 years of follow-up and lower than that for all but 2 treatments at 1 year. At both year 1 and year 3, the NNT for OS ranged from 6 to 100. Imatinib had an OS NNT of 31 at 3 years. Conclusion: With longer follow-up duration, most adjuvant cancer treatments showed a decreased NNT. Imatinib had one of the lowest NNTs among the adjuvant treatments at 1 and 3 years of follow-up using the RFS data.