Evaluating the Utility of a 'N-of-1' Precision Cancer Medicine Strategy: The Case for 'Time-to-Subsequent-Disease Progression'

It is increasingly recognized that cancer is a highly heterogeneous group of illnesses even within a particular organ site (e.g., breast, lung, colon, etc.). This observation presents a serious challenge to the traditional concept of phase 3 randomized trials designed to define therapeutic efficacy of a novel treatment strategy. For while 10% of the patients with a common malignancy (e.g., non-small-cell lung cancer) may be sufficient to consider such an effort, enrolling a sufficient number of patients into a clinical trial in a timely manner to define clinical utility would be extremely difficult if the population in question represented only 1% of this population, and essentially impossible if one wished to explore the benefits of treatment in a rarer neoplasm (e.g. ovarian cancer). Therefore, in the new era of precision cancer medicine, alternative research designs are imperative. One option would be to compare the time-to-disease progression of an individual cancer patient following treatment with a novel therapeutic to the time-to-disease progression for that specific patient on her/his immediately preceding treatment. The rationale for this strategy and early experience with this innovative approach to evaluating the efficacy of anticancer therapy is highlighted in this report. (C) 2016 S. Karger AG, Basel.