Background: Information about the impact of cancer treatments on patients’ quality of life (QoL) is of paramount importance to patients, treating physicians, and policy makers. Although cancer specific and validated QoL instruments exist, reports of randomized clinical trials (RCTs) involving cancer patients often do not include QoL outcomes; instead, they typically focus on survival or tumor size as their primary outcome. Possible reasons for lack of QoL outcomes include failure to collect QoL outcomes and failure to publish collected QoL outcome data.
Objectives: To investigate whether QoL outcomes were specified in protocols of industry- or investigator-initiated RCTs enrolling cancer patients, and whether they were subsequently reported.
Methods: We conducted a retrospective cohort study of RCT protocols approved by six research ethics committees in Switzerland, Germany, and Canada between 2000 and 2003 and compared 173 protocols of cancer trials to 108 corresponding publications that we identified through literature searches and investigator surveys.
Results: Of the 173 RCTs, 90 (52%) specified QoL outcomes in their protocol, two (1%) as primary and 88 (51%) as secondary outcomes; 35 (20%) reported QoL outcomes in a corresponding publication (four modified from the protocol), 37 (21%) remained unpublished, and 18 (10%) were published but failed to report QoL outcomes. Failure to report QoL outcomes was not significantly associated with sponsorship, sample size, single center status, or trial discontinuation. None of the 83 (48%) RCTs that did not specify a QoL outcome in their protocol subsequently reported a QoL outcome.
Conclusions: About half of cancer RCTs specified QoL outcomes in their protocols. However, only 20% reported any QoL data in associated publications. Highly relevant information for decision-making is not available to patients, physicians, systematic reviewers, and policy makers. If published, QoL outcomes in cancer trials are prone to selective reporting.