Measuring the side effects of taxane therapy in oncology

BACKGROUND: Cancer chemotherapy with some of the taxane class of agents can be associated with significant neurotoxicity, arthralgias, myalgias, and skin changes that may offset the therapeutic benefits of taxane use. METHODS: The authors developed and tested a set of questions to assess these important side effects of taxane therapy from the patient's perspective. The current study evaluated the taxane subscale of the Functional Assessment of Chronic Illness Therapy (FACIT) measurement system. Reliability, validity, and responsiveness to expected change were evaluated in the context of an ongoing clinical trial comparing four cycles of carboplatin plus paclitaxel with a strategy of carboplatin plus paclitaxel until disease progression in patients with advanced nonsmall cell lung carcinoma (NSCLC). RESULTS: The 16-item Taxane subscale score and the 11-item peripheral neuropathy subset both demonstrated excellent internal consistency and concurrent validity, and the scores worsened as one would predict during a 12-week treatment course of taxane therapy. Results of the psychometric analyses supported the use of this subscale for measuring the unwanted adverse consequences of effective cancer therapies. Measuring the patient perception of treatment side effects also allowed a preliminary exploration of the relative quality of life (QOL) impact of symptom relief and treatment toxicity. The results indicated that toxicity and symptom improvement may make relatively equivalent contributions to total QOL as measured by the summary score from a multidimensional QOL instrument, the Functional Assessment of Cancer Therapy-General. However, symptom status and improvement appear to play a stronger role than taxane toxicity in patients' global rating of their QOL. CONCLUSIONS: Future research might examine this question of competing benefits as a potential aid to decision-making regarding the administration of toxic therapies in the setting of advanced disease.