Relationship Between Tumor Response and Tumor-Related Symptoms in RAS Wild-Type Metastatic Colorectal Cancer: Retrospective Analyses From 3 Panitumumab Trials
Abstract Background There is no standardised assessment of symptomatic events in metastatic colorectal cancer (mCRC), despite disease symptoms impacting treatment decisions. Data from 3 first-line panitumumab in mCRC trials were retrospectively analysed to assess whether early tumour shrinkage (ETS) and depth of response (DpR) are associated with time to occurrence of tumour-related symptoms. Patients and Methods Patients with RAS wild-type mCRC from PRIME, PEAK and study ‘314 were included. ETS was defined as a reduction of ≥ 30% in the sum-of-the-longest-diameters of lesions at 8 weeks. DpR was calculated as maximum percentage change in tumour size from baseline to nadir. The proportion of patients who developed symptoms (including a composite symptomatic endpoint) during study treatment was calculated. Results Overall, 659 patients were analysed. Onset of symptoms was delayed in patients with ETS ≥ 30% versus ETS Conclusion Both ETS and DpR were associated with delayed onset of symptoms in RAS wild-type mCRC patients. Treatments with high cytoreductive potential may delay symptom development. ClinicalTrials.gov Identifiers PRIME NCT00364013; PEAK NCT00819780; study ‘314 NCT00508404.