3564 Background: We have previously suggested that treatment related toxicity has impact on physical quality of life (QOL) scores, as opposed to global QOL. Moreover, the cumulative effect of experienced toxicities, including low-grades AEs, may be of more importance. The purpose of this observational cohort study was to evaluate the association between cumulative toxicity and physical and global QOL in patients with metastatic colorectal cancer (mCRC) receiving chemotherapy. Methods: 105 patients with mCRC starting first line chemotherapy were evaluated. All patients completed the EORTC-QLQ-C30 questionnaire at baseline and after 10 weeks. Toxicity, clinical outcomes and demographics were retrieved from patient records. For each patient, we calculated cumulative toxicity in three different ways: i) total number of adverse events (AEs) (all grades), ii) total number of grade 3-4 AEs, and iii) total number of AEs multiplied by their grade. The relation between each cumulative toxicity score and QOL assessed at 10 weeks, was studied. Results: The mean age of patients was 64.8 ± 9.7 years, 70.5% were male, and 83.8% received first line oxaliplatin based combination chemotherapy. AEs occurred in 98.1% of patients, grade 3-4 AEs in 37.1%, and grade 1-2 AEs in 61.0%. The mean number of experienced AEs (all grades) was 5.3 ± 2.7. The most common toxicities included diarrhea, neuropathy and fatigue. None of the toxicity scores was related to global QOL outcome. A higher total number of all grades AEs (β = - 2.2, 95%CI = -3.7; -6.6) and total number of AEs multiplied by grade (β = -1.3, 95%CI = -2.2; -3.5) were significantly associated with worse physical QOL. Conclusions: Cumulative toxicity, defined as the total of all grades AEs, significantly affects physical QOL in patients with mCRC receiving first line chemotherapy. Improvement of treatment related toxicity management by reducing the total number of AEs, may result in relevant improvements in patients’ QOL. Our results emphasize that future RCTs should present physical QOL outcomes instead of global QOL, as well as all grades and total number of toxicities for individual patients.
The predictive value of cumulative toxicity for quality of life in patients with metastatic colorectal cancer during first-line palliative chemotherapy