Predicting toxicities from adjuvant treatment in a population-based cohort of early colon cancer (CC) patients (pts): A strategy to improve use of curative chemotherapy.

Abstract

412 Background: CC pts treated with chemotherapy are at risk of experiencing a number of toxicities. The identification of pts who may be at a higher risk of developing toxicities allows clinicians to be more vigilant in preventing and managing side effects early, thus enabling more optimal delivery of chemotherapy. Our aim was to determine clinical factors associated with toxicities from adjuvant FOLFOX in early CC. Methods: Pts diagnosed with stage III CC from 2005 to 2008, seen at any 1 of 5 regional cancer centers of the British Columbia Cancer Agency, and treated with adjuvant FOLFOX chemotherapy were reviewed. We evaluated various toxicities, including gastrointestinal, hematologic, cardiovascular, and neurological side effects. Baseline and clinical factors were assessed in univariate and multivariate models to determine potential predictors for each of the different chemotherapy toxicities. Results: In total, 475 pts were included: median age was 62 years (range 26-89), 16.2% were aged >70 years, and 54.5% were men. In terms of function, the majority (90.1%) was ECOG 0/1. Time to adjuvant chemotherapy (TTAC) >8 weeks (OR 1.91, 95% CI 1.8-3.1, p=0.006) and renal dysfunction with a GFR <50 (OR 1.69, 95% CI 1.1-2.6, p=0.0038) were significantly associated with higher odds of any GI toxicity. Likewise, TTAC >8weeks (OR 2.8, 95% CI 1.5-5.2, p=0.002), ECOG PS >1 (OR 2.86, 95% CI 1.2-6.7, p=0.016), and low white blood cell count <6.4 (OR 2.32, 95% CI 1.3-4.0, p=0.0043) were correlated with a greater risk of significant neutropenia. Multiple toxicities were more prevalent among those who waited >8 weeks to initiate adjuvant FOLFOX (OR 1.69, 95%CI 1.1-2.7, p=0.03). Further, advanced age >70 years was an indepenent risk factor for worse nausea and diarrhea. Conclusions: Consideration of important baseline characteristics such as TTAC, advanced age, renal function, and specific laboratory parameters when recommending adjuvant FOLFOX can be useful in identifying patients with increased likelihood of toxicities. This group of patients may benefit from increased monitoring in order to enable optimal doses of curative chemotherapy to be delivered.