Adjuvant chemotherapy for stage II and stage III colon cancer—What is happening in routine practice?

Abstract

e15046 Background: Randomised studies have defined adjuvant chemotherapy as standard treatment for stage III colon cancer (SIIICC), with multiple options available. For stage II (SII) disease, the selection of patients for adjuvant treatment remains controversial. There remains limited data on clinician decision making regarding adjuvant chemotherapy in routine clinical practice. Methods: A review of patients treated with SII & IIICC at 4 hospitals, utilising data from BioGrid Australia, where clinician choice and rationale were prospectively documented. Results: 372 patients (37%) with SII and 307 (30%) with SIIICC were identified from 1015 CC patients treated from January 2003 till November 2008. Median age was 68 years, 51% were male; 49% female. 66 (25%) of patients with SIIICC were not offered chemotherapy, predominantly due to advanced age or co-morbidity. Since oxaliplatin and capecitabine became widely available in 2005, 66% of treated patients have received oxaliplatin based therapy, 15% bolus 5-FU alone and 19% capecitabine. For SII disease, overall 81 (26%) pts received adjuvant chemotherapy. Age was the dominant influence on treatment choice with 41% aged 70 (p<0.001) receiving treatment. Patients with high risk features were also more likely to receive adjuvant therapy. (p= 0.006 for those with lymphovascular invasion and p= 0.0068 for those with T4 tumours). Dose reductions and completion rates were similar for SII and III disease, and for older and younger patients. Conclusions: Over 25% of patients with SIIICC do not receive adjuvant chemotherapy in routine practice, with physicians basing non-treatment recommendations predominantly on patient age and co-morbidity. Where treatment is used, oxaliplatin-based therapy is the dominant regimen, except in older patients. In SIICC, adjuvant chemotherapy is used in one in four patients, more frequently in younger patients and those with high risk features. No significant financial relationships to disclose.