Patterns of use and outcomes with irinotecan and oxaliplatin in the treatment of 5-fluorouracil (5-FU) refractory metastatic colorectal cancer: An Australian population based analysis

Abstract

3630 Background: Randomised clinical trials have established an important role for oxaliplatin (O) and irinotecan (I) in the management of advanced colorectal cancer (CRC). However, patients (pts) enrolled in clinical studies represent a restricted population and little is known about the use of O and I in the general population and the subsequent outcomes outside clinical studies. We used the Australian Health Insurance Commission (HIC) database to describe prescribing patterns of O and I and their impact on survival in all patients with 5-FU refractory CRC in Australia in 2002 and 2003. Methods: The Australian HIC database was searched to identify all patients with 5-FU refractory CRC who received initial treatment with either O or I in 2002 and 2003. Survival of patients was determined based on subsequent receipt of any other prescriptions for other medication identified in the HIC database. Results: 2999 patients received initial treatment with O or I in Australia in 2002 and 2003. 62% of pts were male and 23% and 2% were aged ≥70 years and ≥80 years respectively. There was a marked increase in initial treatment with O rather than I; 48% of pts received O first in 2002 versus 66% in 2003 (p<0.001). Overall 40–45% of pts received both O and I, however younger pts were more likely to receive both drugs (p<0.001). After 5-FU failure and treatment with O or I, estimated 6-month and 12-month survival was 0.67 (95% CI 0.66–0.69) and 0.42 (95% CI 0.40–0.44) respectively. Six and twelve month survival was superior for pts who received both O and I, however the sequence of O and I had no impact on survival. Survival of older pts (≥70 years) was inferior to younger pts no matter whether O or I was used as initial treatment. Conclusions: Analysis of the Australian HIC database provides a valuable means of assessing patterns of use and outcomes of new therapies. This type of analysis could also be used to evaluate other new agents. [Table: see text]