An Evidence-Based Estimation of Local Control and Survival Benefit of Radiotherapy for Colorectal Cancer (#233)
Evidence-based radiotherapy utilisation benchmark models1-2 have been used as the basis for planning radiotherapy services both nationally and internationally. These models have been further expanded to estimate the benefit of each radiotherapy indication in individual cancer sites3.
Our study aimed at estimating the benefit of definitive or adjuvant radiotherapy to overall survival and local control of colorectal cancer patients if the entire cancer population are treated according to evidence-based treatment guidelines.
The optimal radiotherapy utilization model previously reported for colon and rectal cancers was extended to incorporate overall survival and local control benefit from radiotherapy (radiotherapy vs no radiotherapy, radiotherapy and concurrent chemotherapy vs radiotherapy alone) from published research data (1990-2013). Palliative benefits were not considered.
There were no adjuvant radiotherapy indications recommended for colon cancer and therefore not included in the model. For rectal cancer, the overall gains in 5-year local control and survival were 10% (95% CI 7.0%-13.0%) and 4% (95% CI 0.1%-9.6%) for radiotherapy alone and an additional 6% (95% CI 3.0%-10.0%) and 2% (95% CI 0.0%-3.5%) for radiotherapy with concurrent chemotherapy to bring the total benefit to 16% and 6% respectively. The highest local control (26%) and survival (9%) benefits of adjuvant radiotherapy were for locally advanced resectable rectal cancers (level I evidence).
Our model predicted that if evidence-based guidelines were applied for all rectal cancer population, radiotherapy treatment could prevent 800 local recurrences and save 300 extra lives per 5000 cases (approximate yearly incidence in Australia) of rectal cancer for up to 5 years. Such policy driven evidence-based research would facilitate planning of efficient, equitable radiotherapy services at the population level with a projected estimate of demand and outcome.
1Barton M et al, CCORE, Ingham Institute 2013.
2Delaney G et al, Cancer 2005(104):1029-37.
3 Shafiq J et al, Radiotherapy and Oncology 2007(84):11-17.