Reported rates of surgery in the management of colon and rectal cancer vary, particularly in metastatic disease where reported surgery rates vary from 47% to 88% of all patients presenting with metastatic colon or rectal cancer. This variation highlights the need for a benchmark rate of optimal surgical utilisation to aid in planning and evaluation of surgical services.
To estimate, using the best available evidence, the optimal proportion of new cases of all registered colorectal cancer in Australia that should undergo surgery to treat either the cancer or its complications at least once at some time during the course of their illness.
Models of optimal surgical utilisation for colon and rectal cancer were constructed based on indications for surgery recommended by treatment guidelines. Epidemiological data were identified for each surgical indication. TreeAge software was used to construct the model and to calculate the optimal surgical utilisation rate. Univariate sensitivity analysis assessed the effect of uncertainty in surgical indications or in epidemiological data on the optimal utilisation rate.
The model indicates that surgery is recommended in 86% of all colon cancer patients and 89% of all rectal cancer patients. This rate does not include repeated indications for surgery. There is uncertainty regarding the benefit of surgery for an asymptomatic primary in patients presenting with unresectable metastases; if this indication is included in the model then the optimal surgery utilisation rate rises to 99% for both colon cancer and rectal cancer. International population-based data have shown a trend over time towards declining primary resections in patients with metastatic disease, with recent data from the Netherlands approaching the optimal rate calculated in our model.
Optimal surgical utilisation rates can serve as benchmarks to assess the demand for surgery and to plan and assess surgical service provision.