Colorectal cancer: to screen or not to screen

A US study makes the economic case. There are
savings -- in lives and dollars -- but it's not open and shut

By SH Cyr

Opponents of cancer screening don't deny that it can save lives --they only doubt whether it's a cost-effective way of doing so. That argument might sound callous, except that every health dollar spent on screening means one dollar less for treatment. At the end of the day, wasted money means wasted lives.

So proponents of screening must do more than just prove that they can detect early cancers. They also have to show that their approach gives better value for money by permitting lives to be saved at less expense. That is what the Fred Hutchinson Cancer Research Center in Seattle set out to do in a study published in the journal Gastroenterology.

The researchers retrospectively analysed the diagnosis and treatment of 923 people diagnosed with colorectal cancer from 1993 to 1999 in the Group Health Cooperative, a large health maintenance organization in Washington state. They compared the total healthcare costs of symptomless patients diagnosed by screening to the costs of those who were diagnosed after reporting symptoms. Costs accrued in the three months before final diagnosis of each patient were considered as diagnosis costs, while expenditure over the following 12 months was considered to be treatment cost.

Unsurprisingly, patients whose tumours were detected by screening had, on average, less advanced disease at diagnosis. Of the 206 patients whose cancer first showed up in screening, 53% had either Dukes' stage A (limited to the bowel wall) or in-situ tumours. Of the 717 patients who presented with symptoms, only 30% fell into this category.

Diagnostic costs were significantly lower for the screening-detected group, whose HMO spent an average $7,302 US on them in the three months prior to diagnosis, than for the symptomatic group, whose average health costs were $10,261 US over the same period. The savings were greatest in patients with stage B disease and those aged over 65.

Over the 12 months following diagnosis, the HMO spent an average of $23,344 US on treating patients in the screening-detected group and an average of $29,384 US treating patients in the symptom-detected group. These savings were restricted to patients with stage A cancers.

The overall cost difference between the two patient groups led the authors to conclude that an aggressive screening program could have saved the HMO about $3 million US over the seven years of the study. "Our analysis thus suggests that health plans that invest in screening programs will realize cost savings from reduced diagnosis costs, from moving persons to earlier stages at diagnosis and somewhat from reducing costs within stages at diagnosis," they wrote.

Dr Scott Ramsey, who led the study, said colorectal cancer screening gives better value for money than other less controversial medical interventions like transplants, treating mild cholesterol elevation in people with few risk factors or screening for and treating osteoporosis. "Screening has economic as well as clinical benefits," he said. "There is a business case for screening."