Long-term results from a randomized controlled trial to increase cancer screening among attendees of community health...

We assessed whether increased cancer screening rates that were observed with Cancer Screening Office Systems (Cancer SOS) could be maintained at 24 months' follow-up, a period in which clinics were expected to be largely self-sufficient in maintaining the intervention.

Eight primary care clinics serving disadvantaged populations in Hills-borough County, Fla, agreed to take part in a cluster-randomized experimental trial. Charts of independent samples of established patients aged 50 to 75 years were abstracted, with data collected at baseline (n = 1,196) and at 24 months' follow-up (n = 1,296). Papanicolaou (Pap) smears, mammography, and fecal occult blood testing were assessed.

At 24 months of follow-up, intervention patients had received a greater number of cancer screening tests (mean 1.17 tests vs 0.94 tests, t test = 4.42, P <.0001). In multivariate analysis that controlled for baseline screening rates, secular trends, and other patient and clinic characteristics, the intervention increased the odds of mammograms slightly (odds ratio [OR]) = 1.26; 95% confidence interval [CI], 1.02-1.55; P = .03) but had no effect on fecal occult blood tests (OR = 1.17; 95% CI, 0.92-1.48; P =0.19) or Pap smears (OR = 0.88; 95% CI, 0.0.68-1.15; P = .34).

The Cancer SOS intervention had persistent, although modest, effects on screening at 24 months' follow-up, an effect that had clearly diminished from results reported at 12 months' follow-up. Further study is needed to develop successful intervention strategies that are either self-sustaining or that are able to produce long-term changes in screening behavior.