Surveillance following primary breast cancer therapy: The impact of HMOs

Background: In the US, over 230,000 new cases of breast cancer are diagnosed annually. Patients generally receive curative-intent treatment. Post-treatment surveillance is usually done. We have previously documented dramatic variation in surveillance intensity. The only surveillance modalities endorsed by ASCO for asymptomatic patients are office visit and mammogram. It is often believed that health maintenance organizations (HMOs) restrict test utilization. We measured the effect of HMO penetration rate on the known variation in post-treatment surveillance strategies. Methods: We surveyed the 3245 ASCO members who had indicated that breast carcinoma was their major clinical focus to determine their surveillance practices. We asked members to consider 4 idealized clinical vignettes and indicate their surveillance plan for each. A menu of 12 testing modalities was offered. Practice patterns were stratified in quartiles by HMO penetration rates (0-14%, 14-22%, 22-33%, 33-61%) in each physician's practice location. Repeated-measures ANOVA was used. Results: Of the ASCO members surveyed, 1012 responded; 915 were evaluable. The modalities most frequently recommended were office visit, liver function tests (LFTs), CBC, and diagnostic mammogram. There was significant variation (p<0.05) in the recommended frequency of utilization of diagnostic mammogram, but in no other modalities. For example, in year 1, diagnostic mammogram was recommended 1.9 ± 1.8 (mean ±SD) times for the 0-14% penetration rate cohort and 1.4 ± 1.3 times for the 33-61% cohort. Conclusions: We found little evidence that HMOs limit test utilization. The HMO penetration rate in the clinician's practice location cannot account for the known overall variation in surveillance strategies.