Background: Screening using fecal occult blood testing (FOBt) reduces colorectal cancer mortality, but the test has low sensitivity. A "missed" cancer may cause psychologic harms in the screened population that partially counteract the benefits of early detection.
Methods: Three hundred and eleven people diagnosed with colorectal cancer (i) after a negative FOBt result (interval cancer), (ii) a positive result (screen-detected cancer), or (iii) in regions where screening was not offered, completed questions on quality of life (FACT-C), depression (CES-D), perceived diagnostic delay, and trust in the results of FOBt screening. Fifteen withheld consent to data matching with medical records, leaving a sample size of 296.
Results: Controlling for demographic and clinical variables, patients with an interval cancer reported poorer quality of life (difference in means = 6.16, P = 0.03) and more diagnostic delay (OR, 0.37; P = 0.02) than patients with screen-detected disease, with no differences in depression. No differences were observed between the interval cancer group and the group not offered screening on these measures. Patients with an interval cancer reported the lowest levels of trust in FOBt.
Conclusions: An interval cancer has adverse effects on trust in FOBt, but does not result in worse psychologic outcomes compared with people diagnosed in areas with no screening program. People with an interval cancer report poorer quality of life than people with screen-detected disease.
Impact: Improvements in test sensitivity could improve quality of life among people who complete an FOB test over and above any benefits already conferred by earlier detection. Cancer Epidemiol Biomarkers Prev; 24(7); 1032-8. ©2015 AACR.