INCIDENCE OF INVASIVE CERVICAL-CANCER PRECEDED BY NEGATIVE SCREENING IN HIGH-RISK ALASKA NATIVE WOMEN

Background. Alaska Native women experience higher invasive cervical ca ncer incidence and mortality rates than US whites despite a long-stand ing cancer screening programme including recommendations for annual Pa p smears. Methods. To determine the frequency and results of cytologic al screening preceding their diagnoses, a histological and medical rec ord review was completed for 44 of 46 Alaska Native cases of invasive cervical cancer from a defined population. An interval cancer (no prio r dysplasia and a negative screening report within 3 years of diagnosi s) was determined for 23 women. Mean number of negative reports during the 3- and 5-year intervals before diagnosis was 1.7 and 2.6 respecti vely. The age-adjusted incidence rate for all cervical cancer was 24.0 /100 000 women/year and for interval cancer with single and multiple n egative reports during the 3-year interval before diagnosis it was 11. 6, and 9.6 respectively. Sensitivity of a Pap smear to demonstrate dys plasia during the year before diagnosis was 51%. Conclusions. Annual c ytological screening of all Alaska Native women with current methods w ould provide earlier diagnoses for only an additional 15% of cervical cancer cases. Plausible but unproven explanations include rapid progre ssion through precursor stages of neoplasia or random screening errors . Improved or ancillary screening methods appear necessary.