Complementary procedures in cervical cancer screening in low resource settings

To evaluate the efficacy of pap smear, HPV DNA testing and colposcopy and to determine the approach for cervical cancer screening in low resource settings.

Eight hundred non pregnant married women above 30 years of age were studied and subjected to pap smear examination. Hysterectomised women were excluded from the study. Selected patients were followed by HPV DNA testing by Hybrid Capture II method, colposcopy and biopsy. Sensitivity, specificity, Positive predictive value (PPV), Negative predictive value (NPV), diagnostic accuracy and kappa value (k) were calculated for each screening test.

Out of eight hundred women with mean age 36.5 ± 5.94 years undergoing pap smear, ASCUS was found in 66(8.25%), ASC-H in 2(0.25%), LSIL in 48(6%), HSIL in 8(1%), inflammatory in 540(67.5%). Out of 260 women who underwent HPV DNA testing, 120 (46.15%) had abnormal cytology and/or positive HPV DNA test (Group I, n = 120) and 140(53.8%) had dual negative results (Group II, n = 140) HPV DNA test was found positive in 64 women (53.3%) in Group I. Sensitivity and specificity of pap smear was 69.2 and 63.72% while for HPV DNA testing was 92.3 and 84% respectively. PPV and NPV of pap smear, HPV DNA testing and colposcopy was 18, 40, 76.4% and 94.7, 98.9, 100% respectively. Diagnostic accuracy of pap smear (k = 0.14), HPV DNA test (k = 0.70) and colposcopy (k = 0.81) was 64.29, 84.9, and 96.8% respectively. Combining pap smear & HPV DNA testing (k = 0.25) increased the sensitivity and NPV to 100%.

Sensitivity and diagnostic accuracy of HPV DNA test is more than that of pap smear and the test is not influenced by inflammatory conditions of vagina. In low resource settings, women with ASCUS and LSIL on cervical cytology should be subjected to HPV DNA test and only if found positive should be referred for colposcopy thereby reducing colposcopy referrals. Women with HSIL should be directly subjected to colposcopy guided biopsy. Using this approach, most of the preinvasive cervical lesion will be detected but few cases will still be missed among inflammatory smears, if HPV DNA testing is not supplemented.