The aim of this study was to compare the diagnostic efficacy of colposcopic-directed biopsy and four-quadrant biopsy in detecting high-grade cervical intra-epithelial neoplasia (CIN). Women attending three women's clinics for routine cervical screening were recruited. Colposcopy was arranged for women with any cytologic abnormalities greater than atypical squamous cells of undetermined significance (ASCUS), two consecutive ASCUS results or positive HPV testing. During colposcopy, a cervical biopsy was taken from the most suspicious area, but more than one biopsy was allowed. Four-quadrant biopsies at 3, 6, 9 and 12 o'clock and an endocervical curettage were also taken in all cases. A total of 1522 colposcopies were performed in 1311 subjects from June 2010 to August 2017, with 118 cases of high-grade CIN diagnosed. Colposcopic-directed biopsy detected 50.8% of the 118 high-grade CIN, while four-quadrant biopsy detected 86.4% (p < 0.0001). Twenty-seven cases (22.9%) of high-grade CIN were diagnosed in women with normal or unsatisfactory colposcopy. Among the 64 cases with low-grade colposcopic impression, four-quadrant biopsy detected significantly more high-grade CIN (53 cases, 82.8%) than colposcopic-directed biopsy (35 cases, 56.3%) (p = 0.0011). Four-quadrant cervical biopsies should be considered for all women with an abnormal smear or positive HPV testing, especially in patients with low-grade/normal/unsatisfactory colposcopy.
Keywords: cervical intra-epithelial neoplasia; colposcopy; random cervical biopsy.