S. A. Thiryayi, J. Marshall and D. N. Rana
An audit of liquid-based cervical cytology screening samples (ThinPrep and SurePath) reported as glandular neoplasia
Objectives: The aims of this study were to assess the number of cases diagnosed as glandular neoplasia (national report code 6) of cervical (6A) and non-cervical (6B) types on ThinPrep (TP) and SurePath (SP) liquid-based cytology (LBC) samples and to calculate the positive predictive value (PPV) of these diagnoses for significant glandular and/or squamous pathology for local audit and as a contribution to national data on glandular neoplasia.
Methods: A computerized search identified all screening LBC samples reported as glandular neoplasia during the 24-month period from January 2006 to December 2007. Corresponding histology samples were identified, with a minimum follow-up period of 6 months for each case.
Results: A total of 70 samples, representing 70 patients, were reported as glandular neoplasia, 39 TP (55.7%) and 31 SP (44.3%), with 46 samples (31 TP, 15 SP) reported as 6A and 24 samples (eight TP, 16 SP) as 6B. PPV of glandular neoplasia was calculated for a biopsy diagnosis of cervical glandular intraepithelial neoplasia/adenocarcinoma and/or cervical intraepithelial neoplasia (CIN) 2 or worse. The PPV of 6A was 100% for both TP and SP. The PPV of 6B for adenocarcinoma was 62.5% for TP and 66.7% for SP. The combined PPV for 6A + 6B was 92.3% for TP, 83.3% for SP and 88.4% combined. The overall pick-up rates for the two methods were significantly different (TP 0.031%, SP 0.052%; P = 0.014). Histology showed only CIN3 with endocervical crypt involvement in nine TP cases and one SP case.