Clinical evaluation and budget impact analysis of cervical cancer screening using cobas 4800 HPV screening technology in the public sector of South Africa

Abstract

Cytology remains the mainstay of cervical cancer screening in South Africa (SA), however false negative rates are 25-50%. In contrast, human papillomavirus (HPV) screening techniques have higher sensitivity for cervical cancer precursors. The cobas® 4800 HPV test detects pooled high-risk HPV types and individual genotypes HPV 16 and 18. Using a mathematical budget impact model, the study objective was to evaluate the clinical and budget impact of replacing primary liquid-based cytology (LBC) with primary HPV-based screening strategies. In SA, current LBC screening practice recommends one test every ten years, followed by large loop excision of the transformation zone (LLETZ) if indicated. HPV testing can be performed from an LBC sample, where no additional consultations nor samples are required. In the budget impact model, LBC screening for 2 cycles (one test every ten years) was compared to cobas® 4800 HPV test for 2 cycles (one test every 5 years). The model inputs were gathered from literature and primary data sources. Indicative prices for LBC and cobas® 4800 HPV test were R189 and R457, respectively. Model results indicate that best outcomes for detection of disease were seen using cobas® 4800 HPV test. Forty-eight percent of cervical cancer cases were detected compared to 28% using LBC, and 50% of cervical intraepithelial neoplasia (CIN) 2 and CIN3 cases, compared to 25% with LBC. The budget impact analysis predicted that the cost per detected case of CIN2 or higher would be R 56,835 and R46,980 for the cobas® 4800 HPV and LBC scenarios, respectively. This equates to an incremental cost per detected case of CIN2 or higher of R9 855. From this model we conclude that a primary HPV screening strategy will have a significant clinical impact on disease burden in South Africa.

Fig 1. Primary screening with Liquid based cytology (LBC).

B = no post-LLETZ procedure follow-up testing included in the model.

Fig 2. Primary screening with HPV cobas® 4800 test.

B = post-LLETZ procedure follow-up testing not included in the model.

Fig 3. Impact of screening strategy on detection of disease.

Fig 4. Cervical cancer cases detected and undetected over two screening cycles.

Fig 5. CIN2 and CIN3 cases detected and undetected over two screening cycles.

Fig 6. Cost per cases of ≥CIN2 detected.

Fig 7. Total cost over two cycles (x 10 000).

Fig 8. Effect of sensitivity analysis on cost per case ≥CIN2 detected.

LBC = liquid-based cytology; LLETZ = large loop excision of the transformation zone; HPV = human papillomavirus; hrHPV = high risk human papillomavirus; CIN = cervical intraepithelial neoplasia; ICC = invasive cervical cancer.