Person:

Skates, Steven

Establishing a cancer screening biomarker’s intended performance requires “phase III” specimens obtained in asymptomatic individuals before clinical diagnosis rather than “phase II” specimens obtained from symptomatic individuals at diagnosis. We used specimens from the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial to evaluate ovarian cancer biomarkers previously assessed in phase II sets.

Phase II specimens from 180 ovarian cancer cases and 660 benign disease or general population controls were assembled from four Early Detection Research Network (EDRN) or Ovarian Cancer Specialized Program of Research Excellence (SPORE) sites and used to rank 49 biomarkers. Thirty-five markers, including 6 additional markers from a fifth site, were then evaluated in PLCO proximate specimens from 118 women with ovarian cancer and 474 matched controls.

Top markers in phase II specimens included CA125, HE4, transthyretin, CA15.3, and CA72.4 with sensitivity at 95% specificity ranging from 0.73 to 0.40. Except for transthyretin, these markers had similar or better sensitivity when moving to phase III specimens that had been drawn within six months of the clinical diagnosis. Performance of all markers declined in phase III specimens more remote than 6 months from diagnosis.

Despite many promising new markers for ovarian cancer, CA125 remains the single-best biomarker in the phase II and phase III specimens tested in this study.

Background: To assess the within-trial cost-effectiveness of an NHS ovarian cancer screening (OCS) programme using data from UKCTOCS and extrapolate results based on average life expectancy. Methods: Within-trial economic evaluation of no screening (C) vs either (1) an annual OCS programme using transvaginal ultrasound (USS) or (2) an annual ovarian cancer multimodal screening programme with serum CA125 interpreted using a risk algorithm (ROCA) and transvaginal ultrasound as a second-line test (MMS), plus comparison of lifetime extrapolation of the no screening arm and the MMS programme using both a predictive and a Markov model. Results: Using a CA125–ROCA cost of £20, the within-trial results show USS to be strictly dominated by MMS, with the MMS vs C comparison returning an incremental cost-effectiveness ratio (ICER) of £91 452 per life year gained (LYG). If the CA125–ROCA unit cost is reduced to £15, the ICER becomes £77 818 per LYG. Predictive extrapolation over the expected lifetime of the UKCTOCS women returns an ICER of £30 033 per LYG, while Markov modelling produces an ICER of £46 922 per QALY. Conclusion: Analysis suggests that, after accounting for the lead time required to establish full mortality benefits, a national OCS programme based on the MMS strategy quickly approaches the current NICE thresholds for cost-effectiveness when extrapolated out to lifetime as compared with the within-trial ICER estimates. Whether MMS could be recommended on economic grounds would depend on the confirmation and size of the mortality benefit at the end of an ongoing follow-up of the UKCTOCS cohort.