Biomarker lead time for predicting progression in women with ovarian cancer compared to imaging.

e18074 Background: Both CA125 and HE4 are biomarkers used to monitor women diagnosed with epithelial ovarian cancer (EOC). When these biomarkers increase and suggest progression of disease, imaging is frequently obtained for further assessment and confirmation. This study aims to assess how far in advance these biomarkers begin to trend upwards in comparison to the radiographic evidence of disease progression. Methods: This was an IRB approved retrospective trial. Residual longitudinal serum samples drawn for serum CA125 levels during treatment and monitoring from women with EOC were obtained. The samples were drawn every 3-5-weeks for patients on chemotherapy and every 3 months while monitoring. Serum CA125 and HE4 levels in the residual sera were analyzed at each time point. Imaging data was collected for each patient. Patients were included if either HE4 or CA125 was a marker for their disease. For each patient, the date of time point when the biomarker started to trend upward was identified and the date of radiographic evidence of progression was determined. The lead time (in days) for elevation of both CA125 and HE4 prior to evidence of radiographic progression was determined for each patient. Results: A total of 48 patients undergoing 58 treatment and monitoring events were identified. Each had evidence of disease progression by CA125 levels, HE4 levels, and computed tomography (CT). CA125 was the first biomarker to trend upward for 9 events (15.5%), HE4 was the first biomarker for 10 events (17.2%), and both increased simultaneously for 39 events (67.2%). Mean lead time for CA125 elevation prior to progression on imaging was 60 days (95% CI: 43 - 78, median = 44, range = 0 - 386). For HE4, mean lead time was 66 days (95% CI: 48 – 83, median = 46, range = 0 - 386). There was no significant difference in the average lead times between the two biomarkers (p < 0.01). Conclusions: When used for EOC monitoring both CA125 and HE4 have similar average lead times (~2 months) prior to the detection of progressive or recurrent disease by CT imaging.