High grade, advanced, serous ovarian cancer with low serum CA125 levels

This study compares characteristics of advanced stage, high grade serous ovarian cancer, presenting with high or low serum CA125 level. This was a retrospective cohort of 118 patients with high grade serous ovarian, fallopian tube or primary peritoneal cancer, stages IIIC-IV diagnosed from January 1 1997 through January 9 2017. Patient demographics, tumour characteristics, surgical findings, chemotherapy protocols and clinical outcomes were collected. Three groups were evaluated: group A: 21 patients with CA125 serum level ≤152 U/ml, group B: 97 patients with CA125 serum level >152 U/ml, group C: 43 patients from group B with CA125 serum level >500 U/ml and <1000 U/ml. No significant difference was found between groups regarding age, stage at diagnosis, extent of residual disease or disease volume. More group A patients had surgery as primary treatment compared to groups B and C (p=.003, p=.022, respectively). CA125 level at recurrence was lower in group A as compared to the other groups (162.2 vs. 851.7 and 603.4, p=.003, p=.006). Overall survival and progression-free survival did not differ based on CA125 levels. We conclude that patients with advanced stage, high grade, serous ovarian cancer with low CA125 serum levels had the same clinical outcome as patients with higher levels.Impact StatementWhat is already known on this subject? It is known that CA125 level is a prognostic and predictive factor for epithelial ovarian cancer (EOC) outcome. It is elevated in 80% of the patients and within normal range in only 10% of women with advanced stage EOC. Various studies had addressed the patients with advanced stage serous EOC who had high serum CA125 levels at time of diagnosis. But, no study has addressed the 10% of patients with advanced stage who had low serum CA125 levels at time of diagnosis.What the results of this study add? To the best of our knowledge, this is the first study addressing patients with advanced stage EOC who had low serum CA125 levels at time of diagnosis. According to the results of this study, patients with advanced stage, high grade serous EOC presenting with low serum CA125 levels have similar clinical outcomes as do patients with high serum CA125 levels.What the implications are of these findings for clinical practice and/or further research? Further translational research is encouraged for this group of tumours to identify specific molecular markers that might lead to better understanding and treatment for the disease.