European researchers report that starting treatment early for an ovarian cancer relapse based on CA125 blood levels alone does not improve overall survival, compared with delaying treatment until symptoms arise.

"Women who've completed ovarian cancer treatment often worry about a relapse, and they undergo frequent blood tests for CA125 in the hope of catching it early," said lead author Gordon Rustin, M.D., professor of oncology at Mount Vernon Cancer Center in Hertfordshire, United Kingdom. The study was conducted by the MRC/NCRI and EORTC Gynae Cancer Intergroups. "We thought that delaying chemotherapy might make overall quality of life worse, due to the symptoms of ovarian cancer, but this was not seen in women on this trial. Since there is no benefit from early chemotherapy, patients may choose to avoid the inconvenience and anxiety associated with frequent retesting for CA125 levels as well as unnecessary early initiation of treatment for relapse."

CA125 is a marker of growth for several cancers, including ovarian cancer, and is measured by a blood test. Women who have undergone treatment for ovarian cancer may have their CA125 levels tested as often as every three months for several years after initial treatment.

In this study, investigators compared overall survival between 265 women with ovarian cancer in remission after initial chemotherapy who began second-line chemotherapy after experiencing a rise in CA125, and 264 women with rising CA125 whose treatment was delayed until symptoms of relapse appeared (such as pelvic pain or bloating).

Even though the early treatment group started second-line chemotherapy an average five months before the delayed treatment group, overall survival was the same between both groups: 41 months since completion of first-line chemotherapy.

The researchers added that this trial provides important information that will help women make informed choices about their follow-up and treatment. They can be reassured that treatment can safely be delayed until symptoms develop.