In ovarian cancer, disease that returns within 6 months of treatment following platinum-based therapy is defined as platinum-sensitive. A patient’s platinum-sensitivity status can change with minor decisions made in clinical practice; however, oncologists treating these patients have a variety of therapeutics available to choose from, Bobbie J. Rimel, MD, said during a presentation at the 2020 SGO Winter Meeting.

Rimel, an assistant professor of gynecology and obstetrics at Samuel Oschin Comprehensive Cancer Institute, said that early studies by Maurie Markman, MD, helped elucidate platinum-sensitivity in ovarian cancer. Study investigators had looked at how patient response to treatment changes over time, she said. When they went back to perform secondary cytoreduction, a practice which has since fallen out of favor, they found that the vast majority of patients still had tumors.

Therefore, platinum-sensitivity is a function of time. “Time must pass for your patient to have platinum-sensitive disease,” Rimel said. “It doesn't just mean that the patient responded.”

The typical course of therapy means that patient shows a first response to first-line treatment, then the physician follows up with CA-125 or radiographic imaging. Current guidelines do not establish when to perform these tests, and Rimel said that the definition of “platinum sensitive” can change based on how often the physician screens for recurrence.

Approximately 70% to 80% of patients will relapse and receive a second course of treatment that leads to a second response or stability.

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