Hormone maintenance therapy, when given after primary cytoreductive surgery and platinum-based chemotherapy, prolonged progression-free survival among women who had low-grade serous carcinoma of the ovary or peritoneum, a study showed.

Low-grade serous carcinoma (LGSC) is a rare histologic subtype that is somewhat resistant to conventional chemotherapy, so researchers have been searching for alternative or add-on treatments. To examine whether hormone maintenance therapy would be beneficial, the investigators analyzed information from a longitudinal database of patients with the malignancy who were treated at a single medical center.

They focused on 203 patients diagnosed as having stage II-IV disease of the ovary or peritoneum between 1981 and 2013, who underwent primary cytoreductive surgery followed by platinum-based chemotherapy. Seventy of these patients received hormone maintenance therapy for a median of 33 months (range, 1-223 months), taking letrozole, tamoxifen, leuprolide, anastrozole, medroxyprogesterone, or some combination of these agents. The remaining 133 patients took no hormone therapy and served as a control group, said David M. Gershenson, MD, and his associates at the University of Texas M.D. Anderson Cancer Center, Houston.

Women who took hormone maintenance therapy had a median progression-free survival of 64.9 months, compared with 26.4 months for the control group. This benefit was similar between women who had persistent disease after completing chemotherapy and those who were clinically disease free after completing chemotherapy, the investigators reported (J Clin Oncol. 2017 Feb 21. doi: 10.1200/jco.2016.71.0632).

“The findings of this hypothesis-generating study are potentially practice changing and warrant using a prospective trial design. A phase III randomized trial is currently under development” to compare hormone therapy against placebo in women with LGSC, Dr. Gersehnson and his associates noted.

They added that reports during the last decade showing that LGSC is resistant to platinum-based chemotherapy have led some clinicians to conclude that it is of no benefit at all and should be abandoned in this patient population. “In our view, that perspective is premature based on available data. Although LGSC is indolent and not as chemotherapy sensitive as high-grade serous carcinoma, it is not entirely chemotherapy resistant,” they wrote. Some women do respond, while “a high proportion … have stable disease for a period of time.”