ERT Does Not Increase Endometrial Cancer Recurrence

SAN DIEGO—Estrogen replacement therapy (ERT) does not increase the risk of recurrence in patients who have had endometrial cancer and should not be categorically ruled out in these women, according to research presented at the 31st Annual Meeting of the Society of Gynecologic Oncologists (SGO).

Kimberly A. Suriano, MD, Philip J. DiSaia MD, and their colleagues at the University of California, Irvine, and the Chao Family Comprehensive Cancer Center, Orange, California, conducted a cohort study among women who had either begun or resumed ERT after primary treatment for endometrial cancer.

“We found no evidence that taking ERT following treatment for endometrial cancer adversely affects outcome,” Dr. DiSaia told ONI in an interview. The results showed no increased risk of either recurrence or death, he said. In fact, women who took ERT had a longer disease-free interval and longer disease-free survival than matched control subjects who had not taken ERT after endometrial cancer treatment.

Dr. DiSaia was senior investigator of the study and is director of the Division of Gynecologic Oncology, University of California Irvine Medical Center.

Dr. DiSaia said that this study disproves the assumption that “if the patient takes estrogen and has a focus of cancer, the estrogen will ignite the cancer, like pouring fuel on a fire. What causes cancer and what promotes it are two different things.”

The study included 249 patients with surgical stage I, II, or III endometrial cancer treated between 1984 and 1998, 130 of whom had received ERT after primary cancer treatment. Among the 249 patients, Dr. DiSaia and colleagues were able to identify 75 matched treatment-control pairs. Pairs were matched for age at diagnosis, parity, stage and grade of tumor, depth of myometrial invasion, histology, surgical treatment, lymph node status, postoperative radiation therapy, and concurrent diseases.

The study compared duration of estrogen use, recurrence, and death due to endometrial cancer. All 150 patients underwent pelvic examination and Pap test every 3 months for the first 2 years, then every 6 months. At the time of the report, cases had been followed for a mean of 83 months, and controls had been followed for a mean of 69 months.

There were five endometrial cancer recurrences and two deaths from endometrial cancer among the 130 patients on estrogen. Interestingly, there were no recurrences among women who had a history of previous ERT.

Among the matched case-control patients, there were 2 recurrences among the 75 patients who took ERT (1.4% recurrence rate) and 11 recurrences among the 75 who had not taken ERT (14.3% recurrence rate). The difference was not statistically significant.

The investigators reported that the matched estrogen replacement group experienced a longer disease-free interval than their control counterparts (82 months vs 63 months) and longer disease-free survival. Both of this findings were statistically significant (P = .02 and P = .03, respectively).

Dr. DiSaia doubts that the improved disease-free interval in the women who took ERT indicates a protective effect. Rather, he said, this was more likely due to a bias in the selection of subjects in this retrospective cohort study.

“All I’m pleading for is that we properly inform the patient so that the patient can decide whether to take or continue ERT,” Dr. DiSaia said. “I think that in most cases, a reasonable person would decide to continue. Our job is to give patients the facts and let them decide how they want to live. For many women, ERT is an important quality-of-life issue. Unless we’re sure it will harm them, we should not deny it to patients.”

Dr. DiSaia pointed out that the general use of ERT following endometrial cancer also will be affected by current FDA-required labeling, which states that ERT is contraindicated in such cases. “I don’t know what data that warning is based on, but it does have medical-legal implications in the current climate,” he said.

The effect of ERT following treatment for endometrial cancer is now being studied in a major prospective randomized, controlled trial conducted by the Gynecologic Oncology Group.