Women with advanced endometrial cancer may live longer before their tumors return if they receive immunotherapy and chemotherapy at the same time, according to two studies published Monday in the New England Journal of Medicine.

The findings, which were also to be presented Monday at the Society of Gynecologic Oncology annual meeting in Tampa, Florida, are expected to transform the way oncologists treat women in the later stages of their disease.

«This is going to dramatically change the conversation» with patients, «probably starting tomorrow,» said Dr. David O’Malley, a gynecologic oncologist at The Ohio State University Comprehensive Cancer Center. O’Malley was not involved in the new studies.

In one of the studiesResearchers found that adding the immunotherapy drug pembrolizumab (commonly known by its brand name, Keytruda) to the standard chemotherapy regimen of carboplatin and paclitaxel reduced the risk that patients’ advanced or recurrent endometrial cancer would return by up to 70 %, according to the types of tumors they had.

«We found a profound improvement,» he said senior study author Dr. Carol Aghajanian, a medical oncologist who specializes in gynecologic cancers at Memorial Sloan Kettering Cancer Center in New York City.

Some patients in the study Those who received the combination treatment spent, on average, more than a year (13.1 months) before their disease progressed, compared with 8.7 months, on average, among those who received chemotherapy alone.

The impact was most dramatic in women with a mismatch repair-deficient tumor, a specific type of endometrial cancer.

While women in the chemotherapy-alone group spent an average of 7.6 months before their cancer progressed, women with the mismatch repair-deficient tumor type who received chemotherapy plus immunotherapy are doing about as well a year after, who have not had enough tumor progression to allow researchers to determine how long the benefits might last.

Dr. Pamela Soliman, a gynecologic oncologist at MD Anderson Cancer Center in Houston who was not involved in the new studies, said the findings were exciting.

«Patients with advanced or recurrent endometrial cancer don’t have many opportunities for treatment,» Soliman said. «This really changes the practice.»

Immunotherapy is currently only approved for endometrial cancer as a second line of treatment, after chemotherapy. These findings suggest a significant advantage of using immunotherapy as part of the first line of treatment in these advanced cancers.

The Food and Drug Administration would have to modify its guidance on the use of immunotherapy in this way before it is widely implemented as a protocol to treat late-stage endometrial cancer. Aghajanian said regulators are already reviewing the new data.

Women are not screened for endometrial cancer. Instead, it is usually detected when symptoms develop. The most common symptoms include postmenopausal bleeding or other irregular vaginal bleeding.

He American Cancer Society estimates that 66,200 cases of endometrial cancer will be diagnosed this year and that more than 13,000 women will die from the disease.

Rates of new endometrial cancers rose 0.6% per year between 2010 and 2019, according to the National Cancer Institute.

TO second study published Monday compared chemotherapy with a chemotherapy combination therapy that included a monoclonal antibody called dostarlimab.

Again, depending on the type of endometrial tumor, the risk of the cancer coming back was reduced by up to 61.4% up to two years after treatment.

Both studies were welcomed by doctors frustrated by the rise in endometrial cancer cases.

«Endometrial cancer is one of the few cancers that is increasing, increasing mortality in the United States,» Aghajanian said. «Unfortunately, very few treatments have been developed specifically for it.»

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