Black Women With Endometrial Cancer Completed Treatment More With Peer Support

A statistically significant increase in treatment completion was observed among Black women with high-risk endometrial cancer who attended sessions and received 1:1 peer support. These results, which demonstrate the first-ever national randomized trial to improve outcomes specifically for Black women with endometrial cancer, from the SISTER trial (NCT04930159), were shared at the 2026 Society of Gynecologic Oncology Annual Meeting on Women’s Cancer (SGO).¹

Treatment was completed by 77% of patients who received enhanced usual care, 73% of patients who received 1:1 peer support, and 67% of patients who received group support. Furthermore, the adjusted relative risk (RR) of incomplete treatment was 1.1 (95% CI, 0.67-1.9) for those who received peer support plus group support vs enhanced usual care, 1.0 (95% CI, 0.58-1.9) for those who received peer support vs enhanced usual care, and 1.2 (95% CI, 0.67-2.0) for those who received group support vs enhanced usual care.

Across SISTER, which stands for Social Interventions for Support in Treatment of Endometrial Cancer and Recurrence, 70 enhanced usual care packages were mailed, 801 group sessions were scheduled, and 385 1:1 peer support sessions were scheduled. Among group sessions, topics included free flow (18%), completing treatment (14%), active role in treatment (13%), reclaiming health (13%), coping with diagnosis (13%), empowerment (13%), nutrition (12%), and other (4%).

Conversely, among 1:1 peer sessions, discussion topics included managing adverse effects (AEs; 81%), completing treatment (57%), self-care (56%), nutrition (48%), exercise (41%), intro to treatment (22%), resources for recovery (17%), and other (32%).

The highest rate of treatment completion out of all included groups was observed among patients who received 1:1 peer support and some intervention (84%) vs those who received 1:1 peer support and no intervention (50%; P = .003). Among those who received group support, the rate of treatment completion was 68% in those who received some intervention vs 64% in those who received no intervention. Notably, 72% of patients attended at least 1 session.

Additionally, reasons for treatment discontinuation were disease progression (33%), adverse effects (23%), insurance issues or drug shortage (8%), scheduling (8%), toxicity (8%), comorbidity from non-cancer condition (6%), allergic reaction (5%), lost to follow-up (5%), patient declined (5%), and positive treatment response (2%). The investigators noted that 65% of reasons for treatment discontinuation were not due to disease progression.

Among patients who attended a support session at least once, with 26% discontinuing treatment and 74% completing treatment, compared with patients who never attended a support session, with 43% discontinuing treatment and 57% completing treatment, the relative risk was 0.61 (95% CI, 0.39-0.95). Among patients with an ECOG performance status greater than 0, with 38% discontinuing treatment and 62% completing treatment, and patients with an ECOG performance status of 0, with 19% discontinuing treatment and 81% completing treatment, the relative risk was 2.0 (95% CI, 1.2-3.2). Among patients who had stage IV or recurrent disease, with 39% discontinuing treatment and 61% completing treatment, and patients with stage I, II, or III disease, with 23% discontinuing treatment and 77% completing treatment, the relative risk was 1.7 (95% CI, 1.1-2.5).

“1:1 peer support statistically significantly increased treatment completion among Black women with high-risk endometrial cancer who attended a session,” said presenting study author Kemi M. Doll, MD, MSCR, professor of obstetrics and gynecology and project lead of Endometrial Cancer Action Network for African-Americans (ECANA) at the University of Washington School of Medicine, and coauthors.

SISTER was funded as a first-of-its-kind study for Black women with endometrial cancer. A total of 609 patients were screened, and ultimately 231 patients were included in the cohort. Eligible patients were Black or African American with confirmed high-risk endometrial cancer and a treatment recommendation of immunotherapy, chemotherapy, and/or radiation. All patients were randomly assigned to one of 3 arms: the first received enhanced usual care, the second received an invitation to a weekly support group, and the third received an invitation to 1:1 peer support appointments. Enhanced usual care was mailed self-directed support materials/ECANA care package.

There were 11 study sites with 13 different recruitment locations.

Of the patients enrolled, histology was serous (35%), endometroid (30%), carcinosarcoma (22%), clear cell (5%), mixed (4%), and other (3%); disease stage was I (27%), II (6%), III (32%), IV (16%), and recurrent (17%); and baseline treatment plans were chemotherapy only (72%), radiation plus chemotherapy (17%), and radiation only (11%), with immunotherapy included in 48% of treatments.

Further, patients reported being able to meet their monthly expenses “Not at all” (13%), “A little bit” (14%), “Somewhat” (29%), “Quite a bit” (15%), and “Very much” (26%). Regions included Southeast (39%), Mid-Atlantic (34%), Northeast (15%), Midwest (9%), and West (3%). A live-in caregiver was reported by 62% of patients, and 74% reported other forms of social support.

Concluding the presentation, the investigators included a quote from a participant of the SISTER trial: “The surveys have really helped me in dealing with my diagnosis and treatment. I’ve really learned to be an advocate for my health by taking the surveys.”

Disclaimers:

Doll reported research grant funding from Merck & Co, PCORI, NIH, and KUNI Foundation; and consultant roles for Bayer.

Reference

Doll KM, Monsell S, Alson J, et al. The social interventions for support in treatment of endometrial cancer and recurrence (SISTER) study: a national randomized controlled trial of peer support vs. usual care in Black women with high-risk endometrial cancer. Presented at the 2026 SGO Annual Meeting on Women’s Health; April 10-12, 2026; San Juan, PR.