Adjuvant CRT Linked to 83% Reduced Risk of Death in Endometrial Cancer

Pratibha S. Binder, MD

Women with node-positive stage IIIC endometrial cancer assigned to adjuvant chemoradiation therapy (CRT) had better survival than those assigned to chemotherapy or radiation therapy alone, according to results from a retrospective cohort study.

In results from a retrospective analysis of data collected in the Siteman Cancer Registry, survival after CRT was superior to no adjuvant therapy (P <.001), radiation (P =.010), and chemotherapy (P <.001). Compared with no adjuvant therapy, CRT was associated with an 83% (P <.001) reduced risk for death after adjusting for covariates. Treatment with radiation was associated with a 57% reduced risk for death (P = .024) compared with no adjuvant therapy and chemotherapy led to a 62% reduced risk for death (P = .003).

“For women with stage IIIC endometrial cancer, adjuvant therapy with CRT should be preferred in patients with adequate reserve to tolerate this treatment strategy for its OS benefits over no treatment, radiation therapy alone, or chemotherapy alone, based on the results of a multivariable Cox analysis of almost 200 surgically staged patients in this retrospective study,” first author Pratibha S. Binder, MD, Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Washington University School of Medicine, and coinvestigators wrote.

“Our retrospective analysis is the only review to date that has compared 4 postsurgical adjuvant treatment strategies and shown a survival advantage of CRT compared to all other strategies. Previous single-institution retrospective studies evaluating the efficacy of adjuvant treatment options for stage IIIC endometrial cancer did not compare all 4 treatment strategies that are presented in our study,” added Binder et al.

Investigators at Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine identified 2519 women treated at the facility from 2000 to 2012 before reviewing data on 199 patients with surgically-staged node-positive disease, including 115 stage IIIC1 and 84 stage IIIC2 patients. The median follow-up was 40.1 months (95% CI, 5.8-153.4) and 5-year OS was 36.2%.

Compared with patients with G3 disease, those with G1-2 disease were younger (60.0 vs 66.5 years), had fewer positive nodes (2.0 vs 3.0), were more likely to receive adjuvant treatment with radiation therapy alone (21.3% vs 8.8%), and were less likely to receive chemotherapy alone (12.0% vs 36.3%).

More than half of patients (55.6%) with G1-2 disease were treated with chemoradiation compared with 44.0% of those with G3 disease. Roughly 11% of patients in both groups received no adjuvant therapy. There was no difference between the groups in the number of nodes examined, prevalence of lymphovascular space invasion, pelvic washings, or comorbidity score.

Most patients received CRT (50.3%) followed by chemotherapy (23.1%), radiation (16.1%), and no adjuvant treatment (10.5%). Patients treated with chemoradiation were the youngest (60.5 years), followed by radiation (63.0), chemotherapy (67.5), and no adjuvant treatment (70.0).

Compared with chemoradiation, the adjusted risk of death (HRadj) in the overall population was higher with no adjuvant therapy (5.94; P <.001), radiation (2.56; P = .009), and chemotherapy (2.24; P = .004).

Compared with no adjuvant therapy in low-grade patients, radiation alone and CRT led to a 67% (HRadj, 0.33; P = .039) and 85% (HRadj, 0.15; P <.001) reduction in the risk of death, respectively; however, chemotherapy alone was not linked to a reduction in the risk of death (HRadj, 0.64; P = .441). In patients with high-grade disease, chemotherapy and CRT led to a 72% (HRadj, 0.28; P = .003) and 83% (HRadj, 0.16; P <.001) reduction in the risk of death, respectively, compared with no adjuvant treatment; however, radiation did not lead to a reduction in the risk of death (HRadj, 0.62; P = 0.416).

Binder PS, Kuroki LM, Zhao P, et al. Benefit of combination chemotherapy and radiation stratified by grade of stage IIIC endometrial cancer [published online September 12, 2017]. Gynecol Oncol. doi: 10.1016/j.ygyno.2017.08.031.