Adjuvant therapy in women with early stage uterine serous carcinoma: A multi-institutional study.

Objective: Uterine serous carcinoma is a rare but aggressive subtype of endometrial adenocarcinoma. Our objective was to compare adjuvant treatment strategies for patients with early stage uterine serous carcinoma.

Methods: This multi-institutional, retrospective cohort study evaluated patients with early stage uterine serous carcinoma. Patients with FIGO Stage IA-II disease after surgery, whose tumors had serous or any mixed serous/non-serous histology were included. Patients with carcinosarcoma were excluded. Clinical data were abstracted from local medical records. Summary statistics, Fisher's exact, and Kruskal-Wallis tests were used to analyze demographic and clinical characteristics. Univariable and multivariable analyses were performed for recurrence-free and overall survival.

Results: There were 737 patients included. Most patients had Stage IA disease (75%), 49% of which had no myometrial invasion. Only 164 (24%) tumors had lymphatic/vascular space invasion. Adjuvant treatment varied: 22% received no adjuvant therapy, 17% had chemotherapy alone, 19% had cuff brachytherapy, 35% had cuff brachytherapy with chemotherapy, and 6% underwent pelvic radiation. Adjuvant treatment was significantly associated with a decreased risk of recurrence (p = 0.04). Compared with no adjuvant therapy, patients who received brachytherapy or brachytherapy/chemotherapy had improved recurrence-free survival (HR 0.59, 95% CI 0.40-0.86; HR 0.65, 95% CI 0.49-0.88, respectively) and overall survival (HR 0.53, 95% CI 0.35-0.79; HR 0.49, 95% CI 0.35-0.69, respectively). Improved survival with brachytherapy and brachytherapy/chemotherapy persisted on multivariable analyses. Chemotherapy alone was also associated with improved overall survival compared with no adjuvant treatment (HR 0.55, 95% CI 0.37-0.81).

Conclusions: Adjuvant therapy was associated with a decreased risk of recurrence relative to observation alone. Adjuvant cuff brachytherapy with and without chemotherapy was associated with improved survival outcomes in patients with early stage uterine serous carcinoma.