Stereotactic Hypofractionated Radiation Therapy Well Tolerated in Uterine Cancer

The phase 1/2 SPARTACUS trial assessed the use of stereotactic hypofractionated radiation therapy in patients with uterine cancer; the treatment appeared to be well tolerated.

Stereotactic hypofractionated radiation therapy was found to be well tolerated for patients with uterine cancer, according to short-term findings from the phase 1/2 SPARTACUS trial (NCT04866394) published in JAMA Oncology.

A total of 61 patients enrolled on the trial, 39 of whom had endometrioid adenocarcinoma, 15 had serous or clear cell histology, 3 had carcinosarcoma, and 4 were dedifferentiated histology. Additionally, 16 patients received subsequent therapy and 9 underwent vault brachytherapy. The median follow-up was 9 months.

Prior to starting treatment, 4 patients withdrew and 4 were deemed ineligible. The remaining patients were treated with stereotactic pelvic radiation of 30 Gy in 5 fractions and completed the treatment. Prior to the protocol amendment, 12 patients were treated with a once per-week schedule, and after the amendment, 48 patients were treated every other day, with the exception of 1.

One patient was found to have progressive disease, and after fraction 5 they were no longer followed-up with for toxicity or quality of life assessments.

The physician-reported adverse effects (AEs) included grade 1 gastrointestinal (GI) tract toxicity in 33 patients and 25 patients with genitourinary AEs. Grade 2 GI tract AEs were observed in 8 patients, and 2 had genitourinary AEs. Additionally, 1 patient who received treatment every other day had a grade 3 GI AE—diarrhea 7 times or more per day during fraction 5; at the 6-week follow-up, the AE was decreased to grade 2, and resolved within 3 months.

For 3 months leading up to or after treatment , no patient experienced lymphedema or musculoskeletal symptoms. Grade 1 vaginal discharge was observed in 2 patients, and 1 patient had grade 2 vaginal discharge.

Patient reported outcomes included scores for function, symptoms, and global health status. Investigators noted that the only clinically and statistically significant change was for diarrhea, which was worse during fraction 5 with a score of 35.76 compared with 6.56 at baseline; notably, this improved by the 6-week follow-up with a score of 15.79 and the 3-month follow-up the score was 13.58.

Patients also reported that at fraction 5, gastrointestinal and genitourinary symptoms increased, but improved at follow-up. The global health status remained unchanged during treatment and follow-up. Additionally, sexual and vaginal symptoms remained unchanged, although only 13 patients answered the baseline questions. There were no factors found to be associated with quality of life and changes in the univariate analysis.

In terms of hematologic AEs, 19 patients experiencing grade 1 toxicities, 17 had grade 2 toxicities, and 7 had grade 3. Grade 3 AEs included lymphopenias (n = 6) and leukopenia (n = 1). The majority of any-grade AEs (n = 30) occurred during fraction 5.

Reference

Leung E, Gladwish AP, Davidson M, et al. Quality-of-life outcomes and toxic effects among patients with cancers of the uterus treated with stereotactic pelvic adjuvant radiation therapy: the SPARTACUS phase 1/2 nonrandomized controlled trial. JAMA Oncol. Published Online April 14, 2022. doi:10.1001/jamaoncol.2022.0362