Stereotactic body radiation therapy in the treatment of ovarian cancer

Abstract

Background This study evaluates the outcomes and toxicity of stereotactic body radiation therapy (SBRT) in ovarian cancer. Methods This retrospective analysis considered all patients treated with SBRT from 2009 to 2018 with a primary ovarian tumor. Follow-up included PET-CT and CT scans at 2–3 month intervals. Statistical analysis primarily consisted of univariate analysis, Cox proportional hazards analysis, and the Kaplan-Meier method. Results The study included 35 patients with 98 treatments for lymph nodes (51), local recurrence (21), and de novo solid metastases (26). Median biologically effective dose (BED), gross tumor volume, and planning target volume were 38.40 Gy, 10.41 cc, and 25.21 cc, respectively. 52 lesions showed complete radiographic response, and two-year local control was 80%. Median overall survival (OS) was 35.2 months, and two-year progression-free survival (PFS) was 12%. On univariate analysis, Eastern Cooperative Oncology Group performance status > 0 was predictive of decreased OS (p = 0.0024) and PFS (p = 0.044). Factors predictive of local failure included lower BED (p = 0.016), treatment for recurrence (p = 0.029), and higher pre-treatment SUV (p = 0.026). Kaplan-Meier analysis showed BED ≤35 Gy (p < 0.005) and treatment for recurrence (p = 0.01) to be predictive of local failure. On Cox proportional hazards analysis, treatment of lymph nodes was predictive of complete radiographic response (hazard ratio (HR) = 4.95), as was higher BED (HR = 1.03). Toxicity included 27 cases of grade < 3 toxicity, and one grade 5 late toxicity of GI bleed from a radiation therapy-induced duodenal ulcer. Conclusions SBRT provides durable local control with minimal toxicity in ovarian cancer, especially with BED > 35 Gy and treatment for lymph nodes.

The role of radiotherapy in ovarian cancer

“…In 2020, Kowalchuk et al published a retrospective analysis of 35 ovarian cancer patients with 98 treated lesions to review the toxicity and outcomes of stereotactic radiotherapy in ovarian cancer. They drew similar conclusions to previous studies, that stereotactic radiotherapy was safe with only one toxicity greater than grade 2 (grade 5 late bowel toxicity with gastrointestinal bleeding) and also effective, with 2-year local control rates of 80% 35…”

“…They drew similar conclusions to previous studies, that stereotactic radiotherapy was safe with only one toxicity greater than grade 2 (grade 5 late bowel toxicity with gastrointestinal bleeding) and also effective, with 2-year local control rates of 80%. 35 The excellent rates of local control with stereotactic radiotherapy in oligometastatic gynecological malignancy is promising for the future; however, significant rates of disease progression outside of the radiation field still exist (79-100% of failures). For this reason, careful consideration and patient selection is required to decide whether to treat nodal recurrences with highly focal stereotactic radiotherapy or a more extensive involved field radiation which runs the risk of greater toxicity.…”

Role of stereotactic body radiotherapy in gynecologic radiation oncology

“…34 Another retrospective study including 35 patients with oligometastatic ovarian cancer treated with SBRT yielded a 2-year lesional control of 80%, with a higher dose (BED >35 Gy) associated with improved control. 35 A retrospective study including 20 patients (10 ovarian and 10 uterine) with a single metastatic site treated with SBRT revealed that patients with smaller tumors (<50 mL) had improved local control (5-year local control <50 mL 100% vs >50 mL 65%; p<0.02). 36 In a prospective phase II trial evaluating the efficacy of SBRT in 49 patients with metastatic gynecologic tumors, there was a 96% response rate in the treated lesions with a median PFS of 7.8 months and overall survival of 20.2 months.…”

“…In one study reporting 82 patients diagnosed with ovarian cancer with 156 metastatic lesions treated with SBRT, control of the treated lesions at 2 years was found to be 68% and the median systemic treatment-free interval after SBRT was 7.4 months 34. Another retrospective study including 35 patients with oligometastatic ovarian cancer treated with SBRT yielded a 2-year lesional control of 80%, with a higher dose (BED >35 Gy) associated with improved control 35. A retrospective study including 20 patients (10 ovarian and 10 uterine) with a single metastatic site treated with SBRT revealed that patients with smaller tumors (<50 mL) had improved local control (5-year local control <50 mL 100% vs >50 mL 65%; p<0.02) 36…”

Online Magnetic Resonance-Guided Radiotherapy (oMRgRT) for Gynecological Cancers

“…The effectiveness of SBRT on LC is clearly associated with a doseresponse correlation; higher biologically equivalent dose (BED) leads to better tumor control (71,72). For lymph node metastases, 5year LC rates of uterine, cervical, and ovarian cancer range from 70 to 97%, and favorable disease-free survival and overall survival are reported in retrospective series (64,68,70,(72)(73)(74)(75)(76)(77). Lymph node metastases of gynecologic malignancies are often located in the pelvis or abdomen, where conventional SBRT using CBCT image guidance yields relatively poor soft tissue contrast.…”