Multimodality Approaches Improve Outcomes in Marginally-Inoperable Soft Tissue Sarcoma

A multimodality approach to treatment, which included sequential chemotherapy and radiation therapy followed by surgery, resulted in successful resection for most patients with marginally inoperable soft tissue sarcomas, according to data from a retrospective review presented during the 2021 ASCO Annual Meeting.

At a median follow-up of 72 months (range, 50-86), the median relapse-free survival (RFS) in the entire cohort of patients examined (n = 75) was 26.9 months (95% CI, 0-86.0), and the median overall survival (OS) was 65 months (95% CI, 13.5-116.4).

The receipt of radiotherapy was associated with improved outcomes in terms of RFS (HR, 0.22; 95% CI, 0.10-0.51; P <.001) and OS (HR, 0.23; 95% CI, 0.10-0.52; P =.001) vs those who did not receive the treatment. Additionally, rates of RFS (HR, 0.27; 95% CI, 0.09-0.88; P =.02) and OS (HR, 0.32; 95% CI, 0.10-0.99; P =.04) were higher in patients whose primary tumor origin was in the extremities.

For patients with operable soft tissue sarcoma, the standard-of-care treatment is comprised of surgery, which could include adjuvant or neoadjuvant therapies. Within the Toronto Sarcoma Program (TSP), a multidisciplinary treatment program based in Canada, those with marginally inoperable STS often receive sequential chemotherapy and radiotherapy, followed by surgery. As such, investigators sought to examine the impact of these multimodality approaches in this patient population.

The dual-center, single-program, retrospective review included patients with TPS tumor board–confirmed primary or recurrent marginally inoperable STS, who had previously undergone treatment with chemotherapy and were planned to receive radiotherapy followed by surgery.

Additionally, the review included univariate and multivariate analyses that were performed to assess the influence of disease characteristics and treatment on patient outcomes. RFS and OS were estimated using the Kaplan-Meier method.

Patients included in the analysis had a median age of 52 years (range, 16-72). Fifty-five percent of patients were male and 75% had an ECOG performance status of 1. In terms of histology, 29.3% of patients had dedifferentiated liposarcoma, 26.6% had leiomyosarcoma, 18.6% had synovial sarcoma, 8.0% had myxoid liposarcoma, 5.3% had undifferentiated pleomorphic sarcoma, and 2.6% each had myxofibrosarcoma, malignant fibrous histiocytoma, sarcoma not otherwise specified, spindle cell sarcoma, and malignant pleural nerve sheath tumor. Moreover, 52% of patients had grade 3 disease.

The site of primary disease was the retroperitoneum for 48.0% of patients, the extremities for 22.7%, the pelvis for 12%, the lung/mediastinum for 9.3%, and other for 5.3%. Additionally, all patients received treatment with chemotherapy, with 72% having completed treatment. Moreover, 69% of patients completed their radiotherapy plan, and 79% underwent surgery.

Results from a multivariate analysis of RFS and OS based on histology showed that patients with myxoid liposarcoma had the best OS benefit (HR, 0.87; 95% CI, 0.17-4.5; P =.875), and those with dedifferentiated liposarcoma experienced the worst survival outcomes (HR 2.43; 95% CI, 0.76-7.7; P =.132).

Moreover, patients who experienced disease progression after chemotherapy had poorer outcomes, with a median RFS of 4.7 months (HR, 2.03; 95% CI, 0.61-6.76; P =0.24), and a median OS of 21.9 months (HR, 2.48; 95% CI, 0.73-8.47; P =.144).

Additionally, results from univariate and multivariate analyses indicated that age, gender, performance status, tumor type, tumor grade, and necrosis were not linked with OS or PFS.

In terms of safety, treatments were delivered to patients with low and moderate rates of toxicities or complications.

Reference

1. Vornicova O, Wunder J, Chung PWM, et al. The impact of multimodality therapies in marginally inoperable soft tissue sarcomas (STS): The Toronto Sarcoma Program (TSP) experience. J Clin Oncol. 2021;39(supp 15):11548. doi:10.1200/JCO.2021.39.15_suppl.11548