Are We Ready for Life in the Fast Lane? A Critical Review of Preoperative Hypofractionated Radiotherapy for Localized Soft Tissue Sarcoma

This critical review aims to summarize the relevant published data regarding hypofractionation regimens for preoperative radiation therapy (RT) prior to surgery for soft tissue sarcoma (STS) of the extremity or superficial trunk. We identified peer-reviewed publications using a PubMed search on the MeSH headings of "soft tissue sarcoma" AND "hypofractionated radiation therapy." To obtain complication data on similar anatomical radiotherapeutic scenarios we also searched "hypofractionated radiation therapy" AND "melanoma" as well as "hypofractionated radiation therapy" AND "breast cancer." We then used reference lists from relevant articles to obtain additional pertinent publications. We also incorporated relevant abstracts presented at international sarcoma meetings and relevant clinical trials as listed on the ClinicalTrials.gov website. Detailed data are presented and contextualized for ultra-hypofractionated and moderately hypofractionated regimens with respect to local control, wound complications, and amputation rates. Comparative data are also presented for late toxicities including: fibrosis, joint limitation, edema, skin integrity, and bone fracture or necrosis. These data are compared to a standard regimen of 50 Gy in 25 daily fractions delivered over 5 weeks. This analysis supports the continued use of a standard regimen for preoperative RT for STS of 25 × 2 Gy over 5 weeks without concurrent chemotherapy. Use of concurrent chemotherapy with preoperative RT for STS should be reserved for well-designed clinical trials. A randomized trial of ultra-hypofractionated and moderately hypofractionated pre op RT for STS is warranted, but it is critical for the primary endpoint (or co-primary endpoint) to be late toxicity to: bone, soft tissue, joint, and skin.

Moderate hypofractionated radiation therapy and pathologic response for soft tissue sarcomas (STS) of limbs and trunk: experience from a tertiary cancer center

BACKGROUND

Preoperative radiation therapy following by limb-sparing or conservative surgery is a standard approach for limb and trunk STS. Data supporting hypofractionated radiotherapy schedules are scarce albeit biological sensitivity of STS to radiation would justify it. We sought to evaluate the impact of moderate hypofractionation on pathologic response and its influence on oncologic outcomes.

MATERIAL AND METHODS

From October 2018 to January 2023, 18 patients with limb or trunk STS underwent preoperative radiotherapy at a median dose of 52.5 Gy (range 49.5-60 Gy) in 15 fractions of 3.5 Gy (3.3-4 Gy) with or without neoadjuvant chemotherapy. A favorable pathologic response (fPR) was considered as ≥ 90% tumor necrosis on specimen examination.

RESULTS

All patients completed planned preoperative radiotherapy. Eleven patients (61.1%) achieved a fPR, and 7 patients (36.8%) a complete pathologic response with total disappearance of tumor cells. Nine patients (47%) developed grade 1-2 acute skin toxicity, and 7 patients (38.8%) had wound complications on follow-up. With a median follow-up of 14 months (range 1-40), no cases of local relapse were observed, and actuarial 3-year overall survival (OS) and distant metastases-free survival (DMFS) are 87% and 76.4%, respectively. In the univariate analysis, the presence of a favorable pathologic response (fPR) was associated with improved 3-year OS (100% vs. 56.03%, p = 0.058) and 3-year DMFS (86.91% vs. 31.46%, p = 0.002). Moreover, both complete or partial RECIST response and radiological stabilization of the tumor lesion showed a significant association with higher rates of 3-year distant metastasis-free survival (DMFS) (83% vs. 83% vs. 56%, p < 0.001) and 3-year overall survival (OS) (100% vs. 80% vs. 0, p = 0.002).

CONCLUSIONS

Preoperative moderate hypofractionated radiation treatment for STS is feasible and well tolerated and associates encouraging rates of pathologic response that could have a favorable impact on final outcomes.

Neoadjuvant hypofractionated radiotherapy and chemotherapy for extremity soft tissue sarcomas: Safety, feasibility, and early oncologic outcomes of a phase 2 trial

BACKGROUND AND PURPOSE

Optimal treatment of extremity soft tissue sarcomas (ESTS) is controversial. The aim of this study was to evaluate neoadjuvant chemotherapy (ChT) plus concomitant hypofractionated RT (hypo-RT) in local and distant disease relapse. Here we report safety, feasibility and early outcomes.

MATERIALS AND METHODS

This was a prospective, single arm study with a goal accrual of 70 patients. Between 2015 and 2018, 18 patients with histologically confirmed nonmetastatic ESTS were assigned to receive doxorubicin and ifosfamide for three neoadjuvant cycles, concomitant with hypo-RT (25 Gy in 5 fractions) followed by surgery. The primary endpoint was disease-free survival (DFS). Secondary outcomes were pathologic response, wound complications (WC), and morbidity rates.

RESULTS

Median follow-up was 29 months. At last follow-up, 13/18 patients were alive without evidence of local or systemic disease (DFS 72%), 1 had died due to metastatic disease, and 3 were alive with distant metastasis. One patient presented with local relapse within the irradiated field. Mean DFS time was 48.6 months (95% CI: 37.3-59.9). Six patients (33%) had no residual viable tumor detected in pathologic specimens (3 of these myxoid liposarcomas). There was a significant difference in WC among patients with acute RT skin toxicity. Six patients (33%) developed major WC. No grade 3 or 4 ChT adverse events were reported.

CONCLUSION

Despite the limited sample size, these early outcomes demonstrate that this treatment regimen is feasible and well tolerated with high rates of limb preservation, local control, and pathologic complete response, supporting further investigation in a multi-institutional setting.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02812654; https://clinicaltrials.gov/ct2/show/NCT02812654.