Abstract:

Background and purpose: Surgery alone is not enough to get satisfied outcome for locally high-risk soft tissue sarcoma (STS). We retrospectively assessed the short-term efficacy and safety of preoperative radiotherapy followed by surgery in patients with locally high-risk STS. Methods: Data from consecutive patients treated with preoperative radiotherapy at Fudan University Shanghai Cancer Center from February 2021 to June 2022 were reviewed. The data included clinical characteristics, radiotherapy regimes, radiological images and pathology slides. The target volumes of radiotherapy were delineated on computed tomography (CT) simulation images with reference to fused magnetic resonance imaging (MRI) images slides by slides. All the patients received radiotherapy planned with intensity-modulated radiotherapy (IMRT). Counting data was presented as percentages. The rates of radiological response (complete response, partial response, stable disease, progressive disease, objective response and disease control), pathological response [near-pathologic complete response (near-pCR), defined as ≥90% non-viable tumor cells] and toxicities (acute skin toxicity and major wound complications occurring within 120 d of surgery) were analyzed. Results: Forty-one patients received radiotherapy before surgery, among them 33 patients were eligible: 31 for radiological assessment and 28 for pathological assessment. The median age was 53 years. Thirty (90.0%) cases were histologically classified as Grade 3. Six (19.4%) patients achieved partial response, and 1 patient had progressive disease after radiotherapy. None got complete response. The objective response rate was 19.4%, and the disease control rate was 96.8%. Near-pCR was found in 8 (28.6%) patients. Excluding patients receiving chemotherapy previously, the near-pCR rate was 34.8% (8/23). Grade 1 and 2 skin injuries were found on 33.3% (11/33) and 3.0% (1/33) patients. No grade 3 and 4 skin injury occurred. Major wound complications within 120 d of surgery occured in 1 (3.3%) patient. Conclusion: Preoperative radiotherapy facilitated with fused MRI images and IMRT has good short-term efficacy and tolerable acute toxicities for locally high-risk STS.

Key words: Soft tissue sarcoma, Preoperative radiotherapy, Magnetic resonance imaging, Intensity-modulated radiotherapy, Objective response rate, Wound complication