ESTRO 2024 - Abstract Book

S2085

Clinical - Sarcoma, skin cancer, melanoma

ESTRO 2024

Eighty-two patients with a median age of 58 years (25-76) met the eligibility criteria. Six patients had resectable lung metastases at baseline. Most common sarcoma subtypes diagnosed in these patients were undifferentiated pleomorphic sarcoma - in 33 (40.2%) cases, myxofibrosarcoma - in 15 (18.3%), and malignant peripheral nerve sheath tumor - in 9 (11%). At baseline median tumor diameter was 148.5 mm and 43% of patients presented with anemia of chronic disease. Systemic therapy- related adverse events of grade ≥3 were reported in 39 (47.5%) patients, with most common lymphopenia in 29 (35%) patients, neutropenia in 10 (12%), and febrile neutropenia in 4 (4.9%) patients. Due to toxicity doxorubicin dose was reduced in 19 (23.2%) patients and 4 (4.9%) patients received only one cycle of chemotherapy.

En-bloc R0 resections were achieved in 60 (73%) patients.

Surgery-related adverse events according to the Clavien-Dindo classification were reported in 8 (10%) patients in grade 3a and in 2 (2.4%) patients in grade 3b. No life-threatening complications were reported after surgery. Wound dehiscence (CTCAE grade ≥3) occurred in 16 (20%) cases, but severe bleeding only in 3 (3.7%) patients. In total 10 (12%) patients required reoperation due to wound complications. Wound complications according to O’Sullivan occurred in 22 (27%) patients.

The median follow-up was 34.2 months.

We observed only mild late radiotherapy-related toxicities except for two cases of grade 3 complications that required hospitalization and intervention. Nine patients experienced local recurrence. Median RFS was 20.8 months (10.9 - 40) with 43% of patients free of recurrence at 3 years. , and median OS was not reached (3-year OS rate was 58%); while the longest overall survival was 81.6 months.

Conclusion:

Although preoperative radiotherapy is usually associated with a greater risk of wound complications than postoperative radiotherapy, early radiotherapy with a 6 to 8 weeks gap to surgery presents an acceptable ratio of surgery-related adverse events despite hypofractionation, combination with chemotherapy and the large tumor size in case of marginally resectable sarcomas. Moreover, the radiotherapy-related late toxicity of such a regimen seems to be not higher than in conventionally fractionated regimens.

Keywords: sarcoma, hypofractionation, toxicity

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