Immunotherapy combined with anti-angiogenic therapy, radiotherapy and chemotherapy for the treatment of giant pelvic osteosarcoma: A case report and literature review.

Current therapeutic strategies for pelvic osteosarcoma remain limited, primarily relying on chemotherapy and surgery. Patients ineligible for surgery or those who develop chemoresistance generally have a poor prognosis. The present study reported the case of a 25-year-old female with giant pelvic osteosarcoma who missed the initial surgical window and developed lung metastases. Through a multimodal regimen incorporating chemotherapy, radiotherapy, anti-angiogenic therapy and immunotherapy, sufficient tumor control was successfully achieved to permit surgical resection. The patient maintained a stable condition with no signs of recurrence during follow-up until August 2025. This case underscores the potential of combining novel immunotherapeutic and anti-angiogenic agents with conventional modalities to convert inoperable pelvic osteosarcoma into a resectable state, thereby improving patient outcomes.