Choice B rationale:

Metastasis to the lungs and other bones is a significant concern for Osteosarcoma patients.

Osteosarcoma has a high propensity to metastasize, and the lungs are one of the most common sites for metastatic spread.

Additionally, metastasis to other bones can occur, further complicating the patient's condition.

Monitoring for metastasis and early detection are essential to guide treatment decisions and improve outcomes.

Choice A rationale:

Gastrointestinal bleeding is not a common complication of Osteosarcoma.

While Osteosarcoma primarily affects the bones, it can potentially invade nearby soft tissues, but gastrointestinal bleeding is not a characteristic complication associated with this cancer.

Choice C rationale:

Allergic reactions to chemotherapy are a concern but not a specific complication of Osteosarcoma itself.

Allergic reactions can occur with various medications, including chemotherapy drugs, but they are not unique to Osteosarcoma patients.

Choice D rationale:

Development of autoimmune disorders is not a known complication of Osteosarcoma.

Osteosarcoma primarily involves the growth of malignant bone tissue and is not typically associated with autoimmune-related issues.