Postradiation Osteosarcoma in an Older Prostate Cancer Survivor: Case Study and Literature Review with Emphasis on Geriatric Principles

The aging population and the increasing number of cancer survivors will likely be associated with more second primary malignancies due to prior cancer treatment. Since the incidence of most cancers increases with age, these treatment-associated second malignancies will likely disproportionately impact older adults. Here, we present the case of a 78-year-old man with a history of localized prostate cancer treated with external beam radiation therapy 11 years prior, who developed osteosarcoma of the ilium. Geriatric screening showed a fit older male with few comorbidities, functional independence and no other geriatric syndromes. Given the patient's preference for a limb-sparing operation, neoadjuvant chemotherapy was undertaken. With the paucity of clinical trial data on osteosarcoma in older adults, the patient was given a regimen of carboplatin (substituted for cisplatin), doxorubicin and methotrexate. Unfortunately, he developed methotrexate-induced acute kidney injury. Chemotherapy was discontinued, and he proceeded to hemipelvectomy. His postoperative course was marked by numerous complications, including delirium, depression and recurrent hospitalizations. He ultimately developed a local recurrence and elected for hospice care. This case highlights the challenges of managing older adults with treatment-associated malignancies. Clinicians face a lack of clinical trial data from which to extrapolate limitations of therapeutic options because of prior therapy and a limited ability to precisely predict which elders will experience adverse outcomes. Better approaches are needed to help older patients make decisions which fulfill their goals of care and to improve the care of older adults with treatment-associated malignancies.