Challenges in radiotherapy planning in patients with synchronous rectal and prostate cancer and hip prosthesis

Abstract

Prostate and rectal carcinomas, although among the most common malignancies in males, rarely exhibit synchronous diagnosis and treatment of both malignancies. This paper presents a case of a patient with synchronous prostate and rectal carcinoma and an artificial right hip, which complicates the creation of a radiotherapy plan. Case Report. A 76-year-old male was diagnosed with synchronous mucinous infiltrating adenocarcinoma of the rectum (T3N0M0) and adenocarcinoma of the prostate (T3aN0M0), confirmed by immunohistochemistry. He had a history of testicular carcinoma previously treated with orchiectomy, chemotherapy, and radiotherapy. The treatment approach involved neoadjuvant chemotherapy with 5-fluorouracil and leucovorin, following the protocol for rectal carcinoma, and concurrent radiotherapy for both rectal and prostate carcinoma. The presence of an artificial metal right hip prosthesis made the creation of the radiotherapy plan more challenging. The plan was developed by defining four target volumes and delineating artifacts in the soft tissue and bony structures. It was designed to deliver the prescribed dose using 6 MV photon energy during 25 radiotherapy sessions, applying a simultaneous integrated boost. The best dose delivery was achieved with the VMAT plan, and the analysis of dose-volume histograms (DVH) indicated satisfactory contributions to organs at risk. Conclusion. Individualized approaches in treating patients are particularly important in cases of synchronous tumors. As oncology patients tend to have longer overall survival, special attention must be given to the patient's quality of life, necessitating organ sparing during radiotherapy treatment. The complexity of treatment planning due to the presence of comorbidities and metal implants is overcome through excellent collaboration between radiation oncologists and medical physicists.