This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
Radiotherapy is most useful in which of the following: March 2010 
Select and explain. 
A. Choriocarcinoma, B. Osteosarcoma, C. Seminomas, D. Renal cell carcinoma
C: Seminomas
Answer: C: Seminomas 
Explanation: Ans. C: Seminomas Radiotherapy may be effective alone, or may require the addition of cytotoxic chemotherapy as in the more advanced stages of a Wilm's tumour and Hodgkin's disease. Radiosensitive tumor includes: Malignant lymphomas Seminomas Medulloblastoma Neuroblastoma Wilm's tumour Early cervical carcinoma Vaginal carcinoma Most head and neck tumours Radioresistant tumours are those that do not respond to radiotherapy. This group includes: Osteosarcoma Fibrosarcoma Liposarcoma Myosarcoma Malignant melanoma Large bowel adenocarcinomas Gliomas