A 23-year-old previously healthy man comes to the office after noticing a painless, hard mass in the left testis. Scrotal ultrasound shows a solid testicular mass, and CT scan of the abdomen and pelvis shows left paraaortic lymphadenopathy. Left orchidectomy is performed and postoperative histopathology reveals seminoma of the testis. External beam radiotherapy is administered to the paraaortic metastatic area. Several weeks later, the retroperitoneal nodes are observed to have markedly decreased in size. Which of the following is the most likely effect of the therapy used on the metastatic cells in this patient?

Question

A 23-year-old previously healthy man comes to the office after noticing a painless, hard mass in the left testis.  Scrotal ultrasound shows a solid testicular mass, and CT scan of the abdomen and pelvis shows left paraaortic lymphadenopathy.  Left orchidectomy is performed and postoperative histopathology reveals seminoma of the testis.  External beam radiotherapy is administered to the paraaortic metastatic area.  Several weeks later, the retroperitoneal nodes are observed to have markedly decreased in size.  Which of the following is the most likely effect of the therapy used on the metastatic cells in this patient?

Quizplus · Accepted Answer

Eductional Objective: Exposure to ionizing radiation, including therapeutic and palliative radiation therapy, induces DNA damage through DNA double-strand fractures and the formation of oxygen free radicals.

A 23-Year-Old Previously Healthy Man Comes to the Office After