33 A 55-year-old man with a 60 pack-year history of smoking has been diagnosed with a squamous cell carcinoma of thelarynx. He receives radiation therapy, 4000 cGy in divided doses, to treat the carcinoma. One year later, endoscopy shows no gross evidence of residual carcinoma. Which of the following is most likely to be present in this patient as a result of treatment? (A) Hypocellular bone marrow (B) Absent spermatogenesis (C) Colonic ulceration (D) Vascular fibrosis (E) Cerebral atrophy