Final answer:
In treating bronchogenic carcinoma affecting the mediastinum and superior vena cava, radiation therapy may be used to alleviate symptoms and prolong life. Treatment protocols typically consist of multiple weekly treatments to minimize damage to healthy tissue. Both external beam radiation therapy and brachytherapy are potential options, depending on the specific case.
Step-by-step explanation:
The patient with bronchogenic carcinoma who has a tumor that has grown into the mediastinum and around the superior vena cava may be treated with radiation therapy. However, as lung tissue and blood are particularly sensitive to radiation, high doses are often not possible due to the risk of damaging these sensitive tissues. Therefore, while radiation therapy cannot typically cure lung cancer, it may be used to alleviate symptoms and prolong life. Treatment protocols typically involve three to five 200-rem treatments per week, over several weeks, to spare normal tissues and allow the body time to repair.
Given the location and type of tumor, the patient might also receive external beam radiation therapy, where multiple rays are directed from different angles to intersect at the tumor, minimizing damage to surrounding healthy tissue. In some cases, brachytherapy, which is internal radiation therapy, might be considered if it can be localized adequately to treat the tumor without excessive damage to sensitive structures. The therapeutic doses and treatment modalities would be carefully determined based on the patient's specific circumstances and the response to initial treatments.