The role of radiation therapy in the treatment of esophagus cancer

Abstract

Historical series of external beam radiation therapy alone report 5-year survival rates of 0%–10%. In general, radiation therapy alone should be reserved for palliation or for patients who are medically unable to receive chemotherapy. In the RTOG 85-01 randomized trial, patients with T1–4 primarily squamous cell cancers received 5-FU, cisplatin, and concurrent 50 Gy. The control arm was radiation therapy alone (64 Gy). Patients who received combined modality therapy (CMT) had a significant improvement in both median (14 months vs 9 months), and 5-year survival (27% vs 0%). With a minimum follow-up of 5 years, the 8-year survival was 22%. The incidence of local failure and/or persistence was also lower in the CMT arm (47% vs 65%). INT 0123 was the follow-up trial to RTOG 85-01 to test if higher doses of radiation were helpful. Patients were randomized to a slightly modified RTOG 85-01 CMT regimen with 50.4 Gy versus the same chemotherapy with a higher dose of radiation (64.8 Gy). For the 218 eligible patients, there was no significant difference in median survival (13.0 vs 18.1 months), 2-year survival (31% vs 40%), or local/regional failure and/or local/regional persistence of disease (56% vs 52%) between the high-dose and standard-dose arms. Recent trials have used more novel agents such as paclitaxel, docetaxel, or irinotecan-based chemotherapy. Brachytherapy alone is as a palliative modality and results in a local control rate of 25%–35% and a median survival of approximately 5 months. In the RTOG 92-07 trial, 75 patients received the RTOG 85-01 CMT regimen followed by a intraluminal boost. Local failure was 27%, the cumulative incidence of fistula was 18%/year, and the crude incidence was 14%. Therefore, the additional benefit of adding intraluminal brachytherapy to radiation or combined modality therapy, although reasonable, remains unclear. In the adjuvant setting, one randomized trial reveals a survival advantage with postoperative CMT. A meta-analysis from the Oesphageal Cancer Collaborative Group also showed no clear evidence of a survival advantage with preoperative radiation. There are four randomized trials comparing preoperative CMT with surgery alone in patients with clinically resectable disease; the results are conflicting. Although this approach is reasonable, it remains investigational.