Twice-daily radiotherapy as concurrent boost technique during two chemotherapy cycles in neoadjuvant chemoradiotherapy for resectable esophageal carcinoma: mature results of phase II study.

PURPOSE: To determine the toxicities of neoadjuvant chemoradiotherapy using a three-drug regimen (cisplatin, 5-fluorouracil, and paclitaxel) and a conventional radiotherapy (RT) schedule combined with a concurrent boost technique during chemotherapy cycles, and to determine the rate of tumor response, overall survival, and impact of pathologic tumor response on survival.

METHODS AND MATERIALS: The eligibility criteria included resectable adenocarcinoma or squamous cell carcinoma (T2-T3N0-N1M0), performance score < or =2, and no significant comorbidities for trimodality therapy. Chemotherapy consisted of two cycles of cisplatin, 5-fluorouracil, and paclitaxel. A concurrent boost technique was used in RT for 2 levels of radiation doses: 58.5 Gy in 34 fractions within 5 weeks to the gross tumor volume and 45 Gy in 25 fractions within 5 weeks to the clinical target volume by administering a boost dose of 13.5 Gy in 9 fractions, 1.5 Gy/fraction, as a second daily fraction for 9 days on Days 1-5 and 29-32 of the chemotherapy cycles.

RESULTS: We enrolled 46 patients in the study. The paclitaxel dose was started at 75 mg/m(2) (n = 7) and escalated to 125 mg/m(2) (n = 5), at which point, dose-limiting toxicities occurred. Thereafter, paclitaxel at 100 mg/m(2) was used for an additional 34 patients. Toxicities included Grade 4 neutropenia (22%), febrile neutropenia requiring hospital admission (20%), Grade 3 (48%) and Grade 4 (7%) acute esophagitis, and paclitaxel-associated anaphylaxis (4%). Of the 46 patients, 3 (6.5%) died of treatment-related complications, 1 of pneumonia during induction therapy and 2 of postoperative complications (5% of the 40 patients who underwent resection). The histopathologic tumor response was a pathologic complete response (pT0N0) in 18 (45%) of 40 patients who underwent resection and 18 (39%) of all 46 registered patients. Minimal residual disease (pT1N0) at the primary site was present in 5 (11%) and residual disease in 23 (50%) of all 46 patients. The minimal follow-up for all long-term survivors (n = 16) was 5.5 years. The median survival time was 34 months, and the overall survival rate was 57%, 50%, and 37% at 2, 3, and 5 years, respectively. The 5-year overall survival (56% vs. 24%, p = 0.0214) and disease-free survival (48% vs. 6%) were significantly better statistically for patients with a pathologic complete response and minimal residual disease than for those with residual disease. All long-term survivors beyond 5.5 years without recurrence accrued from patient cohorts with a pathologic complete response or minimal residual disease.

CONCLUSION: An incorporation of twice-daily RT as a concurrent boost to the conventional daily RT schedule during chemotherapy cycles is feasible and warrants additional study for radiation dose intensification. Such research would be prudent for both improved long-term survival and organ preservation in esophageal carcinoma.