according to the RTOG acute radiation morbidity scoring criteria. Late complications in the esophagus included grade 3 for 4patients (6%) and grade 5 for 2 patients (3%) according to the RTOG late radiation morbidity scoring criteria.

Conclusions: The results suggest that proton radiation therapy is an effective modality for patients with locally confinedesophageal cancer. Local control rate for patients irradiated with accelerated fractionation might be better than that forthose irradiated with conventional fractionation. Further studies are needed to determine the role of acceleratedfractionation, optimal fractionation regimens, and optimal combinations of protons and x-rays in the treatment ofesophageal carcinoma with protons.

1033 Neoadjuvant Chemoradiation with Capecitabine Versus Infusional 5-fluorouracil (5-FU) for LocallyAdvanced Rectal Cancer: A Matched Pair Analysis

P. Das,1 E.H. Lin,2 S. Bhatia,1 J.M. Skibber,3 M.A. Rodriguez-Bigas,3 B.W. Feig,3 P.M. Hoff,2 C. Eng,2 R.A. Wolff,2

S. Krishnan,1 N.A. Janjan,1 C.H. Crane1

1Radiation Oncology, U.T. M.D. Anderson Cancer Center, Houston, TX, 2Gastrointestinal Medical Oncology, U.T. M.D.Anderson Cancer Center, Houston, TX, 3Surgical Oncology, U.T. M.D. Anderson Cancer Center, Houston, TX

Purpose/Objective: To retrospectively compare pathologic response, acute toxicity, relapse rate, and survival in locallyadvanced rectal cancer patients treated with pre-operative radiotherapy and either concurrent capecitabine, or concurrentinfusional 5-FU.

Materials/Methods: Between June 2001 and February 2004, 89 patients with rectal adenocarcinoma with no evidence ofdistant metastasis were treated with pre-operative radiotherapy and concurrent capecitabine, followed by mesorectal excision.These patients were individually matched by clinical T and N stage (based on endoscopic ultrasound and CT) with 89 controlpatients treated with pre-operative radiotherapy and concurrent infusional 5-FU, between September 1997 and August 2002.Clinical T stage was T2 in 8%, T3 in 85%, and T4 in 7%. Clinical nodal stage was N0 in 57%, and N1-2 in 43%. Medianradiation dose was 52.5 Gy in both groups. The median dose of capecitabine was 1650 (range 1050–2000) mg/m2/day and themedian dose of 5-FU was 300 (range 250–300) mg/m2. Ninety per cent of patients in each group received adjuvantchemotherapy. The median follow-up was 20.6 months for patients treated with capecitabine and 44.2 months for those treatedwith infusional 5-FU.

Results: The pathologic complete response rate was 21% with capecitabine and 12% with infusional 5-FU (p�0.19). Forty-six(52%) patients in the capecitabine group and 55 (62%) patients in the 5-FU group had downstaging of the T stage afterchemoradiation (p�0.20). The pathologic stage in the capecitabine group was � T1 in 26%, T2 in 25%, T3 in 44%, T4 in 6%,N0 in 73% and N1-2 in 27%. The pathologic stage in the 5-FU group was � T1 in 29%, T2 in 35%, T3 in 32%, T4 in 5%,N0 in 70% and N1-2 in 30%. Sixty-nine (78%) patients in the capecitabine group and 62 (70%) patients in the 5-FU groupsubsequently underwent a sphincter-sparing surgery (p�0.32). In each group, 5 (6%) patients had grade 3–4 toxicity duringchemoradiation. Patients treated with capecitabine had higher rates of hand foot syndrome (p�0.002, all grade 1–2), andpatients treated with 5-FU had higher rates of mucositis (p�0.03). There was a trend towards a higher rate of diarrhea in patientstreated with 5-FU (� grade 2 diarrhea in 45 patients in the capecitabine group and 62 patients in the 5-FU group, p�0.06). Onlyone patient had grade 3 hematologic toxicity (capecitabine group). Three patients in the capecitabine group and 2 patients inthe 5-FU group required hospitalization during chemoradiation. Nine patients in each group required either dose reduction ordiscontinuation of chemotherapy. At a follow-up of 20 months, the locoregional relapse-free survival was 97% for thecapecitabine group and 100% for the 5-FU group (p�0.46), the distant metastasis-free survival was 90% for the capecitabinegroup and 93% for the 5-FU group (p�0.67), and the overall survival was 99% for the capecitabine group and 100% for the5-FU group (p�0.61).

Conclusions: No significant differences were seen in pathologic response, sphincter-preservation, local and distant recurrence,and overall survival in patients treated with radiation and concurrent capecitabine, compared to those treated with radiation andconcurrent 5-FU. Both regimens were well tolerated, with similar, low rates of grade 3–4 acute toxicity. Longer follow-up iswarranted to evaluate rates of local and distant failure and survival in rectal cancer patients treated with pre-operativeradiotherapy with concurrent capecitabine. The NSABP R-04 trial is also addressing this issue.

1034 Impact of Pretreatment Tumor Size and Lymph Nodes on Pathologic Complete Response and Survival ina Prospective Trial of Chemoradiation for Locally Advanced Rectal Cancer

C. Kim,1 P.R. Anne,1 E. Mitchell,2 E. Pequignot,3 J. Palazzo,4 S. Goldstein,5 G. Isenberg,5 W. Curran, Jr.1

1Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, 2Medical Oncology, Thomas Jefferson University,Philadelphia, PA, 3Medicine, Division of Clinical Pharmacology, Biostatistics Section, Thomas Jefferson University,Philadelphia, PA, 4Pathology, Thomas Jefferson University, Philadelphia, PA, 5Surgery, Thomas Jefferson University,Philadelphia, PA

Purpose/Objective: Preoperative chemoradiation (CRT) is becoming the standard therapy for locally advanced rectal cancerpatients. Prognostic factors are important to determine response and outcome. We previously demonstrated that highmicrosatellite instability and p21 are predictive for pathologic complete response (pCR) in patients treated with preoperativeCRT (Charara et al. Anticancer Research, 2004). The aim of this study was to determine if tumor size and lymph node statusare predictive for pCR and survival.

Materials/Methods: 67 patients with locally advanced rectal cancer (cT3/T4) were treated with preoperative CRT on Phase I/IIclinical trial. Patients received CPT-11 (30–50 mg/m2 on days 1,8,15,22) and 5-FU (protracted continuous infusion 300 mg/m2initially, then 225 mg/m2/day on days 1–5 weekly during radiation therapy) and standard radiation therapy (RT) (45–54 Gy).Surgery was performed at 6�10 weeks following completion of therapy. A total of 58 patients were evaluable for tumor size

S164 I. J. Radiation Oncology ● Biology ● Physics Volume 63, Number 2, Supplement, 2005