Neoadjuvant therapy for rectal cancer: Mature results from NSABP protocol R-04.

Abstract

390 Background: The primary aims were to: 1) compare capecitabine (Cape) and continuous intravenous infusion (CVI) 5-FU combined with pelvic radiation therapy (RT) given preoperatively for patients (pts) with stage II or III rectal cancer; 2) determine whether the addition of oxaliplatin (Ox) would improve pt outcomes. Preliminary results focusing on pathologic complete response, sphincter-sparing surgery, surgical downstaging, and toxicity were presented at ASCO 2011 (Roh: J Clin Oncol 29: 2011 Ab 3503). Methods: Pts with clinical stage II or III rectal cancer undergoing preoperative RT (4,500cGy in 25 fractions over 5 wks + boost of 540cGy-1080cGy in 3-6 daily fractions) were randomly assigned to one of four chemotherapy regimens in a 2x2 design: CVI 5-FU (225mg/m2 5 days/wk), with or without intravenous Ox (50mg/m2 /wk x 5) or oral Cape (825 mg/m2 BID 5 days/wk), with or without Ox (50mg/m2/wk x 5). The primary endpoint of local-regional (L-R) tumor control included L-R tumor recurrence, less than an R0 resection (complete surgical resection), and no surgery. Results: From July 2004 to August 2010, 1608 patients were randomly assigned and 99.2% were eligible. There were no significant differences in L-R tumor control, DFS, or OS between regimens for either the 5-FU-Cape (L-R p=0.98) or the Ox-none (L-R p=0.70) comparisons. The addition of Ox was associated with significantly more grade 3-4 diarrhea (p<0.0001). Analysis of the primary endpoint showed 3-yr rates of L-R tumor control ranged from 87.4%-88.2%. 3-yr rates of L-R recurrence among pts who underwent R0 resection ranged from 2-4 % for stage II pts, and from 4-11% for stage III pts. 16% of stage II and 26% of stage III pts developed distant metastases by 5 yrs. From 84% to 97% of pts received >80% of the ideal chemotherapy dose in combination with preoperative RT. Conclusions: CVI 5-FU or oral Cape combined with RT produced similar outcomes and toxicity profiles. Because use of oral Cape avoids the need for central venous catheters and ambulatory infusion pumps, it can be considered a new standard of care in this setting. The addition of Ox provided no improvement in outcomes but did add significant toxicity. Clinical trial information: NCT00058474.