TriangleHEALTH PROFESSIONAL · SOURCE READING
Postoperative chemoradiation therapy
Source: Rectal Cancer Treatment (PDQ®)–Health Professional Version, National Cancer Institute.
Source updated: February 12, 2025 · Captured 2026-09-09.
Selected source text with whitespace normalised. This Triangle page is not an NCI PDQ summary. Independent clinical review is pending.
Context: Treatment of Stages II and III Rectal Cancer / Treatment Options for Stages II and III Rectal Cancer
Progress in the development of postoperative treatment regimens relates to the integration of systemic chemotherapy and radiation therapy, as well as redefining the techniques for both modalities. The efficacy of postoperative radiation therapy and 5-FU-based chemotherapy for stages II and III rectal cancer was established by a series of prospective, randomized clinical trials, including:[9-11][Level of evidence A1]
Source links and citations
Gastrointestinal Tumor Study Group (GITSG-7175).
Mayo/North Central Cancer Treatment Group (NCCTG-794751).
National Surgical Adjuvant Breast and Bowel Project (NSABP-R-01).
These studies demonstrated an increase in DFS interval and OS when radiation therapy was combined with chemotherapy after surgical resection. After the publication in 1990 of the results of these trials, experts at a National Cancer Institute-sponsored Consensus Development Conference recommended postoperative combined-modality treatment for patients with stages II and III rectal carcinoma.[12] Since that time, preoperative chemoradiation therapy has become the standard of care, although postoperative chemoradiation therapy is still an acceptable alternative. For more information, see the Preoperative chemoradiation therapy section.
Source links and citations
Additional evidence (postoperative chemoradiation therapy):
Intergroup protocol 86-47-51 (MAYO-864751) compared continuous-infusion 5-FU (225 mg/m2/day throughout the entire course of radiation therapy) with bolus 5-FU (500 mg/m2/day for 3 consecutive days during the first and fifth weeks of radiation therapy).[13][Level of evidence A1]
Source links and citations
Intergroup protocol 86-47-51 (MAYO-864751) compared continuous-infusion 5-FU (225 mg/m2/day throughout the entire course of radiation therapy) with bolus 5-FU (500 mg/m2/day for 3 consecutive days during the first and fifth weeks of radiation therapy).[13][Level of evidence A1]
A 10% improvement in OS was demonstrated with the use of continuous-infusion 5-FU.
A three-arm randomized trial determined whether continuous-infusion 5-FU given throughout the entire standard six-cycle course of adjuvant chemotherapy was more effective than continuous infusion 5-FU given only during pelvic radiation therapy. Median follow-up was 5.7 years.[14]
Source links and citations
A three-arm randomized trial determined whether continuous-infusion 5-FU given throughout the entire standard six-cycle course of adjuvant chemotherapy was more effective than continuous infusion 5-FU given only during pelvic radiation therapy. Median follow-up was 5.7 years.[14]
Arm 1 received bolus 5-FU in two 5-day cycles before (500 mg/m2/day) and after (450 mg/m2/day) radiation therapy, with protracted venous infusion 5-FU (225 mg/m2/day) during radiation therapy.
A three-arm randomized trial determined whether continuous-infusion 5-FU given throughout the entire standard six-cycle course of adjuvant chemotherapy was more effective than continuous infusion 5-FU given only during pelvic radiation therapy. Median follow-up was 5.7 years.[14]
Arm 2 received continuous infusion 5-FU before (300 mg/m2/day for 42 days), after (300 mg/m2/day for 56 days), and during (225 mg/m2/day) radiation therapy.
A three-arm randomized trial determined whether continuous-infusion 5-FU given throughout the entire standard six-cycle course of adjuvant chemotherapy was more effective than continuous infusion 5-FU given only during pelvic radiation therapy. Median follow-up was 5.7 years.[14]
Arm 3 received bolus 5-FU/LV in two 5-day cycles before (5-FU, 425 mg/m2/day; LV, 20 mg/m2/day) and after (5-FU, 380 mg/m2/day; LV, 20 mg/m2/day) radiation therapy, and bolus 5-FU/LV (5-FU, 400 mg/m2/day; LV, 20 mg/m2/day; days 1 to 4, every 28 days) during radiation therapy. Levamisole (150 mg/day) was administered in 3-day cycles every 14 days before and after radiation therapy.
A three-arm randomized trial determined whether continuous-infusion 5-FU given throughout the entire standard six-cycle course of adjuvant chemotherapy was more effective than continuous infusion 5-FU given only during pelvic radiation therapy. Median follow-up was 5.7 years.[14] › Arm 3 received bolus 5-FU/LV in two 5-day cycles before (5-FU, 425 mg/m2/day; LV, 20 mg/m2/day) and after (5-FU, 380 mg/m2/day; LV, 20 mg/m2/day) radiation therapy, and bolus 5-FU/LV (5-FU, 400 mg/m2/day; LV, 20 mg/m2/day; days 1 to 4, every 28 days) during radiation therapy. Levamisole (150 mg/day) was administered in 3-day cycles every 14 days before and after radiation therapy.
No DFS, OS, or locoregional failure difference was detected (across all arms: 3-year DFS rate, 67%–69%; 3-year OS rate, 81%–83%; locoregional failure rate, 4.6%–8%).
A three-arm randomized trial determined whether continuous-infusion 5-FU given throughout the entire standard six-cycle course of adjuvant chemotherapy was more effective than continuous infusion 5-FU given only during pelvic radiation therapy. Median follow-up was 5.7 years.[14] › Arm 3 received bolus 5-FU/LV in two 5-day cycles before (5-FU, 425 mg/m2/day; LV, 20 mg/m2/day) and after (5-FU, 380 mg/m2/day; LV, 20 mg/m2/day) radiation therapy, and bolus 5-FU/LV (5-FU, 400 mg/m2/day; LV, 20 mg/m2/day; days 1 to 4, every 28 days) during radiation therapy. Levamisole (150 mg/day) was administered in 3-day cycles every 14 days before and after radiation therapy.
Lethal toxicity was less than 1%, with grades 3 to 4 hematologic toxicity in 55% of patients in arm 1 and in 49% of the patients in arm 3, versus in 4% of patients in the continuous-infusion arm.[14][Level of evidence A1]
Source links and citations
The final study results of Intergroup trial 0114 (INT-0114) showed no survival or local-control benefit with the addition of LV, levamisole, or both to 5-FU administered postoperatively for patients with stages II and III rectal cancers at a median follow-up of 7.4 years.[15][Level of evidence A1]
Source links and citations
A pooled analysis of 3,791 patients enrolled in clinical trials demonstrated that, for patients with T3, N0 disease, the 5-year OS rate with surgery plus chemotherapy (OS, 84%) compared favorably with the survival rates of patients treated with surgery plus radiation therapy and bolus chemotherapy (OS rate, 76%) or surgery plus radiation therapy and protracted-infusion chemotherapy (OS rate, 80%).[16]
Source links and citations
Publication references
Read the original reference and check its publication notices.
Preserved source evidence · Independent clinical review pending · Not medical advice