Postoperative chemoradiation therapy

Preoperative chemoradiation therapy is the current standard of care for stages II and III rectal cancer. However, before 1990, the following studies noted an increase in both disease-free survival (DFS) and OS with the use of postoperative combined-modality therapy:

Subsequent studies have attempted to increase the survival benefit by improving radiation sensitization and by identifying the optimal chemotherapeutic agents and delivery systems.

Fluorouracil (5-FU): The following studies examined optimal delivery methods for adjuvant 5-FU:

For detailed information about these study results, see the Treatment of Stages II and III Rectal Cancer section.

Acceptable postoperative chemoradiation therapy for patients with stage II or III rectal cancer not enrolled in clinical trials includes continuous-infusion 5-FU during 45 Gy to 55 Gy pelvic radiation and four cycles of adjuvant maintenance chemotherapy with bolus 5-FU with or without modulation with leucovorin (LV).

Findings from the NSABP-R-01 trial compared surgery alone with surgery followed by chemotherapy or radiation therapy.[33] Subsequently, the NSABP-R-02 study (NCT00410579), addressed whether adding postoperative radiation therapy to chemotherapy would enhance the survival advantage reported in R-01.[34][Level of evidence A1]

In the NSABP-R-02 study, the addition of radiation therapy significantly reduced local recurrence at 5 years (8% for chemotherapy and radiation vs. 13% for chemotherapy alone, P = .02) but failed to demonstrate a significant survival benefit. Radiation therapy appeared to improve survival among patients younger than 60 years and among patients who underwent abdominoperineal resection.

While this trial has initiated discussion in the oncologic community about the proper role of postoperative radiation therapy, omission of radiation therapy seems premature because of the serious complications of locoregional recurrence.