Adjuvant Treatment of Colon Cancer: Past, Present and Future

This manuscript summarizes recent progress in the adjuvant treatment of colon cancer. 5-Fluorouracil plus leucovorin, that have been considered standard therapy over the last 15 years, have now been replaced by combination chemotherapy, at least in stage III disease. The treatment of stage II disease is still somewhat less established. Prognostic and predictive biological markers are urgently needed for further fine-tuning of therapy. Molecular targeted agents have been developed with proven activity in advanced disease and are now being assessed in the adjuvant setting. It is expected that the inclusion of these new agents will lead to a further enhancement of treatment outcome. Those involved in the treatment of colorectal cancer should be encouraged to continue to provide optimal patient care and to participate in clinical trials in order to increase the evidence on which they can base their clinical judgement and to make further progress.

Randomized phase III trial comparing biweekly infusional fluorouracil/leucovorin alone or with irinotecan in the adjuvant treatment of stage III colon cancer: PETACC-3

PURPOSE The primary objective of this randomized, multicenter, phase III trial was to investigate whether the addition of irinotecan to the de Gramont infusional fluorouracil (FU)/leucovorin (LV) adjuvant regimen (LV5FU2) would improve disease-free survival (DFS) in patients with stage III colon cancer. PATIENTS AND METHODS After curatively intentioned surgery, patients with stage II and III colon cancer were randomly allocated surgery to receive LV5FU2 (LV 200 mg/m(2) as a 2-hour infusion, followed by FU; as a 400 mg/m(2) bolus and then a 600 mg/m(2) continuous infusion over 22 hours, days 1 and 2, every 2 weeks for 12 cycles: de Gramont regimen) with or without irinotecan (180 mg/m(2) as a 30- to 90-minute infusion, day 1, every 2 weeks). In total, 260 (7.9%) of 3,278 patients received an alternative high-dose infusional FU/LV regimen (Arbeitsgemeinschaft Internische Onkologie regimen) with or without irinotecan. Results The principal efficacy analysis was based on 2,094 treated patients with stage III disease, randomly allocated in the LV5FU2 strata. After a median follow-up of 66.3 months, the 5-year DFS rate was 56.7% with irinotecan/LV5FU2 and 54.3% with LV5FU2 alone (primary end point: log-rank P = .106). Combining irinotecan with LV5FU2 did not significantly improve overall survival in this patient group compared with LV5FU2 alone (5-year rate 73.6% v 71.3%, respectively; log-rank P = .094). The addition of irinotecan to LV5FU2 was associated with an increased incidence of grade 3 to 4 GI events and neutropenia. CONCLUSION Irinotecan added to LV5FU2 as adjuvant therapy did not confer a statistically significant improvement in DFS or overall survival in patients with stage III colon cancer compared with LV5FU2 alone.

Progress and challenges in the adjuvant treatment of stage II and III colon cancers

Whereas the benefit of adjuvant 5-fluorouracil and leucovorin have been well established in resected stage III colon cancer, a significant benefit for patients with stage II disease has been more difficult to demonstrate. More recently, oxaliplatin-based chemotherapy with regimens such as oxaplatin plus 5-fluorouracil/leucovorin have been shown to improve disease-free and overall survival in these stage III patients. This review will discuss the development of adjuvant chemotherapy in colon cancer, focusing on recent progress and particular topical issues related to its use in this disease, such as the use of surrogate end points for overall survival in contemporary clinical trials.

Phase III study comparing a semimonthly with a monthly regimen of fluorouracil and leucovorin as adjuvant treatment for stage II and III colon cancer patients: final results of GERCOR C96.1

PURPOSE

This randomized, 2 x 2 factorial study compared a semimonthly regimen (fluorouracil [FU] and leucovorin [LV] semi-monthly is LV5FU2) with a monthly regimen of FU and LV (mFU/LV) as well as 24 weeks versus 36 weeks of each regimen as adjuvant treatment of stage II and III colon cancer.

PATIENTS AND METHODS

LV5FU2 was administered semimonthly for 2 days as racemate (dl) or levogyre (l-; 200 or 100 mg/m(2)) as a 2-hour infusion, followed by 400 mg/m(2) FU bolus and a 600-mg/m(2) FU 22-hour continuous infusion. FU and LV were administered monthly (mFU/LV) for 5 days as dl- or l-LV 15-minute infusion, followed by a 400 mg/m(2) FU 15-minute infusion. The primary end point was disease-free survival (DFS).

RESULTS

Between September 1996 and November 1999, 905 patients with stage II (43%) and III (57%) colon cancer were enrolled. The median follow-up was 6 years. There was no statistically significant difference between mFU/LV and LV5FU2 in terms of DFS (150 v 148 events; hazard ratio [HR],1.01; 95% CI, 0.806 to 1.269; P = .94) and overall survival (OS; 104 v 103 events; HR,1.02; 95% CI, 0.77 to 1.34; P = .91). No statistical difference was observed between 24 or 36 weeks of chemotherapy. Median survival from metastatic relapse was 24 months. The survival of patients with metastatic relapse (n = 243) was significantly longer for patients with a longer time from random assignment to relapse (< 1, 1 to 2, >or= 2 years; log-rank test for trend P, .0497).

CONCLUSION

DFS and OS were not statistically different between treatment groups and treatment durations. These data confirm the value of LV5FU2 as control arm in the Multicenter International Study of Oxaliplatin/5FU-LV in the Adjuvant Treatment of Colon Cancer and Pan-European Trials in Adjuvant Colon Cancer studies.

Highlights from the 42nd annual meeting of the American Society of Clinical Oncology

The results of approximately 3700 preclinical and clinical studies were presented at the 42nd annual meeting of the American Society of Clinical Oncology (ASCO) held 2-6 June 2006, in Atlanta, Georgia. The annual ASCO meeting is the largest forum in which oncology professionals from around the world report the latest advances in cancer research, encompassing a wide spectrum of subjects on molecular biology, prevention, diagnosis and therapy of tumours. The present report summarises some of the more important results of the studies presented at the meeting. In particular, the authors focused on findings from randomised Phase III trials that, in their opinion, are most likely to have an immediate effect on clinical practice. The top advances were grouped into four major themes (breast cancer, colorectal cancer, non-small cell lung cancer and selected presentations from the plenary session). In addition, selected Phase I and II studies on promising novel therapeutic agents were briefly described. Finally, a 'question and answer' format was adopted to report results of interesting studies on some hot topics.