The use of 5-fluorouracil (5-FU) as adjuvant therapy in advanced colorectal cancer: (GT 115)
|A||Significantly increases 5-year survival|
|B||Significantly decreases 5-year survival|
|C||Has no demonstrable benefit to 5-year survival|
|D||None of the above|
a. 5-FU remains the backbone of treatment for this disease. Partial responses are obtained in 15–20% of patients.
b. The concomitant administration of folinic acid (leucovorin) improves the efficacy of 5-FU in patients with advanced colorectal cancer, presumably by enhancing the binding of 5-FU to its target enzyme, thymidylate synthase.
c. A threefold improvement in the partial response rate is noted when folinic acid is combined with 5-FU; however, the effect on survival is marginal, and the optimal dose schedule remains to be defined.
e. Irinotecan (CPT-11), a topoisomerase 1 inhibitor, prolongs survival when compared to supportive care in patients whose disease has progressed on 5-FU.
f. The FOLFIRI regimen is as follows: irinotecan, 180 mg/m2 as a 90-min infusion day 1; LV, 400 mg/m2 as a 2-h infusion during irinotecan, immediately followed by 5-FU bolus, 400 mg/m2 and 46-h continuous infusion of 2.4–3 g/m2 every 2 weeks.
g. Diarrhea is the major side effect from irinotecan.
h. Oxaliplatin, a platinum analogue, also improves the response rate when added to 5-FU and LV as initial treatment of patients with metastatic disease.
i. The FOLFOX regimen is the following: 2-h infusion of LV (400 mg/m2 per day) followed by a 5-FU bolus (400 mg/m2 per day) and 22-h infusion (1200 mg/m2) every 2 weeks, together with oxaliplatin, 85 mg/m2 as a 2-h infusion on day 1.
j. Oxaliplatin frequently causes a dose-dependent sensory neuropathy that usually resolves following the cessation of therapy.