Pathologic downstaging of T3-4Nx rectal cancer after chemoradiation: 5-fluorouracil vs. Tegafur.
OBJECTIVE
To describe downstaging effects in locally advanced rectal cancer induced by 2 fluopirimidine radiosensitizing agents given through different routes in conjunction with preoperative radiotherapy.


METHODS
From March 1995 to December 1999, two consecutive groups of patients with cT3-4Nx rectal cancer (94% CT scan, 71% endorectal ultrasound) were treated with either (1) 45-50 Gy (1.8 Gy/day, 25 fractions) and 5-fluorouracil (5-FU) (500-1,000 mg/m2 by 24-h continuous i.v. infusion on Days 1-4 and 21-25) or (2) oral Tegafur (1,200 mg/day on Days 1-35, including weekends). Surgery was performed 4 to 6 weeks after the completion of chemoradiation.


RESULTS
The total T downstaging rate was 46% in the 5-FU group and 53% in the Tegafur group. Subcategories were downstaged by the sensitizing agents (5-FU vs. Tegafur) as follows: pT0-1, 14% vs. 23%; pT2, 32% vs. 32%; pT3, 49% vs. 37%; pT4, 5% vs. 7%; and N(0), 74% vs. 86%. Analysis of residual malignant disease in the specimen discriminated mic/mac subgroups (mic: <20% of microscopic cancer residue), with evident superior downstaging effects in the Tegafur-treated group: pTmic 23% vs. 58% (p = 0.002).


CONCLUSIONS
When administered concurrent with pelvic irradiation, oral Tegafur induced downstaging rates in both T and N categories superior to those induced by intermediate doses of 5-FU by continuous i.v. infusion. In this pilot experience, oral Tegafur reproduced the characteristics of downstaging described previously when full doses of 5-FU have been combined with radiotherapy.
Calvo
F A
FA
Department of Oncology, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
Gómez-Espí
M
M
Díaz-González
J A
JA
Cantalapiedra
R
R
Marcos
P
P
Alvarado
A
A
García Alfonso
P
P
Herranz
R
R
Alvarez
E
E
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy; D005641:Tegafur / Q000627:therapeutic use*
D000964:Antimetabolites, Antineoplastic; D005641:Tegafur; D005472:Fluorouracil