Prospective trial of preoperative concomitant boost radiotherapy with continuous infusion 5-fluorouracil for locally advanced rectal cancer.
BACKGROUND
To evaluate the response to a concomitant boost given during standard chemoradiation for locally advanced rectal cancer.


METHODS
Concomitant boost radiotherapy was administered preoperatively to 45 patients with locally advanced rectal cancer in a prospective trial. Treatment consisted of 45 Gy to the pelvis with 18 mV photons at 1.8 Gy/fraction using a 3-field belly board technique with continuous infusion 5FU chemotherapy (300mg/m(2)) 5 days per week. The boost was given during the last week of therapy with a 6-hour inter-fraction interval to the tumor plus a 2-3 cm margin. The boost dose equaled 7.5 Gy/5 fractions (1.5 Gy/fraction); a total dose of 52.5 Gy/5 weeks was given to the primary tumor. Pretreatment tumor stage, determined by endorectal ultrasound and CT scan, included 29 with T3N0 [64%], 11 T3N1, 1 T3Nx, 2 T4N0, 1 T4N3, and 1 with TxN1 disease. Mean distance from the anal verge was 5 cm (range 0-13 cm). Median age was 55 years (range 33-77 years). The population consisted of 34 males and 11 females. Median time of follow-up is 8 months (range 1-24 months).


RESULTS
Sphincter preservation (SP) has been accomplished in 33 of 42 (79%) patients resected to date. Three patients did not undergo resection because of the development of metastatic disease in the interim between the completion of chemoradiation (CTX/XRT) and preoperative evaluation. The surgical procedures included proctectomy and coloanal anastomosis (n = 16), low anterior resection (n = 13), transanal resection (n = 4). Tumor down-staging was pathologically confirmed in 36 of the 42 (86%) resected patients, and 13 (31%) achieved a pathologic CR. Among the 28 tumors (67%) located <6 cm from the anal verge, SP was accomplished in 21 cases (75%). Although perioperative morbidity was higher, toxicity rates during CTX/XRT were comparable to that seen with conventional fractionation. Compared to our contemporary experience with conventional CTX/XRT (45Gy; 1.8 Gy per fraction), improvements were seen in SP (79% vs. 59%; p = 0.02), SP for tumors <6 cm from the anal verge (75% vs. 42%; p = 0.003), and down-staging (86% vs. 62%; p = 0.003).


CONCLUSIONS
The SP rate with concomitant boost radiation has been highly favorable with rates of response which are higher than those previously reported for chemoradiation without administration of a boost. Further evaluation of this radiotherapeutic strategy appears warranted.
Janjan
N A
NA
Department of Radiation Oncology, University of Texas, M.D. Anderson Cancer Center, Houston 77030, USA.
Crane
C N
CN
Feig
B W
BW
Cleary
K
K
Dubrow
R
R
Curley
S A
SA
Ellis
L M
LM
Vauthey
J
J
Lenzi
R
R
Lynch
P
P
Wolff
R
R
Brown
T
T
Pazdur
R
R
Abbruzzese
J
J
Hoff
P M
PM
Allen
P
P
Brown
B
B
Skibber
J
J
D000328:Adult; D000368:Aged; D001003:Anal Canal / Q000601:surgery; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use*; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011446:Prospective Studies; D011879:Radiotherapy Dosage; D012004:Rectal Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy* / Q000601:surgery
D000964:Antimetabolites, Antineoplastic; D005472:Fluorouracil