A phase I trial of S-1 with concurrent radiotherapy in patients with locally recurrent rectal cancer.
BACKGROUND
The purpose of this phase I trial of S-1 chemotherapy in combination with pelvic radiotherapy for locally recurrent rectal cancer was to determine the maximum tolerated dose (MTD), recommended dose (RD), and dose-limiting toxicity (DLT) of S-1.


METHODS
We enrolled 9 patients between April 2005 and March 2009. Radiotherapy (total dose, 60 Gy in 30 fractions) was given to the gross local recurrent tumor and pelvic nodal metastases using three-dimensional radiotherapy planning. We administered oral S-1 twice a day on days 1-14 and 22-35 during radiotherapy. The dose of S-1 was initially 60 mg/m(2)/day and was increased to determine the MTD and RD for this regimen.


RESULTS
DLT appeared at dose level 2 (70 mg/m(2)/day) in 2 patients, who experienced grade 3 enterocolitis and consequently required suspension of S-1 administration for longer than 2 weeks. Hematological toxicity was mild and reversible. At the initial evaluation, complete regression and partial regression were seen in 1 patient (11%) and 2 patients (22%), respectively.


CONCLUSIONS
This phase I trial of S-1 chemotherapy with pelvic radiotherapy for locally recurrent rectal cancer revealed that the MTD for S-1 was 70 mg/m(2)/day and the RD was 60 mg/m(2)/day.
Department of Radiation Oncology, Miyagi Cancer Center, Nodayama 47-1, Medeshima-shiote, Natori, 981-1293, Japan. hhktk981@gmail.com
Hitoshi
H
Wada
Kenji
K
Nemoto
Takuma
T
Nomiya
Misako
M
Murakami
Motohisa
M
Suzuki
Yuuki
Y
Kuroda
Mayumi
M
Ichikawa
Ibuki
I
Ota
Yasuhito
Y
Hagiwara
Hisanori
H
Ariga
Ken
K
Takeda
Kenji
K
Takai
Keisuke
K
Fujimoto
Masahiro
M
Kenjo
Kazuhiko
K
Ogawa
D000368:Aged; D003131:Combined Modality Therapy; D004338:Drug Combinations; D005260:Female; D006801:Humans; D008297:Male; D020714:Maximum Tolerated Dose; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D010094:Oxonic Acid / Q000008:administration & dosage*; D011829:Radiation Dosage; D012004:Rectal Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D005641:Tegafur / Q000008:administration & dosage*
D004338:Drug Combinations; C079198:S 1 (combination); D005641:Tegafur; D010094:Oxonic Acid