Two-year adjuvant imatinib mesylate after complete resection of localized, high-risk GIST with KIT exon 11 mutation.
OBJECTIVE
To evaluate the efficacy and safety of 2-year adjuvant imatinib for patients at high risk of recurrence after complete resection of localized gastrointestinal stromal tumor with KIT exon 11 mutation.


METHODS
Imatinib 400 mg/d was administered until disease recurrence, intolerable toxicities, or for 2 years. The primary end point was recurrence-free survival.


RESULTS
Patients (n = 47) from 4 centers in Korea were enrolled. Treatment was well tolerated. Grade 3-4 toxicities included neutropenia (27.7%), skin rash (8.5%), anorexia (4.3%), and constipation (2.1%). At a median follow-up of 56.7 months, 19 patients had recurrences. Median recurrence-free survival was 58.9 months, which was significantly longer than 22.7 months from historical data of 27 patients in the pre-imatinib era (P < 0.0001). Imatinib was rechallenged for 15 patients with recurrence after completion of adjuvant imatinib. Thirteen patients had partial response, and two had stable disease. There was only one death so far.


CONCLUSIONS
Postoperative adjuvant imatinib for 2 years was safe and could prolong the recurrence-free survival in patients with a high risk of recurrence after complete resection of localized KIT exon 11 mutated gastrointestinal stromal tumor. Reintroduction of imatinib after recurrence appears to be effective if the recurrence develops after completion of adjuvant imatinib.
Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea. ykkang@amc.seoul.kr
Yoon-Koo
YK
Kang
Byung Woog
BW
Kang
Seock-Ah
SA
Im
Jae-Lyun
JL
Lee
Sook Ryun
SR
Park
Won Ki
WK
Kang
Heung Moon
HM
Chang
Tae Won
TW
Kim
Do-Youn
DY
Oh
Kyung Hae
KH
Jung
Min-Hee
MH
Ryu
D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001549:Benzamides; D017024:Chemotherapy, Adjuvant / Q000379:methods; D018572:Disease-Free Survival; D005091:Exons; D005260:Female; D005500:Follow-Up Studies; D005770:Gastrointestinal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000601:surgery; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy* / Q000235:genetics / Q000601:surgery; D006801:Humans; D000068877:Imatinib Mesylate; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009364:Neoplasm Recurrence, Local; D010879:Piperazines / Q000009:adverse effects / Q000627:therapeutic use*; D011446:Prospective Studies; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D011743:Pyrimidines / Q000009:adverse effects / Q000627:therapeutic use*; D056910:Republic of Korea; D016896:Treatment Outcome
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D019009:Proto-Oncogene Proteins c-kit