Clinical outcome in gastrointestinal stromal tumor patients who interrupted imatinib after achieving stable disease or better response.
BACKGROUND
Imatinib has been found to be effective in the treatment of patients with gastrointestinal stromal tumors (GIST). We sought to evaluate the clinical outcome of imatinib interruption in GIST patients who had achieved stable disease (SD) or showed better response to imatinib therapy.


METHODS
From July 2001 to December 2004, we prospectively collected clinical data from 62 consecutive patients with advanced GIST, of whom 58 (93.5%) achieved SD or better response to imatinib therapy and were included in this study. Imatinib therapy was interrupted in 14 of the 58 patients (interruption group, INT), after a median time of 11.9 months. Progression-free survival (PFS) after imatinib interruption was calculated and imatinib-refractory PFS and overall survival (OS) were compared between the INT group and the 44 patients who continued imatinib treatment (continuation group, CONT).


RESULTS
After a median follow-up of 17.9 months following imatinib interruption, nine patients (64%) had progressive disease (PD) with a median PFS from the date of imatinib interruption of 10.0 months. Median PFS dated from the time of imatinib initiation in the INT group was 21.8 months (95% CI, 17.3-26.3 months), but was not reached in the CONT group (P=0.029). Following imatinib reintroduction in the INT group, 88% of patients achieved disease control. There were no statistically significant differences in imatinib-refractory PFS (P=0.405) and OS (P=0.498) between the groups.


CONCLUSIONS
In GIST patients controlled with imatinib, treatment might be interrupted, at least temporarily, when clinically warranted.
Lee
Jae-Lyun
JL
Division of Oncology, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Songpa-gu, Seoul, 138-736, Korea.
Ryu
Min-Hee
MH
Chang
Heung Moon
HM
Kim
Tae Won
TW
Kang
Hye Jin
HJ
Sohn
Hee Jung
HJ
Lee
Jung Shin
JS
Kang
Yoon-Koo
YK
D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D018572:Disease-Free Survival; D004334:Drug Administration Schedule; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000188:drug therapy* / Q000401:mortality; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy* / Q000401:mortality; D006801:Humans; D000068877:Imatinib Mesylate; D008297:Male; D008875:Middle Aged; D010879:Piperazines / Q000627:therapeutic use*; D011446:Prospective Studies; D011743:Pyrimidines / Q000627:therapeutic use*; D016896:Treatment Outcome
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate