Does imatinib turn recurrent and/or metastasized gastrointestinal stromal tumors into a chronic disease? - single center experience.
BACKGROUND
Gastrointestinal stromal tumors (GIST) are mesenchymal tumors of the gastrointestinal tract supposed to arise from the cells of Cajal because of gain-of-function mutations of the tyrosine receptor kinases c-kit or platelet-derived growth factor receptor A. Imatinib selectively inhibits the kinase activity of both receptors. Despite this breakthrough in the treatment of GIST, resistance against imatinib has been reported to be as high as 50% after the first 2 years of treatment.


OBJECTIVE
Outcome of 13 consecutive patients with relapsed or metastasized GIST who were treated with imatinib was analyzed.


RESULTS
Mean duration of treatment was 53.5 months. Four patients developed progressive disease and died after a mean treatment time of 31 months in spite of increase of imatinib dosages to 800 mg daily. Two patients (23%) developed a progressive disease after 46 months or 52 months of treatment. Two patients had a stable disease and five had a partial response. The overall progression rate was 46%, the mean survival time since primary diagnosis was 85.8 months.


CONCLUSIONS
From our experience, frequency of resistance development to imatinib may be below that given in the literature (50% after 2 years). Individual treatment in specialized centers may improve compliance.
Armbrust
Thomas
T
Department of Gastroenterology and Endocrinology, Georg-August-University of Göttingen, Germany.
Sobotta
Michael
M
Gunawan
Bastian
B
Füzesi
Laszlo
L
Langer
Claus
C
Cameron
Silke
S
Ramadori
Giuliano
G
D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D002908:Chronic Disease; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy* / Q000235:genetics / Q000401:mortality; D006801:Humans; D000068877:Imatinib Mesylate; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D010879:Piperazines / Q000627:therapeutic use*; D011379:Prognosis; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D011743:Pyrimidines / Q000627:therapeutic use*; D017459:Receptors, Amino Acid / Q000037:antagonists & inhibitors; D017479:Receptors, Platelet-Derived Growth Factor / Q000037:antagonists & inhibitors*; D016019:Survival Analysis; D016896:Treatment Outcome
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D017459:Receptors, Amino Acid; C087659:tyrosine receptor; D000068877:Imatinib Mesylate; D017479:Receptors, Platelet-Derived Growth Factor