Different factors are responsible for predicting relapses after primary tumors resection and for imatinib treatment outcomes in gastrointestinal stromal tumors.
BACKGROUND
The development of accurate diagnostic methods in gastrointestinal stromal tumors (GISTs) and the introduction of imatinib (IM) therapy has focused attention on the factors influencing the prognosis of patients with primary lesions as well as of patients with advanced disease treated with imatinib.


METHODS
The clinico-pathological and genetic factors influencing disease-free survival (DFS) in 335 patients with primary CD117-immunopositive tumors (group A; calculated from primary tumor resection) and progression-free survival (PFS) in 232 metastatic/unresectable GIST patients treated with IM (group B; calculated from the start of imatinib therapy) were analyzed.


RESULTS
In group A, statistically significant factors negatively influencing DFS(five-year DFS: 38%), both in univariate and multivariate analysis, were: primary tumor size >5 cm, mitotic index >5/50 HPF (high-power fields), male gender, primary tumor R1 resection or tumor rupture, non-gastric primary tumor localization. In group B, five factors negatively affecting PFS (three-year PFS: 54%) were identified, which were statistically significant both in univariate and multivariate analyses: WHO performance status >/=2, tumor genotype indicating other than exon 11 KIT mutation, high baseline pre-IM granulocyte count, mitotic index >10/50 HPF, and age <45 years at diagnosis.


CONCLUSIONS
Different sets of independent biological and pathological prognostic factors were identified for the assessment of the natural course of primary GIST and for the prediction of PFS during IM therapy for advanced GIST.
Rutkowski
Piotr
P
Department of Soft-Tissue/Bone Sarcoma and Melanoma, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland. rutkowskip@coi.waw.pl
Debiec-Rychter
Maria
M
Nowecki
Zbigniew I
ZI
Wozniak
Agnieszka
A
Michej
Wanda
W
Limon
Janusz
J
Siedlecki
Janusz A
JA
Jerzak Vel Dobosz
Anna
A
Grzesiakowska
Urszula
U
Nasierowska-Guttmejer
Anna
A
Sygut
Jacek
J
Nyckowski
Pawel
P
Krawczyk
Marek
M
Ruka
Włodzimierz
W
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D002648:Child; D018572:Disease-Free Survival; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology / Q000601:surgery*; D006801:Humans; D000068877:Imatinib Mesylate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009154:Mutation; D010879:Piperazines / Q000627:therapeutic use*; D011379:Prognosis; D011446:Prospective Studies; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics; D011743:Pyrimidines / Q000627:therapeutic use*; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics; D016896:Treatment Outcome
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D019009:Proto-Oncogene Proteins c-kit; D020796:Receptor, Platelet-Derived Growth Factor alpha