Gastrointestinal stromal tumors: the incidence, prevalence, clinical course, and prognostication in the preimatinib mesylate era--a population-based study in western Sweden.
BACKGROUND
Recent breakthroughs regarding gastrointestinal stromal tumors (GIST) and their pathogenesis have redefined diagnostic criteria and have led to the development of molecularly targeted drug therapy. New treatment options mandate more accurate information regarding the incidence, prevalence, clinical behavior, and prognostic factors of GIST.


METHODS
All patients (n=1460) who potentially had GIST diagnosed from 1983 to 2000 in western Sweden (population, 1.3-1.6 million) were reviewed, and 288 patients with primary GIST were identified. The incidence and prevalence of GIST were determined, and predictive prognostic factors, including current risk-group stratifications, were analyzed statistically.


RESULTS
Ninety percent of GISTs were detected clinically due to symptoms (69%) or were incidental findings at surgery (21%); the remaining 10% of GISTs were found at autopsy. Forty-four percent of symptomatic, clinically detected GISTs were categorized as high risk (29%) or overtly malignant (15%), with tumor-related deaths occurring in 63% of patients and 83% of patients, respectively (estimated median survival, of 40 months and 16 months, respectively). Tumor-related deaths occurred in only 2 of 170 of patients (1.2%) with very-low-risk, low-risk, or intermediate-risk tumors. The annual incidence of GIST was 14.5 per million. The prevalence of all GIST risk groups was 129 per million (31 per million for the high-risk group and the overtly malignant group).


CONCLUSIONS
GIST has been under recognized: Its incidence, prevalence, and clinical aggressiveness also have been underestimated. Currently existing risk-group stratification systems based on tumor size and mitotic rate delineate GIST patients who have a poor prognosis. Prognostication in patients with GIST can be refined using a proposed risk score based solely on tumor size and proliferative index.
Nilsson
Bengt
B
Department of Surgery, The Lundberg Laboratory for Cancer Research, Sahlgrenska Academy at the University of Göteborg, Göteborg, Sweden.
Bümming
Per
P
Meis-Kindblom
Jeanne M
JM
Odén
Anders
A
Dortok
Aydin
A
Gustavsson
Bengt
B
Sablinska
Katarzyna
K
Kindblom
Lars-Gunnar
LG
D000367:Age Factors; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001549:Benzamides; D013505:Digestive System Surgical Procedures; D046152:Gastrointestinal Stromal Tumors / Q000453:epidemiology* / Q000473:pathology* / Q000628:therapy; D006801:Humans; D000068877:Imatinib Mesylate; D015994:Incidence; D019394:Ki-67 Antigen / Q000378:metabolism; D010879:Piperazines / Q000627:therapeutic use; D015995:Prevalence; D011379:Prognosis; D011743:Pyrimidines / Q000627:therapeutic use; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis; D013548:Sweden
D000970:Antineoplastic Agents; D001549:Benzamides; D019394:Ki-67 Antigen; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate