Re-appraisal of risk classifications for primary gastrointestinal stromal tumors (GISTs) after complete resection: indications for adjuvant therapy.
BACKGROUND
A substantial number of localized gastrointestinal stromal tumor (GIST) patients have recurrences even after complete resection. The risk of recurrence after complete resection should be estimated when considering adjuvant therapy. In this study, we evaluated prognostic factors of GIST recurrence and compared several reported risk-stratification schemes for defining risk of recurrence to guide the use of adjuvant therapy using data from a large Japanese GIST population.


METHODS
We analyzed clinicopathological data collected retrospectively and prospectively from 712 GISTs with complete resection from 1980-2010. We evaluated possible prognostic factors and compared the National Institutes of Health consensus criteria, the Armed Forces Institute of Pathology criteria, Joensuu's modified NIH classification (J-NIHC), the American Joint Committee on Cancer staging system (AJCCS), and the Japanese modified NIH criteria for prediction of tumor recurrence in adjuvant settings.


RESULTS
Univariate analysis suggested that the following factors were prognostic: tumor size, mitotic count, site, clinically malignant features of rupture and/or invasion, and gender. In multivariate analysis, size >5 cm, mitotic count >5/50 HPF, non-gastric location, and the presence of rupture and/or macroscopic invasion were independent adverse prognostic factors. When adjuvant therapy is considered for patients with high-risk GIST, the J-NIHC was the most sensitive classification system, while the AJCCS appeared to be the most accurate for predicting recurrence.


CONCLUSIONS
Tumor size, mitotic count, tumor site, and clinical features of rupture and/or invasion were important prognostic factors for GIST recurrence. Joensuu's classification appeared to best identify candidates for adjuvant therapy.
Department of Surgery, Osaka Police Hospital, Kitayama-cho 10-31, Tennouji-ku, Osaka, 543-0035, Japan.
Yoshitomo
Y
Yanagimoto
Tsuyoshi
T
Takahashi
Kazuya
K
Muguruma
Takahiro
T
Toyokawa
Hiroshi
H
Kusanagi
Takeshi
T
Omori
Toru
T
Masuzawa
Koji
K
Tanaka
Seiichi
S
Hirota
Toshirou
T
Nishida
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D015622:Epithelioid Cells / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D046152:Gastrointestinal Stromal Tumors / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis*; D009367:Neoplasm Staging; D018331:Nevus, Spindle Cell / Q000473:pathology / Q000601:surgery*; D011183:Postoperative Complications; D011379:Prognosis; D011446:Prospective Studies; D012189:Retrospective Studies; D018570:Risk Assessment; D015996:Survival Rate; D055815:Young Adult