[Changes of diagnosis and treatment for gastrointestinal stromal tumors during a 18-year period in four medical centers of China].

OBJECTIVE: To elucidate the historic and current diagnosis and treatment status of gastrointestinal stromal tumor (GIST) in the Chinese population based on four high volume databases.

METHODS: Clinicopathological data of GIST patients with follow-up information between January 1998 and December 2015 from Sun Yat-sen University Cancer Center, Union Hospital of Huazhong University of Science and Technology, Southern Medical University Nanfang Hospital and Guangdong General Hospital were retrospectively analyzed. Kaplan-Meire method was used to draw survival curve. The accumulative survival rate was calculated by life table method. Comparison of survival rate among groups was examined by Log-rank test.

RESULTS: A total of 2 610 cases were enrolled into the study, including 667(25.6%) cases from Sun Yat-sen University Cancer Center, 754(28.9%) cases from Union Hospital of Huazhong University of Science and Technology, 692(26.5%) cases from Southern Medical University Nanfang Hospital and 497 (19.0%) cases from Guangdong General Hospital. There were 1 394 male and 1 216 female cases with the ratio of 1.15 to 1.00. The age of patients was from 18 to 95 (median 58.0) years old. Three-year was used as a time stage, then 18 years were divided into 6 stages. New GIST patients increased gradually year by year. There were 13(0.5%) cases during 1998 to 2000, 68(2.6%) cases during 2001 to 2003, 256(9.8%) cases during 2004 to 2006, 517 (19.8%) cases during 2007 to 2009, 814(31.2%) cases during 2010 to 2012, and 942 (36.1%) cases during 2013 to 2015. Primary GIST sites were esophagus in 50(1.9%) cases, stomach in 1 686(64.6%) cases, duodenum in 206 (7.9%) cases, jejunum and ileum in 446 (17.1%) cases, colon and rectum in 133 (5.1%) cases, and non-gastrointestinal tract in 89 (3.4%) cases. GIST lesions of 2 404(92.1%) cases located in the primary sites and relapse/metastasis occurred in 206 cases when consulting. Among 206 relapse/metastasis cases, liver metastasis was found in 126 (61.2%) cases, abdominal cavity/pelvic cavity metastasis in 64 (31.1%) cases, liver plus abdominal cavity/pelvic cavity metastasis in 12 (5.8%) cases, and other site metastasis in 4 (1.9%) cases. Among all the patients, 352 received gene detection, including 1 (0.4%) during 2004 to 2006, 7 (1.4%) during 2007 to 2009, 150 (18.4%) during 2010 to 2012, and 194 (20.6%) during 2013 to 2015. Most of the primary oncogenic mutational site occurred in c-Kit, including 30 (8.5%) cases in exon 9, 242 (68.8%) cases in exon 11, 4 (1.1%) cases in exon 13, 2 (0.6%) cases in exon 17, while 3 (0.9%) cases in PDGFRA exon 12 and 20 (5.7%) cases in PDGFRA 18, besides, no mutations of KIT and PDGFRA were detected in 51 (14.5%) cases. A total of 2 202 cases underwent operation, including 2 038 (92.6%) of radical resection and 164 (7.4%) of palliative resection. Among 2 038 patients undergoing radical resection, 450 (22.1%) cases were very low risk, 593 (29.1%) cases were low risk, 283 (13.9%) cases were moderate risk and 712 (34.9%) cases were high risk according to NIH risk classification. Of 995 patients with moderate and high risk, 550(55.3%) cases received postoperative imatinib adjuvant therapy, whose ratio in above 6 time stages was as follows: 0, 42.8%(12/28), 19.8%(20/101), 9.8% (21/215), 65.7% (176/268) and 85.6% (321/375). Of 206 relapse/metastasis patients, 200 (97.1%) cases received imatinib as the first-line therapy, and 22 (10.7%) received sunitinib as the second-line therapy. A total of 1 743 patients had complete follow-up data and median follow-up time was 35.9 (0.1 to 173.8) months. The 5-year overall survival rates in very low, low, moderate and high risk patients were 100%, 97%, 95% and 78% respectively.

CONCLUSION: This retrospective study provides the largest data of GIST and indicates the historic changes of clinicopathological characteristics, diagnosis and treatment of GIST for further domestic GIST research.