[Adherence to adjuvant with therapy imatinib in patients with gastrointestinal stromal tumor: a national multi-center...

Objective: To analyze the current adherence to imatinib in patients with gastrointestinal stromal tumors (GIST) in China and its influencing factors. Methods: A cross-sectional survey was conducted. Study period: from October 1, 2020 to November 31, 2020. Study subjects: GIST patients taking imatinib who were diagnosed and treated in public tertiary level A general hospitals or oncology hospitals; those who had not been pathologically diagnosed, those who never received imatinib, or those who had taken imatinib in the past but stopped afterwards were excluded. The Questionnaire Star online surgery platform was used to design a questionnaire about the adherence to adjuvant imatinib therapy of Chinese GIST patients. The link of questionnaire was sent through WeChat. The questionnaire contained basic information of patients, medication status and Morisky Medication Adherence Scale. Results: A total of 2162 questionnaires from 31 provinces, autonomous regions, and municipalities were collected, of which 2005 were valid questionnaires, with an effective rate of 92.7%. The survey subjects included 1104 males and 901 females, with a median age of 56 (22-91) years old. Working status: 609 cases (30.4%) in the work unit, 729 cases (36.4%) of retirement, 667 cases of flexible employment or unemployment (33.3%). Education level: 477 cases (23.8%) with bachelor degree or above, 658 cases (32.8%) of high school, 782 cases (39.0%) of elementary or junior high school, 88 cases (4.4%) without education. Marital status: 1789 cases (89.2%) were married, 179 cases (8.9%) divorced or widowed, 37 cases (1.8%) unmarried. Two hundred and ninety-four patients (14.7%) had metastasis when they were first diagnosed, including 203 liver metastases, 52 peritoneal metastases, and 39 other metastases. One thousand eight hundred and sixty-nine patients underwent surgical treatment, of whom 1642 (81.9%) achieved complete resection. The median time of taking imatinib was 25 (1-200) months. Common adverse reactions of imatinib included 1701 cases (84.8%) of periorbital edema, 1031 cases (51.4%) of leukopenia, 948 cases (47.3%) of fatigue, 781 cases (39.0%) of nausea and vomiting, 709 cases (35.4%) of rash, and 670 cases (33.4%) of lower extremity edema. The score of the Morisky Medication Adherence Scale showed that 392 cases (19.6%) had poor adherence, 1023 cases (51.0%) had moderate adherence, and 590 cases (29.4%) had good adherence. Univariate analysis showed that gender, age, work status, economic income, residence, education level, marriage, the duration of taking medication and adverse reactions were associated with adherence to adjuvant imatinib therapy (all P<0.05). Multivariate analysis showed that female (OR=1.264, P=0.009), non-retirement (OR=1.454, P=0.001), monthly income ≤4000 yuan (OR=1.280, P=0.036), township residents (OR=1.332, P=0.005), unmarried or divorced or widowed (OR=1.362, P=0.026), the duration of imatinib medication >36 months (OR=1.478, P<0.001) and adverse reactions (OR=1.719, P=0.048) were independent risk factors for poor adherence to adjuvant imatinib. Among patients undergoing complete resection, 324 (19.7%) had poor adherence, 836 (50.9%) had moderate adherence, and 482 (29.4%) had good adherence. Meanwhile, 55 patients with good adherence (11.4%) developed recurrence after surgery, 121 patients with moderate adherence (14.5%) developed recurrence, 61 patients with poor adherence (18.8%) developed recurrence, and the difference was statistically significant (P=0.017). Conclusions: The adherence to adjuvant therapy with imatinib in Chinese GIST patients is relatively poor. Females, non-retirement, monthly income ≤4000 yuan, township residents, unmarried or divorced or widowed, the duration of imatinib medication >36 months, and adverse reactions are independently associated with poor adherence of GIST patients. Those with poor adherence have a higher risk of recurrence after surgery. Positive interventions based on the above risk factors are advocated to improve the prognosis of patients with GIST.