National overview of gastrointestinal stromal tumors: Experience from middle income setting.

person Benik Mkhitaryan Hematology center after Prof. R.H. Yeolyan, Yerevan, Armenia info_outline Benik Mkhitaryan, Davit Zohrabyan, Liana Safaryan, Samvel Bardakhchyan, Armen Arzumanyan, Martin Harutyunyan, Armen Mkhitaryan, Amalya Sargsyan, Marine Rushanyan, Gohar Mkrtchyan, Mariam Mailyan, Nune Karapetyan

Authors person Benik Mkhitaryan Hematology center after Prof. R.H. Yeolyan, Yerevan, Armenia info_outline Benik Mkhitaryan, Davit Zohrabyan, Liana Safaryan, Samvel Bardakhchyan, Armen Arzumanyan, Martin Harutyunyan, Armen Mkhitaryan, Amalya Sargsyan, Marine Rushanyan, Gohar Mkrtchyan, Mariam Mailyan, Nune Karapetyan Organizations Hematology center after Prof. R.H. Yeolyan, Yerevan, Armenia, Hematology center after prof. Yeolyan, Yerevan, Armenia, Hematology Center after R.Yeolyan, Yerevan, Armenia, Yerevan State Medical University, Yerevan, Armenia, Hystogen Laboratory, Yerevan, Armenia, Immune Oncology Research Institute, Yerevan, Armenia, Hematology center after prof Yeolyan, Yerevan, Armenia Abstract Disclosures Research Funding No funding received None. Background: Gastrointestinal stromal tumors (GISTs) are mesenchymal malignancies representing 1-2% of all gastrointestinal cancers. There is a general shortage of reported data on GISTs from the Republic of Armenia (RA). This paper aims to conduct a national assessment of the epidemiological, diagnostic, and treatment approaches of the GISTs in RA. Methods: The study utilizes a cross-sectional design. Five-year retrospective data on patients with the moderate and high-risk group has been analyzed (from August 31, 2016, up to February 01, 2023). Data has been obtained through medical records. It was feasible to apply census sampling since each GIST patient receives Imatinib in the Hematology Center after prof. Yeolyan free of charge and all the medical records are centered in this facility. Descriptive analysis has been done to demonstrate patients’ demographic characteristics, the spread of the disease, pathological and genetic features of the tumor, and performed treatment. Results: In total 69 moderate and high-risk patients have been targeted. That counts for about 1% of all GI tumors diagnosed in Armenia in 2021. The mortality rate was 10%. The male-to-female ratio was 1.56:1. Age range was 30-81 years (median 58). Advanced disease was observed in 31.9% of cases. The primary site of the tumor (gastric vs non-gastric) was not significantly associated with the disease stage (p-value: 0.192). Expression of CD34, CD117, and DOG1 was positive in 97.3%, 100%, and 96.7% of cases respectively. However, it is worth mentioning that data on immunohistochemical (IHC) features are lacking due to the incompleteness of medical records and the absence of a joint e-health system in Armenia. Furthermore, significant under-testing of the tumor genetic profile was observed. Only 3 patients were tested for KiT mutation (positive in all cases) and no one for PDGFRA mutation. Under-testing is caused by the high cost of genetic profiling which is covered out-of-pocket in RA. All patients received first-line tyrosine kinase inhibitors (TKI). Adjuvant or palliative radiation therapy (RT) was not applied. The majority of patients (95%) underwent tumor resection for curative or palliative purposes. Conclusions: Demographic and epidemiological profile of GISTs in RA is similar to the reported international data. In contrast, the rate of advanced diseases is higher in RA, possibly due to diagnosis delays. Gastric GISTs N (%) non-Gastric GISTs N (%) Local disease 25 (75.8) 22 (61.1) Advanced disease 8 (24.2) 14 (38.9) CD34 † 14 (100) 22 (95.7) CD117 † 17 (100) 29 (100) DOG1 † 10 (100) 19 (95) Received 1st-line TKI 33 (100) 36 (100) Tumor resection 32 (96,9) 35 (97,2) Adjuvant RT 0(0) 0(0) † Positive test results.