Counting mitoses in gastrointestinal stromal tumours (GISTs): variable practices in the real-world setting and their clinical implications

Pan-Canadian consensus recommendations for GIST management in high- and low-throughput centres across Canada

Gastrointestinal stromal tumours (GISTs) are mesenchymal tumours that originate from the interstitial cells of Cajal. GISTs are mainly driven by gain-of-function mutations in receptor tyrosine kinase or platelet-derived growth factor receptor alpha. Surgical resection is the only curative treatment for localized tumours and all currently approved medical GIST treatments are based on orally available tyrosine kinase inhibitors. Recent discoveries in the molecular and clinical features of GISTs have greatly impacted GIST management. Due to the provincially rather than nationally administered Canadian healthcare system, there have been inconsistencies in the treatment of GISTs across the country. Therefore, guidance on the latest knowledge, clinical management and treatment of GIST is needed to standardize the approach to GIST management nationwide. To establish pan-Canadian guidance, provide up-to-date data and harmonize the clinical practice of GIST management in high- and low-throughput centres across Canada; a panel of 20 physicians with extensive clinical experience in GIST management reviewed relevant literature. This included radiologists, pathologists, interventional radiologists, surgeons and medical oncologists across Canada. The structured literature focused on seven key domains: molecular profiling, radiological techniques/reporting, targeted localized therapy, intricacies of systemic treatments, emerging tests, multidisciplinary care and patient advocacy. This literature review, along with clinical expertise and opinion, was used to develop this concise and clinically relevant consensus paper to harmonize the knowledge and clinical practice on GIST management across Canada. The content presented here will help guide healthcare providers, especially in Canada, in terms of approaching and managing GIST.

Iodothyronine Deiodinase 3 Gene Expression in Gastrointestinal Stromal Tumors: A Pilot Study to Contribute to Risk Assessment

BACKGROUND

In the realm of gastrointestinal stromal tumors (GIST), understanding the molecular landscape and prognostic factors is crucial for effective management. The deiodinase 3 gene (DIO3), known for its role in thyroid hormone regulation and cell proliferation, has emerged as a potential player in GIST pathogenesis. Our study investigated DIO3 expression in GIST samples and its correlation with tumor characteristics, aiming to enhance prognostic stratification and personalized treatment strategies.

MATERIALS AND METHODS

Using a retrospective design, we analyzed data and formalin-fixed paraffin-embedded (FFPE) samples of patients diagnosed with GIST. The study cohort comprised 33 patients, predominantly female, with a median age of 66 years. The tumor characteristics were meticulously documented, including location, size, mitotic count, risk classification, and immunohistochemical markers. Gene expression analysis of DIO3 was conducted using FFPE samples, with a focus on relative quantification and association with immunohistochemical markers and prognostic risk.

RESULTS

DIO3 overexpression was observed in 69.70% of tumors, while underexpression was noted in 30.30% of cases. Association analyses revealed intriguing insights. A notable association was identified between DIO3 expression and the frequency of DOG1, suggesting a potential interplay between these markers in GIST pathobiology. Furthermore, increased DIO3 expression was significantly higher in very low/low-risk prognostic patients, hinting at a possible link between DIO3 levels and tumor progression prognosis.

CONCLUSIONS

 The intricate interplay between DIO3 expression and GIST characteristics uncovered in this study underscores the potential of molecular markers in refining prognostic assessments and therapeutic strategies for GIST patients.

Primary Ovarian Leiomyosarcoma Is a Very Rare Entity: A Narrative Review of the Literature

BACKGROUND

Primary ovarian leiomyosarcoma is a very rare malignancy characterized by unclear management and poor survival. We reviewed all the cases of primary ovarian leiomyosarcoma to identify prognostic factors and the best treatment.

METHODS

We collected and analyzed the articles published in the English literature regarding primary ovarian leiomyosarcoma from January 1951 to September 2022, using PubMed research. Clinical and pathological characteristics, different treatments and outcomes were analyzed.

RESULTS

113 cases of primary ovarian leiomyosarcoma were included. Most patients received surgical resection, associated with lymphadenectomy in 12.5% of cases. About 40% of patients received chemotherapy. Follow-up information was available for 100/113 (88.5%) patients. Stage and mitotic count were confirmed to affect survival, and lymphadenectomy and chemotherapy were associated with a better survival rate. A total of 43.4% of patients relapsed, and their mean disease-free survival was 12.5 months.

CONCLUSIONS

Primary ovarian leiomyosarcomas are more common in women in their 50s (mean age 53 years). Most of them are at an early stage at presentation. Advanced stage and mitotic count showed a detrimental effect on survival. Surgical excision associated with lymphadenectomy and chemotherapy are associated with increased survival. An international registry could help collect clear and reliable data to standardize the diagnosis and treatment.