Quality of treatment and surgical approach for rectal gastrointestinal stromal tumour (GIST) in a large European cohort.

Background: Rectal gastrointestinal stromal tumours (GISTs) are rare tumours. Variability in the management may influence outcome, but there is a lack of understanding regarding contemporary variance in care. A multicenter, international, retrospective cohort study was performed to elucidate characteristics and outcomes of rectal GIST in European practice, with particular reference to surgical approach.

Methods: All rectal GIST patients diagnosed between 2009 and 2018 were identified from five European databases. Recurrence free survival (RFS) and overall survival (OS) were estimated using Kaplan-Meier method. Possible confounders were identified using Cox regression analyses.

Results: From 210 patients, 155 patients had surgery. The three main types of surgery were local tumour resection (LTR, n = 46), low anterior resection (LAR, n = 31) and abdomino-perineal resection (APR, n = 32). Most patients received neoadjuvant (65%) and/or adjuvant imatinib therapy (66%). Local recurrence rate after surgery was 15% and overall recurrence rate 28%. No significant differences were found in terms of RFS nor OS between LTR, LAR and APR. However, locally resected tumours were smaller, while LAR and APR patients more often received perioperative imatinib. General hospitals treated smaller GISTs, offered imatinib less frequently, and had a higher tumour rupture rate. In the multivariate analysis in the group having LTR, APR or LAR, the only significant prognostic factor for local recurrence was higher age (HR 1.06, CI 1.00-1.12, p = 0.048).

Conclusions: In European clinical practice for rectal GIST, LTR, LAR and APR have comparable local control. Multimodal approach is higher and tumour rupture less frequent in specialist centres compared to general hospitals.