Supplementary Table 1.

Rectal GIST cases in the literature

References	Age (years)/gender	Localization and volume	Surgery	Chemotherapy	Radiotherapy	Follow-up
Somu et al. 2016[66]	66/male	3 cm from the anal verge in the right lateral rectal wall 6.3 cm × 5.4 cm × 6.7 cm	Laparoscopic excision	Adjuvant imatinib	None	NA
Ciresa et al. 2009[48]	54/male	Lateral-right rectal wall extending to the anal canal/4.7 cm × 4.0 cm	Patient underwent a sphincter-saving surgical procedure (low anterior resection)	Neoadjuvant imatinib	50.4 Gy 1.8 Gy/day Box or 3-field 3D conformal	NA
Kyo et al. 2016[43]	46/male	8 cm in maximum diameter, anterior wall of the lower rectum	Laparoscopic low anterior resection with total mesorectal excision, coloanal anastomosis, and diverting ileostomy	Neoadjuvant imatinib treatment	None	Alive and disease-free 37 months after surgery
Hamada et al. 2008[67]	60/male	3.0 cm recurrent tm	Fourth excision operation was performed with a perineal approach	Neoadjuvant imatinib treatment	None	Alive and disease-free 42 months after last surgery
Tazawa et al. 2017[68]	75/female	5.3 cm × 4.2 cm, behind the rectum	Partial sphincter saving rectal resection with creation of an ileostomy	Neoadjuvant imatinib treatment	None	No evidence of disease in the 2-year follow-up
Pollock et al. 2001[50]	77/female	2–3 cm left anterior rectal wall, 1–2 cm above the dentate line	Transanal excision and a 7-cm mass was removed. Margins were equivocal so excess redundant mucosa was excised	None	36 Gy whole pelvis. Additional 9 Gy to partial pelvic field. Final 540 cGy to a field determined by a contrast study. The margins 2 cm to CT-based tumor volume	2-year CT scan revealed continued regression of the left anterior rectal tumor
Carlson et al. 2016[69]	51/male	6.5 cm × 6.0 cm rectal mass just proximal to the sphincter	APR	Neoadjuvant imatinib treatment	None	Metastasis to penis 3.5 years after APR

APR: Abdominoperineal resection; 3D: Three-dimensional; NA: Not available; CT: Computed tomography.