Rethinking treatment for non-metastatic deficient mismatch repair colorectal and small bowel cancers

Table 3 Immune checkpoint inhibitor regimen, immune-related adverse events, treatment response, and subsequent management (surgery or watch-and-wait)

	ICI treatment (agent, dose, number of cycles)	ir-AEs	Treatment response	Subsequent management	AP	Actual situation	Follow-up (months)
P1	Pembrolizumab 2 mg/kg every 21 days, 18 cycles	No	Complete radiological resolution of the mural thickening	W&W	-	Asymptomatic, alive	12 meses
P2	Pembrolizumab 2 mg/kg every 21 days, 10 cycles	Hospitalized for respiratory infection and heart failure exacerbation	Complete radiological and endoscopic response, with no evidence of tumor	W&W	-	Asymptomatic, alive	4 meses
P3	Nivolumab 3 mg/kg and ipilimumab 1 mg/kg every 3 weeks. 4 (N + I) + 4 (N)	No	Radiological improvement with reduction in tumor size	Laparoscopic right hemicolectomy	ypT0N0 (0/28 lymph nodes)	Asymptomatic, alive
P4	Pembrolizumab 2 mg/kg every 21 days, 5 cycles	No	Decreased in size; reduction in the size of the necrotic pathological lymph node adjacent to the tumor	Robotic right hemicolectomy	ypT0N0 (0/60 lymph nodes)	Asymptomatic, alive
P5	Pembrolizumab2 mg/kg every 21 days, 4 cycles	No	Resolution of the wall thickening in the blind section with persistent lymphadenopathy and a slight increase in metabolism	Robotic right hemicolectomy	ypT0N0 (0/30 lymph nodes)	Asymptomatic, alive
P6	Dostarlimab 500 mg every 3 weeks, 9 cycles	No	Complete clinical response on DRE, colonoscopy, CT and PET/CT	W&W	-	Asymptomatic, alive	27 meses
P7	Dostarlimab 500 mg every 3 weeks, 9 cycles (after CRT + XELOX1)	No	Complete clinical response (CCR) on DRE, colonoscopy (scar in the rectum with good endoscopic appearance), and MRI	W&W	-		22 meses
P8	Dostarlimab 500 mg every 3 weeks, 9 cycles (after CRT)	No	Endoscopic stenosis without malignancy	Robot-assisted TME	ypT0N0 (tumor regression 0/4)	Asymptomatic, alive	20 meses

W&W: Watch & wait; TME: Total mesorectal excision; ir-AEs: Immune-related adverse events; CRT: Chemoradiotherapy; ICI: Immune checkpoint inhibitor; CT: Computed tomography; MRI: Magnetic resonance imaging; PET/CT: Positron emission tomography/computed tomography; AP: Anatomical pathology; DRE: Digital rectal examination.