Near-complete clinical response after neoadjuvant therapy in rectal cancer: Decision-making between organ preservation and surgery

Table 1 Key findings suggestive of favorable or unfavorable near-complete clinical response and their management implications

Finding	Interpretation (risk of residual tumor)	Suggested clinical implication
Endoscopic nCR1
Small nodularity	Variable risk; may still evolve to cCR (favorable nCR pattern)	Supports repeat reassessment at 6-12-week intervals, with close surveillance limited to the first 6 months
Irregular mucosa	Intermediate risk; may represent either ongoing tumor regression or residual disease (unfavorable nCR pattern)	Consider early surgical intervention or intensified evaluation
Superficial ulceration	Increased likelihood of residual tumor (unfavorable nCR pattern)	Consider early surgical intervention or intensified evaluation
MRI nCR2
Absence of EMVI	Favorable biologic response pattern (favorable nCR pattern)	Supports repeat reassessment at 6-12-week intervals, with close surveillance limited to the first 6 months
Low rectal tumor location	Associated with an increased probability of complete response (favorable nCR pattern)	Supports repeat reassessment at 6-12-week intervals, with close surveillance limited to the first 6 months

¹Endoscopic features associated with favorable or unfavorable near-complete clinical response, adapted from Williams et al[18].

²Magnetic resonance imaging-based predictors of complete response, including tumor location and extramural vascular invasion status, adapted from Yilmaz et al[22].

nCR: Near-complete clinical response; cCR: Clinical complete response; MRI: Magnetic resonance imaging; EMVI: Extramural venous invasion.

Table 2 Quantitative outcomes reported in studies of near-complete clinical response after neoadjuvant therapy in rectal cancer

Ref.	nCR rate	cCR rate	nCR → cCR conversion	Local regrowth (nCR vs cCR)	Distant metastasis	Organ preservation (nCR vs cCR)
Rosen et al[17], 2025	15% (189/1230)	32% (395/1230)	-	40% vs 24%1	48% vs 17%2 (OR: 4.59)	53% vs 73%
Hupkens et al[11], 2018	40% (68/170)	60% (102/170)	90% (44/49)	27% vs 16%3	-	Sustained W&W4
Verheij et al[7], 2024	-	-	-	94% < 2 years5	-	Approximately 50% (overall)

¹Three-year local-regrowth rate.

²Distant metastasis after local regrowth: Near-complete clinical response converting to clinical complete response on watch-and-wait vs persistent near-complete clinical response resected.

³Two-year local-regrowth rate (converted near-complete clinical response vs clinical complete response).

⁴Forty-four of 49 converted patients managed nonoperatively, with outcomes comparable to primary clinical complete response.

⁵Proportion of all local regrowth occurring within 2 years in the OPRA watch-and-wait cohort (99% within 3 years).

In the comparison columns, values are shown as near-complete clinical response vs clinical complete response. nCR: Near-complete clinical response; cCR: Clinical complete response; W&W: Watch-and-wait; OR: Odds ratio.