Table 2: Treatment decision and three-dimensional ultrasound measurements in 76 patients 50-55 days after completion of neoadjuvant chemoradiotherapy for rectal cancer.

Sphincter preserving surgeryAbdominoperineal resectionWatch-and-wait strategy
Patients n (%) 44 (58) 24 (31) 8 (11)
Distance (cm)a
Mean (SD) 3.1 (1.3)b 0.4 (0.5)b Complete regression
Range (1-6) (0-1.6)
Length reduction ratio (%)
Mean (SD) 63 (18)c 41 (24)c 100
Range (10-100) (7-67)

aDistance between the distal tumor edge and the proximal border of the sphincter; bSignificant increase in the distance between the distal tumor edge and the proximal border of the sphincter (p = 0.001); cSignificant increase in length reduction ratio compared sphincter preservation group with abdominal resection and (p = 0.004).