PROPOSAL: Evaluate the post-chemoradiotherapy response for treatment of rectal tumor using three-dimensional anorectal ultrasound-3D-US to determine the best surgical approach
METHODS: 32 patients with lower and middle rectal cancer were prospectively staged using 3D-US to identify anal canal invasion and the distance(cm) between tumor and the internal anal sphincter-IAS, Group l:with anal canal invasion; Group II-with distance =2cm; Group III-with distance >2. They were submitted to neoadjuvant chemoradiation-CRT and the 3-D US was repeated 50-55 days later. The choice of the surgical approach was based on the post-chemoradiation response identified by the 3D-US comparing with pathologic findings.
RESULTS: The post-chemoradiation/3D-US findings were concordant with pathologic results in 31/32(97%). It was identified residual tumors in 26/27(96% sensibility), 19(59%) with partial response and 7(22%) without response. Complete response was demonstrated in 5/5 by 3D-US, with specificity and predictive valor in 100%. Negative predictive valor in 83% since one(3%) case was inconclusive. Sphincter-saving resection was performed in 16 patients, 5 with complete response, 10 with partial response and one inconclusive, with distal margin >2cm. The pathologic findings confirmed distal margins without tumor. It was demonstrated high concordance(87.5%) concerning the lymph nodes evaluation(Kappa test).
CONCLUSION: 3D-US can be useful to determine the patients who should be submitted to sphincter-saving resections.
