Sphincter preservation for distal rectal cancer: how low is too low?

Organ Preservation in MSS Rectal Cancer

Rectal cancer is a heterogeneous disease with complex genetic and molecular subtypes. Emerging progress of neoadjuvant therapy has led to increased pathological and clinical complete response (cCR) rates for microsatellite stable (MSS) rectal cancer, which responds poorly to immune checkpoint inhibitor alone. As a result, organ preservation of MSS rectal cancer as an alternative to radical surgery has gradually become a feasible option. For patients with cCR or near-cCR after neoadjuvant treatment, organ preservation can be implemented safely with less morbidity. Patient selection can be done either before the neoadjuvant treatment for higher probability or after with careful assessment for a favorable outcome. Those patients who achieved a good clinical response are managed with nonoperative management, organ preservation surgery, or radiation therapy alone followed by strict surveillance. The oncological outcomes of patients with careful selection and organ preservation seem to be noninferior compared with those of radical surgery, with lower postoperative morbidity. However, more studies should be done to seek better regression of tumor and maximize the possibility of organ preservation in MSS rectal cancer.

Multimodal preoperative evaluation system in surgical decision making for rectal cancer: a randomized controlled trial

PURPOSE

Multimodal preoperative evaluation (MPE) is a novel strategy for surgical decision making, incorporating the transrectal ultrasound (TRUS), 64 multi-slice spiral computer tomography (MSCT), and serum amyloid A protein (SAA) for rectal cancer. This trial aims to determine the accuracy of MPE in preoperative staging and its role in surgical decision making for rectal cancer.

METHODS

Two hundred twenty-five participants with histologically proven rectal cancer with tumor height less than 10 cm were randomly assigned into three arms in the ratio 1:1:1. Arm A (MPE) was multimodal staged by the combination of MSCT, TRUS, and SAA. Arm B (MSCT+SAA) was staged by MSCT and SAA. Arm C (MSCT) was staged only by MSCT. The primary endpoints were the accuracy of preoperative staging and expected surgical procedures. This study is registered as an International Standard Randomised Controlled Trial, number ChiCTR-DT-00000409.

RESULTS

The analysis showed statistical difference in the accuracy of T staging between arm A and B (94.6% vs. 77.8%, P=0.003) and arm A and C (94.6% vs. 80.6%, P=0.010). Statistical difference was also observed between the accuracies of preoperative N staging between arm A and C (85.1% vs. 69.4%, P=0.023) and arm A and B (85.1% vs. 84.7%, P=0.029). Surgical decision making in arm A was more accurate than that in arm C (95.9% vs. 80.6%, P=0.001). Pathological T stage (P<0.001), N stage (P<0.001), tumor node metastasis stage (P<0.001), serum level of SAA (P=0.002), and tumor height (P=0.030) were significantly associated with final surgical procedures.

CONCLUSION

MPE is an effective strategy in preoperative staging and more accurate than other available strategies in surgical decision making for rectal cancer.