Precision Therapy and Surgery for Rectal Cancer

16:20-16:40, Room 101 (101講堂)

Abstract - 

Precision Therapy and Surgery for Rectal Cancer

In the past two decades, we have witnessed dramatic improvements in the outcomes of patients with rectal cancer. Advances in surgical pathology, refinements in surgical techniques and instrumentation (robotic surgery), new imaging modalities, and the widespread use of neoadjuvant therapy have all contributed to these improvements. Concurrent chemoradiotherapy (CCRT) followed by surgery is the mainstay treatment for locally advanced rectal cancer (LARC). Preoperative CCRT substantially improves local control and sphincter preservation rates, decreasing treatment-related toxicity compared with that in a postoperative setting. However, many experts question whether all of these patients should be treated as a homogeneous group. There is growing evidence that not all patients with LARC are high risk, and a more individualized approach has been advocated. The rationale for change is based on (1) treatment-related toxicities, (2) concerns regarding a delay in systemic chemotherapy, and (3) the potential for unnecessary overtreatment. 

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The multidisciplinary approach of neoadjuvant chemoradiotherapy (nCRT) followed by total mesorectal excision (TME) and postoperative adjuvant chemotherapy has been accepted worldwide as the standard treatment for patients with locally advanced rectal cancer. Poor patient compliance with adjuvant chemotherapy is also a serious concern in clinical practice; therefore, the efficacy of adjuvant chemotherapy in rectal cancer treatment remains controversial. Total neoadjuvant therapy offers a chance to deliver aggressive treatment against the development and progression of micrometastases, potentially increasing survival rates in locally advanced rectal cancer. Furthermore, there is tremendous interest and desire for organ preservation in rectal cancer partly driven by patients who want to preserve a decent quality of life in the modern era. The total neoadjuvant therapy approach may facilitate a greater number of patients having the potential for organ preservation. 

Several questions emerge as we learn of the benefits or lack thereof for components of the current multimodality treatment in subgroups of patients with LARC. What is the optimal surgical technique for distal rectal cancers? Do all patients need postoperative chemotherapy? Do all patients need radiation? What is the optimal timing of T4 rectal cancer after the completion of CCRT remains controversial due to the potential unresectability of primary tumor and the preservation of surrounding invaded organs? Do all patients need surgery, or is a nonoperative, organ-preserving approach warranted in selected patients? Answering these questions will lead to more precise treatment regimens, based on patient and tumor characteristics that will improve outcomes while preserving quality of life. In addition to radiotherapy techniques such as CCRT, the progress of chemotherapy, appropriate time interval between CCRT and surgery, relationship between tumor location and CCRT efficacy/safety, wait and watch policy, and predictors of treatment response following CCRT will be presented.

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Conventionally, high ligation of the inferior mesenteric artery (IMA) is one of the important surgical steps in rectal or sigmoid colon cancer surgery. However, this technique may reduce blood flow in the bowel and increase the risk of ischemia and anastomosis leakage. Herein, we will present our robotic-assisted high dissection and selective ligation of the IMA method, of which it leads to low postoperative complication rates, enables the harvesting of sufficient lymph nodes, and provides equivalent oncologic outcome compared with the conventional high ligation technique.