cTis(M) cancer or cT1(SM) cancer treatment strategy based on the JSCCR Guidelines for the Treatment of Colorectal Cancer 2016
13.2 Current Additional Surgical Resection Criteria for Endoscopic Resected Colorectal pT1 (SM) Cancer
- 1.
If the vertical tumor cut margin is positive, additional surgical resection is preferred (recommendation level/evidence level 1C).
- 2.
If one or more of the below findings is noted in the histological examination of the resected specimen, additional surgery with lymph node dissection should be considered (evidence level B).
- (a)
SM invasion depth is ≥1000 μm.
- (b)
Vascular invasion.
- (c)
The presence of poorly differentiated adenocarcinoma, signet-ring cell carcinoma, mucinous carcinoma.
- (d)
Budding grade at the deepest portion of the invasive front—Grade 2/3.
- (a)
![../images/461529_1_En_13_Chapter/461529_1_En_13_Fig2_HTML.png](https://i0.wp.com/abdominalkey.com/wp-content/uploads/2020/08/461529_1_En_13_Fig2_HTML.png?w=960)
Therapeutic strategy for submucosal (T1) CRC resected endoscopically based on the JSCCR Guidelines for the Treatment of Colorectal Cancer 2016
Since the guidelines committee did not reach a consensus regarding (2) revealed above, the recommendation level has not been described thus far.
![../images/461529_1_En_13_Chapter/461529_1_En_13_Fig3_HTML.png](https://i0.wp.com/abdominalkey.com/wp-content/uploads/2020/08/461529_1_En_13_Fig3_HTML.png?w=960)
Points to consider for additional endoscopic resection of pT1 cancer. Endoscopic treatment is an total excisional biopsy; therefore, before the additional surgery, it is important to inform the patient that it is necessary to visit the doctor in order to understand the curability, to comprehensively evaluate the patient’s background and risk of postoperative metastatic/recurrent potential, and to discuss whether additional surgery is required or not
13.3 Recent Information on Management of Colorectal T1 Cancer
Based on the recent accumulation of cases, it has been clarified that additional surgery with lymph node dissection is not always necessary, even in endoscopic resected pT1b (SM invasion depth is ≥1000 μm) cancer. In addition, there has also been evaluated as clinical research regarding the feasibility of endoscopic resection as total excisional biopsy for cases of SM invasive cancer that have previously been indicated for surgery, depending on various conditions [2].
We reported a 1.2% of lymph node metastatic risk of T1 colorectal cancer, irrespective of the degree of SM invasion, if the following conditions were never detected: (1) the presence of vascular invasion; (2) poorly differentiated adenocarcinoma, signet-ring cell carcinoma, or mucinous carcinoma; and (3) at the deepest portion of the invasive front—budding Grade 2/3 [3]. Yoshii et al. [4] investigated the prognosis of T1b cancer after endoscopic resection and reported that in the absence of unfavorable histology, vascular invasion, and high degree of budding grade, the recurrent rate with endoscopic resection alone was 3.4% and that with endoscopic resection plus additional surgery was 2.3%; the rates were low in both groups with no significant difference. In addition, recently, the JJSCCR undertook the “Project research on the stratification of the metastatic risk of SM T1b cancer (Committee Chair, Prof Yoichi Ajioka)” and found that even cases with T1b cancer, when no other metastatic risk factors besides SM deep invasion (i.e., unfavorable histology components, vascular invasion, and high degree of budding grade) were observed, the rate of lymph node metastasis was only 1.4% (data under submission preparation).
Yoda et al. [5] investigated the prognosis after endoscopic treatment of T1 cancer in 302 cases that were considered for additional surgery and found that the recurrence rate was 3.6% for 196 cases who required additional surgery and 6.6% for 106 cases who underwent endoscopic resection alone with further surveillance; the recurrence rate was significantly higher in the latter. However, we have to pay attention to the fact that even with additional surgery, 3.6% of patients experience recurrence. On the other hand, in a multicenter study (14 centers), Kobayashi et al. [6] reported that surgery without preceding endoscopic treatment yielded the following results: overall postoperative recurrence rate was 2.3% in 798 patients with colorectal T1 cancer (excluding transanal resection) that was surgically resected with lymph node dissection (recurrence rates: 1.5% for colon cancer and 4.2% for rectal cancer, P = 0.02), and lymph node metastasis and histologic grade were independent risk factors (poorly differentiated or mucinous, P < 0.0001). Further, according to a survey by the Japanese Society of Gastroenterological Surgery [7], the nationwide mean incidence of operational death during colorectal surgery is 0.24–0.7%, which indicates a constant, albeit low, risk of operational death.
As stated above, it is important to acknowledge the following information when considering additional surgery for pT1b cancer after endoscopic resection: (1) the incidence of lymph node metastasis is 1.2–1.4% if there are no other metastatic risk factors, even with SM highly invasive cancer; (2) the postoperative recurrence rate is 2.3%, even in T1 cancer treated by surgery with lymph node dissection, and this recurrence rate is 1.5% for colon cancer and 4.2% for rectal cancer; and (3) the incidence of operational death from surgery is not 0%.
13.4 Future Direction for Management (Endoscopic Treatment) for Colorectal T1 Cancer
With the current aging society, many factors such as the patient’s age, underlying disease, level of physical activity, patients’ will, and possibility of a colostomy (Miles’ operation) should be considered in order to determine whether a patient should undergo surgery. In particular, the postoperative quality of life after Miles’ surgical procedure for lower rectal cancer is problematic in terms of sexual and excretory function. Then finally, the patient himself/herself must decide whether he/she will undergo the surgery by enough understanding of disease and discussion with doctor (Fig. 13.3).
![../images/461529_1_En_13_Chapter/461529_1_En_13_Fig4a_HTML.png](https://i0.wp.com/abdominalkey.com/wp-content/uploads/2020/08/461529_1_En_13_Fig4a_HTML.png?w=960)
![../images/461529_1_En_13_Chapter/461529_1_En_13_Fig4b_HTML.png](https://i0.wp.com/abdominalkey.com/wp-content/uploads/2020/08/461529_1_En_13_Fig4b_HTML.png?w=960)
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