Prognostic impact of primary tumour location after curative resection in Stage I-III colorectal cancer: a single-centre retrospective study.

OBJECTIVE: The relationship of tumour site with post-recurrence course and outcome after primary surgery in resectable colorectal cancer is unclear. This study investigated the prognostic impact of primary tumour location following radical resection without preoperative treatment in Stage I-III colorectal cancer. METHODS: We analyzed 3770 patients with Stage I-III colorectal cancer who underwent curative resection at our hospital during 2000-15. We defined the right-sided colon as the cecum, ascending colon and transverse colon, and the left-sided colon as the descending colon, sigmoid and rectosigmoid junction. Patients were divided into three groups according to tumour site: right-sided colon, left-sided colon and rectum. Endpoints were overall survival, recurrence-free survival by stage and survival after recurrence, respectively. RESULTS: The 5-year overall survival rates of patients with stage I left-sided colon cancer, right-sided colon cancer and rectal cancer were 98.2, 97.3 and 97.2%, respectively (P = 0.488). The 5-year overall survival rates of patients with Stage II left-sided colon cancer, right-sided colon cancer and rectal cancer were 96.2, 88.7 and 83.0, respectively (P = 0.070). The 5-year overall survival rates of patients with Stage III left-sided colon cancer, right-sided colon cancer and rectal cancer were 88.7, 83.0 and 80.2, respectively (P = 0.001). The 5-year recurrence-free survival rates of patients with Stage I left-sided colon cancer, right-sided colon cancer and rectal cancer were 95.1, 94.5 and 90.6% (P = 0.027). The 5-year recurrence-free survival rates of patients with Stage II left-sided colon cancer, right-sided colon cancer and rectal cancer were 85.2, 90.2 and 76.1%, respectively (P < 0.001). The 5-year recurrence-free survival rates of patients with Stage III left-sided colon cancer, right-sided colon cancer and rectal cancer were 75.3, 75.3 and 59.8%, respectively (P < 0.001). Right-sided colon cancer was significantly associated with better recurrence-free survival compared with left-sided colon cancer (HR 1.29, 95% CI 1.03-1.63; P = 0.025) and rectal cancer (HR 1.89, 95% CI 1.51-2.38; P < 0.001) after adjusting for clinical factors. Amongst patients with recurrence, right-sided colon cancer was significantly associated with poorer survival after recurrence compared with left-sided colon cancer (HR 0.68, 95% CI 0.48-0.97; P = 0.036), and showed a tendency towards poorer survival after recurrence compared with rectal cancer (HR 0.79, 95% CI 0.57-1.10; P = 0.164). CONCLUSIONS: In Stage I-III colorectal cancer without preoperative treatment, our results suggest that the three tumour sites (right-sided colon, left-sided colon or rectum) may have prognostic significance for recurrence-free survival and survival after recurrence, rather than sidedness alone.

Cost-effectiveness of surveillance intervals after curative resection of colorectal cancer.

BACKGROUND: Major guidelines consistently recommend 5 years of postoperative surveillance for patients with colorectal cancer. However, they differ in their recommendations for examination intervals and whether they should vary according to disease stage. Furthermore, there are no reports on the cost-effectiveness of the different surveillance schedules. The objective of this study is to identify the most cost-effective surveillance intervals after curative resection of colorectal cancer. METHODS: A total of 3701 patients who underwent curative surgery for colorectal cancer at the National Cancer Center Hospital were included. A cost-effectiveness analysis was conducted for the five surveillance strategies with reference to the guidelines. Expected medical costs and quality-adjusted life years after colorectal cancer resection were calculated using a state-transition model by Monte Carlo simulation. The incremental cost-effectiveness ratio per quality-adjusted life years gained was calculated for each strategy, with a maximum acceptable value of 43 500-52 200 USD (5-6 million JPY). RESULTS: Stages I, II and III included 1316, 1082 and 1303 patients, respectively, with 45, 140 and 338 relapsed cases. For patients with stage I disease, strategy 4 (incremental cost-effectiveness ratio $26 555/quality-adjusted life year) was considered to be the most cost-effective, while strategies 3 ($83 071/quality-adjusted life year) and 2 ($289 642/quality-adjusted life year) exceeded the threshold value. In stages II and III, the incremental cost-effectiveness ratio for strategy 3 was the most cost-effective option, with an incremental cost-effectiveness ratio of $18 358-22 230/quality-adjusted life year. CONCLUSIONS: In stage I, the cost-effectiveness of intensive surveillance is very poor and strategy 4 is the most cost-effective. Strategy 3 is the most cost-effective in stages II and III.

Prognostic impact of extramural venous invasion detected by contrast-enhanced CT colonography in colon cancer.

BACKGROUND: The impact of computed tomography (CT)-detected extramural venous invasion on the recurrence of colon cancer is not fully understood. The aim of this study was to investigate the clinical significance of extramural venous invasion diagnosed before surgery by contrast-enhanced CT colonography using three-dimensional multiplanar reconstruction images. METHODS: Patients with colon cancer staged greater than or equal to T2 and/or stage I-III who underwent contrast-enhanced CT colonography between 2013 and 2018 at the National Cancer Center Hospital in Japan were retrospectively investigated for CT-detected extramural venous invasion. Inter-observer agreement for the detection of CT-detected extramural venous invasion was evaluated and Kaplan-Meier survival curves were plotted for recurrence-free survival using CT-TNM staging and CT-detected extramural venous invasion. Preoperative clinical variables were analysed using Cox regression for recurrence-free survival. RESULTS: Out of 922 eligible patients, 544 cases were analysed (50 (9.2 per cent) were diagnosed as positive for CT-detected extramural venous invasion and 494 (90.8 per cent) were diagnosed as negative for CT-detected extramural venous invasion). The inter-observer agreement for CT-detected extramural venous invasion had a κ coefficient of 0.830. The group positive for CT-detected extramural venous invasion had a median follow-up of 62.1 months, whereas the group negative for CT-detected extramural venous invasion had a median follow-up of 60.7 months. When CT-TNM stage was stratified according to CT-detected extramural venous invasion status, CT-T3 N(-)extramural venous invasion(+) had a poor prognosis compared with CT-T3 N(-)extramural venous invasion(-) and CT-stage I (5-year recurrence-free survival of 50.6 versus 89.3 and 90.1 per cent respectively; P < 0.001). In CT-stage III, the group positive for CT-detected extramural venous invasion also had a poor prognosis compared with the group negative for CT-detected extramural venous invasion (5-year recurrence-free survival of 52.0 versus 78.5 per cent respectively; P = 0.003). Multivariable analysis revealed that recurrence was associated with CT-T4 (HR 3.10, 95 per cent c.i. 1.85 to 5.20; P < 0.001) and CT-detected extramural venous invasion (HR 3.08, 95 per cent c.i. 1.90 to 5.00; P < 0.001). CONCLUSION: CT-detected extramural venous invasion was found to be an independent predictor of recurrence and could be used in combination with preoperative TNM staging to identify patients at high risk of recurrence.

A multicenter prospective observational study of lymph node metastasis patterns and short-term outcomes of extended lymphadenectomy in right-sided colon cancer.

Background: The lymph node metastasis rate in right-sided colon cancer is unknown, and the optimal central vascular ligation level remains controversial. We aimed to determine the lymph node metastasis rate and short-term results of radical surgery with extended lymph node dissection in right-sided colon cancer. Methods: This prospective multicenter observational study included patients with stage II/III right-sided colon cancer from five cancer hospitals. The metastasis rate of each node station was analyzed according to tumor location and main feeding artery. Results: Between April 2018 and August 2021, 208 patients underwent dissection around the superior mesenteric artery (SMA) and vein (SMV). In transverse colon cancer, 7.5% and 2.5% of metastases occurred around the SMV and SMA at the root of the middle colic artery (MCA), respectively; 6.7% and 6.7% at the root of the right colic artery. In caecal cancer, 1.9% of metastases occurred around the SMV and 1.9% around the SMA. In ascending colon cancer, the rate was 1.1% around the SMV. Of the tumors, 17% fed mainly by the ileocolic artery had node metastases along the middle or right colic artery, as did 66.7% fed mainly by the right colic artery and 41.2% fed by the MCA (p = 0.01). Postoperative complications occurred in 42 patients (20.2%). Conclusion: Routine prophylactic extended lymphadenectomy around the SMA might not be necessary in caecum and ascending colon cancer. Dissection around the SMA may be necessary in cases of transverse colon cancer or when the feeding artery is the MCA.

Lateral pelvic lymph node metastasis in T2 low rectal cancer: is TME alone sufficient for cure?

BACKGROUND: Some patients with even T2 low rectal cancer are known to develop lateral pelvic lymph node metastasis. This study aimed to investigate real-world evidence regarding lateral nodal metastasis on T2 low rectal cancer treatment. METHODS: Consecutive patients with pathological T2 low rectal adenocarcinoma who underwent curative-intent surgery between January 2007 and December 2015 at two Japanese cancer centres dedicated to lateral pelvic lymph node dissection were identified and included in the analysis. Lateral pelvic lymph node metastasis was defined as pathologically confirmed metastatic lateral pelvic lymph node or lateral-local recurrence after primary surgery. RESULTS: A total of 215 consecutive patients, including 101 and 114 patients who did and did not undergo bilateral lateral pelvic lymph node dissection, were included in the analysis. Overall, 19 (8.8%) patients had lateral pelvic lymph node metastasis, including 13 with pathologically confirmed metastatic lateral pelvic lymph node and six with lateral-local recurrence. A total of 10 (4.7%) patients had local recurrence, including six with lateral-local recurrence, two with central-local recurrence and two with anastomotic recurrence. Five/7-year cumulative risks of lateral-local recurrence in patients with and without lateral pelvic lymph node dissection were 1.1/1.1% and 3.9/5.2%, respectively. CONCLUSION: The problem of the relatively high rate of lateral local recurrence remains in treating T2 low rectal cancer with only total mesorectal excision. The selection of high-risk patients of lateral pelvic lymph node metastasis and the indication of additional treatment in T2 low rectal cancer should be discussed further.

A review of 14 cases of perianal Paget's disease: characteristics of anorectal cancer with pagetoid spread.

BACKGROUND: Perianal Paget's disease (PPD) is an intraepithelial invasion of the perianal skin and is frequently associated with underlying anorectal carcinoma. The relatively rare nature of this disease has made it difficult to develop treatment recommendations. This study aims to analyze the clinical and pathological features of perianal Paget's disease (PPD) and to explore rational treatment options and follow-up for this disease. METHODS: The National Cancer Center Hospital database was searched for all cases of perianal Paget's disease diagnosed between 2006 and 2021. In the 14 patients identified, we reviewed the diagnosis, management, and outcomes of adenocarcinoma with pagetoid spread, including suspected or recurrent cases. RESULTS: All 14 cases met the inclusion criteria. The median follow-up period after diagnosis was 4.5 (range, 0.1-13.0) years. Pagetoid spread before initial treatment was suspected in 12 cases (85.7%). Underlying rectal cancer was identified in 6 cases, and no primary tumor was detected in the other 6 cases. Seven patients had recurrent disease, with the median time to recurrence of 34.6 (range, 19.2-81.7) months. The time to the first relapse was 3 months, and that to the second relapse was 6 months. The overall 5-year survival rate was 90.0%. CONCLUSIONS: Endoscopic and radiologic evaluation, as well as immunohistologic examination, should be performed. is to differentiate PPD with and without underlying anorectal carcinoma. The time to first recurrence varies widely, and long-term and regular follow-up for more than 5 years is considered necessary for local recurrence and distant metastasis.

Prognostic differences between oligometastatic and polymetastatic disease after resection in patients with colorectal cancer and hepatic or lung metastases: Retrospective analysis of a large cohort at a single institution.

BACKGROUND: Long-term survival data are lacking, and prognostic factors are not well-defined for patients with colorectal cancer and hepatic or lung metastases. This study evaluated the outcomes after resection of oligometastatic hepatic or lung metastases from colorectal cancer and sought to identify prognostic factors. METHODS: We retrospectively investigated 1,123 patients with colorectal cancer and hepatic or pulmonary metastases who underwent curative surgery between January 1991 and December 2016. RESULTS: Of the 1,123 patients, 719 had hepatic metastases, 287 had pulmonary metastases, and 117 had both. The 5-year overall survival rate was 52.3% in the hepatic metastases group, 70.4% in the pulmonary metastases group, and 71.4% in the hepatic and pulmonary metastases group (P < .001). In total, 1,045 patients had oligometastases (1-5 metastatic lesions in 1 or 2 organs) and 78 had polymetastases (≥6 metastases in 1 or 2 organs). Prognosis was significantly better in patients with oligometastases than in those with polymetastases. The 5-year overall survival rate was 59.0% in the oligometastases group and 35.3% in the polymetastases group (P < .001); the respective 5-year relapse-free survival rates were 37.5% and 11.6% (P < .001). Multivariable analysis identified predictors of both poor overall survival and relapse-free survival to be a high carcinoembryonic antigen level before the first metastasectomy, largest metastasis measuring ≥2 cm, polymetastases, and synchronous metastases. CONCLUSION: Prognosis after curative resection was better in patients with oligometastatic colorectal cancer in the liver or lung than in those with polymetastases. Multidisciplinary decision-making strategies, including about surgery, should be based on number of metastases rather than their site.

Risk of non-colorectal cancer-related death in elderly patients with the disease: A comparison of five preoperative risk assessment indices.

BACKGROUND: A considerable number of elderly patients with colorectal cancer (CRC) die of non-CRC-related causes. The Controlling Nutritional Status (CONUT) score, American Society of Anesthesiologists Physical Status classification, Charlson Comorbidity Index, National Institute on Aging, and National Cancer Institute Comorbidity Index, and Adult Comorbidity Evaluation-27 score are all known predictors of survival in patients with CRC. However, the utility of these indices for predicting non-CRC-related death in elderly CRC patients is not known. METHODS: The study population comprised 364 patients aged 80 years or more who received curative resection for stage I-III CRC between 2000 and 2016. The association of each index with non-CRC-related death was compared by competing-risks analysis such as the cumulative incidence function and proportional subdistribution hazards regression analysis as well as time-dependent receiver-operating characteristic (ROC) analysis. RESULTS: There were 85 deaths (40 CRC-related and 45 non-CRC-related) during a median observation period of 53.2 months. Cumulative incidence function analysis identified CONUT score as the most suitable for risk stratification for non-CRC-related death. In proportional subdistribution hazards regression, risk of non-CRC-related death increased significantly as CONUT score worsened (2/3/4 vs. 0/1, hazard ratio 1.73, 95% confidence interval [CI] 0.91-3.15; ≥5 vs. 2/3/4, hazard ratio 2.71, 95% CI 1.08-6.81). Time-dependent ROC curve analysis showed that CONUT score were consistently superior to other indices during the 5-year observation period. CONCLUSIONS: The majority of deaths in elderly patients with CRC were not CRC-related. CONUT score was the most useful predictor of non-CRC-related death in these patients.

Treatment outcomes and prognostic factors in 47 patients with primary anorectal malignant melanoma in the immune therapy era.

PURPOSE: Primary anorectal melanoma (ARM) accounts for approximately 1.2% of all melanomas and 16.5% of all mucosal melanomas. ARM is associated with the shortest interval to disease progression and the highest rate of metastasis; however, optimal therapeutic strategies for ARM remain controversial. This study aimed to assess the ideal surgical intervention for ARM and to determine the effect of immune checkpoint inhibitors (ICI). METHODS: We included 47 patients with ARM treated at the National Cancer Center Hospital in Japan from 2011 to 2020. We performed a survival analysis for each of these groups: (i) patients with ARM (n = 47); (ii) operable non-stage IV cases at initial presentation (n = 35); and (iii) stage IV cases (n = 32). RESULTS: The 5-year overall survival (OS) was 53.6%, and the median OS was 78.7 months in patients with ARM. No statistically significant difference in 5-year OS was found between rectal and anal sites (50.9% vs. 56.7%). In the non-stage IV subgroup, the type of surgery (abdominoperineal resection or wide local excision) did not correlate with OS (HR 1.85; 95% CI 0.46-7.5; p = 0.39). In the stage IV subgroup, the 2-year OS of the ICI treatment group was 61.4%, whereas that of the dacarbazine regimen group was 0% (p = 0.048). CONCLUSION: Our ARM prognosis was better than that of previous studies. Our findings suggest that the availability of ICI therapy may improve survival in patients with advanced ARM. However, further research is warranted to identify both the clinical and molecular predictors of response to improve patient selection.

Prognostic impact of conversion hepatectomy for initially unresectable colorectal liver metastasis.

PURPOSE: This study aimed to evaluate the prognostic impact of conversion hepatectomy in patients with initially unresectable colorectal liver metastasis (CRLM) and to identify prognostic factors after conversion hepatectomy. METHODS: Correlations of conversion hepatectomy with relapse-free survival (RFS) and overall survival (OS) were retrospectively investigated in 554 consecutive patients who underwent hepatectomy for CRLM in 2000-2017. Prognostic factors after conversion hepatectomy were examined in multivariable analysis. RESULTS: Five hundred and nine patients (92%) had initially resectable CRLM at diagnosis and underwent hepatectomy (primary resection group) and 45 (8%) underwent conversion hepatectomy following chemotherapy (conversion group). The 5-year RFS was 30.0% in the primary resection group and 19.8% in the conversion group (p = 0.042); the respective 5-year OS rates were 62.0% and 52.4% (p = 0.253). Multivariable analysis did not identify conversion hepatectomy as a significant prognostic factor for RFS (hazard ratio [HR] 0.95, 95% confidence interval [CI] 0.64-1.37, p = 0.796) or OS (HR 1.12, 95% CI 0.67-1.79, p = 0.667). In the conversion group, multivariable analysis identified the following independent prognostic factors: timing of liver metastases for RFS (synchronous: HR 3.14, 95% CI 1.20-8.24, p = 0.020) and preoperative CEA level for RFS (> 5 ng/ml: HR 3.10, 95% CI 1.45-6.61, p = 0.003) and OS (> 5 ng/ml: HR 3.29, 95% CI 1.18-9.17, p = 0.023). CONCLUSIONS: RFS and OS rates after conversion hepatectomy were not inferior to those after primary resection in patients with CRLM. Patients with a normal CEA level before hepatectomy can be expected to have good long-term prognosis after conversion hepatectomy.

Laparoscopic resection of a solitary fibrous tumor in the mesentery of the small intestine: a case report.

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms that are usually localized in the mesothelium of soft tissues. Although SFTs of pleural origin are common, SFTs arising in the small intestine are extremely rare, and there are few reports of laparoscopic resection of these tumors. A 74-year-old woman presented to her local physician with intermittent pain in the lower abdomen. Computed tomography showed a 25 mm mass in the ileum with extramural protrusion and small intestine capsule endoscopy showed a submucosal tumor-like elevation covered by normal mucosa. The diagnosis was ileal tumor, which was removed by laparoscopic partial resection of the small intestine. Macroscopically, the tumor was found to be a substantial mass within subplasmalemmal fatty tissue that had no continuity with the muscular layer. Histological analysis showed proliferation of homogeneous spindle-shaped cells against a background of fibrous stroma. Immunostaining was positive for STAT6 and negative for KIT, Dog1, and S100, and SFT was diagnosed. The tumor was low risk according to Demicco's risk classification. In conclusion, a less invasive laparoscopic procedure is preferable if the tumor can be resected completely without applying excessive external force that results in seeding of tumor cells in the abdominal cavity.

Clinical outcomes of surgical and imatinib treatment for rectal gastrointestinal stromal tumours: retrospective cohort study.

BACKGROUND: Rectal gastrointestinal stromal tumours (GISTs) are rare and treated mainly by radical surgery. Although the importance of perioperative imatinib has been recognized, there are few reports on its outcomes. METHOD: Consecutive patients diagnosed with rectal GISTs between July 2008 and February 2021 were identified from a prospective database. Effects of perioperative imatinib were investigated, and surgical and survival outcomes were compared between neoadjuvant imatinib and upfront surgery. RESULTS: 34 patients meeting the inclusion criteria were identified. Compared with upfront surgery (n = 11), the neoadjuvant imatinib group (n = 23) had significantly larger tumours (median size 8.3 versus 2.5 cm; P = 0.01) and included a significantly greater proportion of high-risk patients according to the modified Fletcher classification (20/23 (87.0%) versus 6/11 (54.5%); P = 0.02). Comparing the operation planned based on imaging before neoadjuvant imatinib and the operation performed, there was an increase in sphincter-preserving surgery (4/23 (17.4%) to 11/23 (47.8%); P = 0.02), abdominoperineal resection 11/23 (47.8%) reduced to 7/23 (30.4%); P = 0.13) and total pelvic exenteration reduced from 8/23 (34.8%) to 5/23 (21.7%); P = 0.01). Tumours were downsized by a median of 30 per cent (range 0 per cent to -56 per cent; P = 0.01). During follow-up (median 42, range 5-131 months), there was no postoperative recurrence in 29 patients who received perioperative imatinib. One of the five patients who underwent surgery without neoadjuvant or adjuvant imatinib developed local recurrence. CONCLUSION: Treatment with imatinib for rectal GISTs seems to improve outcomes, and neoadjuvant imatinib increases the rate of sphincter-preserving surgery.

A metastatic G2 neuroendocrine tumor smaller than 5 mm: A case report.

BACKGROUND: Neuroendocrine tumors (NETs) measuring <10 mm are widely thought to be at low risk of lymph node metastasis. Here we report a case of lymph node metastasis in a patient with a 4-mm NET that was classified as grade 2. PRESENTATION OF CASE: A 32-year-old woman was referred to our hospital after a positive fecal occult blood test. Colonoscopy revealed a 4-mm yellowish submucosal tumor, which was diagnosed as NET of the upper rectum and removed by endoscopic submucosal resection with ligation. Pathological examination of the specimen showed a 4-mm grade 2 NET with a Ki-67 labeling index of 4.4% without lymphatic or venous invasion. In accordance with the European Neuroendocrine Tumor Society guidelines, we performed robotic-assisted laparoscopic low anterior resection with lymph node dissection. Final pathological examination revealed invasion confined to the submucosal layer and metastasis to one lymph node (pT1aN1M0, Stage IIIB). There were no residual tumor cells in the scar after endoscopic submucosal resection with ligation. DISCUSSION: Should G2 neuroendocrine tumors smaller than 5 mm be surgically resected? CONCLUSIONS: We encountered a rare case of a small NET with lymph node metastasis that was treated by robotic-assisted laparoscopic low anterior resection with lymph node dissection. Additional surgery is an option to be considered for grade 2 NET even if it is small because of the possibility of lymph node metastasis.

Post-Immunotherapy Robotic-Assisted Resection for Primary Anorectal Melanoma: A Case Report.

Anorectal malignant melanoma (AMM) is a rare and aggressive neoplasm. Here, we report a case of AMM that was treated with robotic-assisted abdominoperineal resection (APR) after immunotherapy. A 68-year-old Japanese woman presented at our hospital because of diagnosis AMM. Computed tomography revealed a mass in the lower anorectal region and enlarged perirectal lymph nodes, but showed no evidence of distant metastases. We determined that radical resection would be difficult; therefore, the patient received immunotherapy with pembrolizumab for nine cycles. The size of pararectal lymph nodes was reduced, and the patient subsequently underwent robot-assisted APR and lymph node dissection. Histopathological examination showed spindle-shaped atypical melanocytes with acidophilic changes indicative of tumor cell necrosis in the rectal mucosa. We found no viable tumor cells in all 48 lymph nodes that were resected, and resection margins were tumor free. The patient was able to complete 15 cycles of adjuvant immunotherapy with pembrolizumab and remained relapse free at the 2-year postoperative follow-up. The present case showed that combination of complete surgical resection and immunotherapy is expected to improve outcomes in AMM patients if immunotherapy is effective.

Evaluation of the learning curve for robot-assisted rectal surgery using the cumulative sum method.

BACKGROUND: There is no clear evidence on the number of cases required to master the techniques required in robot-assisted surgery for different surgical fields and techniques. The purpose of this study was to clarify the learning curve of robot-assisted rectal surgery for malignant disease by surgical process. METHOD: The study retrospectively analyzed robot-assisted rectal surgeries performed between April 2014 and July 2020 for which the operating time per process was measurable. The following learning curves were created using the cumulative sum (CUSUM) method: (1) console time required for total mesorectal excision (CUSUM tTME), (2) time from peritoneal incision to inferior mesenteric artery dissection (CUSUM tIMA), (3) time required to mobilize the descending and sigmoid colon (CUSUM tCM), and (4) time required to mobilize the rectum (CUSUM tRM). Each learning curve was classified into phases 1-3 and evaluated. A fifth learning curve was evaluated for robot-assisted lateral lymph node dissection (CUSUM tLLND). RESULTS: This study included 149 cases. Phase 1 consisted of 32 cases for CUSUM tTME, 30 for CUSUM tIMA, 21 for CUSUM tCM, and 30 for CUSUM tRM; the respective numbers were 54, 48, 45, and 61 in phase 2 and 63, 71, 83, and 58 in phase 3. There was no significant difference in the number of cases in each phase. Lateral lymph node dissection was initiated in the 76th case where robot-assisted rectal surgery was performed. For CUSUM tLLND, there were 12 cases in phase 1, 6 in phase 2, and 7 cases in phase 3. CONCLUSIONS: These findings suggest that the learning curve for robot-assisted rectal surgery is the same for all surgical processes. Surgeons who already have adequate experience in robot-assisted surgery may be able to acquire stable technique in a smaller number of cases when they start to learn other techniques.

Evaluation of Recurrence Risk After Curative Resection for Patients With Stage I to III Colorectal Cancer Using the Hazard Function: Retrospective Analysis of a Single-institution Large Cohort.

OBJECTIVE: This study aimed to investigate transitions of recurrence hazard and peak recurrence time in patients with nonmetastatic CRC using the hazard function. SUMMARY OF BACKGROUND DATA: A postoperative surveillance period of 5 years is consistent across major guidelines for patients with nonmetastatic CRC, but surveillance intervals differ. Estimates of instantaneous conditional recurrence rate can help set appropriate intervals. METHODS: The study population consisted of 4330 patients with stage I to III CRC who underwent curative resection at the National Cancer Center Hospital between January 2000 and December 2013. Hazard rates of recurrence were calculated using the hazard function. RESULTS: Recurrence rates in patients with stage I, II, and III CRC were 4% (50/1432), 11% (136/1231), and 25% (424/1667), respectively. The hazard curve for stage I was relatively flat and hazard rates were consistently low (<0.0015) for 5 years after surgery. The hazard curve for stage II had a peak hazard rate of 0.0046 at 13.7 months, after which the curve had a long hem to the right. The hazard curve for stage III had an earlier and higher peak than that of stage II (0.0105 at 11.6 months), with a long hem to the right. CONCLUSIONS: Changes in recurrence hazard for CRC patients varied considerably by stage. Our findings suggest that short-interval surveillance might be unnecessary for stage I patients for the first 3 years after surgery, whereas short-interval surveillance for the first 3 years should be considered for stage III patients.

Laparoscopic surgery using 8 K ultra-high-definition technology: Outcomes of a phase II study.

INTRODUCTION: Currently, laparoscopic surgery generally relies on 2 K high-definition image quality. The National Cancer Center Hospital, Olympus Corporation, and NHK Engineering System Inc. recently developed a new laparoscopic system with an 8 K ultra-high-definition (UHD) camera that provides images with a high-resolution, wide color range, high frame rate, and high dynamic range. This study aimed to investigate the effectiveness and safety of a new laparoscopic system which uses an 8 K UHD camera system (8K UHD system). METHODS: This phase II study enrolled 23 patients with colon or rectosigmoid cancer who were indicated for radical resection with laparoscopic colectomy using the 8 K UHD system. The primary endpoint was the proportion of patients with ≥30 mL of intraoperative blood loss. RESULTS: Of the 23 patients, 22 completed laparoscopic surgery with the 8 K UHD system. One patient was converted to the 2 K high-definition laparoscopic system due to technical difficulties with the 8 K UHD system during surgery. The median amount of intraoperative blood loss was 14 mL (range, 2-71 mL), and number of patients with intraoperative blood loss ≥30 mL was four (17.4%). None of the patients had >100 mL of intraoperative blood loss. No intraoperative complications were noted, and four (17.4%) patients developed postoperative complications. Pathological complete resection was achieved in all patients, and no conversion to open surgery was required. CONCLUSIONS: Laparoscopic surgery using the 8 K UHD system appears to be both safe and effective. However, further refinements may be necessary to improve usability.

Surveillance of patients with stage I or II colorectal cancer in Japan: a JCOG study group questionnaire survey.

Japanese Society for Cancer of the Colon and Rectum guidelines recommend regular, more intensive surveillance of patients who have undergone curative resection of pathological stages I-III colorectal cancer compared with guidelines in Western countries. We conducted a questionnaire survey to clarify the status of surveillance for patients with stage I or II colorectal cancer in high-volume centers in Japan on behalf of the Colorectal Cancer Study Group of the Japan Clinical Oncology Group. Questionnaires were distributed in September 2019. The response rate was 98.3% (59/60 institutions). The survey results indicated that about half of colorectal cancer specialists in Japan perform surveillance for stages I and II colorectal cancer according to the Japanese Society for Cancer of the Colon and Rectum guidelines. For stages I and II disease, 45% and 55% of surgeons, respectively, perform surveillance less intensively than recommended. Our findings suggest the possibility of less intensive surveillance for patients with stage I or II colorectal cancer in Japan.

Comparison of model fit and discriminatory ability of the 8th edition of the tumor-node-metastasis classification and the 9th edition of the Japanese classification to identify stage III colorectal cancer.

BACKGROUND: The most widely accepted staging system for colorectal cancer (CRC) is the tumor-node-metastasis (TNM) classification. In Japan, the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma (JCCRC) system is used. The two systems differ mainly in relation to tumor deposits (TD) and metastasis in the regional lymph nodes along the main feeding arteries and lateral pelvic lymph nodes (N3). Here, we investigated the prognostic ability of the two systems for stage III CRC. METHODS: We reviewed 696 consecutive patients who underwent curative resection of stage III CRC at the National Cancer Center Hospital between May 2007 and April 2014. We examined the clinicopathological features of CRC and predicted overall survival (OS) and relapse-free survival (RFS) according to the 8th TNM and 9th JCCRC systems. The systems were compared using Akaike's information criterion (AIC), Harrell's concordance index (C-index), and time-dependent receiver-operating characteristic (ROC) curves. RESULTS: The 9th JCCRC system was more clinically effective according to AIC (OS, 1199 vs. 1206; RFS, 2047 vs. 2057), showed better discriminatory ability according to the C-index (OS, 0.65 vs. 0.62; RFS, 0.62 vs. 0.58), and its time-dependent ROC curve was superior compared with the 8th TNM system. CONCLUSION: These results suggest that the 9th JCCRC system has superior discriminative ability to the 8th TNM system, because the 9th JCCRC accounts for the presence of TD and N3 disease, which were both significant predictors of poor prognosis. Reconsidering the clinical value of these two factors in the TNM system could improve its clinical significance.

Preoperative Nutritional Scores as Host-Related Prognostic Factors for Both Overall Survival and Postoperative Complications in Patients With Stage II to III Colorectal Cancer.

BACKGROUND: In the TNM eighth edition, nutritional status and inflammatory scores are newly described as host-related prognostic factors for esophageal cancer, hepatocellular carcinoma, and pancreatic cancer. However, only age and race are listed as host-related prognostic factors for colorectal cancer. OBJECTIVE: The purpose of this study was to evaluate the prognostic significance of nutritional and inflammatory scores for postoperative outcomes in patients with colorectal cancer. DESIGN: This was a retrospective study using a database that prospectively collects data. SETTINGS: The study was conducted at a high-volume multidisciplinary tertiary cancer center in Japan. PATIENTS: Study participants were 1880 consecutive patients with stage II to III colorectal cancer who underwent curative resection at the National Cancer Center Hospital between 2004 and 2012. Two nutritional scores (prognostic nutritional index and controlling nutritional status score) and 4 inflammatory scores (modified Glasgow prognostic score, neutrophil:lymphocyte ratio, platelet:lymphocyte ratio, and C-reactive protein:albumin ratio) were calculated. MAIN OUTCOME MEASURES: Correlations of nutritional scores and inflammatory scores with overall survival and postoperative complications were measured. RESULTS: After adjusting for key clinical and pathologic factors by multivariable analysis, 2 nutritional scores (prognostic nutritional index and controlling nutritional status score) and 2 inflammatory scores (neutrophil:lymphocyte ratio and C-reactive protein:albumin ratio) were independent prognostic factors for overall survival. With respect to discriminative ability, time-dependent receiver operating characteristic curves and Harrell concordance index revealed that prognostic nutritional index and controlling nutritional status score were superior to the 4 inflammatory scores for predicting overall survival. Multivariable logistic regression analyses also revealed that prognostic nutritional index, controlling nutritional status score, and C-reactive protein:albumin ratio were independent predictors for postoperative complications. LIMITATIONS: The retrospective design of the study was a limitation. CONCLUSIONS: Preoperative nutritional scores are promising host-related prognostic factors for overall survival and postoperative complications in patients with stage II and III colorectal cancer. See Video Abstract at http://links.lww.com/DCR/B587. EVALUACIN DE SCORE NUTRICIONALES PREOPERATORIOS COMO FACTORES PRONSTICOS PARA SOBREVIDA Y COMPLICACIONES POSTOPERATORIAS EN PACIENTES CON CANCER COLORECTAL ETAPA II Y III: ANTECEDENTES:En las últimas etapificaciones T-N-M, tanto el estado nutricional como inflamatorio han sido descritos como factores pronósticos en cáncer de esófago, hepático y pancreático. Sin embargo en cáncer colorectal solo la edad y la raza son enumerados como factores pronósticos.OBJETIVO:Evaluar la importancia pronóstica de los scores nutricionales e inflamatorias para los resultados posoperatorios en pacientes con cáncer colorrectal.DISEÑO:Estudio retrospectivo utilizando una base de datos.AJUSTE:Centro oncológico teciario en Japón.PACIENTES:Fueron incluidos en el estudio 1880 pacientes, consecutivos, con cancer colorectal etapa II y III sometidos a reseeción curativa en el National Cancer Center Hospital entre 2004 y 2012. Se aplicaron dos scores: nutricional (índice nutricional pronóstico y puntuación del estado nutricional) e inflamatorias (Glasgow modificada, proporción de neutrófilos a linfocitos, de plaquetas a linfocitos y de proteína C reactiva a albúmina).PRINCIPALES MEDIDAS DE RESULTADO:Evaluar scores nutricional e inflamatorio con sobrevida y complicaciones postoperatoria.RESULTADOS:Después de ajustar los factores clínicos y patológicos clave mediante análisis multivariable, dos scores nutricionales (índice nutricional pronóstico y puntuación del estado nutricional de control) y dos inflamatorias (proporción de neutrófilos a linfocitos y proporción de proteína C reactiva a albúmina) fueron pronósticos independientes factores para la sobrevida. Con respecto a la capacidad discriminativa, las curvas de características operativas del receptor, dependientes del tiempo y el índice de concordancia de Harrell, revelaron que el índice nutricional pronóstico y del estado nutricional de control eran superiores a las cuatro inflamatorias para predecir la sobrevida general. Los análisis de regresión logística multivariable también revelaron que el índice nutricional pronóstico, el estado nutricional de control y la relación proteína C reactiva / albúmina fueron predictores independientes de complicaciones postoperatorias.LIMITACIONES:Estudio de tipo retrospectivo.CONCLUSIONES:Los scores nutricionales preoperatorias son factores pronósticos prometedores relacionados con la sobrevida y las complicaciones postoperatorias en pacientes con cáncer colorrectal en estadio II y III. Consulte Video Resumen en http://links.lww.com/DCR/B587.