Use of 3D-CT-derived psoas major muscle volume in defining sarcopenia in colorectal cancer.

BACKGROUND: Sarcopenia is characterized by reduced skeletal muscle volume and is a condition that is prevalent among elderly patients and associated with poor prognosis as a comorbidity in malignancies. Given the aging population over 80 years old in Japan, an understanding of malignancies, including colorectal cancer (CRC), complicated by sarcopenia is increasingly important. Therefore, the focus of this study is on a novel and practical diagnostic approach of assessment of psoas major muscle volume (PV) using 3-dimensional computed tomography (3D-CT) in diagnosis of sarcopenia in patients with CRC. METHODS: The subjects were 150 patients aged ≥ 80 years with CRC who underwent primary tumor resection at Juntendo University Hospital between 2004 and 2017. 3D-CT measurement of PV and conventional CT measurement of the psoas major muscle cross-sectional area (PA) were used to identify sarcopenia (group S) and non-sarcopenia (group nS) cases. Clinicopathological characteristics, operative results, postoperative complications, and prognosis were compared between these groups. RESULTS: The S:nS ratios were 15:135 for the PV method and 52:98 for the PA method. There was a strong positive correlation (r = 0.66, p < 0.01) between PVI (psoas major muscle volume index) and PAI (psoas major muscle cross-sectional area index), which were calculated by dividing PV or PA by the square of height. Surgical results and postoperative complications did not differ significantly in the S and nS groups defined using each method. Overall survival was worse in group S compared to group nS identified by PV (p < 0.01), but not significantly different in groups S and nS identified by PA (p = 0.77). A Cox proportional hazards model for OS identified group S by PV as an independent predictor of a poor prognosis (p < 0.05), whereas group S by PA was not a predictor of prognosis (p = 0.60). CONCLUSIONS: The PV method for identifying sarcopenia in elderly patients with CRC is more practical and sensitive for prediction of a poor prognosis compared to the conventional method.

Tyrosine kinase alterations in colorectal cancer with emphasis on the distinct clinicopathological characteristics.

AIMS: Tyrosine kinase (TK) alterations, such as anaplastic lymphoma kinase (ALK) fusion, neurotrophic tyrosine receptor kinase (NTRK) fusion, c-ros oncogene 1 (ROS1) fusion and mesenchymal-epithelial transition factor (MET) exon 14 skipping, have been reported in colorectal cancers (CRC). We have previously reported CRCs with NTRK fusion among our cohort. However, their clinicopathological features have not been fully elucidated. METHODS AND RESULTS: Tissue microarray (TMA)-based immunohistochemistry (IHC) was performed on 951 CRC lesions from 944 patients. IHC was evaluated as positive or negative for ALK and ROS1 and 0 to 3+ for c-MET. For ALK and ROS1 IHC-positive cases, RNA-based imbalanced gene expression assays, Archer FusionPlex assays and reverse transcription-polymerase chain reaction (RT-PCR) followed by Sanger sequencing were performed. For c-MET IHC 3+ cases, RT-PCR followed by Sanger sequencing were performed. ALK IHC was positive in three cases (0.2%) and all showed imbalanced ALK gene expression. The following ALK fusions were confirmed: EML4 (exon 21)::ALK (exon 20), EML4 (exon 6)::ALK (exon 19) and HMBOX1 (exon 6)::ALK (exon 20). Two showed microsatellite instability-high/mismatch repair (MMR)-deficient, and all were located in the right colon. ROS1 IHC was positive in one case; however, imbalanced expression and ROS1 fusion was negative. Forty-two cases (4.4%) showed c-MET IHC3+. MET exon 14 skipping was confirmed in nine cases. All cases were microsatellite stable/MMR-proficient, and eight were located in the left colon and rectum. CONCLUSIONS: CRCs with these TK alterations had distinct clinicopathological features. Together with our previous study, 15 cases (1.6%) harboured targetable TK alterations (three NTRK fusion, three ALK fusion, nine MET exon 14 skipping).

The methylation level of a single cancer risk marker gene reflects methylation burden in gastric mucosa.

BACKGROUND: Gastric cancer risk can be accurately predicted by measuring the methylation level of a single marker gene in gastric mucosa. However, the mechanism is still uncertain. We hypothesized that the methylation level measured reflects methylation alterations in the entire genome (methylation burden), induced by Helicobacter pylori (H. pylori) infection, and thus cancer risk. METHODS: Gastric mucosa of 15 healthy volunteers without H. pylori infection (G1), 98 people with atrophic gastritis (G2), and 133 patients with gastric cancer (G3) after H. pylori eradication were collected. Methylation burden of an individual was obtained by microarray analysis as an inverse of the correlation coefficient between the methylation levels of 265,552 genomic regions in the person's gastric mucosa and those in an entirely healthy mucosa. RESULTS: The methylation burden significantly increased in the order of G1 (n = 4), G2 (n = 18), and G3 (n = 19) and was well correlated with the methylation level of a single marker gene (r = 0.91 for miR124a-3). The average methylation levels of nine driver genes tended to increase according to the risk levels (P = 0.08 between G2 vs G3) and was also correlated with the methylation level of a single marker gene (r = 0.94). Analysis of more samples (14 G1, 97 G2, and 131 G3 samples) yielded significant increases of the average methylation levels between risk groups. CONCLUSIONS: The methylation level of a single marker gene reflects the methylation burden, which includes driver gene methylation, and thus accurately predicts cancer risk.

Prognostic factors in patients with high-risk stage II colon cancer after curative resection: a post hoc analysis of the JFMC46-1201 trial.

PURPOSE: The goal of the current study was to identify prognostic factors for disease-free survival (DFS) and overall survival (OS) in high-risk stage II colon cancer. METHODS: The subjects were patients with histologically confirmed stage II colon cancer undergoing R0 resection who met at least one of the following criteria: T4, perforation/penetration, poorly differentiated adenocarcinoma, mucinous carcinoma, and < 12 examined lymph nodes. Patients self-selected surgery alone or a 6-month oral uracil and tegafur plus leucovorin (UFT/LV) regimen. Serum CEA mRNA at ≥ 24 h after surgery and < 2 weeks after registration was also examined as a potential prognostic factor for stage II colon cancer. This study is registered with UMIN-CTR (protocol ID: UMIN000007783). RESULTS: 1880 were included in the analysis to identify prognostic factors for DFS and OS in patients with high-risk stage II colon cancer. In multivariate analyses, gender, depth of tumor invasion, extent of lymph node dissection, number of examined lymph nodes, and postoperative adjuvant chemotherapy (POAC) emerged as significant independent prognostic factors for DFS. Similarly, multivariate analysis showed that age, gender, depth of tumor invasion, perforation/penetration, extent of lymph node dissection, number of examined lymph nodes, and POAC were significant independent prognostic factors for OS. Univariate analyses showed no significant difference in DFS or OS for CEA mRNA-positive and mRNA-negative cases. CONCLUSION: This study showed that gender, depth of tumor invasion, extent of lymph node dissection, number of examined lymph nodes, and lack of use of POAC were significant independent prognostic factors in stage II colon cancer.

Risk factors for small-bowel obstruction after colectomy for colorectal cancer: a retrospective study.

PURPOSE: Postoperative adhesions are a concerning complication of abdominal surgery with major implications on quality of life. This study aimed to investigate the risk factors for postoperative small-bowel obstruction (SBO) after colectomy for colorectal cancer. METHODS: We reviewed the clinicopathological variables of 1646 patients who underwent colectomy for colorectal cancer between 2009 and 2018. RESULTS: SBO occurred following primary tumor resection for colorectal cancer in 67 (4.1%) of the 1646 patients. The median observation period was 7.5 (range: 3.0-12.0) years. Multivariate analysis revealed that rectal tumors, anastomotic leakages, previous abdominal surgeries, and longer operating times were all correlated with postoperative SBO, but there were no differences in the incidence of SBO between laparoscopic vs. open surgery. The use of adhesion prevention material had no effect on SBO. Our data showed that the onset of SBO tended to be relatively early, within a year after surgery (89.5%). CONCLUSIONS: Tumor localization in the rectum is associated with several problems, including a wide resection area, prolonged operative duration, and high risk of anastomotic leakage, which may increase the risk of SBO. Laparoscopic surgery and adhesion prevention material did not demonstrate a clear preventive effect against SBO.

Examination of colorectal cancer cases with metal allergy.

PURPOSE: To report our initiatives and treatment results for patients with colorectal cancer with metal allergy. METHODS: A total of 27 patients (2.6%) with a history of metal contact dermatitis were identified among 1027 patients who underwent curative resection of colorectal cancer from 2014 to 2020. The results of the patch test, perioperative results, and postoperative colonoscopy findings were also investigated. RESULTS: The patch test for metal allergens and staples was performed in 21 patients (77.8%), and 13 of them (61.9%) tested positive for at least one metal allergen. Ni (38.1%), Co (28.6%), and Pd (19.0%) showed higher positive rates than other metals, and 1 patient (4.8%) tested positive for staples. Stapled anastomosis/suturing was performed as planned in 15 of 27 patients. In 10 patients, the anastomosis method was changed from stapled to hand-sewn according to the no-patch test results (60%), positivity for multiple metals (20%), positivity for staples (10%), and surgeon's judgment (10%). No complications and abnormal colonoscopy findings were found to be associated with stapled anastomosis/suturing. CONCLUSION: The patch test is useful for selecting an optimal anastomosis method for patients with suspected metal allergy.

[A Case of Cecum Cancer with Lymph Node Metastasis and Invasion in the Superior Mesenteric Vein Treated with Combined SMV Resection and Reconstruction].

The patient was a 77-year-old woman. She visited her family doctor with a complaint of bloody stools, and was pointed out a Type 3 colon cancer in the cecum with a colonoscopy. In addition, an enlarged lymph node(#203)was found on the right side of the superior mesenteric vein(SMV). Laparoscopic surgery was initiated, and when the patient was moved to vascular processing, a firm adhesion of the lymph node(#203)was observed on the right side of the SMV. A small laparotomy was added, and a partial combined resection of the SMV was performed en bloc to complete the ileal resection. Histopathological findings showed T4b(transverse colon)N3M0, pStage Ⅲc, and metastatic lymph node(#203)showed evidence of invasion to the SMV. Adjuvant chemotherapy was administered, but lung metastases appeared 4 months and liver metastasis appeared 29 months after surgery. The patient was transferred to a different hospital for best supportive care(BSC)at 34 months after surgery.

Efficacy and safety of regorafenib dose-escalation therapy for Japanese patients with refractory metastatic colorectal cancer (RECC study).

BACKGROUND: Regorafenib significantly improves overall survival in previously treated metastatic colorectal cancer patients. However, various toxicities, such as hand-foot skin reaction (HFSR), fatigue, and liver dysfunction have limited the use of regorafenib. These toxicities appear soon after treatment initiation. The ReDOS study demonstrated the effectiveness of a weekly dose-escalation therapy of regorafenib starting with a lower daily dose; however, its usefulness in Asian subjects is unknown. We conducted a phase II study to evaluate the safety and survival benefit of regorafenib dose-escalation therapy for Japanese patients. METHODS: Patients with sufficient organ function, who had previously received more than two lines of chemotherapy were included. Regorafenib was started at 80 mg/day and escalated to 120 mg/day in Week 2 and 160 mg/day in Week 3, if no severe drug-related toxicities were observed. The primary endpoint was cancer progression-free survival (PFS). Tumor response and progression were assessed radiologically every 8 weeks. This study was registered in the University Hospital Medical Information Network (UMIN#UMIN000028933). RESULTS: 57 patients were enrolled and all started regorafenib at 80 mg/day. 32 patients (56.1%) were subsequently escalated to 120 mg/day and 19 (33.3%) to 160 mg/day. Only 8 patients (14.0%) discontinued treatment because of adverse events. Median PFS was 1.9 months. Median overall survival was 8.9 months, the response rate was 0%, and the disease control rate was 31.6%. The most frequent adverse event greater than grade 3 was hypertension (19.3%), followed by HFSR (14.0%). CONCLUSIONS: Regorafenib dose-escalation therapy is well tolerated with PFS-like regorafenib standard therapy.

[A Case of Recurrence in the Abdominal Wall and Perineal Region of Rectal Cancer Successfully Treated with Minimally Invasive Surgery and Radiation Therapy].

Local recurrence after rectal cancer surgery is often difficult to treat because there are few effective treatments. In this study, we report a case of parastomal and perineal recurrence after Miles' surgery in an elderly patient who had a favorable outcome after laparoscopic surgery and radiation therapy. Our results suggest that a combination of minimally invasive treatment may be effective in elderly patients and after polysurgery.

[A Case Report for Peritoneal Recurrences by Laparoscopic Surgery after Colorectal Cancer Resection].

We report a cases report of colorectal cancer who underwent repeated resection for peritoneal recurrences by laparoscopic surgery. In 2013, a 70-year-old woman diagnosed with an ascending colon cancer underwent laparoscopic right hemicolectomy. The pathological diagnosis was tub2, pT4aN1M0, Stage Ⅲb. Postoperative adjuvant chemotherapy(uracil and tegafur/Leucovorin)was administered. PET-CT performed at 25 months after the surgery because of CEA elevation. It revealed a peritoneal recurrence in the pouch of Douglas. The following peritoneal recurrences were removed by laparoscopic Hartmann's procedure. Chemotherapy(5-fluorouracil/levofolinate/oxaliplatin/bevacizumab)was administered 11 courses and after that chemotherapy(5-fluorouracil/levofolinate/bevacizumab)was administered 6 courses. PET-CT performed 37 months after the second surgery revealed a peritoneal recurrence near the right ovary in the pouch of Douglas. The following peritoneal recurrences was removed. Chemotherapy(tegafur/gimeracil/oteracil/bevacizumab)was administered 11 courses. The long-term survival has been continued for 7 years and 7 months after first operation. It was considered that laparoscopic surgery for peritoneal recurrence in colorectal cancer is contributed to one of the surgical procedures in selected patients.

[A Case Report of a Giant GIST Markedly Responsive to Neoadjuvant Chemotherapy with Imatinib Mesylate].

Male in his 50s complaining of abdominal pain was referred to our hospital. Abdominal CT scan showed a giant tumor which had diameter of approximately 50 mm in lower rectum. A biopsy specimen was positive for CD34 and c-kit. Based on these findings, it was diagnosed as gastrointestinal stromal tumor(GIST). We treated the patient with neoadjuvant therapy using imatinib mesylate(IM)to reduce the tumor size and to avoid the extensive surgery. The patient started to take IM at a daily dose of 400 mg. After 3 months, CT and MRI revealed that the tumor size decreased(40% reduction). We performed the robot assisted intersphincteric resection(ISR). Although it has been 28 months since the surgery, there are no obvious signs of recurrence. A patient diagnosed with giant GIST could avoid an extensive surgery due to neoadjuvant therapy with IM.

[Management of a perforated duodenal diverticulum using an endoscopic nasobiliary drainage tube:a case report].

A man in his 70s visited our hospital for abdominal pain. Upon admission, abdominal computed tomography findings suggested a duodenal diverticular perforation. Upper gastrointestinal endoscopy revealed an incarcerated enterolith in the periampullary diverticulum. We achieved conservative management by inserting an endoscopic nasobiliary drainage tube into the duodenal diverticulum to aid drainage. The patient was discharged without serious complications 35 days after admission. We report a case of duodenal diverticular perforation with an incarcerated enterolith managed conservatively using endoscopic therapy.

Significance of postoperative adjuvant chemotherapy with an oxaliplatin-based regimen after simultaneous curative resection for colorectal cancer and synchronous colorectal liver metastasis: a propensity score matching analysis.

BACKGROUND: Expansion of the indication for liver resection and new regimens for systemic chemotherapy have improved postoperative outcomes for synchronous colorectal liver metastases (CRLM). However, such cases can still have a high recurrence rate, even after curative resection. Therefore, there is a need for postoperative adjuvant chemotherapy (POAC) after liver resection in patients with CRLM. There are few studies of the efficacy of POAC with an oxaliplatin-based regimen after simultaneous resection for colorectal cancer and CRLM with curative intent. The goal of the study was to compare POAC with oxaliplatin-based and fluoropyrimidine regimens using propensity score (PS) matching analysis. METHODS: The subjects were 94 patients who received POAC after simultaneous resection for colorectal cancer and synchronous CRLM, and were enrolled retrospectively. The patients were placed in a L-OHP (+) group (POAC with an oxaliplatin-based regimen, n = 47) and a L-OHP (-) group (POAC with a fluoropyrimidine regimen, n = 47). Recurrence-free (RFS), cancer-specific (CSS), unresectable recurrence-free (URRFS), remnant liver recurrence-free (RLRFS), and extrahepatic recurrence-free (EHRFS) survival were analyzed. RESULTS: Before PS matching, the L-OHP (+) and (-) groups had no significant differences in RFS, CSS, URRFS, RLRFS, and EHRFS. Univariate analysis indicated significant differences in age, preoperative serum CEA (≤ 30.0 ng/mL/ > 30.0 ng/mL), differentiation of primary tumor (differentiated/undifferentiated), T classification (T1-3/T4), number of hepatic lesions and maximum diameter of the hepatic lesion between the L-OHP (+) and (-) groups. After PS matching using these confounders, RFS was significantly better among patients in the L-OHP (+) group compared with the L-OHP (-) group (HR 0.40, 95% CI 0.17-0.96, p = 0.04). In addition, there was a trend towards better RLRFS among patients in the L-OHP (+) group compared with the L-OHP (-) group (HR 0.42, 95% CI 0.17-1.02, p = 0.055). However, there were no significant differences in CSS, URRFS and EHRFS between the L-OHP (+) and (-) groups. CONCLUSIONS: PS matching analysis demonstrated the efficacy of POAC with an oxaliplatin-based regimen in RFS and RLRFS.

Creatine kinase elevation after robotic surgery for rectal cancer due to a prolonged lithotomy position.

BACKGROUND: Robotic surgery for rectal cancer, which is now performed worldwide, can be associated with elevated creatine kinase levels postoperatively. In this study, we compared postoperative complications between patients undergoing robotic surgery and laparoscopic surgery. METHODS: We identified 66 consecutive patients who underwent curative resection for rectal cancer at Juntendo University Hospital between January 2016 and February 2019. Patients were divided into a conventional laparoscopic surgery (CLS) group (n = 38) and a robotic-assisted laparoscopic surgery (RALS) group (n = 28) before comparing various clinicodemographic factors between the groups. RESULTS: Patient age and gender, surgical approach (CLS/RALS), pathological T factor, pathological stage, duration of postoperative hospital stay, and postoperative complications were not significantly different between the RALS and CLS groups. However, the operation time was significantly longer in the RALS group (407 min) than in the CLS group (295 min; p < 0.001). Notably, the serum level of creatine kinase on postoperative day 1 was significantly higher in the CLS group (154 IU/L) than in the RALS group (525 IU/L; p < 0.001), despite there being no significant differences in the incidence of rhabdomyolysis. The multivariate analysis showed that RALS/CLS (HR 6.0 95% CI 1.3-27.5, p = 0.02) and operation time (HR 15.9 95% CI 3.79-67.4, p = 0.001) remained independent factors of CK elevation on postoperative day 1. CONCLUSIONS: Clinically relevant positioning injuries and rhabdomyolysis may occur in patients who are subjected to a prolonged and extreme Trendelenburg position or who have extra force applied to the abdominal wall because of remote center displacement. The creatine kinase value should therefore be measured after RALS to monitor for the sequelae of these potential positioning injuries.

Prognostic Impact of Phosphorylated Discoidin Domain Receptor-1 in Esophageal Cancer.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is common in East Asia and also is often deadly. We sought to determine whether measuring the discoidin domain receptor-1 (DDR1)-both total and phosphorylated proteins-could improve our ability to predict recurrence in ESCC. MATERIALS AND METHODS: Total DDR1 and phosphorylated DDR1 (pDDR1) were measured using semiquantitative immunohistochemistry in a cohort of 60 patients with ESCC. Association between these immunohistochemical measurements and standard clinical-pathological variables such as patient recurrence-free survival was examined using univariate and multivariate analyses. RESULTS: Six patients (10.0%) had regional recurrence and eight patients (13.3%) had distant recurrence. In univariate analysis, early disease recurrence correlated with intense staining of total DDR1 (P = 0.03) as well as intense staining of pDDR1 (P < 0.001). On multivariate analysis, only regional lymph node metastasis (P = 0.04, HR = 4.20) and intensity of pDDR1 immunohistochemistry (P = 0.03, HR = 4.27) emerged as significant independent prognostic factors for recurrence. CONCLUSIONS: This study suggests that immunohistochemical measurements of both the DDR1 protein and pDDR1 can provide prognostic value in ESCC, even when other clinical and pathological factors are also being considered.

DNA methylation genome-wide analysis in remnant and primary gastric cancers.

BACKGROUND: Although primary (PGC) and remnant gastric cancers (RGC) both originate from the same gastrointestinal organ, they have very distinct clinicopathological behaviors. We hypothesized that there would be distinct differences in DNA methylation patterns that would occur during carcinogenesis of RGC and PGC, and that the differences in methylation patterns may help identify the primary factor contributing to chronic inflammation in patients with RGC. METHODS: We investigated the genome-wide DNA methylation patterns of PGC and RGC tissues from 48 patients using the Infinium HumanMethylation450 Beadchip assay. The results were validated by quantitative methylation-specific PCR (qMSP) in separate, independent cohorts. RESULTS: We found that in our training cohort of 48 patients, the most variable genes from the gastric cancer tissues identified by the Infinium HumanMethylation450 Beadchip clustered the resultant heatmap into high and low methylation groups. On multivariate analysis, PGCs contributed significantly to the high methylation group (p = 0.004, OR 12.33), which suggested that the promoter methylation status in PGC is higher than that in RGC. Supporting this conclusion was the finding that in a separate qMSP analysis in a test cohort, the EPB41L3 gene, chosen because of its high ß value on microarray analysis in the gastric cancer tissues, had significantly higher DNA promoter methylation in cancer tissues in the validation PGC tissues than in RGC. CONCLUSIONS: This study demonstrated that promoter methylation status in PGC is higher than in RGC. This result may reflect the effects of the absence of Helicobacter pylori on the reduced DNA methylation in the remnant stomach.

[A Case of Good Quality of Life(QOL)and Favorable Response to Transarterial Chemoembolization(TACE)against Synchronous Multiple Liver Metastases].

We report a case of good quality of life(QOL)and favorable response to transarterial chemoembolization(TACE)against synchronous multiple liver metastases. An 85-year-old man was admitted to our hospital because of melena. Colonoscopy showed multiple type 2 tumors in the sigmoid colon and upper rectum. CT and EOB-MRI examinations revealed that there were multiple liver metastases. Because of his age and surgical stress, he underwent a laparoscopic Hartmann's procedure. After the resection of the primary tumor, he received tegafur/uracil for his liver metastases. However, he discontinued receiving the drugs 2 weeks later because of the development of adverse events. Instead of systemic chemotherapy, he chose to undergo TACE. He underwent TACE with irinotecan and HepaSphereTM(BioSphere Medical)8 times for his multiple liver metastases. Consequently, all multiple liver metastases disappeared. Therefore, TACE may be useful for patients who are not suitable for systemic chemotherapy.

[A Case of Systemic Chemotherapy Combined with Molecular Drug Treatment Following Biliary Stent Implantation for Obstructive Jaundice Due to Metastases of Liver Gland Lymph Node after Colorectal Cancer Surgery].

We report a case of systemic chemotherapy after biliary stent placement for obstructive jaundice due to hepatic portal lymph node metastasis after colorectal cancer surgery. The patient was a 40s woman. Laparoscopic anterior resection for rectosigmoidRS cancer was performed. The pathological diagnosis was T3N0M0PUL0R0, pStage Ⅱ according to the 8th edition of colorectal cancer handling regulations. Because multiple liver metastases were observed 8 months after the surgery, partial resection of the posterior region of the liver was performed. Multiple lung metastases were observed 1 year after hepatectomy, but she wantedto undergo follow-up observation. Jaundice was observed 1 year after the diagnosis of lung metastasis, and obstructive jaundice due to hepatic portal lymph node metastasis was diagnosed. Endoscopic retrograde biliary drainage(ERBD)was performed, and a bile duct stent was placed. After improving jaundice, 12 courses of mFOLFOX6 plus cetuximab therapy were performed. Currently, because of the exacerbation of lung metastasis, FOLFIRI plus bevacizumab therapy is being administered. Systemic chemotherapy containing a molecular-targeted drug is being administered in our case, but complications relatedto the biliary stent have not been observed. There are few reports on similar cases, andfollow - up observation with careful attention to long-term safety is necessary.

Endoscopic Submucosal Dissection Decreases Additional Colorectal Resection for T1 Colorectal Cancer.

BACKGROUND There are 3 methods of treating T1 colorectal cancer (T1 CRC), which include endoscopic resection, endoscopic resection followed by additional colorectal resection, and surgical resection. In this retrospective study, changes in the management of T1 CRC after introduction of endoscopic submucosal dissection (ESD) were investigated by comparison with the 10-year period before introduction of ESD. MATERIAL AND METHODS During a 20-year period from 1996 to 2015, 835 patients with T1 CRC were treated, including 331 patients before introduction of ESD (Group A) and 504 patients after introduction of ESD (Group B). Clinicopathological findings and treatment methods were compared between these 2 groups. RESULTS As the initial treatment, endoscopic treatment was performed in 185 patients (55.9%) in Group A and 288 (57.1%) in Group B. In Group B, ESD was performed in 161 patients (55.9%), accounting for more than half of the T1 CRC patients receiving endoscopic treatment. In Groups A and B, observation after endoscopic resection was selected for 54.2% and 67.3% of T1a patients, respectively (p=0.04). A similar trend was noted for T1b patients, and there was no significant difference of the treatment approach. Among all T1 CRC patients, the percentage undergoing observation after endoscopic resection was significantly higher in Group B than in Group A (34.3% vs. 26.9%, p=0.02), and the percentage of patients undergoing additional colorectal resection was significantly lower in Group B (22.8% vs. 29.0%, p=0.04). CONCLUSIONS After introduction of ESD, it was performed in more than half of all patients with T1 CRC undergoing endoscopic treatment. The percentage of patients undergoing observation following endoscopic resection of T1 CRC increased after introduction of ESD.

[A Study of Treatment for Pathological T1(SM)Colorectal Cancer Patients after Endoscopic Resection at Our Department].

Approximately 10% of pathological T1(SM)colorectal cancer patients develop lymph node metastases. Therefore additional colectomy with lymph node dissection is recommended when it applies to the specific criteria in the current JSCCR guidelines. However, additional colectomy would not be done in some cases, because surgery is too invasive for some patients. Endoscopic treatment(ESD or EMR)for T1(SM)cancer was performed in 324 cases between 2008 and 2016. Of those, 231 cases had satisfied the criteria for additional colectomy. Among them, 74 cases(32.0%)did not undergo, and additional colectomy(+)groupwas 153 cases(66.2%). Between the 2 groups, no difference in prognosis could be found. We considered there was no difference, because the prognosis of SM cancer is relatively good. In consideration of patient background, the treatment policy has to be chosen according to feasibility.