How Does Omitting Additional Surgery After Local Excision Affect the Prognostic Outcome of Patients With High-risk T1 Colorectal Cancer?

OBJECTIVE: To investigate how omitting additional surgery after local excision (LE) affects patient outcomes in high-risk T1 colorectal cancer (CRC). BACKGROUND: It is debatable whether additional surgery should be performed for all patients with high-risk T1 CRC regardless of the tolerability of invasive procedures. METHODS: Patients who had received LE for T1 CRC at the Japanese Society for Cancer of the Colon and Rectum institutions between 2009 and 2016 were analyzed. Those who had received additional surgical resection and those who did not were matched one-on-one by the propensity score-matching method. A total of 401 propensity score-matched pairs were extracted from 1975 patients at 27 Japanese Society for Cancer of the Colon and Rectum institutions and were compared. RESULTS: Regional lymph node metastasis was observed in 31 (7.7%) patients in the LE + surgery group. Comparatively, the incidence of oncologic adverse events was low in the LE-alone group, such as the 5-year cumulative risk of local recurrence (4.1%) or overall recurrence (5.5%). In addition, the difference in the 5-year cancer-specific survival between the LE + surgery and LE-alone groups was only 1.8% (99.7% and 97.9%, respectively), whereas the 5-year overall survival was significantly lower in the LE-alone group than in the LE + surgery group [88.5% vs 94.5%, respectively ( P = 0.002)]. CONCLUSIONS: Those who had decided to omit additional surgery at the dedicated center for CRC treatment presented a small number of oncologic events and a satisfactory cancer-specific survival, which may suggest an important role of risk assessment regarding nononcologic adverse events to achieve a best practice for each individual with high-risk T1 tumors.

Long-Term Outcomes of Additional Surgery After Endoscopic Resection Versus Primary Surgery for T1 Colorectal Cancer.

INTRODUCTION: There is considerable concern about whether endoscopic resection (ER) before additional surgery (AS) for T1 colorectal cancer (CRC) has oncologically potential adverse effects. Therefore, the aim of this study was to compare the long-term outcomes, including overall survival (OS), of patients treated with AS after ER vs primary surgery (PS) for T1 CRC using a propensity score-matched analysis from a large observational study. METHODS: This study investigated 6,105 patients with T1 CRC treated with either ER or surgical resection between 2009 and 2016 at 27 high-volume Japanese institutions, with those undergoing surgery alone included in the PS group and those undergoing AS after ER included in the AS group. Propensity score matching was used for long-term outcomes of mortality and recurrence analysis. RESULTS: After propensity score matching, 1,219 of 2,438 patients were identified in each group. The 5-year OS rates in the AS and PS groups were 97.1% and 96.0%, respectively (hazard ratio: 0.72, 95% confidence interval: 0.49-1.08), indicating the noninferiority of the AS group. Moreover, 32 patients (2.6%) in the AS group and 24 (2.0%) in the PS group had recurrences, with no significant difference between the 2 groups (odds ratio: 1.34, 95% confidence interval: 0.76-2.40, P = 0.344). DISCUSSION: ER before AS for T1 CRC had no adverse effect on patients' long-term outcomes, including the 5-year OS rate. ER is a viable first-line treatment option for endoscopically resectable T1 CRC.

Treatment Decision for Locally Resected T1 Colorectal Carcinoma-Verification of the Japanese Guideline Criteria for Additional Surgery Based on Long-Term Clinical Outcomes.

INTRODUCTION: To verify the value of the pathological criteria for additional treatment in locally resected pT1 colorectal carcinoma (CRC) which have been used in the Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines since 2009. METHODS: We enrolled 4,667 patients with pT1 CRC treated at 27 institutions between July 2009 and December 2016 (1,257 patients with local resection alone [group A], 1,512 patients with additional surgery after local resection [group B], and 1,898 patients with surgery alone [group C]). All 5 factors of the JSCCR guidelines (submucosal resection margin, tumor histologic grade, submucosal invasion depth, lymphovascular invasion, and tumor budding) for lymph node metastasis (LNM) had been diagnosed prospectively. RESULTS: Any of the risk factors were present in 3,751 patients. The LNM incidence was 10.4% (95% confidence interval 9.4-11.5) in group B/C patients with risk factors, whereas it was 1.8% (95% confidence interval 0.4-5.3) in those without risk factors ( P < 0.01). In group A, the incidence of recurrence was 3.6% in patients with risk factors, but it was only 0.4% in patients without risk factors ( P < 0.01). The disease-free survival rate of group A patients classified as risk positive was significantly worse than those of groups B and C patients. However, the 5-year disease-free survival rate in group A patients with no risk was 99.6%. DISCUSSION: Our large-scale real-world multicenter study demonstrated the validity of the JSCCR criteria for pT1 CRC after local resection, especially regarding favorable outcomes in patients with low risk of LNM.

Efficacy of endoscopic submucosal resection with a ligation device for small rectal neuroendocrine tumor: study protocol of a multicenter open-label randomized control trial (BANDIT trial).

BACKGROUND: Endoscopic resection is widely accepted as a local treatment for rectal neuroendocrine tumors sized ≤ 10 mm. However, there is no consensus on the best method for the endoscopic resection of rectal neuroendocrine tumors. As a simplified endoscopic procedure, endoscopic submucosal resection with a ligation device (ESMR-L) indicates a histologically complete resection rate comparable to that of endoscopic submucosal dissection (ESD). We hypothesized that ESMR-L than ESD would be preferred for rectal neuroendocrine tumors. Hence, this trial aimed to verify whether ESMR-L is non-inferior to ESD in terms of histologically complete resection rate. METHODS: This is a prospective, open-label, multicenter, non-inferiority, randomized controlled trial of two parallel groups, conducted at the Shizuoka Cancer Center and 31 other institutions in Japan. Patients with a lesion endoscopically diagnosed as a rectal neuroendocrine tumor ≤ 10 mm are eligible for inclusion. A total of 266 patients will be recruited and randomized to undergo either ESD or ESMR-L. The primary endpoint is the rate of en bloc resection with histologically tumor-free margins (R0 resection). Secondary endpoints include en bloc resection rate, procedure time, adverse events, hospitalization days, total devices and agents cost, adverse event rate between groups with and without resection site closure, outcomes between expert and non-expert endoscopists, and factors associated with R0 resection failure. The sample size is determined based on the assumption that the R0 resection rate will be 95.2% in the ESD group and 95.3% in the ESMR-L group, with a non-inferiority margin of 8%. With a one-sided significance level of 0.05 and a power of 80%, 226 participants are required. Assuming a dropout rate of 15%, 266 patients will be included in this study. DISCUSSION: This is the first multicenter randomized controlled trial comparing ESD and ESMR-L for the R0 resection of rectal neuroendocrine tumors ≤ 10 mm. This will provide valuable information for standardizing endoscopic resection methods for rectal neuroendocrine tumors. TRIAL REGISTRATION: Japan Registry of Clinical Trials, jRCTs042210124. Registered on Jan 6, 2022.

Deep Submucosal Invasion Is Not an Independent Risk Factor for Lymph Node Metastasis in T1 Colorectal Cancer: A Meta-Analysis.

BACKGROUND & AIMS: Deep submucosal invasion (DSI) is considered a key risk factor for lymph node metastasis (LNM) and important criterion to recommend surgery in T1 colorectal cancer. However, metastatic risk for DSI is shown to be low in the absence of other histologic risk factors. This meta-analysis determines the independent risk of DSI for LNM. METHODS: Suitable studies were included to establish LNM risk for DSI in univariable analysis. To assess DSI as independent risk factor, studies were eligible if risk factors (eg, DSI, poor differentiation, lymphovascular invasion, and high-grade tumor budding) were simultaneously included in multivariable analysis or LNM rate of DSI was described in absence of poor differentiation, lymphovascular invasion, and high-grade tumor budding. Odds ratios (OR) and 95% CIs were calculated. RESULTS: Sixty-seven studies (21,238 patients) were included. Overall LNM rate was 11.2% and significantly higher for DSI-positive cancers (OR, 2.58; 95% CI, 2.10-3.18). Eight studies (3621 patients) were included in multivariable meta-analysis and did not weigh DSI as a significant predictor for LNM (OR, 1.73; 95% CI, 0.96-3.12). As opposed to a significant association between LNM and poor differentiation (OR, 2.14; 95% CI, 1.39-3.28), high-grade tumor budding (OR, 2.83; 95% CI, 2.06-3.88), and lymphovascular invasion (OR, 3.16; 95% CI, 1.88-5.33). Eight studies (1146 patients) analyzed DSI as solitary risk factor; absolute risk of LNM was 2.6% and pooled incidence rate was 2.83 (95% CI, 1.66-4.78). CONCLUSIONS: DSI is not a strong independent predictor for LNM and should be reconsidered as a sole indicator for oncologic surgery. The expanding armamentarium for local excision as first-line treatment prompts serious consideration in amenable cases to tailor T1 colorectal cancer management.

Computer-aided diagnosis of early-stage colorectal cancer using nonmagnified endoscopic white-light images (with videos).

BACKGROUND AND AIMS: Differentiation of colorectal cancers (CRCs) with deep submucosal invasion (T1b) from CRCs with superficial invasion (T1a) or no invasion (Tis) is not straightforward. This study aimed to develop a computer-aided diagnosis (CADx) system to establish the diagnosis of early-stage cancers using nonmagnified endoscopic white-light images alone. METHODS: From 5108 images, 1513 lesions (Tis, 1074; T1a, 145; T1b, 294) were collected from 1470 patients at 10 academic hospitals and assigned to training and testing datasets (3:1). The ResNet-50 network was used as the backbone to extract features from images. Oversampling and focal loss were used to compensate class imbalance of the invasive stage. Diagnostic performance was assessed using the testing dataset including 403 CRCs with 1392 images. Two experts and 2 trainees read the identical testing dataset. RESULTS: At a 90% cutoff for the per-lesion score, CADx showed the highest specificity of 94.4% (95% confidence interval [CI], 91.3-96.6), with 59.8% (95% CI, 48.3-70.4) sensitivity and 87.3% (95% CI, 83.7-90.4) accuracy. The area under the characteristic curve was 85.1% (95% CI, 79.9-90.4) for CADx, 88.2% (95% CI, 83.7-92.8) for expert 1, 85.9% (95% CI, 80.9-90.9) for expert 2, 77.0% (95% CI, 71.5-82.4) for trainee 1 (vs CADx; P = .0076), and 66.2% (95% CI, 60.6-71.9) for trainee 2 (P < .0001). The function was also confirmed on 9 short videos. CONCLUSIONS: A CADx system developed with endoscopic white-light images showed excellent per-lesion specificity and accuracy for T1b lesion diagnosis, equivalent to experts and superior to trainees. (Clinical trial registration number: UMIN000037053.).

Nomogram as a novel predictive tool for lymph node metastasis in T1 colorectal cancer treated with endoscopic resection: a nationwide, multicenter study.

BACKGROUND AND AIMS: Since 2009, the Japanese Society for Cancer of the Colon and Rectum guidelines have recommended that tumor budding and submucosal invasion depth, in addition to lymphovascular invasion and tumor grade, be included as risk factors for lymph node metastasis (LNM) in patients with T1 colorectal cancer (CRC). In this study, a novel nomogram was developed and validated by usirge-scale, real-world data, including the Japanese Society for Cancer of the Colon and Rectum risk factors, to accurately evaluate the risk of LNM in T1 CRC. METHODS: Data from 4673 patients with T1 CRC treated at 27 high-volume institutions between 2009 and 2016 were analyzed for LNM risk. To prepare a nonrandom split sample, the total cohort was divided into development and validation cohorts. Pathologic findings were extracted from the medical records of each participating institution. The discrimination ability was measured by using the concordance index, and the variability in each prediction was evaluated by using calibration curves. RESULTS: Six independent risk factors for LNM, including submucosal invasion depth and tumor budding, were identified in the development cohort and entered into a nomogram. The concordance index was .784 for the clinical calculator in the development cohort and .790 in the validation cohort. The calibration curve approached the 45-degree diagonal in the validation cohort. CONCLUSIONS: This is the first nomogram to include submucosal invasion depth and tumor budding for use in routine pathologic diagnosis based on data from a nationwide multi-institutional study. This nomogram, developed with real-world data, should improve decision-making for an appropriate treatment strategy for T1 CRC.

Computer-aided diagnosis of serrated colorectal lesions using non-magnified white-light endoscopic images.

PURPOSE: Computer-aided diagnosis systems for polyp characterization are commercially available but cannot recognize subtypes of sessile lesions. This study aimed to develop a computer-aided diagnosis system to characterize polyps using non-magnified white-light endoscopic images. METHODS: A total of 2249 non-magnified white-light images from 1030 lesions including 534 tubular adenomas, 225 sessile serrated adenoma/polyps, and 271 hyperplastic polyps in the proximal colon were consecutively extracted from an image library and divided into training and testing datasets (4:1), based on the date of colonoscopy. Using ResNet-50 networks, we developed a classifier (1) to differentiate adenomas from serrated lesions, and another classifier (2) to differentiate sessile serrated adenoma/polyps from hyperplastic polyps. Diagnostic performance was assessed using the testing dataset. The computer-aided diagnosis system generated a probability score for each image, and a probability score for each lesion was calculated as the weighted mean with a log10-transformation. Two experts (E1, E2) read the identical testing dataset with a probability score. RESULTS: The area under the curve of classifier (1) for adenomas was equivalent to E1 and superior to E2 (classifier 86%, E1 86%, E2 69%; classifier vs. E2, p < 0.001). In contrast, the area under the curve of classifier (2) for sessile serrated adenoma/polyps was inferior to both experts (classifier 55%, E1 68%, E2 79%; classifier vs. E2, p < 0.001). CONCLUSION: The classifier (1) developed using white-light images alone compares favorably with experts in differentiating adenomas from serrated lesions. However, the classifier (2) to identify sessile serrated adenoma/polyps is inferior to experts.

Risk of Delayed Bleeding after Cold Snare Polypectomy in Patients with Antithrombotic Therapy.

BACKGROUND: Cold snare polypectomy is being increasingly adopted; however, there are few reports of cold snare polypectomy regarding antithrombotic therapy. AIMS: This study aimed to investigate the real-world safety of cold snare polypectomy during antithrombotic therapy. METHODS: We collected data from consecutive patients undergoing cold snare polypectomy in a single hospital between 2013 and 2017. Indications for cold snare polypectomy were any ≤ 10 mm polyp. The primary outcome was delayed bleeding. We compared rates of delayed bleeding between patients with and without antithrombotic therapy and analyzed risk factors for delayed bleeding using binary logistic regression model with firth procedure. RESULTS: In 2152 patients (mean age 67.6 years; male 1411), 4433 colorectal polyps (mean diameter 5.0 mm) underwent cold snare polypectomy. Clipping during the procedure was performed for 5.8%. Delayed bleeding occurred in 0.51% (11/2152) of patients and 0.25% (11/4433) of polyps, but no major delayed bleeding occurred. A total of 244 (11%) patients received antithrombotic therapy. Patients on antithrombotic therapy were older (p < 0.001), more likely male (p < 0.001) and had cold snare polypectomy in the proximal colon (p = 0.011). The rate of delayed bleeding was higher in patients on antithrombotic therapy (1.64% vs. non-antithrombotic therapy 0.37%, p = 0.009). Larger polyp size (> 5 mm), use of clips, and antithrombotic therapy were significant risk factors for delayed bleeding. There was no clear association between specific antithrombotic agents and delayed bleeding. CONCLUSIONS: Delayed bleeding after cold snare polypectomy was rare even in patients with antithrombotic therapy, and no major delayed bleeding occurred.

[The Evaluation of Neoadjuvant Chemotherapy for Locally Advanced Rectal Cancer].

We evaluated the efficacy of neoadjuvant chemotherapy(NAC)for 38 patients with locally advanced rectal cancer (LARC). We administered mFOLFOX6 in 15, FOLFIRI in 3, CAPOX in 10, IRIS in 1 and FOLFOXIRI in 9 patients. We also used bevacizumab in 31 and panitumumab in 7 patients. There were 27 male and 11 female patients, with a median age of 64 years, and location was RS 2, Ra 9, Rb 21, and P 6. Synchronous distant metastasis was recognized in 13 patients. Nine patients had suffered adverse event of Grade 3, however all patients could complete NAC. Clinical response was CR 3, PR 31, SD 4, response rate was 91.9%, and reduction rate was 43.3(range 18.8-100)%. Clinical response of distant metastasis was CR 3, PR 9 and SD 1. Laparoscopic surgery was performed in 29 patients. Postoperative complications of Grade 2 of Clavien- Dindo classification were recognized in 14 and Grade 3 in 4 patients. Three- and five-year overall survival rate of 25 patients without distant metastasis were 79.6% and 74.9%, respectively; and 13 with distant metastasis were 61.6% and 52.6%, respectively. The efficacy, safety and postoperative outcomes of NAC for LARC are favorable, and we think that NAC will be one of the treatments for LARC.

Polyp detection algorithm can detect small polyps: Ex vivo reading test compared with endoscopists.

BACKGROUND AND STUDY AIMS: Small polyps are occasionally missed during colonoscopy. This study was conducted to validate the diagnostic performance of a polyp-detection algorithm to alert endoscopists to unrecognized lesions. METHODS: A computer-aided detection (CADe) algorithm was developed based on convolutional neural networks using training data from 1991 still colonoscopy images from 283 subjects with adenomatous polyps. The CADe algorithm was evaluated on a validation dataset including 50 short videos with 1-2 polyps (3.5 ± 1.5 mm, range 2-8 mm) and 50 videos without polyps. Two expert colonoscopists and two physicians in training separately read the same videos, blinded to the presence of polyps. The CADe algorithm was also evaluated using eight full videos with polyps and seven full videos without a polyp. RESULTS: The per-video sensitivity of CADe for polyp detection was 88% and the per-frame false-positive rate was 2.8%, with a confidence level of ≥30%. The per-video sensitivity of both experts was 88%, and the sensitivities of the two physicians in training were 84% and 76%. For each reader, the frames with missed polyps appearing on short videos were significantly less than the frames with detected polyps, but no trends were observed regarding polyp size, morphology or color. For full video readings, per-polyp sensitivity was 100% with a per-frame false-positive rate of 1.7%, and per-frame specificity of 98.3%. CONCLUSIONS: The sensitivity of CADe to detect small polyps was almost equivalent to experts and superior to physicians in training. A clinical trial using CADe is warranted.

Prospective randomized trial comparing the pocket-creation method and conventional method of colorectal endoscopic submucosal dissection.

BACKGROUND AND AIMS: Colorectal endoscopic submucosal dissection (ESD) is recognized as a challenging procedure. Previously, we reported that a new ESD strategy using the pocket-creation method (PCM) is useful for colorectal ESD, but no prospective randomized study has evaluated the efficacy of the PCM. The aim of this study was to evaluate the efficacy and safety of PCM for colorectal ESD compared with the conventional method (CM). METHODS: This was a prospective randomized controlled trial at 3 institutions in Japan. Patients with superficial colorectal neoplastic lesions >20 mm predicted to be intramucosal were randomly assigned to undergo ESD using the PCM or CM. Primary outcome was the ESD completion rate defined as completion of colorectal ESD with an en bloc resection using the assigned ESD method without changing to other methods or assisted by other devices. RESULTS: We analyzed 59 patients with 59 colorectal tumors in the PCM group and 55 in the CM group. The ESD completion rate was significantly higher in the PCM group compared with the CM group (93% [55/59] vs 73% [40/55]; P  = .01). En bloc resection rates, R0 resection rates, procedure time, and dissection speed were not significantly different between the 2 groups. The incidence of adverse events was similar in the 2 groups. CONCLUSIONS: Use of the PCM allows the endoscopist to complete the procedure with the intended method more often than the CM with similar clinical outcomes. (Clinical trial registration number: UMIN 000024394.).

Colon Capsule Endoscopy versus CT Colonography in Patients with Large Non-Polypoid Tumours: A Multicentre Prospective Comparative Study (4CN Study).

BACKGROUND/AIMS: Non-polypoid colon lesions compared with polypoid lesions has a high malignant potential. The diagnostic performance of colon capsule endoscopy (CCE) and CT colonography (CTC) for large colorectal non-polypoid tumours, that is, laterally spreading tumours is still unclear. The aim of this study is to evaluate the performance of CCE and CTC for the diagnosis of large non-polypoid tumours. METHODS: Thirty patients referred for endoscopic submucosal dissection of non-polypoid tumours measuring ≥20 mm were enrolled. Patients first underwent CCE, then colonoscopy (without resection) and CTC on the same day. An experienced gastroenterologist in a third hospital evaluated the CCE and recorded the location, size and morphology of all lesions detected, blinded to the colonoscopic findings. An experienced radiologist read the CTC under the same conditions. Colonoscopic findings were defined as the reference. RESULTS: A total of 30 lesions (T1 cancer: 3, Tis cancer: 7, adenoma: 14, sessile serrated adenoma/polyp: 6) in 27 patients were observed for evaluation. The capsule excretion rate within 8 h was 85% (23/27), and all capsules went beyond the target lesions. Non-polypoid tumours tend to be depicted as polypoid on CCE. Per patient sensitivities were 0.89 (24/27) by CCE and 0.70 (19/27) by CTC (p = 0.0253, McNemar), and per lesion sensitivities were 0.87 (26/30) and 0.67 (20/30) respectively (p = 0.0143). Most lesions missed by both modalities were located in the proximal colon. CONCLUSION: Eighty-seven per cent of non-polypoid tumours were detected by CCE, and the sensitivity using CCE was higher than that obtained using CTC (UMIN0000014772).

A novel volume-reduced CT colonography regimen using hypertonic laxative (polyethylene glycol with ascorbic acid): randomized controlled trial.

OBJECTIVES: The aim of this study is to investigate the feasibility of bowel preparation using a hypertonic laxative (polyethylene glycol with ascorbic acid, PEG + Asc) for CT colonography (CTC) and to examine the volume limit of laxative. METHODS: In one institution, patients who met the indications for CTC were enrolled and randomly assigned to CTC with regimen A (800 ml PEG + Asc), B (600 ml PEG + Asc), or C (400 ml PEG + Asc). Sodium diatrizoate was given orally for fecal tagging. On the previous day, patients ate low-residue meals and took the assigned lavage solution after dinner. A reader blinded to the preparation graded residual stool/fluid and fecal tagging quality in six segments of the colorectum. The primary outcome was a proportion of colon segments without stool. One hundred twenty segments in 20 patients with each regimen were needed to show a non-inferiority margin of 15%, assuming 85% of no stool. RESULTS: A total of 360 segments in 60 patients were analyzed. There were 83% of segments with no stool in regimen A, 89% in regimen B, and 88% in regimen C. Using the delta method, the 95% confidence interval of the risk difference (6.7%) between regimens A and B was - 2.2% to 15.6%, and the risk difference (5.0%) between regimens A and C was - 4.1% to 14%, both within the non-inferiority margin. Residual fluid and fecal tagging quality were also within the non-inferiority margin. No adverse events occurred. CONCLUSIONS: A novel CTC regimen using hypertonic laxative demonstrated optimal colon cleansing effectiveness even with the lowest volume of laxative (UMIN000022851). KEY POINTS: • A novel CTC regimen using a hypertonic laxative is feasible. • The lowest volume of laxative provides excellent colon imaging. • However, the lowest volume of laxative did not improve patient acceptance.

Inhibitory effect of lidocaine on colonic spasm during colonoscopy: A multicenter double-blind, randomized controlled trial.

OBJECTIVES: Colonic spasm can interfere with colonoscopy, but antispasmodic agents can cause complications. This study aimed to assess the inhibitory effect of topical lidocaine compared with a placebo control. METHODS: In five tertiary-care hospitals in Japan, 128 patients requiring endoscopic resection of a colorectal lesion were enrolled and randomly and double-blindly allocated to colonoscopy with topical administration of 2% lidocaine solution 20mL (LID, n = 64) or normal saline 20mL (control, n = 64). During colonoscopy, the assigned solution was applied with a spray catheter near the lesion and the area was observed for three minutes. primary endpoint was the inhibitory effect at three time-points (1, 2 and 3 minutes after dispersion), using a three-point scale (excellent, fair, poor). Secondary endpoints were rebound spasm and adverse events. All endpoints were scored in real time. Serum lidocaine levels were measured in 32 patients (LID 16, control 16). RESULTS: There were no significant differences between groups in patient demographics. At all time-points, the proportion of patients with "excellent" scores was greater in LID group than control group, with significant differences observed at 2 minutes (p = 0.02) and 3 minutes (p = 0.02). In LID group, the rate of "excellent" scores increased by 12.5% at 2 minutes and was maintained at 3 minutes. Rebound spasm did not occur in LID group, compared with 15.6% of control group (p = 0.001). There were no adverse events in LID group. All serum lidocaine levels were below detectable levels. CONCLUSIONS: Topical lidocaine is an effective and safe method for suppressing colorectal spasm during colonoscopy (UMIN000024733).

[Curative Transanal Resection after Neoadjuvant Chemotherapy for Lower Rectal Cancer-A Case Report].

A 53-year-old woman was referred to our hospital with melena. Examinations revealed advanced rectal cancer involving the anal canal with invasion of the left-sided levator ani muscle. Neoadjuvant chemotherapy was administered to preserve anal function. A first course of capecitabine and oxaliplatin(CapeOX)plus bevacizumab was administered. CapeOX plus panitumumab was administered from the 2nd to the 8th courses after confirming the absence of RAS mutation. Endoscopy and computed tomography confirmed the disappearance of the tumor after completion of the chemotherapy. A biopsy of the scar tissue revealed no cancer cells. However, diffusion weighted-magnetic resonance imaging(MRI-DWI)revealed a suspected residual tumor. To determine the subsequent treatment, a transanal resection was performed. No carcinoma was identified in the specimen. Thus, additional surgical treatment and adjuvant chemotherapy were not administered. The patient was followed-up over 2.5 years post local resection and showed no recurrence.

[Two Cases of Advanced Colorectal Cancer Achieving Complete Response by FOLFOXIRI plus Bevacizumab-A Case Report].

We report 2 cases of advanced colorectal cancer achieving complete response by FOLFOXIRI plus bevacizumab. Case 1 was a 65-year-old male diagnosed with descending colon cancer with multiple liver metastases. Six courses of FOLFOXIRI plus bevacizumab were administered after laparoscopic-assisted left hemicolectomy. Ten partial hepatectomies and 1 radiofrequency ablation were performed as the liver metastases resolved. A pathological complete response was confirmed. Adjuvant chemotherapy was not administered, and recurrence-free survival was 21 months after hepatectomy. Case 2 was a 77-yearold male diagnosed with rectal cancer invading the pelvic wall and sacral foramen with bilateral lateral lymph node metastasis. Additionally, there was a cancer embolism in the right internal iliac vein. Six courses of FOLFOXIRI plus bevacizumab were administered, and the cancer tissue was absent on subsequent CT and MRI. The cancer was scarred by colonoscopy, and the biopsy showed no malignant cells. Six courses of FOLFIRI plus panitumumab were administered as second-line chemotherapy, and the patient survived without any recurrence after 12 months from initiation of chemotherapy.