ctDNA-based molecular residual disease and survival in resectable colorectal cancer.

The interim analysis of the CIRCULATE-Japan GALAXY observational study demonstrated the association of circulating tumor DNA (ctDNA)-based molecular residual disease (MRD) detection with recurrence risk and benefit from adjuvant chemotherapy (ACT) in resectable colorectal cancer (CRC). This updated analysis with a 23-month median follow-up, including 2,240 patients with stage II-III colon cancer or stage IV CRC, reinforces the prognostic value of ctDNA positivity during the MRD window with significantly inferior disease-free survival (DFS; hazard ratio (HR): 11.99, P < 0.0001) and overall survival (OS; HR: 9.68, P < 0.0001). In patients who experienced recurrence, ctDNA positivity correlated with shorter OS (HR: 2.71, P < 0.0001). The significantly shorter DFS in MRD-positive patients was consistent across actionable biomarker subsets. Sustained ctDNA clearance in response to ACT was an indicator of favorable DFS and OS compared to transient clearance (24-month DFS: 89.0% versus 3.3%; 24-month OS: 100.0% versus 82.3%). True spontaneous clearance rate with no clinical recurrence was 1.9% (2/105). Overall, our findings provide evidence for the utility of ctDNA monitoring for post-resection recurrence and mortality risk stratification that could be used for guiding adjuvant therapy.

Usefulness of a powered circular stapler compared with a manual circular stapler in patients undergoing colorectal cancer surgery: A retrospective cohort study and systematic review.

Postoperative complications related to anastomosis, including postoperative anastomotic bleeding and anastomotic leakage, remain a serious issue. The effect of anastomotic devices on suture complications during intestinal anastomosis remains unclear. The present study examined the utility of automated anastomotic devices for reducing anastomotic complication risks. A retrospective cohort study of colorectal cancer surgeries in which an anastomosis device was used at Osaka University Hospital (Suita, Japan) between January 2018 and December 2022 was conducted. Cases of emergency surgery, inflammatory bowel disease and simultaneous surgery for other cancers were excluded. Experienced gastrointestinal surgeons performed manual anastomosis using the ETHICON Circular Stapler CDH or EEA Circular Stapler, and automatic anastomosis using the ECHELON CIRCULAR Powered Stapler, with no observed operator bias. Additionally, a meta-analysis that included other study results was performed. The outcomes included postoperative complications, mainly anastomotic leakage. The study included 414 patients: 183 in the manual circular stapler group and 231 in the powered circular stapler (PCS) group. Although this retrospective study found no statistically significant association between the anastomotic device used and anastomotic complications, an increased risk ratio was observed in the manual group compared with the automatic group when restricted to elderly patients. Similarly, a meta-analysis found a significantly higher anastomotic complication risk in the manual group compared with the automatic group (random-effects model; odds ratio, 0.376; 95% confidence interval, 0.232-0.610; P<0.0001). The findings of the present study suggested that a PCS is useful for reducing the anastomotic complication risk in patients undergoing colorectal cancer surgery.

Surgical approach for a refractory enterocutaneous fistula by combining laparoscopic surgery and a planned open conversion: a case report.

BACKGROUND: An enterocutaneous fistula (ECF) is defined as an abnormal communication between the gastrointestinal tract and skin. ECFs are rarely encountered in clinical practice, yet are frequently difficult to treat. Few reports exist regarding the surgical techniques for the treatment of an ECF. Therefore, we report a case of refractory ECF with concomitant severe adhesions, in which we performed combined laparoscopic adhesiolysis and planned open conversion. CASE PRESENTATION: A 57-year-old female patient underwent a laparotomy for an ovarian cyst in her 20s. At 46 years, adhesiolysis without bowel resection was performed for adhesive small bowel obstruction (SBO). However, her symptoms did not improve. Eighteen days postoperatively, she underwent a reoperation and jejunostomy. An ECF developed post-reoperation; therefore, stoma closure and radical surgery for the ECF were planned. Due to the severe adhesions, only stoma closure was performed, based on intraoperative assessments. The patient was subsequently referred to our hospital. First, skin care around the fistula was provided during an outpatient visit. Appropriate sizing of the stoma pouch was performed, to improve erosions and ulcers. Thereafter, debridement of the perifistula skin and simple closure of the ECF outlet were attempted; however, the ECF recurred shortly thereafter. After 8 years of regular skin care, with the ECF remaining stable, however, manifesting as symptomatic SBO, she underwent laparoscopic adhesiolysis. This procedure was initiated in the epigastric region, where relatively fewer adhesions were anticipated. Post-open conversion, partial resection of the small intestine at four locations, including the fistula site, was performed. Postoperatively, jejunal edema and peristaltic dysfunction, due to narrowing of the superior mesenteric artery occurred. Regular drainage by percutaneous endoscopic gastrostomy was required. However, she improved and was discharged 3 months post-operatively. Three years post-operatively, the ECF and SBO did not recur. CONCLUSIONS: We reported a case of refractory ECF in which we were able to safely perform surgery, by combining laparoscopic adhesiolysis and a planned open conversion. Therefore, the surgical approach used in this case may be an option for securing a safe surgical field, while avoiding collateral damage.

Postoperative venous thromboembolism after surgery for locally recurrent rectal cancer.

BACKGROUND: Local recurrence is common after curative resections of rectal cancer. Surgical resection is considered a primary curative treatment option for patients with locally recurrent rectal cancer (LRRC). LRRC often requires a combined resection of other organs, especially in the case of posterior recurrence, which requires a combined resection of the sacrum, making the surgery highly invasive. Venous thromboembolism (VTE) is one of the lethal complications in the postoperative period, particularly in the field of pelvic surgery. We found no reports regarding the risks of postoperative VTE in surgery for LRRC, a typical highly invasive procedure in the field of colorectal surgery. This study aims to evaluate the risk of postoperative VTE in surgery for LRRC patients. METHODS: From April 2010 to March 2022, a total of 166 patients underwent surgery for LRRC in the pelvic region at our institutions. Clinicopathological background and VTE incidence were compared retrospectively. RESULTS: Among the 166 patients included in the study, 55 patients (33.1%) needed sacral resection. Pharmacological prophylaxis for prevention of VTE was performed in 121 patients (73.3%), and the incidence of VTE was 9.09% (5/55 patients) among those who underwent surgery for LRRC with sacral resection, while it was 1.8% (2/111 patients) in those without sacral resection. In univariate analysis, the combination with sacral resection was identified as a risk factor for VTE in surgery for LRRC (p = 0.047). CONCLUSIONS: This study demonstrates that surgery for LRRC combined with sacral resection could be a significant risk factor for VTE.

Assessing risk factors for elevated creatine kinase levels as an indicator of compartment syndrome following laparoscopic or robot-assisted colorectal cancer surgery in the lithotomy-trendelenburg position.

BACKGROUND: Well-leg compartment syndrome (WLCS) can occur due to compression and lower limb circulation disturbances caused by the surgical position during the procedure. Although rare, with an incidence of 1 in 3500 surgeries performed in the lithotomy position, it can lead to serious complications. Therefore, prevention and early diagnosis are critical. Symptoms of WLCS, such as leg pain, swelling, paresthesia, and serum creatine kinase (CK) levels are useful for diagnosis. This study aimed to investigate the risk factors for postoperative CK elevation in laparoscopic or robot-assisted colorectal cancer surgery performed in the lithotomy-Trendelenburg position. METHODS: Postoperative CK levels were measured in 178 patients who underwent laparoscopic or robot-assisted colorectal cancer surgery between February 2022 and March 2023. We compared patient backgrounds, short-term outcomes, and thigh/calf circumferences between patients with CK levels ≥ 250 (n = 62) and those with CK levels < 250 (n = 116). We investigated risk factors for elevated CK levels using both univariate and multivariate analyses. RESULTS: Four patients with CK levels of 22405 U/L, 4685 U/L, 4050 U/L, and 3824 U/L reported symptoms, which improved with conservative treatment. The following independent prognostic factors were identified by multivariate analysis: male sex (odds ratio [OR], 4.403; 95% CI, 1.960 to 9.892), rectal surgery (OR, 2.779; 95% CI, 1.249 to 6.184), continuous head-down position duration ≥ 180 min (OR, 3.523; 95% CI, 1.552 to 7.997), and preoperative calf circumference ≥ 33 cm (OR, 2.482; 95% CI, 1.154 to 5.339). CONCLUSIONS: Risk factors for CK elevation after colorectal cancer surgery in the lithotomy position include male sex, rectal surgery, an extended continuous head-down position without position changes, and a larger preoperative calf circumference. This study highlights the potential importance of intraoperative position changes every 3 h for preventing elevated CK levels, although the preventive effect was not specifically examined.

A Case of Transanal Endoscopic Excision for Rectal Tumor Using Surgical Instruments With Multi-jointed Structures.

BACKGROUND/AIM: Transanal endoscopic local excision requires fine operation in a very narrow space in the rectum. We report a case in which the use of surgical instruments with a multi-jointed structure allowed safe resection of a lesion with a stable field of view, resulting in preservation of postoperative function. CASE REPORT: The patient was a 49-year-old man who had a rectal neuroendocrine tumor (NET) (G1) with erosive changes in the lower rectum. Preoperative imaging showed no evidence of surrounding lymph node or distant metastasis; thus, we performed a transanal endoscopic local excision of the tumor. After positioning the patient under general anesthesia and securing the field of view in the intra-rectal cavity, the flexion of the surgical instruments with a multi-jointed structure was used to secure the operating space to not interfere with the camera and the surgeon's right hand. The operating field was developed, and the tumor was incised by stable traction. After the excision, the needle was advanced in the direction of the intestinal axis using the multi-jointed holder, and continuous suturing was performed. The patient has no recurrence without any defecation disorder. CONCLUSION: The use of multi-jointed surgical instruments in transanal endoscopic excision of rectal tumors can provide a stable operative field and preserve postoperative function. The advanced flexibility of these instruments allows precise manipulation in the narrow rectal space, resulting in successful tumor resection with minimal invasiveness and no postoperative complications. These findings suggest that multi-jointed instruments are valuable for enhancing the safety and efficacy of minimally invasive rectal surgery.

The potential of an artificial intelligence for diagnosing MRI images in rectal cancer: multicenter collaborative trial.

BACKGROUND: An artificial intelligence-based algorithm we developed, mrAI, satisfactorily segmented the rectal tumor, rectum, and mesorectum from MRI data of rectal cancer patients in an initial study. Herein, we aimed to validate mrAI using an independent dataset. METHODS: We utilized MRI images collected in another nationwide research project, "Open versus Laparoscopic Surgery for Advanced Low Rectal Cancer Patients". MRIs from 467 cases with upfront surgery were utilized; six radiologists centralized the MRI evaluations. The diagnostic accuracies of mrAI and the radiologists for tumor depth were compared using pathologic diagnosis as a reference. RESULTS: For all cases, centralized diagnosis demonstrated 84.2% sensitivity, 37.7% specificity, and 73.7% accuracy; mrAI exhibited 70.6% sensitivity, 61.3% specificity, and 68.5% accuracy. After limiting MRIs to those acquired by a Philips scanner, with an inter-slice spacing of ≤ 6 mm-both conditions similar to those used in the development of mrAI-the performance of mrAI improved to 76.8% sensitivity, 76.7% specificity, and 76.7% accuracy, while the centralized diagnosis showed 81.8% sensitivity, 36.7% specificity, and 71.3% accuracy. Regarding relapse-free survival, the prognosis for tumors staged ≥ T3 was significantly worse than for tumors staged ≤ T2 (P = 0.0484) in the pathologic diagnosis. While no significant difference was observed between ≥ T3 and ≤ T2 tumors in the centralized diagnosis (P = 0.1510), the prognosis for ≥ T3 was significantly worse in the mrAI diagnosis (P = 0.0318). CONCLUSION: Proper imaging conditions for MRI can enhance the accuracy of mrAI, which has the potential to provide feedback to radiologists without overestimating tumor stage.

BRAF V600E-induced distinct DNA damage response defines the therapeutic potential of p53 activation for TP53 wild-type colorectal cancer.

BRAF V600E, one of the most frequent mutations in the MAPK pathway, confers poor prognosis to colorectal cancers (CRCs), partly because of chemotherapeutic resistance. Oncogene-induced DNA damage responses (DDRs) that primarily activate p53 are important mechanistic barriers to the malignant transformation of cells; however, the mechanism underlying this impairment in cancer remains unknown. Here, we evaluated the responses of BRAFV600E-induced DDRs in two CRC cell lines, SW48 and LIM1215, both of which harbor wild-type TP53, KRAS, and BRAF. BRAFV600E transduction exhibited distinct phenotypes in these cells: SW48 cell proliferation markedly decreased, whereas that of LIM1215 increased. BRAFV600E expression induced the activation of oncogene-induced DDR signaling in SW48 cells, but not in LIM1215 cells, whereas chemotherapeutic agents similarly activated DDRs in both cell lines. Knockdown experiments revealed that these responses in SW48 cells were mediated by p53-p21 pathway activation. Comet assay (both alkaline and neutral) revealed that BRAFV600E increased single-strand breaks to the same extent in both cell lines; however, in case of LIM1215 cells, it only facilitated double-strand breaks. Furthermore, the proliferation of LIM1215 cells, wherein no oncogene-induced DDRs occurred, was synergistically inhibited upon MDM2 inhibitor-mediated p53 activation combined with MEK inhibition. Taken together, these distinct DDR signaling responses highlight the novel characteristics of BRAFV600E-mutated CRC cells and define the therapeutic potential of p53 activation combined with MAPK inhibition against TP53 wild-type CRC harboring a BRAFV600E mutation.

Feasibility of robotic-assisted surgery in advanced rectal cancer: a multicentre prospective phase II study (VITRUVIANO trial).

BACKGROUND: The potential benefits of robotic-assisted compared with laparoscopic surgery for locally advanced cancer have not been sufficiently proven by prospective studies. One factor is speculated to be the lack of strict surgeon criteria. The aim of this study was to assess outcomes for robotic surgery in patients with locally advanced rectal cancer with strict surgeon experience criteria. METHODS: A criterion was set requiring surgeons to have performed more than 40 robotically assisted operations for rectal cancer. Between March 2020 and May 2022, patients with rectal cancer (distance from the anal verge of 12 cm or less, cT2-T4a, cN0-N3, cM0, or cT1-T4a, cN1-N3, cM0) were registered. The primary endpoint was the rate positive circumferential resection margin (CRM) from the pathological specimen. Secondary endpoints were surgical outcomes, pathological results, postoperative complications, and longterm outcomes. RESULTS: Of the 321 registered patients, 303 were analysed, excluding 18 that were ineligible. At diagnosis: stage I (n = 68), stage II (n = 84) and stage III (n = 151). Neoadjuvant therapy was used in 56 patients. There were no conversions to open surgery. The median console time to rectal resection was 170 min, and the median blood loss was 5 ml. Fourteen patients had a positive CRM (4.6%). Grade III-IV postoperative complications were observed in 13 patients (4.3%). CONCLUSION: Robotic-assisted surgery is feasible for locally advanced rectal cancer when strict surgeon criteria are used.

Salvage surgery for pouch-related complication after ileal pouch-anal anastomosis: a report of two cases.

BACKGROUND: Pouch-related complications (PRCs), such as pelvic abscesses and perianal complex fistulas, can occur after ileal pouch-anal anastomosis (IPAA) in ulcerative colitis (UC). They are often difficult to treat and require salvage surgery. We report two cases of PRC associated with fistulas. CASE PRESENTATION: First case: A 38-year-old man was diagnosed with UC at age 26 years. Four months after the diagnosis of UC, the patient underwent hand-assisted laparoscopic restorative proctocolectomy, IPAA, and ileostomy for acute fulminant UC. Two years after the closure of the ileostomy, the patient developed a perianal abscess and underwent ileostomy reconstruction. He was referred to our department at 35 years of age, because his symptoms did not improve despite repeated seton drainage of a complicated perineal fistula. We diagnosed PRC with a pelvic abscess and complicated pouch fistula and performed salvage surgery. This diagnosis was revised to Crohn's disease. SECOND CASE: A 50-year-old man was diagnosed with UC at age 18 years and was administered high doses of steroids; however, his symptoms did not improve. He underwent restorative proctocolectomy, IPAA, and ileostomy at another hospital. The ileostomy was closed, and his condition stabilized thereafter. At 35 years of age, perianal pain developed, and he was diagnosed with a complicated pouch-perineal fistula. A fistula was observed near the staple line of the ileal end closure on the head side of the pouch. Reconstruction of the ileostomy and seton drainage were performed; however, his symptoms did not improve, and he was referred to our hospital. We diagnosed PRC with a pelvic abscess and a complicated pouch fistula and performed salvage surgery. The resected specimen showed strictures in two locations: at the oral site of the afferent limb (at the pouch) and at the IPAA. Both patients returned to society and are currently outpatients. CONCLUSIONS: We encountered two cases of PRC after IPAA that did not improve with seton drainage or ileostomy. Pouch resection was performed after considering the patient's quality of life and reintegration into society.

Laparoscopic Colectomy for Cecal Cancer and Intestinal Malrotation: A Case Report.

Background/Aim: Intestinal malrotation (IM) often remains undetected until adulthood, being discovered during testing or surgery for other comorbidities. Preoperative understanding of this anatomical abnormality is crucial. Case Report: An 80-year-old woman presented with cecal cancer. Three-dimensional computed tomography (CT) revealed that the cecum was located at the midline of the abdominal cavity, the duodenum did not cross the midline, and the ileocolic vein ran to the left. Clinically diagnosed with stage IVc cecal cancer complicated by IM, the patient underwent laparoscopic surgery. The ascending colon and cecum were not fixed to the retroperitoneum. The duodenum lacked the second, third, and fourth portions and the small bowel was distributed on the left and right sides of the abdominal cavity. Adhesions had shortened the mesentery, which were released close to their normal positions. Conclusion: Although laparoscopic surgery is superior to open surgery in terms of securing the field of view in a narrow space, providing a magnifying effect, and minimal invasiveness, it has a limited field of view and is inferior in terms of grasping the overall anatomy, which may be disadvantageous in cases of anatomical abnormalities. Colorectal cancer with IM is rare; however, the rate of preoperative diagnosis seems to be increasing thanks to improvements in diagnostic imaging, such as three-dimensional CT scans. In this study, we also reviewed 49 cases of colorectal cancer associated with IM.

Venous Thromboembolism Following Lateral Lymph Node Dissection for Rectal Cancer.

BACKGROUND/AIM: Postoperative venous thromboembolism (VTE) is a well-recognized complication that leads to morbidity and mortality. Lateral lymph node dissection (LLND) for rectal cancer is thought to potentially increase the risk of VTE due to its technical complexity. However, the relationship between LLND and VTE remains inadequately understood. The aim of this study was to elucidate the impact of LLND on the incidence of postoperative VTE. PATIENTS AND METHODS: This is a retrospective analysis of patients who underwent rectal cancer resection between 2010 and 2018 to identify the risk factors associated with postoperative VTE. Patients were divided into two groups: those who underwent surgery with LLND (LLND+ group) and those who underwent surgery without LLND (LLND- group). RESULTS: A total of 543 patients were enrolled in this study, and 113 patients underwent surgery for rectal cancer with LLND. VTE developed in 8 patients (1.47%), with the incidence rates being 4.42% in the LLND+ group and 0.69% in the LLND- group, respectively (p=0.012). Three of 8 patients had developed severe postoperative complications, and the other two patients needed intraoperative repair of the iliac vein during LLND procedure. Multivariate analysis identified the incidence of postoperative complications and LLND as the independent risk factors of VTE. CONCLUSION: Patients undergoing rectal cancer surgery with LLND should be closely monitored for signs of VTE.

Standardization of robot-assisted pelvic lymph node dissection-Development of a common understanding of regional anatomy and surgical technique based on cross-disciplinary discussion among colorectal surgery, urology, and gynecology.

BACKGROUND: Pelvic lymph node dissection is a procedure performed in gastroenterological surgery, urology, and gynecology. However, due to discrepancies in the understanding of pelvic anatomy among these departments, cross-disciplinary discussions have not been easy. Recently, with the rapid spread of robotic surgery, the importance of visual information in understanding pelvic anatomy has become even more significant. In this project, we attempted to clarify a shared understanding of pelvic anatomy through cross-disciplinary discussions. METHOD: From May 2020 to November 2021, a total of 11 discussions were held entirely online with 5 colorectal surgery specialists, 4 urologists, and 4 gynecologists. The discussions focused on evidence from each specialty and surgical videos, aiming to create a universally understandable pelvic anatomical illustration. RESULTS: The common area of dissection recognized across the three departments was identified as the obturator lymph nodes. A dynamic illustration of pelvic anatomy was created. In addition to a bird's-eye view of the pelvis, a pelvic half view was developed to enhance understanding of the deeper pelvic anatomy. The following insights were incorporated into the illustration: (1) the cardinal ligament in gynecology partly overlaps with the vesicohypogastric fascia in colorectal surgery; (2) the obturator lymph nodes continue cephalad into the fossa of Marcille in urology; and (3) the deep uterine vein in gynecology corresponds to the inferior vesical vein in colorectal surgery. CONCLUSION: Based on the dynamic illustration of pelvic anatomy from cross-disciplinary discussions, we anticipate advancements in pelvic lymph node dissection aiming for curative and safe outcomes.

High Level Sacral Bone Resection for Locally Recurrent Rectal Cancer.

BACKGROUND/AIM: Locally recurrent rectal cancer (LRRC) involving the upper sacrum is generally considered a contraindication for curative surgery. In the surgical management of LRRC, sacrectomy is frequently performed to secure clear resection margins. Nonetheless, the indications for high sacrectomy remain controversial due to potential postoperative complications, questions about radicality, and the increased complexity of the operation. Furthermore, comprehensive studies addressing this issue are notably absent. This study aimed to assess the feasibility, safety, and surgical prognosis in high sacrectomy for LRRC. PATIENTS AND METHODS: All patients with LRRC who required concomitant sacrectomy, but did not include the inferior margin of the second sacral vertebra, between 2003 and 2014, were reviewed retrospectively. RESULTS: Eight patients with a median age of 59 years were included in this study. The proximal resection line for sacral bone resection was the central part of the S1 vertebra in one patient, lower edge of the S1 vertebra in six patients, and central part of the S2 vertebra in one patient. Negative margin resection was achieved in five out of the eight patients. The median operative time was 922 min, and the median operative blood loss volume was 6,370 ml. Major complications included pelvic abscess (n=5), ileus (n=1), and pulmonary vein embolism (n=1), none of which proved fatal during the postoperative period. Both the 5-year local re-recurrence-free survival rate and the 5-year distant metastasis-free survival rate were 50% (4/8). CONCLUSION: High sacrectomy is safe and feasible to achieve negative margins in patients with LRRC.

Laparoscopic Colorectal Cancer Surgery for Patients With Severe Chronic Heart Failure.

BACKGROUND/AIM: Laparoscopic surgery with pneumoperitoneum is not usually recommended for patients with heart failure due to the potential risks associated with cardiopulmonary stress. Few studies, however, have directly examined whether a laparoscopic approach can be used safely in patients with severe chronic heart failure. PATIENTS AND METHODS: We retrospectively evaluated the safety and feasibility of laparoscopic colorectal cancer surgery in 13 patients with severe chronic heart failure, defined as left ventricular ejection fraction <40% and/or brain natriuretic peptide >100 pg/ml (NT-proBNP >400 pg/ml). Intraoperative hemodynamics, including systolic blood pressure, diastolic blood pressure, mean blood pressure, and heart rate, were carefully monitored. RESULTS: The median left ventricular ejection fraction value was 35% (18-62%), and the median brain natriuretic peptide value was 171.7 pg/ml (109.5-961.4 pg/ml). The time-series mean ratio of the patients' blood pressure and heart rate during surgery indicated that soon after the induction of general anesthesia, mean blood pressure was significantly decreased (p<0.05) from baseline. In all 13 cases, laparoscopic surgery was performed successfully, with no significant complications. CONCLUSION: The present study showed that laparoscopic surgery for colorectal cancer can be performed safely in patients with severe chronic heart failure.

Treatment response prediction of neoadjuvant chemotherapy for rectal cancer by deep learning of colonoscopy images.

In current clinical practice, several treatment methods, including neoadjuvant therapy, are being developed to improve overall survival or local recurrence rates for locally advanced rectal cancer. The response to neoadjuvant therapy is usually evaluated using imaging data collected before and after preoperative treatment or postsurgical pathological diagnosis. However, there is a need to accurately predict the response to preoperative treatment before treatment is administered. The present study used a deep learning network to examine colonoscopy images and construct a model to predict the response of rectal cancer to neoadjuvant chemotherapy. A total of 53 patients who underwent preoperative chemotherapy followed by radical resection for advanced rectal cancer at the Osaka University Hospital between January 2011 and August 2019 were retrospectively analyzed. A convolutional neural network model was constructed using 403 images from 43 patients as the learning set. The diagnostic accuracy of the deep learning model was evaluated using 84 images from 10 patients as the validation set. The model demonstrated a sensitivity, specificity, accuracy, positive predictive value and area under the curve of 77.6% (38/49), 62.9% (22/33), 71.4% (60/84), 74.5% (38/51) and 0.713, respectively, in predicting a poor response to neoadjuvant therapy. Overall, deep learning of colonoscopy images may contribute to an accurate prediction of the response of rectal cancer to neoadjuvant chemotherapy.

Surgery for Rectal Cancer With Mixed Reality of 3D Model During Operation: A Case Report.

Background/Aim: Recently, robotic surgery for rectal cancer has become a common minimally invasive surgery. In addition, the technology of augmented and mixed reality is applied in various living environments, including medicine. We successfully performed robotic surgery for rectal cancer with three-dimensional (3D) images as mixed reality (MR) using HoloLens2. Case Report: The patient was diagnosed with rectal cancer by colonoscopy and a positron-emission computed-tomography scan, and we performed robot-assisted anterior resection. The operator used HoloLens2 and performed the surgery while visualizing 3D images of pelvic anatomy with the location of the rectal cancer as hologram. The operation was performed completely and safely, and she was discharged 11 days after surgery with no postoperative complications. Conclusion: This case presents the usefulness of a MR system offering organ visualization as hologram during surgery.

The Clinical Potential of FBPA-PET/CT Imaging for Colorectal Cancer and its Liver Metastases Expressing LAT1.

BACKGROUND/AIM: 18F-fluoro-deoxy-glucose positron emission tomography (18F-FDG PET) has become indispensable for staging colorectal cancer but has limitations. Thus, PET with a focus on metabolism other than glucose, mainly amino acid metabolism, has been developed. L-type amino acid transporter 1 (LAT1) is known to be a cancer-specific amino acid transporter and, although 4-Borono-2-(18)F-fluoro-phenylalanine (FBPA) has been reported to be useful as a probe for LAT1, the significance of LAT1 expression in colorectal cancer is ambiguous and implementation of 18F-FBPA-PET in colorectal cancer has not yet been reported. MATERIALS AND METHODS: The aims of this study were to investigate the expression of LAT1 in primary lesions and metastatic lesions of colorectal cancer by immunohistochemical analysis and report the initial experience of performing 18F-FBPA-PET on colorectal cancer patients in clinical practice. RESULTS: There was a significant correlation between LAT1 protein expression in primary tumors and liver metastases. Furthermore LAT-1 expression was positively correlated with recurrence (p=0.033). We performed 18F-FBPA-PET on three rectal cancer patients and detected cancer. CONCLUSION: LAT1 protein is expressed not only in the primary colorectal tumor, but also in liver metastases. 18F-FBPA-PET can be safely performed in patients with colorectal cancer.

A case of fulminant amoebic colitis during systemic chemotherapy for gastric cancer.

Amoebiasis is a parasitic infection caused by the protozoan, Entamoeba histolytica. At times, amoebiasis is activated under immunosuppressive conditions such as chemotherapy. We report a case of fulminant amoebic colitis resulting from an asymptomatic Entamoeba histolytica infection, which was activated by chemotherapy for gastric cancer. The patient developed diarrhea and fever after three courses of chemotherapy for gastric cancer and was diagnosed with acute enteritis. A colonoscopy and biopsy were performed because of the bloody stool. Histopathological findings revealed amoebic invasion of the rectum. Therefore, the patient was diagnosed with amoebic colitis and was treated with metronidazole. Emergency surgery was performed because intestinal perforation was suspected after which his general condition improved and was discharged. Subsequently, gastric cancer surgery was performed and the patient was discharged without postoperative complications. Hence, amoebic colitis should be listed as a differential diagnosis, and a colonoscopic biopsy should be performed when colitis occurs during chemotherapy for cancer.

A Case of Rectal Cancer with Vaginal Invasion Using Indocyanine Green to Determine the Extent of Resection.

Here we report a case of locally advanced rectal cancer with vaginal invasion, which was successfully resected via laparoscopic surgery using intraoperative indocyanine green (ICG) navigation to determine the vaginal cut line. Based on preoperative examinations, an 81-year-old female was diagnosed with locally advanced rectal cancer with vaginal invasion. After preoperative chemoradiotherapy, the lesion was judged to be resectable. During surgery, the gynecologist transvaginally injected ICG into the vaginal submucosa to determine the caudal margin of the vaginal invasion, and laparoscopically dissected under the near-infrared image of the stained area. Pathological analysis of the resection specimen revealed negative resection margins. One year after surgery, there has been no recurrence.