Development of a laparoscopic sigmoidectomy simulator: Sigmaster.

The sigmoid colon simulator was designed to accurately reproduce the anatomical layer structure and the arrangement of characteristic organs in each layer, and to have conductivity so that energy devices can be used. Dry polyester fibers were used to reproduce the layered structures, which included characteristic blood vessels, nerve sheaths, and intestinal tracts. The adhesive strength of the layers was controlled to allow realistic peeling techniques. The features of the Sigmaster are illustrated through a comparison of simulated sigmoidectomy using Sigmaster and actual surgery. We developed a laparoscopic sigmoidectomy simulator called Sigmaster. Sigmaster is a training device that closely reproduces the membrane structures of the human body and allows surgeons to experience the entire laparoscopic sigmoidectomy process.

Cytological Analysis of the Surgical Field During Transanal Total Mesorectal Excision for Rectal Cancer: A Prospective Study.

BACKGROUND: An unexpectedly large number of patients experienced local recurrence with transanal total mesorectal excision in Norway. This appears to be associated with cancer cell spillage during surgery. OBJECTIVE: To investigate the surgical field cytology during transanal total mesorectal excision. DESIGN: This was a prospective cohort study. SETTINGS: This study was conducted at a single center between June and December 2020. PATIENTS: Forty patients with rectal cancer underwent transanal total mesorectal excision. Following the irrigation of the surgical field, the water specimens were cytologically evaluated at six representative steps. The first sample was used as an initial control. The second, third, fourth, fifth, and sixth samples were collected after the 1st purse-string suture, rectotomy, the 2nd purse-string suture, specimen resection, and anastomosis, respectively. The clinicopathological features and intraoperative complications of the patients were reviewed. MAIN OUTCOME MEASURES: The primary outcome was to evaluate the presence of cancer cells in washing cytological samples. RESULTS: Of the 40 consecutive patients enrolled in this study, 18 patients underwent neoadjuvant chemoradiotherapy. Incomplete first pursestring suture and rectal perforation were observed in 4 (10.0%) and 3 (7.5%) cases, respectively. In the first sample, 31 (77.5%) patients had malignant cells. Malignant findings were detected in two patients (5.0%) from the second to fifth samples. None of the sixth sample exhibited any malignant findings. LIMITATIONS: This single center study had a small sample size. CONCLUSIONS: Cancer cells were initially detected by cytology, but only a few were observed throughout the procedure; however, cancer cells were not detected in the final surgical field. Further follow-up and novel studies are required to obtain clinically significant findings using cytology during transanal total mesorectal excision. See Video Abstract.

Long-term outcomes of single-incision laparoscopic colectomy for right-sided colon cancer utilising a craniocaudal approach.

INTRODUCTION: This study aimed to evaluate the short- and long-term outcomes of single-incision laparoscopic colectomy (SILC) for right-sided colon cancer (CC) using a craniocaudal approach. PATIENTS AND METHODS: The data of patients who underwent SILC for right-sided CC at our hospital between January 2013 and December 2022 were retrospectively collected. Surgery was performed using a craniocaudal approach. Short- and long-term operative outcomes were analysed. RESULTS: In total, 269 patients (127 men, 142 women; median age 74 years) underwent SILC for right-sided CC. The cases included ileocaecal resection (n = 138) and right hemicolectomy (n = 131). The median operative time was 154 min, and the median operative blood loss was 0 ml. Twenty-seven cases (10.0%) required an additional laparoscopic trocar, and 9 (3.3%) were converted to open surgery. The Clavien-Dindo classification Grade III post-operative complications were detected in 7 (2.6%) cases. SILC was performed by 25 surgeons, including inexperienced surgeons, with a median age of 34 years. The 5-year cancer-specific survival (CSS) was 96.1% (95% confidence interval [CI] 91.3%-98.2%), and CSS per pathological disease stage was 100% for Stages 0-I and II and 86.2% (95% CI 71.3%-93.7%) for Stage III. The 5-year recurrence-free survival (RFS) was 90.6% (95% CI 85.7%-93.9%), and RFS per pathological disease stage was 100% for Stage 0-I, 91.7% (95% CI 80.5%-96.6%) for Stage II and 76.1% (95% CI 63.0%-85.1%) for Stage III. CONCLUSIONS: SILC for right-sided CC can be safely performed with a craniocaudal approach, with reasonable short- and long-term outcomes.

Short-term outcomes following intracorporeal vs. extracorporeal anastomosis after laparoscopic right and left-sided colectomy: a propensity score-matched study.

BACKGROUND: To compare the short-term outcomes of patients undergoing intracorporeal anastomosis (IA) during laparoscopic colectomy to those undergoing extracorporeal anastomosis (EA). METHODS AND MATERIALS: The study was a single-centre retrospective propensity score-matched analysis conducted. Consecutive patients who underwent elective laparoscopic colectomy without the double stapling technique between January 2018 and June 2021 were investigated. The main outcome was overall postoperative complications within 30 days after the procedure. The authors also performed a sub-analysis of the postoperative results of ileocolic anastomosis and colocolic anastomosis, respectively. RESULTS: A total of 283 patients were initially extracted; after propensity score matching, there were 113 patients in each of the IA and EA groups. There were no differences in patient characteristics between the two groups. The IA group had a significantly longer operative time than the EA group (208 vs. 183 min, P =0.001). The rate of overall postoperative complications was significantly lower in the IA group ( n =18, 15.9%) than in the EA group ( n =34, 30.1%; P =0.02), especially in colocolic anastomosis after left-sided colectomy (IA: 23.8% vs. EA: 59.1%; P =0.03). Postoperative inflammatory marker levels were significantly higher in the IA group on postoperative day 1 but not on postoperative day 7. There was no difference in the postoperative lengths of hospital stay between the two groups, and no deaths occurred. CONCLUSION: The data suggest that performing IA during laparoscopic colectomy can potentially reduce the risk of postoperative complications, especially in colocolic anastomosis after left-sided colectomy.

Automatic purse-string suture skill assessment in transanal total mesorectal excision using deep learning-based video analysis.

BACKGROUND: Purse-string suture in transanal total mesorectal excision is a key procedural step. The aims of this study were to develop an automatic skill assessment system for purse-string suture in transanal total mesorectal excision using deep learning and to evaluate the reliability of the score output from the proposed system. METHODS: Purse-string suturing extracted from consecutive transanal total mesorectal excision videos was manually scored using a performance rubric scale and computed into a deep learning model as training data. Deep learning-based image regression analysis was performed, and the purse-string suture skill scores predicted by the trained deep learning model (artificial intelligence score) were output as continuous variables. The outcomes of interest were the correlation, assessed using Spearman's rank correlation coefficient, between the artificial intelligence score and the manual score, purse-string suture time, and surgeon's experience. RESULTS: Forty-five videos obtained from five surgeons were evaluated. The mean(s.d.) total manual score was 9.2(2.7) points, the mean(s.d.) total artificial intelligence score was 10.2(3.9) points, and the mean(s.d.) absolute error between the artificial intelligence and manual scores was 0.42(0.39). Further, the artificial intelligence score significantly correlated with the purse-string suture time (correlation coefficient = -0.728) and surgeon's experience (P< 0.001). CONCLUSION: An automatic purse-string suture skill assessment system using deep learning-based video analysis was shown to be feasible, and the results indicated that the artificial intelligence score was reliable. This application could be expanded to other endoscopic surgeries and procedures.

Two-team lateral lymph node dissection assisted by the transanal approach for locally advanced lower rectal cancer: comparison with the conventional transabdominal approach.

BACKGROUND: An optimal surgical approach to lateral lymph node dissection (LLND) remains controversial. With the recent popularity of transanal total mesorectal excision, a two-team procedure combining the transabdominal and transanal approaches was established as a novel approach to LLND. This study aimed to clarify the safety and feasibility of two-team LLND (2team-LLND) and compare its short-term outcomes with those of conventional transabdominal LLND (Conv-LLND). METHODS: Between April 2013 and March 2020, 463 patients diagnosed with primary locally advanced rectal cancer underwent a transanal total mesorectal excision; among them, 93 patients who underwent bilateral prophylactic LLND were included in this single-center, retrospective study. Among these patients, 50 and 43 patients underwent Conv-LLND (the Conv-LLND group) and 2team-LLND (the 2team-LLND group), respectively. The short-term outcomes, including the operation time, blood loss volume, number of complications, and number of harvested lymph nodes, were compared between the two groups. RESULTS: The intraoperative and postoperative complications in the 2team-LLND group were equivalent to those in the Conv-LLND group; furthermore, the incidence of postoperative urinary retention in the 2team-LLND group was acceptably low (9%). Compared with the Conv-LLND group, the 2team-LLND group had a significantly shorter operation time (P = 0.003), lower median blood loss (P = 0.02), and higher number of harvested lateral lymph nodes (P = 0.0005). CONCLUSION: The intraoperative and postoperative complications of 2team-LLND were comparable with those of Conv-LLND. Thus, 2team-LLND was safe and feasible for advanced lower rectal cancer. Moreover, it was superior to Conv-LLND in terms of the operation time, blood loss volume, and number of harvested lateral lymph nodes. Therefore, it can be a promising LLND approach.

Single-center comparative study of short-term outcomes of transanal and laparoscopic total mesorectal excisions for low and middle rectal cancers.

BACKGROUND: Transanal total mesorectal excision is a promising surgical treatment for rectal cancer. However, evidence regarding the differences in outcomes between the transanal and laparoscopic total mesorectal excisions is scarce. We compared the short-term outcomes of transanal and laparoscopic total mesorectal excisions for low and middle rectal cancers. METHODS: This retrospective study included patients who underwent low anterior or intersphincteric resection for middle (5-10 cm) or low (< 5 cm) rectal cancer at the National Cancer Center Hospital East, Japan, from May 2013 to March 2020. Primary rectal adenocarcinoma was confirmed histologically. Circumferential resection margins (CRMs) of resected specimens were measured; margins ≤ 1 mm were considered positive. The operative time, blood loss, hospitalization length, postoperative readmission rate, and short-term treatment results were compared. RESULTS: Four hundred twenty-nine patients were divided into two mesorectal excision groups: transanal (n = 295) and laparoscopic (n = 134). Operative times were significantly shorter in the transanal group than in the laparoscopic group (p < 0.001). The pathological T stage and N status were not significantly different. The transanal group had significantly lower positive CRM rates (p = 0.04), and significantly lower incidence of the Clavien-Dindo grade III (p = 0.02) and IV (p = 0.03) complications. Both groups had distal margin positivity rates of 0%. CONCLUSIONS: Compared to laparoscopic, transanal total mesorectal excision for low and middle rectal cancers has lower incident postoperative complication and CRM-positivity rates, demonstrating the safety and usefulness of local curability for middle and low rectal cancers.

Efficacy of transperineal minimally invasive surgery with laparoscopic abdominoperineal excision for lower rectal cancer.

PURPOSE: In abdominoperineal excision (APE), the advantages of the "down-to-up" approach are expected to be more obvious when performed as a two-team approach, including transperineal minimally invasive surgery (TpMIS). We investigated the efficacy of TpMIS with laparoscopic APE for lower rectal cancer. METHODS: Patients who underwent laparoscopic APE with (n = 20) or without (n = 30) TpMIS between December 2013 and April 2020 were retrospectively reviewed. Patient and tumor characteristics, intraoperative outcome, short-term outcome, and pathological findings were compared. Additional subgroup analyses were performed in technically challenging cases, including male patients, obese patients, and patients with tumors located at the anterior wall. RESULTS: There was no marked difference in the patient or tumor characteristics or short-term outcomes, including morbidity and mortality between the two groups. Pathological results were comparable, and the circumferential resection margin (CRM) positive rate was 10% in both groups. TpMIS achieved a significant reduction in operative time (p = 0.02). In a subgroup analysis, the amount of blood loss was also smaller in males (p = 0.02) and patients with a high BMI (> 25) (p = 0.005) than in others. CONCLUSION: Simultaneously performing TpMIS and laparoscopic APE is feasible owing to the favorable complication and CRM-positive rates. In terms of operative time and blood loss, TpMIS is expected to be advantageous in both easy and challenging cases.

Morphological characteristics of lateral pelvic lymph nodes in locally advanced lower rectal cancer: A retrospective study.

Aim: This study aimed to investigate the potential of the size and aspect ratio of metastatic and non-metastatic lateral pelvic lymph nodes (LPLNs) as low-risk markers for locally advanced lower rectal cancer, without treatment by neoadjuvant chemoradiation therapy or LPLN dissection. Methods: This single-center, retrospective cohort study evaluated 310 consecutive patients diagnosed with lower rectal cancer (T: T3/T4, N: any, and M: M0) who underwent curative surgery without neoadjuvant therapies between 2010 and 2018. The harvested LPLNs were categorized into groups A (metastasis-positive lymph nodes), B (metastasis-negative lymph nodes in the area bearing metastasis-positive lymph nodes), C (metastasis-negative lymph nodes in a metastasis-negative area in metastasis-positive patients), and D (lymph nodes in non-metastatic patients). The main outcome measure was the relationship among lymph node size, aspect ratio, and metastasis in the LPLNs. Results: Overall, 3962 LPLNs were harvested. The long and short axes and the aspect ratio were significantly longer and higher, respectively, in group A than in the other groups (P < .001). The aspect ratio in group B was significantly higher than that in groups C and D (P < .001). The aspect ratio in group C was significantly higher than that in group D (P < .001). Furthermore, no metastasis-positive lymph nodes had an aspect ratio of less than 0.4. Metastasis-positive LPLNs tended to be larger and rounder than their metastasis-negative counterparts. Conclusions: Metastatic LPLNs in patients with lower rectal cancer are significantly larger and have a higher aspect ratio. Lymph nodes with aspect ratios of <0.4 were metastasis negative.

Trans-anal surgery with the taTME technique for rectal gastrointestinal stromal tumors: a retrospective study.

PURPOSE: Rectal gastrointestinal stromal tumors (GISTs) surgery is often challenging owing to the anatomical constraints of the narrow pelvis and tumor hugeness. Despite the increasing number of patients undergoing trans-anal total mesorectal excision (taTME) globally, the feasibility of trans-anal surgery with the taTME technique for rectal GISTs remains unclear. We aimed to evaluate the feasibility of trans-anal surgery with the taTME technique for rectal GISTs. METHODS: Using a prospectively collected database, we retrospectively analyzed the clinical findings, surgical outcomes, pathological outcomes, urinary and anal functions, and prognoses of patients who underwent trans-anal surgery with the taTME technique for primary rectal GISTs at the National Cancer Center Hospital East from September 2014 to March 2020. RESULTS: Twenty-one patients with primary rectal GISTs were included in this study. The median distance from the anal verge to the lower edge of the tumor was 40 mm (range, 15-60 mm), and the median tumor size was 59 mm (range, 11-175 mm). Moreover, seven and 14 patients underwent one-team and two-team surgeries, respectively, with curative intent. Nineteen patients (90.5%) underwent anus-preserving surgery, and the urinary tracts were preserved in all cases. Two-team surgery showed a significantly lower blood loss volume and shorter operation time than one-team surgery (58 vs. 222 mL, P = 0.017; 184 vs 356 min, P = 0.041, respectively). The pathological negative-margin resection rate was 100%. During the follow-up period, no patient developed local GIST recurrence and one (4.8%) developed distant metastasis. CONCLUSION: Trans-anal surgery with the taTME technique is feasible for rectal GISTs, and two-team surgery may be more advantageous than one-team surgery in terms of operation time and blood loss.

Transanal total mesorectal excision for treating a lower rectal inflammatory myofibroblastic tumor: A case report.

Rectal inflammatory myofibroblastic tumors are extremely rare, with no reports of their preoperative diagnosis. A 17-year-old woman who presented with low-grade fever, repeated diarrhea, constipation, and a 1-month history of anal pain was referred to our hospital. Rectal examination revealed a palpable hard mass with a smooth surface at the posterior wall 4 cm from the anal verge. Colonoscopy revealed a 4.0-cm submucosal tumor in the upper edge of the anal canal. Computed tomography and magnetic resonance imaging revealed a 5.0 × 4.0 cm-sized well-defined tumor contacting the rectum. Computed tomography-guided biopsy was performed, and an inflammatory myofibroblastic tumor was diagnosed. There have been no reports of surgery for a rectal inflammatory myofibroblastic tumor using transanal total mesorectal excision. We preoperatively diagnosed the patient with an inflammatory myofibroblastic tumor in the lower rectum and achieved anorectal preservation and curative resection with transanal total mesorectal excision, providing good view of the deep pelvis.

Validation study of a skill assessment tool for education and outcome prediction of laparoscopic distal gastrectomy.

BACKGROUND: The Japanese operative-rating scale for laparoscopic distal gastrectomy (JORS-LDG) was developed through cognitive task analysis together with the Delphi method to measure intraoperative performance during laparoscopic distal gastrectomy. This study aimed to investigate the value of this rating scale as an educational tool and a surgical outcome predictor in laparoscopic distal gastrectomy. METHODS: The surgical performance of laparoscopic distal gastrectomy was assessed by the first assistant, through self-evaluation in the operating room and by video raters blind to the case. We evaluated inter-rater reliability, internal consistency, and correlations between the JORS-LDG scores and the evaluation methods, patient characteristics, and surgical outcomes. RESULTS: Fifty-four laparoscopic distal gastrectomy procedures performed by 40 surgeons at 16 institutions were evaluated in the operating room and with video recordings using the proposed rating scale. The video inter-rater reliability was > 0.8. Participating surgeons were divided into the low, intermediate, and high groups based on their total scores. The number of laparoscopic surgeries and laparoscopic gastrectomy procedures performed differed significantly among the groups according to laparoscopic distal gastrectomy skill levels. The low, intermediate, and high groups also differed in terms of median operating times (311, 266, and 229 min, respectively, P < 0.001), intraoperative complication rates (27.8, 11.8, and 0%, respectively, P = 0.01), and postoperative complication rates (22.2, 0, and 0%, respectively, P = 0.002). CONCLUSIONS: The JORS-LDG is a reliable and valid measure for laparoscopic distal gastrectomy training and could be useful in predicting surgical outcomes.

Validation of a novel virtual reality simulation system with the focus on training for surgical dissection during laparoscopic sigmoid colectomy.

BACKGROUND: Mastery of technical skills is one of the fundamental goals of surgical training for novices. Meanwhile, performing laparoscopic procedures requires exceptional surgical skills compared to open surgery. However, it is often difficult for trainees to learn through observation and practice only. Virtual reality (VR)-based surgical simulation is expanding and rapidly advancing. A major obstacle for laparoscopic trainees is the difficulty of well-performed dissection. Therefore, we developed a new VR simulation system, Lap-PASS LP-100, which focuses on training to create proper tension on the tissue in laparoscopic sigmoid colectomy dissection. This study aimed to validate this new VR simulation system. METHODS: A total of 50 participants were asked to perform medial dissection of the meso-sigmoid colon on the VR simulator. Forty-four surgeons and six non-medical professionals working in the National Cancer Center Hospital East, Japan, were enrolled in this study. The surgeons were: laparoscopic surgery experts with > 100 laparoscopic surgeries (LS), 21 were novices with experience < 100 LS, and five without previous experience in LS. The participants' surgical performance was evaluated by three blinded raters using Global Operative Assessment of Laparoscopic Skills (GOALS). RESULTS: There were significant differences (P-values < 0.044) in all GOALS items between the non-medical professionals and surgeons. The experts were significantly superior to the novices in one item of GOALS: efficiency ([4(4-5) vs. 4(3-4)], with a 95% confidence interval, p = 0.042). However, both bimanual dexterity and total score in the experts were not statistically different but tended to be higher than in the novices. CONCLUSIONS: Our study demonstrated a full validation of our new system. This could detect the surgeons' ability to perform surgical dissection and suggest that this VR simulator could be an effective training tool. This surgical VR simulator might have tremendous potential to enhance training for surgeons.

Computer-assisted real-time automatic prostate segmentation during TaTME: a single-center feasibility study.

BACKGROUND: Urethral injuries (UIs) are significant complications pertaining to transanal total mesorectal excision (TaTME). It is important for surgeons to identify the prostate during TaTME to prevent UI occurrence; intraoperative image navigation could be considered useful in this regard. This study aims at developing a deep learning model for real-time automatic prostate segmentation based on intraoperative video during TaTME. The proposed model's performance has been evaluated. METHODS: This was a single-institution retrospective feasibility study. Semantic segmentation of the prostate area was performed using a convolutional neural network (CNN)-based approach. DeepLab v3 plus was utilized as the CNN model for the semantic segmentation task. The Dice coefficient (DC), which is calculated based on the overlapping area between the ground truth and predicted area, was utilized as an evaluation metric for the proposed model. RESULTS: Five hundred prostate images were randomly extracted from 17 TaTME videos, and the prostate area was manually annotated on each image. Fivefold cross-validation tests were performed, and as observed, the average DC value equaled 0.71 ± 0.04, the maximum value being 0.77. Additionally, the model operated at 11 fps, which provides acceptable real-time performance. CONCLUSIONS: To the best of the authors' knowledge, this is the first effort toward realization of computer-assisted TaTME, and results obtained in this study suggest that the proposed deep learning model can be utilized for real-time automatic prostate segmentation. In future endeavors, the accuracy and performance of the proposed model will be improved to enable its use in practical applications, and its capability to reduce UI risks during TaTME will be verified.

Delorme surgery for colonic mucosal prolapse after intersphincteric resection.

PURPOSE: Mucosal prolapse at the site of anastomosis is a long-term complication unique to ISR. It reduces the QOL of patients due to a worsened anal function and local symptoms around the anus. We herein sought to assess the surgical outcomes after Delorme surgery for these patients. METHODS: ISR was performed in 720 patients with low rectal cancer between January 2001 and March 2019 at the National Cancer Center Hospital East. Among these patients, the 33 (4.5%) who underwent initial Delorme surgery for postoperative colonic mucosal prolapse were identified from the medical records and then were analyzed retrospectively. We estimated the anal function using Wexner's incontinence score and assessed whether local anal symptoms due to the prolapse improved postoperatively. RESULTS: Stoma closure was performed before Delorme surgery in 15 (45.5%) patients, and we compared the preoperative and postoperative anal function in these patients. The average Wexner's incontinence score changed from 15.1 before to 12.9 after Delorme surgery. Local symptoms around the anus improved in all 33 (100%) patients. Recurrence of colonic mucosal prolapse occurred in 5 patients (15%), and Delorme surgery was reperformed in these cases. CONCLUSION: Delorme surgery for colonic mucosal prolapse following ISR has clinical benefits for both improving anal local symptoms and slightly improving the anal function.

Laparoscopic repair with cone-shaped mesh implantation for perineal hernia occurred after laparoscopic abdominoperineal resection.

INTRODUCTION: Perineal hernia after abdominoperineal resection (APR) is a rare complication, and no standard surgical procedures are established. We describe a simple laparoscopic mesh implantation technique utilizing a large synthetic flat mesh. PRESENTATION OF CASE: We report a case of perineal hernia after APR. We performed laparoscopic repair using a soft and large synthetic mesh with simple technique. The essence of this technique is that mesh is inserted into the abdominal cavity without trimming and it forms in a conical shape to better adjust to the pelvic cavity. DISCUSSION: The perineal and laparoscopic approaches for perineal hernia repair have been performed most commonly in recent years, but the recurrence rate after repair remains high (24.1%). Using a large mesh could cover the hernial orifice with a sufficient margin, reducing a risk of recurrence caused by shrinkage and slippage of the mesh. CONCLUSION: Our technique utilizing a large, lightweight, synthetic mesh can be practical and useful for perineal hernia repair after laparoscopic APR.

Pathological complete response of locally advanced colon cancer after preoperative radiotherapy: a case report and narrative review of the literature.

BACKGROUND: The oncological effectiveness of preoperative radiotherapy for locally advanced colon cancer is unclear. We report a case of pathological complete response in a patient with locally advanced ascending colon cancer after preoperative radiotherapy following failure of chemotherapy. CASE PRESENTATION: A 65-year-old Japanese woman presented with malaise and hematochezia. A computed tomography (CT) revealed a tumor in the ascending colon which seemed to infiltrate the adjacent structures. She was diagnosed with locally advanced ascending colon cancer stages T4b, N2a, M0, and IIIC. We selected modified FOLFOX6 with panitumumab as neoadjuvant chemotherapy. However, we discontinued the chemotherapy after the 8th cycle because of disease progression and severe adverse effects. The patient then underwent radiotherapy of 60 Gy in 30 fractions, resulting in significant tumor size reduction. One month after the radiotherapy, we performed a right hemicolectomy with multivisceral resection without complications. Histopathologically, we found no residual cancer cells in the resected specimen. The patient remains alive and has not required additional therapies for 24 months, as there are no signs of recurrence. CONCLUSIONS: The present case suggests that preoperative radiotherapy might be an effective treatment options for locally advanced colon cancer.

Preoperative diagnosis of portal vein invasion in pancreatic head cancer: appropriate indications for concomitant portal vein resection.

BACKGROUND: The surgical indications for patients with pancreatic head cancer (PHC) with clinical portal vein (PV) invasion (cPV) remain controversial. The present study aimed to determine the ability of computed tomography (CT) to diagnose pathological PV involvement (pPV) in PHC. METHODS: We evaluated the morphological features (length and circumference) and two sets of diagnostic criteria for cPV determined from preoperative CT findings of 112 consecutive patients who underwent pancreatoduodenectomy for PHC. This study is listed in the UMIN Clinical Trials Registry (UMIN-CTR; No: UMIN000016827). RESULTS: Five patients were excluded because enhanced CT data were missing. Morphological features have low diagnostic ability for pPV. We diagnosed 67 patients with cPV based on our diagnostic criteria and those of Klauss, and 42 of them had pPV. The negative predictive values of these diagnostic criteria for pPV were satisfactory (>95%) and the positive predictive value was relatively low (61.2%). Postoperative survival could be predicted based on the cPV type. CONCLUSION: An accurate diagnosis of pPV based on morphological features determined by preoperative CT is difficult. However, preoperative CT appears useful for selecting patients with PHC who could be candidates for pancreaticoduodenectomy with or without PV resection.

[Indication of limited pulmonary resection for small-sized lung cancer based on preoperative clinical data].

Limited pulmonary resection is performed mostly based on the size of lung cancer and ground-glass opacity (GGO). It has been proposed to determine the indication of segmentectomy according to hilar lymph node involvement. There is a potential risk of underestimation for lymph node involvement since there may be a skip mediastinal lymph node metastasis without hilar involvement. We propose to use standardized uptake value( SUV) max of primary lung cancer as an indicator of non-invasive lung cancer. None of 44 small-sized lung cancers with SUVmax lower than 1 had lymph node metastasis or vessel invasion. A small-sized lung cancer ≤ 2 cm with SUVmax ≤ 1 is indicated wedge resection if GGO area is greater than 75% of tumor. Segmentectomy is indicated if the GGO area is less than 75%. We also propose selective lymphadenectomy for small-sized lung cancer. The lower mediastinal lymphadenectomy may be omitted if a small-sized tumor is located in the right upper lobe or the left upper segment. The upper mediastinal lymphadenectomy may be omitted if a small-sized lung cancer is located in the lower lobe and if the lower mediastinal lymph node involvement is excluded.