Effects of neoadjuvant chemotherapy for patients with obstructive colon cancer: A multicenter propensity score-matched analysis (YCOG2101)

Aim

Obstructive colon cancer is locally advanced colon cancer with poor prognosis. However, the effect of neoadjuvant chemotherapy (NAC) on obstructive colon cancer remains unclear. Therefore, this study aimed to investigate the safety and efficacy of NAC in patients with obstructive colon cancer.

Methods

From January 2012 to December 2017, we collected patient data for clinical stage II/III obstructive colon cancer at seven Yokohama Clinical Oncology Group (YCOG) institutions. The long-term outcomes of the NAC and non-NAC groups were analyzed retrospectively after adjusting for patients' background characteristics using propensity score matching.

Results

Among the 202 eligible patients, propensity score matching extracted 51 patients each for the NAC and non-NAC groups. After matching, the groups showed no marked differences in the background factors. All the patients in the NAC group underwent diverting stoma construction. Nineteen patients (37.3%) experienced grade 3-4 adverse events during NAC. The incidence of postoperative complications was similar between groups. The 5-year progression-free survival rates were 75.8% in the NAC group and 63.0% in the non-NAC group (p = 0.22, log-rank test). The 5-year overall survival rates were 88.5% in the NAC group and 78.8% in the non-NAC group (p = 0.09, log-rank test).

Conclusion

Although NAC was feasible for obstructive colon cancer after diverting stoma construction, its effects on long-term outcomes could not be proven.

Multicenter randomized phase II study on S-1 and oxaliplatin therapy as an adjuvant after hepatectomy for colorectal liver metastases (YCOG1001)

PURPOSE

The high recurrence rate of colorectal cancer liver metastasis (CRCLM) after surgery remains a crucial problem. However, adjuvant chemotherapy after hepatectomy for CRCLM has not yet been established. This study evaluated the efficacy of adjuvant therapy with S-1 and oxaliplatin (SOX).

METHODS

In a multicenter, randomized, phase II study, patients undergoing curative resection of CRCLM were randomly enrolled in a 1:1 ratio to either the low- or high-dose group. S-1 and oxaliplatin were administered from days 1 to 14 of a 3-week cycle as a 2-h infusion every 3 weeks. The dose of S-1 was fixed at 80 mg/m2. The doses in the low- and high-dose oxaliplatin groups were 100 mg/m2 (low-dose group) and 130 mg/m2 (high-dose group), respectively. This treatment was repeated eight times. The primary endpoint was the rate of discontinuation owing to toxicity. The secondary endpoints were the relapse-free survival (RFS) and frequency of adverse events (AEs).

RESULTS

Between August 2010 and March 2015, 44 patients (low-dose group: 31 patients and high-dose group: 13 patients) were enrolled in the study. Of these, one patient was excluded from the efficacy analysis. In the high-dose group, five of nine patients were unable to continue the study due to toxicity in February 2013. At that time, recruitment to the high-dose group was stopped from the protocol. The relative dose intensity (RDI) for S-1 in the low- and high-dose groups were 49.8 and 48.7% (p = 0.712), and that for oxaliplatin was 75.9 and 73.0% (p = 0.528), respectively. The rates of discontinuation due to toxicity were 60 and 53.8% in the low- and high-dose groups, respectively, with no marked difference noted between the groups (p = 0.747). The frequency of grade ≥ 3 common adverse events was neutropenia (23.3%/23.1%), diarrhea (13.3%/15.4%), and peripheral sensory neuropathy (6.7%/7.7%). The disease-free survival (DFS) at 3 years was 52.9% in the low-dose group, which was not significantly different from that in the high-dose group (46.2%; p = 0.705).

CONCLUSIONS

SOX regimens as adjuvant therapy after hepatectomy for CRCLM had high rates of discontinuation due to toxicity in both groups. In particular, the RDI of S-1 was < 50%. Therefore, the SOX regimen is not recommended as adjuvant chemotherapy after hepatectomy for CRCLM.

Short-term and Mid-term Outcomes of Indocyanine Green Fluorescence Imaging-Guided Laparoscopic Right-Sided Colectomy: A Propensity Score-Matched Cohort Study

BACKGROUND

With the use of indocyanine green fluorescence imaging, intraoperative lymphatic flow assessment is possible. However, no report has indicated mid-term outcomes of indocyanine green fluorescence imaging-guided laparoscopic right-sided colectomy.

OBJECTIVE

To analyze the mid-term outcomes of indocyanine green fluorescence imaging-guided laparoscopic right-sided colectomy.

DESIGN

This was a retrospective, multi-institutional study that used propensity score matching.

SETTINGS

We conducted this study within the framework of the Yokohama Clinical Oncology Group in Japan.

PATIENTS

A total of 921 patients who underwent laparoscopic right-sided colectomy with lymph node dissection for colon cancer with clinical stages I to III between January 2009 and December 2020 were included. The patients were divided into 2 groups: 233 patients who underwent the lymphatic flow evaluation (indocyanine green group) and 688 patients who did not undergo lymphatic flow evaluation (non-indocyanine green group).

MAIN OUTCOMES MEASURES

The 3-year relapse-free survival after laparoscopic right-sided colectomy with and without indocyanine green fluorescence imaging were compared.

RESULTS

After propensity score matching, 231 patients were matched in each group. The numbers of dissected central lymph nodes (6 vs 4, p < 0.001), intermediate lymph nodes (7 vs 6, p = 0.03), and the total number of dissected lymph nodes (31 vs 27, p = 0.047) were significantly higher in the indocyanine green group. The median follow-up was 36.9 months. The estimated respective 3-year relapse-free survival and overall survival rates were 88.8% and 94.5% in the indocyanine green group and 89.4% and 94.7% in the non-indocyanine green group ( p = 0.721 and 0.300), respectively, with no difference between the 2 groups.

LIMITATIONS

Retrospective design of the study.

CONCLUSIONS

Indocyanine green fluorescence imaging-guided laparoscopic right-sided colectomy could increase the number of total, intermediate, and central lymph nodes. However, there was no difference in mid-term outcomes. See Video Abstract.

RESULTADOS A CORTO Y MEDIO PLAZO DE LA COLECTOMA LAPAROSCPICA DEL LADO DERECHO GUIADA POR IMGENES DE FLUORESCENCIA CON VERDE DE INDOCIANINA UN ESTUDIO DE COHORTE EMPAREJADO POR PUNTAJE DE PROPENSIN

ANTECEDENTES:Con el uso de imágenes de fluorescencia verde de indocianina, es posible la evaluación del flujo linfático intraoperatorio. Sin embargo, no hay ningún reporte que indique los resultados a medio plazo de la colectomía laparoscópica del lado derecho guiada por imágenes de fluorescencia con verde de indocianina.OBJETIVO:Examinar los resultados a mediano plazo de la colectomía laparoscópica del lado derecho guiada por imágenes de fluorescencia con verde de indocianina.DISEÑO:Estudio multiinstitucional retrospectivo con emparejamiento de puntuación de propensión.CONFIGURACIÓN:Realizado en el marco del Grupo de Oncología Clínica de Yokohama en Japón.PACIENTES:Un total de 921 pacientes sometidos a colectomía laparoscópica del lado derecho con disección de ganglios linfáticos por cáncer de colon con estadio clínico I a III entre enero de 2009 y diciembre de 2020. Los pacientes se dividieron en dos grupos: 233 pacientes sometidos a la evaluación del flujo linfático (grupo con verde de indocianina) y 688 pacientes que no sometidos a la evaluación del flujo linfático (grupo sin verde de indocianina).PRINCIPALES MEDIDAS DE RESULTADOS:Se comparó la supervivencia libre de recaídas a los 3 años después de la colectomía laparoscópica del lado derecho con y sin imágenes de fluorescencia con verde de indocianina.RESULTADOS:Después de emparejar el puntaje de propensión, 231 pacientes fueron emparejados en cada grupo. El número de ganglios linfáticos centrales disecados (6 frente a 4, p < 0,001) y de ganglios linfáticos intermedios (7 frente a 6, p = 0,03) y el número total de ganglios linfáticos disecados (31 frente a 27, p = 0,047) fueron significativamente mayor en el grupo verde de indocianina. La mediana de seguimiento fue de 36,9 meses. Las tasas respectivas estimadas de supervivencia libre de recaídas y supervivencia general a los 3 años fueron del 88,8 % y el 94,5 % en el grupo con verde de indocianina y del 89,4 % y el 94,7 % en el grupo sin verde de indocianina ( p = 0,721 y 0,300), sin diferencias entre los dos grupos.LIMITACIONES:Estudio de diseño retrospectivo.CONCLUSIONES:La colectomía laparoscópica del lado derecho guiada por imágenes de fluorescencia con verde de indocianina puede aumentar el número de ganglios linfáticos totales, intermedios y centrales. Sin embargo, no hubo diferencias en los resultados a medio plazo. (Traducción-Dr. Fidel Ruiz Healy ).

Surgical outcomes of a prospective, phase 2 trial of robotic surgery for resectable right-sided colon cancer (the ROBOCOLO trial)

Aim

We evaluated the safety of robotic surgery for right-sided colon cancer in Japan.

Methods

This was a prospective, open-label, single-arm phase II trial conducted at two institutions. Patients ≥20 years old with stage I-III right-sided colon cancer and scheduled for radical resection with ≥D2 lymph node dissection were eligible. The criterion for surgeons was experience performing robot-assisted rectal resection in ≥40 cases. The primary endpoint was the postoperative complication rate ≤30 days after surgery.

Results

From August 2021 to February 2023, 42 patients were enrolled; three were excluded, with 39 analyzed as the full analysis set. The median age was 72 years, and the median body mass index was 23.2. The tumor was located in the cecum in 13 cases (33.3%), ascending colon in 20 cases (51.3%), and transverse colon in six cases (15.4%). Ileocolic resection was performed in 17 cases (43.5%) and right hemicolectomy in 22 cases (56.5%), both with D3 lymph node dissection. The median console time was 109 min, and the operative time was 170 min. The mean blood loss was 7.7 mL. Intracorporeal anastomosis was performed in 28 patients (71.8%). There were no conversions and no intraoperative adverse events. The median postoperative stay was 5 days. Postoperative complications occurred in four patients (10.2%; paralytic ileus [n = 3] and pneumonia [n = 1]). All postoperative complications were grade 1 or 2, with no mortalities noted. R0 resection was achieved in all patients.

Conclusions

This study demonstrated the safety and feasibility of robotic surgery for right-sided colon cancer.

Exploratory randomized phase II trial for optimizing treatment dosage and duration of adjuvant S-1 plus oxaliplatin in patients with stage III colon cancer: YCOG1402 (SOAP trial)

Introduction

Conventionally, the recommended duration of adjuvant chemotherapy of colon cancer had been 6 months. The IDEA Collaboration suggested that shortening capecitabin and oxaliplatin (CAPOX) adjuvant chemotherapy may be possible. S-1 and oxaliplatin (SOX) treatment is standard treatment in metastatic colorectal cancer in Japan. The aim of this study was to optimize treatment dosage and duration of adjuvant SOX in stage III colon cancer.

Methods

This trial was as open-label multi-center randomized phase II study. Patients with stage III colon cancer were randomly assigned to 3 months or 6 months of adjuvant SOX treatment in different doses: 130 mg/m2 (3 months) or 100 mg/m2 (6 months) of oxaliplatin. The primary endpoint was 3-year disease-free survival (DFS) and the null hypothesis for the primary endpoint was that the 3-year DFS was ≤72% in each arm and was tested with a one-sided significance level of 10%.

Results

Eighty-two patients were assigned to the 6 months arm and 81 to the 3 months arm. The 3-year DFS was 75.0% (80% CI 67.95-80.72, p = 0.282) in the 6 months arm and 76.9% (80% CI 70.1-82.38, p = 0.171) in the 3 months arm. Treatment completion rate and relative dose intensity (RDI) were higher in 3 months than 6 months arm. The adverse events (AE) were similar in both arms.

Conclusions

The 3-year DFS was not significantly superior to null hypothesis in both 3 months and 6 months arms for the stage III colon cancer. Primary endpoint was not achieved. The SOX regimen was not feasible in long-term outcomes.

Blood Perfusion Assessment by Indocyanine Green Fluorescence Imaging for Minimally Invasive Rectal Cancer Surgery (EssentiAL trial): A Randomized Clinical Trial

OBJECTIVE

The aim of the present randomized controlled trial was to evaluate the superiority of indocyanine green fluorescence imaging (ICG-FI) in reducing the rate of anastomotic leakage in minimally invasive rectal cancer surgery.

BACKGROUND

The role of ICG-FI in anastomotic leakage in minimally invasive rectal cancer surgery is controversial according to the published literature.

METHODS

This randomized, open-label, phase 3, trial was performed at 41 hospitals in Japan. Patients with clinically stage 0-III rectal carcinoma less than 12 cm from the anal verge, scheduled for minimally invasive sphincter-preserving surgery were preoperatively randomly assigned to receive a blood flow evaluation by ICG-FI (ICG+ group) or no blood flow evaluation by ICG-FI (ICG- group). The primary endpoint was the anastomotic leakage rate (grade A+B+C, expected reduction rate of 6%) analyzed in the modified intention-to-treat population.

RESULTS

Between December 2018 and February 2021, a total of 850 patients were enrolled and randomized. After the exclusion of 11 patients, 839 were subject to the modified intention-to-treat population (422 in the ICG+ group and 417 in the ICG- group). The rate of anastomotic leakage (grade A+B+C) was significantly lower in the ICG+ group (7.6%) than in the ICG- group (11.8%) (relative risk, 0.645; 95% confidence interval 0.422-0.987; P =0.041). The rate of anastomotic leakage (grade B+C) was 4.7% in the ICG+ group and 8.2% in the ICG- group ( P =0.044), and the respective reoperation rates were 0.5% and 2.4% ( P =0.021).

CONCLUSIONS

Although the actual reduction rate of anastomotic leakage in the ICG+ group was lower than the expected reduction rate and ICG-FI was not superior to white light, ICG-FI significantly reduced the anastomotic leakage rate by 4.2%.

Long-term outcomes of indocyanine green fluorescence imaging-guided laparoscopic lateral pelvic lymph node dissection for clinical stage II/III middle-lower rectal cancer: a propensity score-matched cohort study

BACKGROUND

We previously reported that indocyanine green fluorescence imaging (ICG-FI)-guided laparoscopic lateral pelvic lymph node dissection (LPLND) was able to increase the total number of harvested lateral pelvic lymph nodes without impairing functional preservation. However, the long-term outcomes of ICG-FI-guided laparoscopic LPLND have not been evaluated. The aim of the present study was to compare the long-term outcomes of ICG-FI-guided laparoscopic LPLND to conventional laparoscopic LPLND without ICG-FI.

METHODS

This was a retrospective, multi-institutional study with propensity score matching. The study population included consecutive patients with middle-low rectal cancer (clinical stage II to III) who underwent laparoscopic LPLND between January 2013 and February 2018. The main evaluation items in this study were the 3-year overall survival, relapse-free survival (RFS), local recurrence rate, and lateral local recurrence (LLR) rate.

RESULTS

A total of 172 patients with middle-lower rectal cancer who had undergone laparoscopic LPLND were included in this study. After propensity score matching, 58 patients were matched in each of the ICG-FI and non-ICG-FI groups. There were no substantial differences in the baseline characteristics between the two groups. The ICG-FI group and non-ICG-FI group included 40 and 38 women and had a median age of 65 (IQR 60-72) and 66 (IQR 60-73) years, respectively. The median follow-up for all patients was 63.7 (IQR 51.3-76.8) months. The estimated respective 3-year overall survival, RFS, and local recurrence rates were 93.1%, 70.7%, and 5.2% in the ICG-FI group and 85.9%, 71.7%, and 12.8% in the non-ICG-FI group (p = 0.201, 0.653, 0.391). The 3-year cumulative LLR rate was 0% in the ICG-FI group and 9.3% in the non-ICG-FI group (p = 0.048).

CONCLUSIONS

This study revealed that laparoscopic LPLND combined with ICG-FI was able to decrease the LLR rate. It appears that ICG-FI could contribute to improving the quality of laparoscopic LPLND and strengthening local control of the lateral pelvis.

TRIALS REGISTRATION

This study was registered with the Japanese Clinical Trials Registry as UMIN000041372 ( http://www.umin.ac.jp/ctr/index.htm ).

Elucidating colorectal cancer-associated bacteria through profiling of minimally perturbed tissue-associated microbiota

Sequencing-based interrogation of gut microbiota is a valuable approach for detecting microbes associated with colorectal cancer (CRC); however, such studies are often confounded by the effect of bowel preparation. In this study, we evaluated the viability of identifying CRC-associated mucosal bacteria through centimeter-scale profiling of the microbiota in tumors and adjacent noncancerous tissue from eleven patients who underwent colonic resection without preoperative bowel preparation. High-throughput 16S rRNA gene sequencing revealed that differences between on- and off-tumor microbiota varied considerably among patients. For some patients, phylotypes affiliated with genera previously implicated in colorectal carcinogenesis, as well as genera with less well-understood roles in CRC, were enriched in tumor tissue, whereas for other patients, on- and off-tumor microbiota were very similar. Notably, the enrichment of phylotypes in tumor-associated mucosa was highly localized and no longer apparent even a few centimeters away from the tumor. Through short-term liquid culturing and metagenomics, we further generated more than one-hundred metagenome-assembled genomes, several representing bacteria that were enriched in on-tumor samples. This is one of the first studies to analyze largely unperturbed mucosal microbiota in tissue samples from the resected colons of unprepped CRC patients. Future studies with larger cohorts are expected to clarify the causes and consequences of the observed variability in the emergence of tumor-localized microbiota among patients.

Initial experience with the transanal approach for lateral pelvic lymph node dissection in rectal cancer

BACKGROUND

The efficacy and safety of transanal lateral pelvic lymph node dissection (TaLPLND) in rectal cancer has not yet been clarified. The aim of the present study was to evaluate the short-term results as an initial experience of TaLPLND.

METHODS

This retrospective study included patients with middle to lower rectal cancer who underwent TaLPLND from July 2018 to July 2021. Our institutions targeted lymph nodes in the internal iliac area and the obturator area for lateral pelvic lymph node dissection (LPLND).

RESULTS

A total of 30 consecutive patients with rectal cancer were included in this analysis. The median age was 60 years (range, 36-83 years), and the male-female ratio was 2:1. The median operative time was 362 min (IQR, 283-661 min), and the median intraoperative blood loss was 74 ml (IQR, 5-500 ml). Intraoperative blood transfusion was required in one case. No cases required conversion to laparotomy. TaLPLND was performed bilaterally in 13 patients (43.3%). Five patients (16.7%) underwent LPLND with combined resection of the internal iliac vessels. The median distance of the distal margin from the anal verge was 20 mm. The pathological radial margin (pRM) was positive in one case, and the negative pRM rate was 96.7%. Short-term postoperative complications (Clavien-Dindo classification grade ≥ II) were observed in nine cases (30.0%). There were no cases of reoperation or mortality. The median number of harvested lateral pelvic lymph nodes was 11 (range, 3-28). On pathological examination, lateral pelvic lymph nodes were positive for metastasis in seven cases (23.3%).

CONCLUSIONS

TaLPLND appeared to be beneficial from an oncological point of view because it was close to the upstream lymphatic drainage from the tumor. The short-term outcomes of this initial experience indicate that this novel approach is feasible.

Optimal bowel resection margin in colon cancer surgery: prospective multicentre cohort study with lymph node and feeding artery mapping

Background

There are no standardised criteria for the 'regional' pericolic node in colon cancer, which represents a major cause of the international uncertainty regarding the optimal bowel resection margin. This study aimed to determine 'regional' pericolic nodes based on prospective lymph node (LN) mapping.

Methods

According to preplanned in vivo measurements of the bowel, the anatomical distributions of the feeding artery and LNs were determined in 2996 stages I-III colon cancer patients who underwent colectomy with resection margin >10 cm at 25 institutions in Japan.

Findings

The mean number of retrieved pericolic nodes was 20.9 (standard deviation, 10.8) per patient. In all patients except seven (0.2%), the primary feeding artery was distributed within 10 cm of the primary tumour. The metastatic pericolic node most distant from the primary tumour was within 3 cm in 837 patients, 3-5 cm in 130 patients, 5-7 cm in 39 patients and 7-10 cm in 34 patients. Only four patients (0.1%) had pericolic lymphatic spread beyond 10 cm; all of whom had T3/4 tumours accompanying extensive mesenteric lymphatic spread. The location of metastatic pericolic node did not differ by the feeding artery's distribution. Postoperatively, none of the 2996 patients developed recurrence in the remaining pericolic nodes.

Interpretation

The pericolic nodes designated as 'regional' were those located within 10 cm of the primary tumours, which should be fully considered when determining the bowel resection margin, even in the era of complete mesocolic excision.

Funding

Japanese Society for Cancer of the Colon and Rectum.

Randomized controlled trial evaluating the effect of the use of a laparoscopic lens-cleaning device during laparoscopic colorectal surgery on the multidimensional workload (YCOG1903)

BACKGROUND

OpClear® is a newly developed laparoscopic lens-cleaning device that can be attached to a laparoscope. The present study determined whether or not the use of a OpClear® reduces the multidimensional surgery-specific workload of the operator during laparoscopic colorectal surgery for colorectal cancer compared with the reference technique (warm saline) by a randomized controlled trial.

METHODS

Patients diagnosed with colorectal cancer and scheduled for laparoscopic colorectal surgery were randomly allocated to the warm saline arm or Opclear® arm. The primary endpoint was the multidimensional workload of the first operator (value of SURG-TLX). The secondary endpoints were the operative time and total number of lens washes outside the abdominal cavity.

RESULTS

Between March 2020 and January 2021, a total of 120 patients were enrolled in this study. A total of 4 patients were excluded from the full analysis set. A total of 116 patients (warm saline arm: 59 patients, Opclear® arm: 57 patients) were therefore analyzed. The baseline factors were well-balanced between the two arms. Regarding SURG-TLX, there was no significant difference in the overall workload between the two arms. Operators in the Opclear® arm required significantly less physical demand than in the warm saline arm (Opclear® arm: 6, warm saline arm: 7; p = 0.046). The operative time was similar between the two arms. The total number of lens washes outside the abdominal cavity in the Opclear® arm was significantly lower than that in the warm saline arm (Opclear® arm: 2, warm saline arm: 10; p < 0.001).

CONCLUSIONS

There was no significant difference in the overall workload, but the physical demand and total number of lens washes outside the abdominal cavity were significantly lower in the Opclear® arm than in the warm saline arm. The use of this device may thus help reduce operator stress in terms of physical demand. The study was registered with the Japanese Clinical Trials Registry as UMIN0000038677.

Curable leakage in stapled IPAA has little effect on the long-term pouch function

PURPOSE

This study aimed to evaluate the frequency and grade of anastomotic leakage (AL) in stapled ileal pouch-anal anastomosis (IPAA) and its long-term impact on the pouch functions.

METHODS

A longitudinal cohort study was conducted on UC patients who underwent stapled IPAA at Yokohama City University Medical Center between 2007 and 2018. The diagnosis and grading of AL were performed in accordance with the recommendations of the International Study Group of Rectal Cancer. We assessed the functional pouch rate, late complication, pouch survival rate, bowel function (bowel movements per day, soiling, spotting, difficulty in distinguishing feces from flatus) and pouch inflammation (pouchitis disease activity index; PDAI) in the long-term period.

RESULTS

Two hundred seventy-six patients were analyzed. Twenty-three (8.3%; grade B/C; 13/10) patients were diagnosed with AL, but a functional pouch was achieved in all the twenty-three patients. Anastomotic stricture was significantly more common in patients with AL (AL group) than in patients without AL (non-AL group; AL/non-AL: 13.0/3.2%, p = 0.020). There were no differences in other late complications. Furthermore, the pouch survival rate did not differ between the AL and non-AL groups (100.0/97.9%/10 years, p = 0.494). There were no differences between the groups in bowel movements per day, spotting, soling, difficulty in distinguishing feces from flatus, or PDAI postoperatively.

CONCLUSIONS

Curable AL may not affect late complications (except anastomotic stricture), pouch survival, the bowel function, or pouch inflammation over the long term. Perioperative management to prevent the severity of AL is as important as preventing its occurrence.

Abstract 5252: In colorectal cancer (CRC), neuroendocrine carcinoma (NEC) is contaminated in the cancer given a confirmed diagnosis of poorly differentiated adenocarcinoma (P-ad-ca)

Background: Most of CRC were well or moderately differentiated adenocarcinoma and P-ad-ca is very rare. In Japan, P-ad-ca was reported to be only 4-6% of all CRC. NEC is also rare. The incidence of that were reported to be less than 1%. One of their points of common is morphological poorly differentiated appearance. In this study, we evaluated the incidence of NEC contaminated in the CRC given a confirmed diagnosis as P-ad-ca.

Material and Method: From 2009 to 2019, 816 CRCs were resected in department of Yokohama City University Hospital and 74 cases showing P-ad-ca or having a small region of P-ad-ca with well or moderately differentiated ad-ca (W-ad-ca, M-ad-ca). Among the 74 cases, there were 8 of P-ad-ca, 4 of W-ad-ca with P-ad-ca, 44 of M-ad-ca with P-ad-ca, and 18 W-ad-ca and M-ad-ca with P-ad-ca. Immunohistochemistry (IHC) using neuroendocrine markers (NM) including chromogranin A, synaptophysin and insulinoma-associated protein 1 (INSM1) was performed to identified NEC. Recently, a high incidence of Rb protein loss was reported in NEC of several organs, then IHC using Rb monoclonal antibody was also performed. The cancers showing immunohistochemically positive of at least one of the three NM and negative of Rb were identified as true NEC in this study.

Results: At least one of the three NM was positive in the 39 cases. In these 39 cases, 3 cases were also Rb negative. Two of the three cases were region of P-ad-ca. These 2 P-ad-ca regions showed positive of NM. Interestingly, in the other one case, region of W-ad-ca showed positive of NM and negative of Rb. Region of P-ad-ca of the case showed positive of all three NM and Rb. From morphological appearance, this case was quite unlikely to true NEC.

Conclusion: In 74 P-ad-ca, 2 cases might be true NEC in our small evaluation. NEC might be contaminated in the P-ad-ca of CRC which is difficult to be distinguished by only pathological findings of HE staining.

Citation Format: Yuhan Rong, Yuma Takeda, Naoki Okubo, Akihiro Suzuki, Motohiko Tokuhisa, Noritoshi Kobayashi, Atsushi Ishibe, Ikuma Kato, Shoji Yamanaka, Satoshi Fujii, Itaru Endo, Yasushi Ichikawa. In colorectal cancer (CRC), neuroendocrine carcinoma (NEC) is contaminated in the cancer given a confirmed diagnosis of poorly differentiated adenocarcinoma (P-ad-ca) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5252.

Intratumoral density of regulatory T cells is a predictor of host immune response and chemotherapy response in colorectal cancer

Regulatory T cells (Tregs) are a subset of CD4+ T lymphocytes known to dampen the host immune response against cancer cells. Within the tumor microenvironment, Tregs are potent facilitators of immune tolerance, and a higher proportion of Tregs compared to cytotoxic T cells predicts a worse outcome in most solid tumors. We studied the association between Treg density, and cancer biology and clinical outcome in colorectal cancer (CRC). We used xCell to estimate intratumoral Tregs in total of 898 CRC patients in the Cancer Genome Atlas (TCGA) and GCE39582 cohorts. High-Treg CRCs enriched immune response-related gene sets; inflammatory response, IFN-γ and IFN-α response, IL2/IL6 signaling, and allograft rejection, and had significantly high infiltration of CD8, CD4, M1 and M2 macrophage, and dendritic cells in both cohorts. While high-Treg CRCs enriched multiple pro-cancer signaling pathways compared to low-Treg CRCs, such as Epithelial Mesenchymal Transition, K-ras, Hypoxia, TGF-β, TNF-α, and angiogenesis, Treg infiltration was surprisingly associated with earlier CRC stage in TCGA. Notably, in two separate cohorts a higher proportion of Tregs predicted an improved response to chemotherapy. In the GSE28702 cohort, metastatic CRCs with more Tregs showed a significantly better response to mFOLFOX6 versus low-Treg CRC metastases (88.9% response vs. 16.7%, P<0.001). In the GSE72970 cohort, high-Treg CRCs were found to have a 68.8% response to FOLFOX/FOLFIRI without bevacizumab, compared to 44% response in the low-Treg CRCs. Additionally, high-Treg CRCs were associated with increased expression of immune checkpoint molecules PD-L1/PD-L2, CTLA4, TIGIT and BTLA, implying susceptibility to immunotherapy. We also found that CRCs with higher proportions of Tregs were associated with lower amounts of three microorganisms in the tumor: Lachnoclostridium, flavivirus, and Ornithobacterium. In conclusion, we show that amount of Treg in the tumor is a predictor of host immune response and chemotherapy response in CRC.

Safety, efficacy, and operability of a newly developed absorbable adhesion barrier (GM142) in patients with primary rectal cancer scheduled for diverting ileostomy during laparoscopic surgery: Randomized controlled trial

Aim

The aim of this study was to compare the outcomes of GM142, a newly developed gelatin film with a concave and convex structure to a commercially available conventional film, hyaluronate‐carboxymethylcellulose.

Methods

Patients with primary rectal cancer who were scheduled for diverting ileostomy during laparoscopic surgery were eligible for this study. Patients were randomized before surgery and an antiadhesion film was applied under the umbilical incision. The primary outcome was the incidence of adhesion under the midline incision confirmed by second‐look surgery for diverting ileostomy closure. The secondary outcomes were the adhesion severity score, the extent of adhesion score, the presence of intestinal obstruction, and the success of all patching.

Results

A total of 146 patients were enrolled. A total of 123 patients were included in the full analysis set. The primary outcome of “no adhesion” was observed in 66.1% in the GM142 group and 55.7% in the conventional film group. The noninferiority of GM142 to conventional film was confirmed (P = .0005). The secondary outcomes were similar between the groups. For the safety evaluation, there were no safety concerns regarding allergic reactions to gelatin or increased gelatin‐specific IgE antibody titers.

Conclusions

The noninferiority of GM142 to conventional film was shown. GM142 showed no major safety issues. The clinical safety profiles of GM142 suggested certain physiological benefits of the gelatin film as an adhesion barrier.

Evaluating the Effect of Intraoperative Near-Infrared Observation on Anastomotic Leakage After Stapled Side-to-Side Anastomosis in Colon Cancer Surgery Using Propensity Score Matching

BACKGROUND

Recent studies have clarified that near-infrared observation using indocyanine green has the advantage of evaluating perfusion of the anastomotic site, especially in rectal cancer surgery, resulting in a reduction in anastomotic leak.

OBJECTIVE

The aim of this study was to evaluate the efficacy of near-infrared observation for reducing the anastomotic leak after stapled side-to-side anastomosis in colon cancer surgery.

DESIGN

This was a retrospective propensity score case-matched study.

SETTINGS

The study was conducted at 3 institutions in the Yokohama Clinical Oncology Group.

PATIENTS

From January 2011 to December 2019, patients who underwent colon cancer surgery with stapled side-to-side anastomosis were included.

MAIN OUTCOME MEASURES

The main outcome was the percentage of anastomotic leak within 30 days after surgery.

RESULTS

A total of 1034 patients were collected. There were 532 patients who underwent near-infrared observation and 502 who did not. A total of 370 patients were matched to the near-infrared and non-near-infrared groups. In the near-infrared group, 12 patients (3.2%) were judged to have poor perfusion (4 patients) and no perfusion (8 patients), so the planned transection point was changed. There were no cases of anastomotic leak among these 12 patients. The anastomotic leak rates were 3.5% (13/370) in the non-near-infrared group and 0.8% (3/370) in the near-infrared group. The anastomotic leak and reoperation rates were significantly lower in the near-infrared group than in the non-near-infrared group (OR, 0.224; 95% CI, 0.063-0.794, p = 0.001; OR, 0.348; 95% CI, 0.124-0.977, p = 0.036).

LIMITATIONS

Although we reduced selection bias by performing propensity score matching, this was a retrospective study and was not randomized.

CONCLUSION

This large-scale case-matched study showed that assessing perfusion by near-infrared observation significantly reduced the anastomotic leak and reoperation rates after stapled side-to-side anastomosis in colon cancer surgery and may be better suited to colo-colonic anastomosis. Video Abstract at http://links.lww.com/DCR/B513.Japanese Clinical Trials Registry: UMIN-CTR000039977.

EVALUACIN DEL EFECTO DE LA OBSERVACIN INTRAOPERATORIA CON INFRARROJO CERCANO SOBRE LA FUGA ANASTOMTICA DESPUS DE UNA ANASTOMOSIS LATEROLATERAL CON ENGRAPADORA EN LA CIRUGA DE CNCER DE COLON MEDIANTE EL EMPAREJAMIENTO POR PUNTAJES DE PROPENSIN

ANTECEDENTES:Estudios recientes han aclarado que la observación con infrarrojo cercano con verde de indocianina tiene la ventaja de evaluar la perfusión del sitio anastomótico, especialmente en la cirugía de cáncer de recto, lo que resulta en una reducción de la fuga anastomótica.OBJETIVO:El objetivo de este estudio fue evaluar la eficacia de la observación con infrarrojo cercano para reducir la fuga anastomótica después de una anastomosis latero-lateral con engrapadora en la cirugía de cáncer de colon.DISEÑO:Este fue un estudio retrospectivo emparejado con puntaje de propensión.AJUSTE:El estudio se llevó a cabo en tres instituciones del Grupo de Oncología Clínica de Yokohama.PACIENTES:Desde enero de 2011 hasta diciembre de 2019, se incluyeron pacientes que se sometieron a cirugía de cáncer de colon con anastomosis latero-lateral con engrapadora.PRINCIPALES MEDIDAS DE RESULTADO:El resultado principal fue el porcentaje de fuga anastomótica dentro de los 30 días posteriores a la cirugía.RESULTADOS:Se recogió un total de 1034 pacientes. Hubo 532 pacientes que se sometieron a observación con infrarrojo cercano y 502 que no. Un total de 370 pacientes fueron emparejados con los grupos de infrarrojo cercano y no infrarrojo cercano. En el grupo de infrarrojo cercano, se consideró que 12 casos (3,2%) tenían mala perfusión (4 casos) y ninguna perfusión (8 casos), por lo que se cambió el punto de transección planificado. No hubo casos de fuga anastomótica entre estos 12 casos. Las tasas de fuga anastomótica fueron del 3,5% (13/370) en el grupo sin infrarrojo cercano y del 0,8% (3/370) en el grupo con infrarrojo cercano. Las tasas de fuga anastomótica y de reintervención fueron significativamente menores en el grupo con infrarrojo cercano que en el grupo sin infrarrojo cercano (razón de posibilidades 0,224, intervalo de confianza del 95% 0,063-0,794, p = 0,001; razón de posibilidades 0,348, intervalo de confianza del 95% 0,124 -0,977, p = 0,036, respectivamente).LIMITACIONES:Aunque se redujo el sesgo de selección al realizar el emparejamiento por puntaje de propensión, este fue un estudio retrospectivo y no fue aleatorio.CONCLUSIÓN:Este estudio de casos emparejados a gran escala demostró que la evaluación de la perfusión mediante la observación con infrarrojo cercano redujo significativamente la fuga anastomótica y las tasas de reintervención después de la anastomosis latero-lateral con engrapadora en la cirugía de cáncer de colon y puede ser más adecuada para la anastomosis colo-colónica. Consulte Video Resumen en http://links.lww.com/DCR/B513.Registro japonés de ensayos clínicos: UMIN-CTR000039977.

[Nutritional Status after Laparoscopic-Assisted Pylorus-Preserving Gastrectomy]

PATIENTS AND METHODS

Patients with gastric cancer who underwent laparoscopic-assisted pylorus-preserving gastrectomy (LAPPG group)or laparoscopic-assisted distal gastrectomy(LADG group)between January 2010 and December 2019 were reviewed and their postoperative nutritional status and long-term outcomes retrospectively evaluated.

RESULTS

In total, 83 patients(LAPPG group, n=23; LADG group, n=60)were included. Weight loss rates 1, 6, 12, and 24 months postoperatively in the LAPPG and LADG groups were 5.7% and 7.1%, 6.6% and 9.6%, 5.8% and 10.1%, and 5.2% and 8.7%, respectively. The LADG group exhibited a significantly higher weight loss than the LAPPG group at 6, 12, and 24 months (p=0.007, 0.002, and 0.022, respectively). No recurrence was observed in either group within 5 years of surgery. The 5- year overall survival rate of patients with pathological Stage Ⅰ cancer( LAPPG group, n=23, LADG group, n=51) was higher in the LAPPG group than in the LADG group(100% vs 82.9%, p=0.027). There were 6 cases of death from other diseases in the LADG group(pneumonia, n=2, other cancer, n=2, postoperative bleeding, n=1, and heart failure, n=1)but none in the LAPPG group.

CONCLUSION

The weight loss after LAPPG was significantly lower than that after LADG. Furthermore, the former showed a good prognosis without death from other diseases, such as pneumonia.

Sulphur metabolism in colon cancer tissues: a case report and literature review

Sulphur-containing compounds have been linked to colorectal cancer by factors such as the presence of methyl mercaptan in intestinal gas and long-term dietary intake associated with sulphur-metabolizing microbiota. Therefore, this current case report hypothesized that active sulphur metabolism in colorectal cancer results in the formation of sulphur compounds in the intestine and, thus, examined sulphur metabolites possibly associated with sulphur respiration in colon cancer tissues. The patient was a 73-year-old female that underwent laparoscopic right hemicolectomy for ascending colon cancer. During the surgery, colon cancer tissues and normal intestinal mucosa samples were collected. After optimizing the sample concentrations for homogenization (pre-treatment), the samples were stabilized using a hydroxyphenyl-containing derivative and the relevant metabolites were quantified using liquid chromatography with tandem mass spectrometry. The results showed that cysteine persulfide and cysteine trisulfide levels were higher in colon cancer tissues than in normal mucosal tissues. Thus, sulphur metabolism, possibly sulphur respiration, is enhanced in colon cancer tissues.

Pathological Changes in the Lymphatic System of Patients with Secondary Lower Limb Lymphedema Based on Single Photon-Emission Computed Tomography/Computed Tomography/Lymphoscintigraphy Images

Background:

In patients with secondary upper limb lymphedema, positive correlations have been observed between the dermal back flow (DBF) type and visualization of lymph nodes around the clavicle, between the former and the lymph flow pathway type, and between the latter and the visualization of lymph nodes around the clavicle when using single photon-emission computed tomography/computed tomography/lymphoscintigraphy (SPECT-CT LSG).

Methods and Results:

We analyzed the associations between the visualization of inguinal lymph nodes, the lymph flow pathway type, and the DBF type using SPECT-CT LSG in 81 patients with unilateral secondary lower limb lymphedema by statistical analysis using Fisher's exact test. We revealed that the lymph flow pathways in the lower limb can be classified into nine types because the type in the lower leg is not always equal to the type in the thigh. Associations were observed between the visualization of inguinal lymph nodes and types of DBF (p < 0.01), between the types of lymph flow pathway in the thighs and visualization of the inguinal lymph nodes (p = 0.02), and between the lymph flow pathway types in the thighs and lower legs (p < 0.01).

Conclusion:

Detriment to the superficial lymph flow pathways in the lower limb appears to usually start from the proximal side, and deep pathways are considered to become dominant from a compensatory perspective as lymphedema severity increases.

Preoperative risk factors of incisional surgical site infection in severe or intractable ulcerative colitis

PURPOSE

The present study explored preoperative risk factors (predictors) of incisional surgical site infection (I-SSI) in severe or intractable ulcerative colitis (UC).

METHODS

This was a retrospective study of 230 consecutive patients who underwent primary surgery for UC. Patients whose surgical indications were UC with cancer or dysplasia were excluded. SSI was defined as an infection according to the Centers for Disease Control and Prevention Guidelines. Preoperative variables were examined by univariate, receiver operating characteristic curve, and multivariate analyses.

RESULTS

We analyzed 208 patients in this study. In a multivariate logistic analysis, C-reactive protein (CRP) ≥ 1.7 mg/dl [odds ratio (OR) 5.35; 95% confidence interval (CI) 1.50-19.06; p = 0.01), albumin ≤ 2.4 g/dl (OR 5.77; 95% CI 1.41-23.57; p = 0.02), and preoperative blood transfusion (OR 3.21; 95% CI 1.04-9.96; p = 0.04) were predictors of I-SSI. Patients with all predictors had a more than 50% incidence of I-SSI, a higher incidence of all severe complications (13.6% vs. 3.2%; p = 0.02), and a longer postoperative hospital stay (19.5 vs. 17.0 days, p = 0.04) than the other patients.

CONCLUSIONS

CRP ≥ 1.7 mg/dl, albumin ≤ 2.4 g/dl, and transfusion are predictors of I-SSI in severe or intractable UC. Clinician should carefully evaluate the surgical options before these predictors appear.

Relationship between stromal regulatory T cells and the response to neoadjuvant chemotherapy for locally advanced rectal cancer

BACKGROUND

In addition to the direct power of anticancer drugs, the effectiveness of anticancer therapy depends on the host immune function. The present study investigated whether or not the reduction rate and histological response of preoperative chemotherapy were related to the immune microenvironment surrounding a primary tumor of the rectum.

METHODS

Sixty-five patients received preoperative chemotherapy followed by resection from 2012 to 2014; all of these patients were retrospectively analyzed. CD3, CD8, and FoxP3 were immunohistochemically examined as markers for T lymphocytes, cytotoxic T lymphocytes, and regulatory T lymphocytes (Treg), respectively. The correlation between the tumor-infiltrating lymphocyte composition and the tumor reduction rate and histological response to neoadjuvant chemotherapy was investigated.

RESULTS

The average tumor reduction rate was 41.5% ± 18.8%. According to RECIST, 47 patients (72.3%) achieved a partial response (PR), and 1 patient (1.5%) achieved a complete response (CR). Eight patients (12.3%) showed a grade 2 histological response, and 2 (3.1%) showed a grade 3 response. A multivariate analysis demonstrated that a low Treg infiltration in stromal cell areas was significantly associated with the achievement of a PR or CR [odds ratio (OR) 7.69; 95% confidence interval (CI) 1.96-33.33; p < 0.01] and a histological grade 2 or 3 response (OR 11.11; 95% CI 1.37-98.04; p = 0.02).

CONCLUSION

A low Treg infiltration in the stromal cell areas may be a marker of a good response to neoadjuvant chemotherapy in patients with locally advanced rectal cancer.

A multicenter, propensity score-matched cohort study about short-term and long-term outcomes after laparoscopic versus open surgery for locally advanced rectal cancer

PURPOSE

This study evaluated the results of laparoscopic surgery (LAP) compared to open surgery (OP) for locally advanced mid-to-lower rectal cancer.

METHODS

From February 2008 to December 2014, we collected patient data with clinical stage II/III mid-to-lower rectal cancer who underwent resection with LAP or OP at 13 institutions associated with the Yokohama Clinical Oncology Group (YCOG). The short-term outcomes and long-term prognoses associated with LAP and OP were analyzed after adjusting for the patients' backgrounds using propensity score matching.

RESULTS

Among 1091 eligible cases, a propensity score matching with six covariates-age, sex, body mass index, American Society of Anesthesiologists physical status category, tumor location, and clinical stage-extracted 237 cases each for the LAP and OP groups, respectively. After matching, there were no differences in background factors between the two groups except for the presence or absence of preoperative treatment. Operative time was significantly longer in the LAP group than that in the OP group (p < 0.001), while the amount of bleeding and the length of postoperative hospital stay were significantly lower in the LAP group than that in the OP group (p < 0.001 and p = 0.001, respectively). There were no significant differences between groups in the incidence of postoperative complications. The 3-year overall survival and relapse-free survival rates were 90.5% and 88.6% and 78.3% and 71.6% in the LAP and OP groups, respectively, which did not differ significantly.

CONCLUSIONS

The short-term outcomes and long-term prognoses of LAP in this cohort study indicated that LAP could be a therapeutic option for locally advanced rectal cancer.

TRIAL REGISTRATION

UMIN000040406.

Identification of Patients with Locally Advanced Rectal Cancer in Whom Preoperative Radiotherapy Can Be Omitted: A Multicenter Retrospective Study at Yokohama Clinical Oncology Group (YCOG1307)

Objectives:

The present study aimed to identify patients with locally advanced rectal cancer in whom preoperative radiotherapy (RT) can be omitted.

Methods:

This study was a retrospective multi-institutional study for patients with pathological stage II and III rectal cancer who underwent surgery without preoperative therapy between January 2008 and December 2012. Clinicopathological factors were examined by univariate and multivariate analyses to clarify independent risk factors of local recurrence (LR).

Results:

The 5-year cumulative local recurrence rate (LRR) of 815 patients was 11.2%. Independent predictive factors of LR were determined by a multivariate analysis to be a tumor location of <10 cm from the anal verge, a tumor diameter of ≥50 mm, undifferentiated histological type, and advanced T-N substage (T3N+ or T4Nany). In lower rectal cancer located <10 cm from the anal verge (n = 510), the 5-year cumulative LRR of patients without any remaining three factors was 4.4%, with one factor was 13.0%, with two factors was 22.2%, and with all three factors was 41.6%.

Conclusions:

Preoperative RT may be omitted in patients with lower rectal cancer with no risk factors. However, in addition to the present risk factors, we need to further examine the extramural vascular invasion (EMVI) status and circumferential resection margin (CRM) using magnetic resonance imaging (MRI) findings.

The trial was registered with UMIN Clinical Trails Registry, number 000006039.

Five-millimeter Trocar Site Hernia with a Parastomal Hernia Sac: A Case Report

Here, we report our experience with a 5-mm trocar site hernia (TSH) near a stoma. This is the first report describing the relationship between TSH and extraperitoneal colostomy. A 72-year-old man underwent laparoscopic abdominoperineal resection with extraperitoneal sigmoid colostomy and partial hepatectomy for rectal cancer accompanied by synchronous liver metastasis (pT3N1aM1a Stage IVA Union for International Cancer Control [UICC] 8th edition). The surgical procedures were completely performed without morbidity. After 1 year, he presented to our hospital with sudden nausea. Computed tomography (CT) revealed small bowel obstruction due to a 5-mm TSH, 1 cm from the stoma. The patient underwent laparoscopic hernia repair. The incidence of a 5-mm TSH is low. However, an abdominal wall vulnerability caused by the extensive exfoliation of the retroperitoneum due to the construction of the colostomy was observed, and the extraperitoneal colostomy influenced the onset of the 5-mm TSH. When the port and hernia sites are located in close proximity to each other, even a 5-mm trocar site may increase the incidence of TSH.

The histopathological evaluation based on the indocyanine green fluorescence imaging of regional lymph node metastasis of splenic flexural colon cancer by near-infrared observation

PURPOSE

The purpose of this study was to investigate the relationship between the fluorescence on indocyanine green fluorescent imaging (ICG-FI) and the histopathological findings of regional lymph node (LN) metastasis of splenic flexural colon cancer.

METHODS

From July 2013 to December 2018, consecutive patients with splenic flexural colon cancer with a preoperative diagnosis of N0 who underwent laparoscopic surgery were enrolled. The distribution of cancer sites in metastatic LNs (completely/not completely occupied by metastatic foci) was evaluated with hematoxylin and eosin-stained preparations. We compared the relationship between the distribution of cancer site and fluorescence of paraffin block in metastatic LNs.

RESULTS

Seventy-two patients were enrolled, of whom 13 (18.1%) had metastatic LNs. A total of 25 metastatic LNs were evaluated. The median short axis of the occupied LNs was 4.5 mm, which was significantly larger than that of the non-occupied LNs (3.0 mm; p = 0.036). In the near-infrared observation of the paraffin block, the completely occupied LNs showed no fluorescence, regardless of the LN size, but 8 of 10 non-occupied LNs showed fluorescence (p < 0.001). Even the non-occupied LNs that showed fluorescence, the cancer site did not show fluorescence.

CONCLUSIONS

The occupied LNs showed no fluorescence, but 80% of the non-occupied LNs showed fluorescence. Even in non-occupied LNs that showed fluorescence, the cancer site did not show fluorescence. This demonstrated LN dissection should not be omitted, even if no fluorescence is noted on intraoperative ICG-FI.

Impact of subdivision of pathological stage I colorectal cancer

AIM

Stage II-IV colorectal cancers are subdivided according to TNM categories. However, stage I cases are a single category, despite the inclusion of both T1 and T2 cases, which may have different outcomes. The aim of this study was to evaluate the usefulness of subdividing stage I colorectal cancers by T category.

METHODS

From 1984 to 2015, 844 patients with stage I colorectal cancer (T1: 446, T2: 398) underwent colorectal resection with lymph node dissection at three hospitals. The long-term survival and recurrence rates were compared between T1 and T2. A Cox regression analysis was used to evaluate the risk factors associated with cancer recurrence.

RESULTS

A comparison of the T1 and T2 groups revealed significant differences in 5-year overall (95.9% vs 91.4%, P = .008), recurrence-free (94.8% vs 87.1%, P = .0007), and cancer-specific survival (97.6% vs 93.6%, P = .004), and in the overall (2.5% vs 6.8%, P = .003), local (0.2% vs 1.5%, P = .04), and lymph node recurrence rates (0.2% vs 1.5%, P = .04). All local and lymph node recurrences were associated with lower rectal cancer, and this difference was significant. The Cox multivariate analysis identified male sex (P = .01, hazard ratio: 4.00, 95% confidence interval: 1.38-11.55), T2 (P = .02, hazard ratio: 2.98, 95% confidence interval: 1.17-7.60), and venous invasion (P = .03, hazard ratio: 2.38, 95% confidence interval: 1.12-5.10) as risk factors for recurrence.

CONCLUSIONS

The subdivision of stage I colorectal cancer according to T category clearly reflected the long-term outcomes.

The incidence, risk factors, and new prediction score for fluorescence abnormalities of near-infrared imaging using indocyanine green in laparoscopic low anterior resection for rectal cancer

PURPOSE

Several studies have reported the efficacy of near-infrared imaging using indocyanine green in laparoscopic low anterior resection (LAR), but a detailed examination of its fluorescence abnormalities is still insufficient. The purpose of this study was to clarify the incidence of fluorescence abnormalities and to create a new prediction score in laparoscopic LAR.

METHODS

This was a retrospective, multicenter study that included patients with rectal cancer who underwent laparoscopic LAR from September 2014 to November 2018.

RESULTS

A total of 336 patients were included. The transection line was changed due to fluorescence abnormalities in 5.4% (18/336) of cases, and the median length of additional resection was 70 mm. Anastomotic leakage of Clavien-Dindo grade ≥ II occurred in 6.0% (20/336). The gender and the intraoperative pre-planned proximal margin (IpPM) were significant factors for fluorescence abnormalities. We devised the fluorescence abnormality prediction score (FAPS) derived from the gender, IpPM, and tumor height from the anal verge (TumorAV). The area under the curve of the FAPS was 0.784 (95% CI: 0.677-0.891). When the cutoff was 4, the sensitivity was 0.833, and the specificity was 0.626. The preoperative pre-planned proximal margin (PpPM) was calculated as follows: PpPM (mm) = 189 (mm) - TumorAV (mm) + 61 × Male (1/0). The proximal margin should be set to be larger than the PpPM to avoid fluorescence abnormalities.

CONCLUSION

The incidence of fluorescence abnormalities in laparoscopic LAR was 5.4%. If the FAPS is used, the PpPM may be set from the viewpoint of the blood perfusion.

TRIAL REGISTRATION

Japanese Clinical Trials Registry: UMIN000032654 ( http://www.umin.ac.jp/ctr/index.htm ).

A novel discriminant formula for the prompt diagnosis of strangulated bowel obstruction

PURPOSES

The diagnosis of strangulated bowel obstruction (SBO) is sometimes difficult. We attempted to create and verify a discriminant formula for use as a diagnostic aid for the early diagnosis of SBO.

METHODS

This retrospective study included 97 patients who underwent an operation for SBO from January 2007 to September 2018. First, a discriminant analysis was performed for 73 patients who underwent an operation from January 2007 to December 2015 in order to obtain a formula. Next, we analyzed 34 patients who underwent an operation from January 2016 to September 2018 to verify the formula.

RESULTS

The risk factors for SBO included ascites, signs of preperitoneal irritation, and lactate > 1.16 mmol/L. The discriminant formula is as follows: 1.954 × collection of ascites (1 or 0) + 1.239 × peritoneal irritation sign (1 or 0) + 0.378 × lactate - 2.331 (1: positive, 0: negative). The predictive value was as follows: sensitivity, 87.5%; specificity, 64.7%; and predictive accuracy, 73.5%. In patients who presented within 24 h of the onset, the sensitivity was 92.3%, the specificity was 75.0%, and the predictive accuracy was 85.7%.

CONCLUSION

Our discriminant formula seems useful for the rapid diagnosis of SBO.

Comparison of the continuation and discontinuation of perioperative antiplatelet therapy in laparoscopic surgery for colorectal cancer: A retrospective, multicenter, observational study (YCOG 1603)

AIM

The present study aimed to examine the effect of continuing antiplatelet therapy in the perioperative period for patients undergoing laparoscopic resection for colorectal cancer who had received preoperative antiplatelet therapy.

METHODS

This retrospective, multicenter, observational study included patients who underwent laparoscopic surgery for colorectal cancer between January 2011 and May 2020. The study population was limited to patients who used antiplatelet therapy preoperatively.

RESULTS

A total of 214 colorectal cancer patients who received antiplatelet therapy preoperatively were included in the present study. Eighty-nine patients underwent surgery under the continuation of antiplatelet therapy, and 125 patients underwent surgery under the discontinuation of antiplatelet therapy before surgery. There were no significant differences between the two groups with regard to intraoperative blood loss (P = .889), intraoperative blood transfusion (P = 1.000), and conversion to laparotomy (P = 1.000). There were no significant differences between the two groups in the incidence of postoperative hemorrhagic complications (Clavien-Dindo Grade ≥II, P = .453; Grade ≥III, P = .572) or three-point major adverse cardiovascular events (P = .268). However, there were two cases of postoperative non-fatal stroke in the discontinued antiplatelet therapy group.

CONCLUSIONS

The present study revealed that there were no significant differences in the surgical outcomes and postoperative complications between colorectal cancer patients who underwent laparoscopic resection with the continuation of antiplatelet therapy in the perioperative period and those in whom antiplatelet therapy was discontinued during the perioperative period. From the viewpoint of cardiovascular and cerebrovascular risk, it may be better for patients undergoing laparoscopic surgery for colorectal cancer to continue antiplatelet therapy. This study was registered with the Japanese Clinical Trials Registry as UMIN000038707 (http://www.umin.ac.jp/ctr/index.htm).

Multilayered Human Skeletal Muscle Myoblast Sheets Promote the Healing Process After Colonic Anastomosis in Rats

Colorectal anastomotic leakage is one of the most feared and fatal complications of colorectal surgery. To date, no external coating material that can prevent anastomotic leakage has been developed. As myoblasts possess anti-inflammatory capacity and improve wound healing, we developed a multilayered human skeletal muscle myoblast (HSMM) sheet by periodic exposure to supraphysiological hydrostatic pressure during repeated cell seeding. We assessed whether the application of an HSMM sheet can promote the healing process after colonic anastomosis. Partial colectomy and insufficient suturing were employed to create a high-risk colo-colonic anastomosis model in 60 nude rats. Rats were divided into a control group (n = 30) and an HSMM sheet group (n = 30). Macroscopic findings, anastomotic bursting pressure, and histology at the colonic anastomotic site were evaluated on postoperative day (POD) 3, 5, 7, 14, and 28. The application of an HSMM sheet significantly suppressed abscess formation at the anastomotic site compared to the control group on POD3 and 5. The anastomotic bursting pressure in the HSMM sheet group was higher than that in the control group on POD3 and 5. Inflammatory cell infiltration in the HSMM sheet group was significantly suppressed compared to that in the control group throughout the time course. Collagen deposition in the HSMM sheet group on POD3 was significantly abundant compared to that in the control group. Regeneration of the mucosa at the colonic anastomotic site was promoted in the HSMM sheet group compared to that in the control group on POD14 and 28. Immunohistochemical analysis demonstrated that surviving cells in the HSMM sheet gradually decreased with postoperative time and none were detected on POD14. These results suggest that the application of a multilayered HSMM sheet may prevent postoperative colonic anastomotic leakage.

Uselessness of Serum p53 Antibody for Detecting Colitis-associated Cancer in the Era of Immunosuppressive Therapy

BACKGROUND/AIM

The present study examined the utility of serum p53 antibody (Ab) for detecting colitis-associated cancer (CAC) in the era of immunosuppressive therapy.

PATIENTS AND METHODS

Two hundred and fifty patients were analyzed, 219 had no carcinoma or dysplasia (Group non-CAC), and 31 had carcinoma or dysplasia (Group CAC). Serum p53 Abs were detected with an enzyme-linked immunosorbent assay. Immunohistochemical detection was performed in Group CAC.

RESULTS

Immunosuppressive therapy was performed in 98.1% of Group non-CAC and 80.6% of Group CAC. There were no differences in serum p53 Abs positivity between Groups non-CAC and CAC (8.7% vs. 3.2%, p=0.30). p53 staining positivity was noted in 90.3% of Group CAC, and the rate of serum p53 positivity was significantly lower in patients with immunosuppressive therapy than in those without in Group CAC (0.0% vs. 16.7%, p=0.04).

CONCLUSION

The utility of serum p53 Ab for detecting CAC is dubious in the era of immunosuppressive therapy.

Incidence and risk factors for fluorescence abnormalities on near-infrared imaging using indocyanine green in stapled functional end-to-end anastomosis in laparoscopic colectomy

PURPOSE

Recently, several studies have suggested that near-infrared (NIR) imaging using indocyanine green (ICG) may contribute to the reduction of anastomotic leakage (AL) after colorectal cancer (CRC) surgery. However, few reports have focused on the usefulness of NIR imaging for AL after stapled functional end-to-end anastomosis (stapled FEEA). The purpose of this study was to clarify the frequency of fluorescence abnormalities on NIR imaging, in cases reconstructed with stapled FEEA.

METHODS

This retrospective study included patients with colon or appendiceal cancer who underwent laparoscopic colectomy with stapled FEEA reconstruction between March 2016 and August 2019.

RESULTS

A total of 400 patients who were managed at our three institutions were included in the present study. The rate of Clavien-Dindo (CD) grade > III AL was 1.0% (4/400). The median length of postoperative hospital stay was 7 days (IQR 25-75th percentile 6-8 days). In 11 patients (2.8%), the transection line was changed by NIR imaging, due to fluorescence abnormalities. The rate of transverse colon involvement in anastomosis was significantly higher in cases with fluorescence abnormalities than in cases with normal fluorescence (p = 0.035).

CONCLUSIONS

The frequency of fluorescence abnormalities on NIR was 2.8% in cases of colon resection with reconstruction by using stapled FEEA. There was a probability of abnormal fluorescence on NIR in cases where the transverse colon was involved in the anastomosis. This means that NIR may have potential benefit in such cases.

TRIAL REGISTRATION

UMIN000039977.

The comparison of health-related quality of life and patient satisfaction between single-incision and multiport laparoscopic colectomy for cancer: A sub-study of a randomized, prospective clinical trial

AIM

The present study clarified the effect on the health-related quality of life and patient satisfaction of single-incision laparoscopic colectomy compared with multiport laparoscopic colectomy for colorectal cancer.

METHODS

We conducted a multicenter, randomized, control trial comparing single-incision and multiport laparoscopic colectomy for colon cancer. We performed a pre-planned secondary analysis of health-related quality of life and patient satisfaction data of 200 patients. Health-related quality of life was evaluated using the Japanese 36-item Short Form Health Survey (SF-36) version 2.0 before surgery and at 1 month after surgery. Patient satisfaction was compared using seven questionnaires at 1 month after surgery.

RESULTS

One hundred patients were assigned to each group. After excluding 18 patients (9.0%) who did not complete the SF-36, 182 patients (91.0%) were included in the analysis (92 cases of single-incision laparoscopic colectomy and 90 cases of multiport laparoscopic colectomy). The SF-36 scores at 1 month after surgery were not significantly different between the two arms. The role physical, bodily pain, vitality and physical component summary were significantly lower at 1 month after surgery than before in both groups. However, the role emotional was significantly lower after surgery than before only in the single-incision laparoscopic colectomy group. In terms of patient satisfaction at 1 month after surgery, there were no significant differences in any of the seven items on the questionnaire.

CONCLUSIONS

Single-incision laparoscopic colectomy was similar to multiport laparoscopic colectomy in terms of health-related quality of life and patient satisfaction. However, single-incision laparoscopic colectomy may be inferior than multiport laparoscopic colectomy in terms of the role emotional.

Optimal extent of central lymphadenectomy for right-sided colon cancers: is lymphadenectomy beyond the superior mesenteric vein meaningful?

PURPOSE

The objective of the current study was to assess the therapeutic benefit of lymphadenectomy according to the extent of lymphadenectomy.

METHODS

Patients undergoing colectomy for right-sided colon cancer were identified. Distribution of lymph node metastases (DLNM) of 1, 2 and 3 were defined as lymph node metastasis (LNM) in the pericolic nodes, the intermediate nodes and the front of the SMV near the origin of the major artery, respectively. The therapeutic index (TI) was calculated based on the frequency of LNM and the 5 year overall survival (OS) rate of patients with LNM.

RESULTS

Among 344 patients who met the inclusion criteria, roughly half had LNM (n = 150, 43.7%). While 107 (31.1%) and 30 (8.7%) patients had DLNM1 and DLNM2, respectively, only 13 patients (3.8%) were defined as DLNM3. However, there was no significant difference in 5 year OS by DLNM (DLNM1 71.1%, DLNM2 78.7%, DLNM3 50.4%, p = 0.61). Overall, the TI of lymphadenectomy for D3 area was approximately 1/10 of the TI for D1 (1.9 vs.22.1), given the low frequency of LNM (3.8%) and poor 5 year OS of patients with LNM (50.4%). This trend was consistent irrespective of primary tumor locations.

CONCLUSION

The survival benefit from central lymphadenectomy namely D3 was low among patients with right-sided colon cancers.

Hernia incidence following a randomized clinical trial of single-incision versus multi-port laparoscopic colectomy

BACKGROUND

The short-term results of single-incision laparoscopic colectomy (SILC) showed the safety, feasibility, and effectiveness when performed by skilled laparoscopic surgeons. However, the long-term complications, such as SILC-associated incisional hernia, have not been evaluated. The aim of this study was to determine the incidence of incisional hernia after SILC compared with multi-port laparoscopic colectomy (MPC) for colon cancer.

METHODS

From March 2012, to March 2015, a total of 200 patients were enrolled in this study. The patients were randomized to the MPC arm and SILC arm. A total of 200 patients (MPC arm; 100 patients, SILC arm; 100 patients) were therefore analyzed. In all cases the specimen was extracted through the umbilical port, which was extended according to the size of the specimen. A diagnosis of incisional hernia was made either based on a physical examination or computed tomography.

RESULTS

The baseline factors were well balanced between the arms. The median follow-up period was 42.4 (range 9.4-70.0) months. Twenty-one patients were diagnosed with incisional hernia, giving an incidence rate of 12.1% in the MPC arm and 9.0% in the SILC arm at 36 months (P = 0.451). In the multivariate analysis, the body mass index (≥ 25 kg/m²) (hazard ratio [HR] 3.03; 95% confidence interval [CI] 1.03-8.92; P = 0.044), umbilical incision (≥ 5.0 cm) (HR 3.22; 95% CI 1.16-8.93; P = 0.025), and history of umbilical hernia (HR 3.16; 95% CI 1.02-9.77; P = 0.045) were shown to be correlated with incisional hernia.

CONCLUSIONS

We found no significant difference in the incidence of incisional hernia after SILC arm versus MPC arm with a long-term follow-up. However, this result may be biased because all specimens were harvested through the umbilical port. The study was registered with the Japanese Clinical Trials Registry as UMIN000007220.

The effect of TJ-28 (Eppikajutsuto) on the prevention of hand-foot syndrome using Capecitabine for colorectal cancer: The Yokohama Clinical Oncology Group Study (YCOG1102)

BACKGROUND

Eppikajututo (TJ-28, a Kampo medicine) is effective against rheumatoid arthritis and eczema. We conducted a randomized comparative trial to assess the efficacy of TJ-28 for preventing hand-foot syndrome (HFS) as a complication of adjuvant chemotherapy using capecitabine.

METHODS

The present study was a multi-institutional randomized-controlled trial (UMIN000005899). Colorectal cancer patients scheduled to receive capecitabine chemotherapy as adjuvant therapy were randomly assigned to receive TJ-28 (7500 mg/day) or oral pyridoxine (60 mg/day). Patients were monitored for the development of grade ≥ 2 HFS according to the National Cancer Institute Common Toxicity Criteria until chemotherapy completion.

RESULTS

Twenty-two patients were enrolled in this study. The relative dose intensity of capecitabine was 76.2% in the TJ-28 group and 68.2% in the pyridoxine group. Grade ≥ 2 HFS developed in 6 (50.0%) of 12 TJ-28 patients and in 4 (40.0%) of 10 pyridoxine patients. Chemotherapy treatment failure was observed in seven patients, mainly due to HFS, liver dysfunction, diarrhea, and neutropenia. Chemotherapy treatment failure due to HFS occurred in none of the TJ-28 group and 2 patients (20.0%) in the pyridoxine group (p = 0.114).

CONCLUSION

Capecitabine-associated HFS was not markedly prevented by TJ-28 compared with pyridoxine. However, TJ-28 might support the continuation of chemotherapy with capecitabine. Further studies are warranted to clarify the benefits of TJ-28.

Randomized controlled trial to evaluate laparoscopic versus open surgery in transverse and descending colon cancer patients

BACKGROUND

The safety and efficacy of laparoscopic surgery for transverse and descending colon cancer remain controversial. This study aimed to evaluate the short- and long-term outcomes of this procedure.

METHODS

We conducted a single-institutional randomized controlled trial. Patients with transverse or descending colon cancer were randomly allocated to receive laparoscopic surgery (LAC) or conventional open surgery (OC). The primary endpoint was the overall complication rate between the two groups. The secondary endpoints were the length of the postoperative hospital stay, the health-related quality of life (HRQOL) score (at 1, 6, and 12 months after surgery), the 5-year relapse-free survival (RFS), and the 5-year overall survival (OS).

RESULTS

Between August 2008 and October 2012, a total of 66 patients were enrolled (33 in the LAC group and 33 in the OC group). The patient characteristics showed no significant differences between the two groups. The complication rates (≥ grade 3) were 6.1% in the LAC group and 12.1% in the OC group (p = 0.392). The length of postoperative stay was not significantly different between the two groups. Regarding the HRQOL, the physical functioning, role physical, bodily pain, social functioning, mental health, and role component summary at 1 month after surgery and the social functioning and mental health at 6 months after surgery were better in the LAC group than in the OC group. The 5-year RFS and OS rates were similar between the LAC and OC groups (RFS 90.5% and 87.3%, respectively, p = 0.752; OS 93.3% and 100.0%, respectively, p = 0.543).

CONCLUSIONS

The short- and long-term outcomes of laparoscopic surgery for transverse and descending colon cancer are almost equal to those of open surgery. Laparoscopic resection is a better choice than open surgery for managing this cancer with regard to the short- and mid-term QOL.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01861691 .

Clinical analysis of preoperative deep vein thrombosis risk factors in patients with colorectal cancer: Retrospective observational study

AIM

Deep vein thrombosis (DVT) is a major complication of cancer. The postoperative prevalence of DVT in colorectal cancer (CRC) surgery is high, but the preoperative prevalence and the risk factors have not been clarified in detail. The objective of this retrospective study was to investigate the preoperative prevalence and risk factors of DVT in patients admitted to hospital for CRC surgery.

METHODS

From January 2013 to March 2017, 1006 patients admitted for CRC surgery were deemed eligible for this retrospective study. Diagnosis of preoperative DVT was confirmed by compression ultrasonography. Prevalence of silent DVT in lower limbs in patients before CRC surgery was assessed, and the risk factors for preoperative DVT were investigated regarding the correlation of DVT with the patient's background.

RESULTS

Preoperative DVT and asymptomatic pulmonary thromboembolism were diagnosed in 136 (13.5%) and in 10 (1.0%) of 1006 patients overall, respectively. Multivariate analysis showed that increased age (≥75 years), female gender, and an elevated d-dimer level (>1.0 μg/mL) were independent risk factors for preoperative DVT in this study. Notably, the prevalence of preoperative DVT exceeded 50% in patients with all three predictors.

CONCLUSIONS

A high prevalence (13.5%) of preoperative DVT was found in patients admitted to the hospital for CRC surgery. The present results suggest that instrumental screening should be encouraged, at least in subgroups at a higher risk of preoperative DVT.

Long-term outcome and prognostic factors for patients with para-aortic lymph node dissection in left-sided colorectal cancer

BACKGROUND

Para-aortic lymph node (PALN) metastasis of colorectal cancer is rare, and the treatment strategy for PALN metastasis (PALNM) is not established in contrast to liver or lung metastases. We sought to evaluate the survival outcomes and prognostic factors among patients undergoing surgery combined with extended lymphadenectomy for PALNM from left-sided colorectal cancer.

METHODS

From 1992 to 2012, 322 patients who underwent PALN dissection (PALND) synchronously with primary resection, among 1819 left-sided colorectal surgical cases, were retrospectively examined. We investigated the overall survival (OS) and prognostic factors for patients with PALNM.

RESULTS

Of the 322 patients, 62 (19.3%) were histologically confirmed to have PALNM. The 5-year OS in patients with and without PALNM was 19.5% and 67.0% (p < 0.001), respectively. Among patients with PALNM, on the multivariable analysis, the positive resection margin (hazard ratio (HR) 3.61; 95% confidence interval (CI) 1.85-7.06), undifferentiated histological type ((por/muc/sig), HR 4.51; 95% CI, 2.22-9.19), ≥ 4 PALNMs (HR 3.34; 95% CI 1.53-7.31), and preoperative CEA ≥ 10 ng/mL (HR 2.1; 95% CI 1.11-4.27) were significant prognostic factors. Among R0 resected cases, the 5-year OS of the 17 cases with ≤ 3 PALNM and well/moderately differentiated adenocarcinoma was 54.2%, which was comparable to that of patients undergoing PALND and diagnosed with stage IIIC (49.6%).

CONCLUSION

Patients with PALNM of colorectal cancer had a poor prognosis. However, curative resection, ≤ 3 PALNM, and well/moderately differentiated histology type were associated with the long-term survival.

Risk factors for incisional surgical site infection after elective laparoscopic colorectal surgery

BACKGROUND

Surgical site infection (SSI) is a common morbidity in patients undergoing colorectal surgery, and the focus of previous studies has primarily been on incisional SSI. Most reports thus far have focused on open surgery rather than on laparoscopic colorectal surgery (Lap CR). Therefore, the aim of the present study was to identify the risk factors for incisional SSI in patients undergoing elective Lap CR.

METHODS

This retrospective study was conducted to evaluate the occurrence and risk factors of incisional SSI for elective Lap CR. From January 2008 to June 2018, 1825 consecutive patients with a preoperative diagnosis of colorectal cancer who underwent Lap CR were analyzed at a single institution.

RESULTS

Incidence of incisional SSI was 3.3%. Postoperative hospital stay (days) was significantly longer in the incisional SSI group than in the non-incisional SSI group (8 [6-12] vs 10 [8-19], P < 0.001). Incisional SSI were significantly associated with five operative factors: blood loss (g) (P < 0.014), midline wound length (mm) (P = 0.038), suture materials (P = 0.014), suture technique (interrupted vs continuous mass closure, P = 0.003), and organ/space SSI (P = 0.041). Multivariate analysis showed that continuous mass closure (odds ratio 0.290; 95% confidence interval 0.101-0.831, P = 0.021) was the only factor independently associated with the incidence of incisional SSI.

CONCLUSIONS

Incidence of incisional SSI was comparable to that in previous reports. Continuous mass closure decreased the risk of incisional SSI in elective Lap CR.

Acute iliac arterial thrombosis during laparoscopic abdominoperineal resection

Background

Acute iliac arterial thrombosis during surgery is very rare complication. There were few reports on this complication relative to gastroenterological surgery, and the risk has not been recognized.

Case presentation

A 70-year-old man, diagnosed with a rectal cancer (adenocarcinoma of rectum) with known history heavy cigarette smoking with no known history of peripheral vascular disease underwent a laparoscopic abdominoperineal resection. He presented severe pain in the left leg in the recovery room. A computed tomography (CT) scan revealed the complete obstruction of the left common iliac artery. A successful revasculization was achieved through a thrombotectomy and percutaneous transluminal angioplasty with a stent immediately after the diagnosis. The pain in the left leg disappeared immediately after the revasculization.

Conclusion

An acute arterial thrombosis is a potential complication of the laparoscopic colorectal surgery with the lithotomy position.

Randomized clinical trial of high versus low inferior mesenteric artery ligation during anterior resection for rectal cancer

BACKGROUND

The optimal level for inferior mesenteric artery ligation during anterior resection for rectal cancer is controversial. The aim of this randomized trial was to clarify whether the inferior mesenteric artery should be tied at the origin (high tie) or distal to the left colic artery (low tie).

METHODS

Patients were allocated randomly to undergo either high- or low-tie ligation and were stratified by surgical approach (open or laparoscopic). The primary outcome was the incidence of anastomotic leakage. Secondary outcomes were duration of surgery, blood loss and 5-year overall survival.

RESULTS

Some 331 patients entered the trial between June 2006 and September 2012. The trial was stopped prematurely as recruitment was slow. Seven patients were excluded after randomization but before operation because of procedural changes. High tie and low tie were performed in 164 and 160 patients respectively. The incidence of anastomotic leakage was not significantly different (17·7 versus 16·3 per cent respectively; P = 0·731). The incidence of severe complications requiring intervention was 2·4 versus 5·0 per cent for high and low tie respectively (P = 0·222). In multivariable analysis, risk factors for anastomotic leakage included male sex (odds ratio 4·36, 95 per cent c.i. 1·56 to 12·18) and distance of the tumour from the anal verge (odds ratio 0·99, 0·98 to 1·00). At 5 years there were no significant differences in overall (87·2 versus 89·4 per cent respectively; P = 0·386) and disease-free (76·3 versus 77·6 per cent; P = 0·765) survival.

CONCLUSION

The level of ligation of the inferior mesenteric artery does not significantly influence the rate of anastomotic leakage. Registration number: NCT01861678 ( https://clinicaltrials.gov).

Absorptive anti-adhesion barrier for the prevention of bowel obstruction after laparoscopic colorectal cancer surgery

Objectives: The protective efficacy of an absorptive adhesion prevention product (Seprafilm^Ⓡ) against bowel obstruction (BO) during open surgery was demonstrated in a large-scale randomized controlled clinical trial in Europe and America. However, the efficacy of Seprafilm against BO in laparoscopic surgery remains uncertain. The objective of this study was to clarify the protective efficacy of Seprafilm against BO after laparoscopic surgery for colorectal cancer. Methods: From 2009 to 2016, 1328 laparoscopic colorectal resections were performed for colorectal cancer. From 2009, Seprafilm was used for preventing BO in laparoscopic colorectal surgery. The incidence of BO and short-term results were compared between the Seprafilm and non-Seprafilm groups after propensity score matching. Results: Propensity scoring generated 270 matched patients per group for the comparisons between the Seprafilm and non-Seprafilm groups. The two groups showed no significant differences regarding patients' backgrounds. Among all patients, 73.1% (19/26) of BO occurred within 30 days after the surgery. Significantly lower incidences of all grade (2.6% vs. 7.0%; p = 0.016) and grade 2 + 3a (1.5% vs. 5.2%; p = 0.017) BO were observed in the Seprafilm group than in the non-Seprafilm group; no significant difference regarding grade 3b BO (1.1% vs. 1.9%; p = 0.476) was found. A significant difference in BO within 30 days was also noted between the two groups (1.9% vs. 5.2%, p = 0.036). There were no significant differences between the groups regarding anastomotic leakage and deep surgical site infection. Conclusions: Seprafilm was useful for preventing BO, requiring decompression therapy of the bowel, after laparoscopic colorectal surgery without increasing adverse events.

Detection of gas components as a novel diagnostic method for colorectal cancer

Background

The fecal occult blood test (FOBT) is widely accepted as the most economic and non‐invasive screening method for colorectal cancer (CRC). However, the FOBT is inconvenient because it requires a fecal sample and shows limited accuracy. Alternatively, we hypothesized that fecal gas compounds from bowel movements may be a non‐invasive biomarker for CRC.

Methods

Gas compounds were collected from the bowel movements of 30 patients with CRC and from 26 healthy controls. The patient group comprised 17 males and 13 females, and the average age was 68 years. Additionally, 22 patients had colon cancer, and eight patients had rectal cancer. Gas compounds were analyzed using gas chromatography and compared with those from healthy controls.

Results

In the gas analysis, methyl mercaptan was significantly higher in the CRC group than in the control group. Hydrogen was significantly lower in the CRC group than in the control group and was correlated with tumor depth and advanced disease stage. Sensitivity, specificity, and accuracy of detection by a discriminant formula were 90%, 57.7%, and 75%, respectively.

Conclusion

Gas compounds from defecation constitute a promising, novel non‐invasive approach for CRC screening. (UMIN000028256)

This study analyzed the gas compounds of colorectal cancer (CRC) patients and healthy controls at defecation in toilet using an extremely non‐invasive technique. The volatile organic compounds from defecation are different compared with CRC patients and healthy controls. The sensitivity, specificity, and accuracy of the discriminant formula for colorectal cancer were 90%, 57.7%, and 75%, respectively. We concluded that gas compounds from defecation constitute a promising, novel non‐invasive approach for CRC screening.

[A Case of Rhabdomyolysis Related to SOX Therapy for Liver Metastasis of Gastric Cancer]

We report a case of rhabdomyolysis related to S-1 plus oxaliplatin(SOX)therapy for liver metastasis of gastric cancer. A 76- year-old man who had received SOX therapy for metastatic gastric cancer was admitted to our hospital for a chief complaint of fatigue and weakness. He diagnosed with rhabdomyolysis related to SOX therapy because of his symptoms and because his laboratory studies showed significant elevation of his serum creatine kinase(CK)level. The symptoms disappeared and the CK level normalized following large-volume transfusions. Rhabdomyolysis following SOX therapy is a very rare, but severe adverse event. This is the first detailed case report of rhabdomyolysis related to SOX therapy.