Clinicopathological features and prognosis of primary small bowel adenocarcinoma: a large multicenter analysis of the JSCCR database in Japan

BACKGROUND

The clinicopathological features and prognosis of primary small bowel adenocarcinoma (PSBA), excluding duodenal cancer, remain undetermined due to its rarity in Japan.

METHODS

We analyzed 354 patients with 358 PSBAs, between January 2008 and December 2017, at 44 institutions affiliated with the Japanese Society for Cancer of the Colon and Rectum.

RESULTS

The median age was 67 years (218 males, 61.6%). The average tumor size was 49.9 (7-100) mm. PSBA sites consisted of jejunum (66.2%) and ileum (30.4%). A total of 219 patients (61.9%) underwent diagnostic small bowel endoscopy, including single-balloon endoscopy, double-balloon endoscopy, and capsule endoscopy before treatment. Nineteen patients (5.4%) had Lynch syndrome, and 272 patients (76.8%) had symptoms at the initial diagnosis. The rates for stages 0, I, II, III, and IV were 5.4%, 2.5%, 27.1%, 26.0%, and 35.6%, respectively. The 5-year overall survival rates at each stage were 92.3%, 60.0%, 75.9%, 61.4%, and 25.5%, respectively, and the 5-year disease-specific survival (DSS) rates were 100%, 75.0%, 84.1%, 59.3%, and 25.6%, respectively. Patients with the PSBA located in the jejunum, with symptoms at the initial diagnosis or advanced clinical stage had a worse prognosis. However, multivariate analysis using Cox-hazard model revealed that clinical stage was the only significant predictor of DSS for patients with PSBA.

CONCLUSIONS

Of the patients with PSBA, 76.8% had symptoms at the initial diagnosis, which were often detected at an advanced stage. Detection during the early stages of PSBA is important to ensure a good prognosis.

Prognostic factors of para-aortic lymph node metastasis from colorectal cancer in highly selected patients undergoing para-aortic lymph node dissection

PURPOSE

We investigated the surgical outcomes of para-aortic lymph node (PALN) dissection in patients with colorectal cancer and assessed the prognostic factors related to the survival.

METHODS

This single-center retrospective study included 31 patients with synchronous or metachronous PALN metastasis from colorectal cancer who underwent PALN dissection between January 2006 and December 2018.

RESULTS

Twenty-one patients had synchronous PALN metastasis, and 10 had metachronous PALN metastasis. Seven patients had either simultaneous distant metastasis or a history of distant metastasis other than PALN metastasis at the time of PALN dissection. Eighteen patients underwent adjuvant chemotherapy. The 5-year overall and recurrence-free survival rates were 54.2 and 17.2%, respectively. A multivariable analysis revealed that rectal cancer, metachronous PALN metastasis, and three or more pathological PALN metastases were significantly poor prognostic factors for the recurrence-free survival. Among patients with rectal cancer, lower rectal cancer and lateral pelvic lymph node metastasis were poor prognostic factors for the overall survival.

CONCLUSION

Curative PALN dissection for PALN metastasis from colorectal cancer is feasible with favorable long-term outcomes. A multidisciplinary approach, including surgery and chemotherapy, is needed for colorectal cancer with PALN metastasis to improve the long-term outcomes.

Outcomes of Metastatic and Unresectable Small Bowel Adenocarcinoma in Japan According to the Treatment Strategy: A Nationwide Observational Study

PURPOSE

Limited information is available regarding the characteristics and outcomes of stage IV small bowel adenocarcinoma (SBA) in Japan. This study examined the clinical and pathological characteristics and outcomes according to the treatment strategies in patients with stage IV SBA.

METHODS

This retrospective observational study used the data of patients with jejunal or ileal adenocarcinoma collected by the Small Bowel Malignant Tumor Project of the Japanese Society for Cancer of the Colon and Rectum. Descriptive statistics were expressed as the mean (standard deviation) or median (range). Survival analysis was performed using Kaplan-Meier curves and pairwise log-rank tests.

RESULTS

Data from 128 patients were analyzed. The treatment strategies were chemotherapy alone (26 of 128, 20.3%), surgery alone (including palliative surgery; 21 of 128, 16.4%), surgery + chemotherapy (74 of 128, 57.8%), and best supportive care (7 of 128, 5.5%). The median (range) overall survival was 16 (0-125) months overall, and 11 (1-38) months, 8 (0-80) months, 18 (0-125) months, and 0 (0-1) months for the chemotherapy, surgery, surgery + chemotherapy, and best supportive care groups, respectively. Three main categories of chemotherapeutic regimen were used: a combination of fluoropyrimidine and oxaliplatin (F + Ox), fluoropyrimidine and irinotecan (F + Iri), and single-agent fluoropyrimidine. Among patients treated with chemotherapy, the median (range) OS was 16 (1-106) months overall, and 17 (1-87) months, 29 (7-39) months, and 16 (1-106) months in patients treated with fluoropyrimidine, F + Iri, and F + Ox, respectively.

CONCLUSION

Patients treated with surgery, chemotherapy, or both had a better prognosis than those who received best supportive care. Among patients who received chemotherapy, survival did not differ according to the chemotherapeutic regimen.

Negative impact of behavior restriction amidst a clustered COVID-19 infection on immobility syndrome in older patients negative for COVID-19: report from a chronic care hospital in Japan

Previous studies have reported on associations between immobility syndrome and the COVID-19 pandemic. However, little is known about the aggravation of this syndrome in older patients negative for COVID-19 infection amidst behavior restriction due to a clustered COVID-19 infection. Patients hospitalized one month before a clustered COVID-19 infection occurred in our hospital were recruited. Rehabilitation therapy was suspended for 25 days during behavior restriction. The ability of daily living of the patients was evaluated with the functional independence measure and Barthel index. Chronological changes in the functional independence measure and Barthel index scores were evaluated monthly, beginning one month before the clustered COVID-19 infection to one month after re-initiation of rehabilitation therapy. Patients with minimum scores in the functional independence measure (18) and Barthel index (0) prior to the clustered COVID-19 infection were excluded. Functional independence measure scores of 73 older patients and the Barthel index scores of 48 patients were analyzed. The mean total functional independence measure score amidst the behavior restriction significantly changed from 36.3 to 35.1 (p = 0.019), while statistical significance was not detected in the mean motor subtotal (from 21.6 to 20.9 with p = 0.247) or cognitive subtotal functional independence measure scores (from 14.6 to 14.2 with p = 0.478). During the behavior restriction, the mean Barthel index scores declined from 25.8 to 23.2 without statistical significance (p = 0.059). Behavior restriction due to a clustered COVID-19 infection may aggravate immobility syndrome in older patients who are negative for COVID-19.

Tumor-informed or tumor-agnostic circulating tumor DNA as a biomarker for risk of recurrence in resected colorectal cancer patients

Introduction

Circulating tumor DNA (ctDNA) has been increasingly recognized as a promising minimally-invasive biomarker that could identify patients with minimal residual disease and a high risk of recurrence after definitive treatment. In this study, we've compared the clinical utility and sensitivity of 2 different approaches to ctDNA analyses: tumor-informed and tumor-agnostic in the management of colorectal (CRC) patients. The clinical benefits of a single timepoint ctDNA analysis compared to serial ctDNA monitoring after definitive treatment were also evaluated to uncover the ideal surveillance protocol.

Methods

Patient-paired resected tumor tissues, peripheral blood cells, and a total of 127 pre-operative and serial plasma cell-free DNA (cfDNA) samples after definitive treatment from 38 CRC patients that had undergone curative intent surgery were analyzed using a commercial NGS cfDNA panel.

Results

Up to 84% (32/38) of the recruited patients were detected with at least 1 genomic alteration from the tumor tissues that could be monitored using the tumor-informed ctDNA approach and none of the detected alterations were clonal hematopoiesis (CH) related. In contrast, 37% (14/38) of patients were detected with at least 1 monitoring alteration after exclusion of CH mutations using the tumor-agnostic approach. Serial plasma samples after definitive therapy were available for 31 patients. In the landmark ctDNA analysis, 24% (7/29) of patients had detectable ctDNA and were more likely to relapse than ctDNA-negative patients (p < 0.05). The landmark analysis sensitivity and specificity for recurrence were 67% and 87%, respectively. The incorporation of longitudinal ctDNA analysis at 6-months intervals improved the sensitivity to 100%. The median variant allele frequency (VAF) of the ctDNA mutations detected during surveillance was 0.028% (range: 0.018-0.783), where up to 80% (8/10) of the mutations were detected at VAF lower than the tumor-agnostic detection limit of 0.1%. Utilizing the tumor-agnostic approach reduced the recurrence detection sensitivity to 67% (4/6). Serial ctDNA analyses predicted disease recurrence at a median of 5 months ahead of radiological imaging.

Conclusion

Longitudinal monitoring using tumor-informed ctDNA testing shows high analytical sensitivity, low probability of false-positive results due to CH mutations, and improved sensitivity in detecting recurrence which may modify the clinical management of CRC.

POS1014 IMPACT OF SERUM INTERLEUKIN 22 AS A BIOMARKER FOR THE DIFFERENTIAL USE OF MOLECULAR TARGETED DRUGS FOR PSORIATIC ARTHRITIS

Background

Although each bDMARD target different molecules, no optimal drug selection method has been established. Because studies directly comparing TNF-i and IL-17-i have shown that these drugs are equally effective, the establishment of an optimal selection method for these drugs can contribute to better patient outcomes. We reported the possibility of stratification of patients by peripheral blood lymphocytes phenotyping and precision medicine based on the selective use of bDMARDs in psoriatic arthritis (PsA). However, since peripheral blood lymphocytes phenotyping is complex, the development of simple methods using biomarkers to stratify patients and simple treatment strategies based on such methods is needed to promote precision medicine in a real-world clinical setting.

Objectives

We explored whether serum cytokines could be used as biomarkers for optimal use TNF-i and IL-17-i in patients with PsA.

Methods

In cohort 1 (IL-17-i [n=23] or TNF-i [n=24] for ≥1 year), we identified serum cytokines that predicted the achievement of DAPSA remission (REM), PASI 90 and Minimal Disease Activity after 1 year of TNF-i or IL-17-i therapy. Subsequently, we developed treatment strategies based on the identified cytokines. In cohort 2, treatment responses were compared between the strategic treatment group (n=17), which was treated based on the treatment strategies, and the mismatched treatment group (n=17) to verify the validity of the treatment strategies developed using serum cytokines as biomarkers.

Results

In cohort 1, serum IL-22 concentrations were statistically identified as a predictor of DAPSA remission after 1 year of IL-17-i therapy. However, no baseline serum cytokines were identified as factors contributing to achievement of DAPSA-REM in the TNF-i-treated group or achievement of PASI90 and Minimal Disease Activity in either group. Using a cut-off value of 0.61376 (sensitivity, 81.8%; specificity, 91.7%; area under the curve, 0.848) determined by a ROC analysis, we stratified 47 patients into the IL-22 high group (n=25) (0.61376<) and the IL-22 low group (n=22) (< 0.61376). Serum IL-17 concentrations were significantly higher in both the IL-22 high and IL-22 low groups than in the healthy control (HC), whereas no significant difference was observed between the IL-22 high and IL-22 low groups. The serum TNF-α concentrations did not significantly differ between the IL-22 low and HC; however, they were significantly higher in the IL-22 high group than in the HC and IL-22 low groups. Based on these results, we created treatment strategies using TNF-i and IL-17-i based on serum IL-22 concentrations, that is, initiation of IL-17-i therapy in patients with low IL-22 concentrations and TNF-i therapy in patients with high IL-22 concentrations. To validate the efficacy of the treatment strategies, we retrospectively compared the efficacy of the bDMARDs at 1 year between the following groups in cohort 2. The strategic treatment group (n=17) included patients with low IL-22 concentrations who were treated with IL-17-i and those with high IL-22 concentrations who were treated with TNF-i. The mismatched treatment group (n=17) included patients with low IL-22 concentrations who were treated with TNF-i and those with high IL-22 concentrations who were treated with IL-17-i. No statistically significant differences were observed between the two groups in baseline characteristics at the initiation of bDMARD. After initiation of bDMARD, tender joint counts, swollen joint counts, CRP, DAPSA, and PASI were significantly improved in both groups. When the treatment responses over 1 year were compared between the two groups, the rate of achieving DAPSA-REM (58.8% vs. 25.3%, P=0.0399) and Minimal Disease Activity (82.3% vs. 41.2%, P=0.0162) at M12 was significantly higher in the strategic treatment group. There were no statistically significant differences in the rates of achieving PASI75 or PASI90 at M 6 or 12.

Conclusion

We verified that serum IL-22 can be used as a simple biomarker for the proper selection of TNF-i and IL-17-i.

Acknowledgements

The authors thank the study participants, without whom this study could not have been

accomplished, and all medical staff at all participating institutions for providing the data,

especially Ms. Hiroko Yoshida, Ms. Youko Saitou, Ms. Machiko Mitsuiki and Ms. Ayumi

Maruyama for the excellent data management. The authors thank Ms. M.

Hirahara for providing excellent technical assistance. We also thank Dr Kazuyoshi Saito at

Tobata General Hospital; Dr Kentaro Hanami and Dr Shunsuke Fukuyo at Wakamatsu Hospital

of the University of Occupational and Environmental Health; Dr Keisuke Nakatsuka at Fukuoka

Yutaka Hospital, and all staff members at Kitakyushu General Hospital and Shimonoseki

Saiseikai Hospital. Nakama Municipal Hospital, and Steel Memorial Yawata Hospital for their

engagement in data collection.

Disclosure of Interests

Ippei Miyagawa: None declared, Shingo Nakayamada Speakers bureau: consulting fees, speaking fees, and/or honoraria from Bristol-Myers, Pfizer, GlaxoSmithKline, Sanofi, Astellas, Asahi-kasei, and Boehringer Ingelheim and research grants from Mitsubishi-Tanabe and Novartis., Masanobu Ueno: None declared, Yusuke Miyazaki: None declared, Yoshiya Tanaka Speakers bureau: speaking fees and/or honoraria from Daiichi-Sankyo, Eli Lilly, Novartis, YL Biologics, Bristol-Myers, Eisai, Chugai, Abbvie, Astellas, Pfizer, Sanofi, Asahi-kasei, GSK, Mitsubishi-Tanabe, Gilead, and Janssen, Consultant of: consultant fees from Eli Lilly, Daiichi-Sankyo, Taisho, Ayumi, Sanofi, GSK, and Abbvie., Grant/research support from: research grants from Abbvie, Mitsubishi-Tanabe, Chugai, Asahi-Kasei, Eisai, Takeda, and Daiichi-Sankyo

Non-operative management after chemoradiotherapy plus consolidation or sandwich (induction with bevacizumab and consolidation) chemotherapy in patients with locally advanced rectal cancer: a multicentre, randomised phase II trial (NOMINATE trial)

INTRODUCTION

Total mesorectal excision (TME) and postoperative adjuvant chemotherapy following neoadjuvant chemoradiotherapy (CRT) is the standard treatment for locally advanced rectal cancer (LARC). However, neoadjuvant CRT has no recognised impact on reducing distant recurrence, and patients suffer from a long-lasting impairment in quality of life (QOL) associated with TME. Total neoadjuvant therapy (TNT) is an alternative approach that could reduce distant metastases and increase the proportion of patients who could safely undergo non-operative management (NOM). This study is designed to compare two TNT regimens in the context of NOM for selecting a more optimal regimen for patients with LARC.

METHODS AND ANALYSIS

NOMINATE trial is a prospective, multicentre, randomised phase II selection design study. Patients must have clinical stage II or III (T3-T4Nany) LARC with distal location (≤5 cm from the anal verge or for those who are candidates for abdominoperineal resection or intersphincteric resection). Patients will be randomised to either arm A consisting of CRT (50.4 Gy with capecitabine) followed by consolidation chemotherapy (six cycles of CapeOx), or arm B consisting of induction chemotherapy (three cycles of CapeOx plus bevacizumab) followed by CRT and consolidation chemotherapy (three cycles of CapeOx). In the case of clinical complete response (cCR) or near cCR, patients will progress to NOM. Response assessment involves a combination of digital rectal examination, endoscopy and MRI. The primary endpoint is the proportion of patients achieving pathological CR or cCR≥2 years, defined as the absence of local regrowth within 2 years after the start of NOM among eligible patients. Secondary endpoints include the cCR rate, near cCR rate, rate of NOM, overall survival, distant metastasis-free survival, locoregional failure-free survival, time to disease-related treatment failure, TME-free survival, permanent stoma-free survival, safety of the treatment, completion rate of the treatment and QOL. Allowing for a drop-out rate of 10%, 66 patients (33 per arm) from five institutions will be accrued.

ETHICS AND DISSEMINATION

The study protocol was approved by Wakayama Medical University Certified Review Board in December 2020. Trial results will be published in peer-reviewed international journals and on the jRCT website.

TRIAL REGISTRATION NUMBER

jRCTs051200121.

Characteristics of anal canal cancer in Japan

Anal canal cancer (ACC) has been reported to be an uncommon cancer in Japan, as in the USA, Europe, and Australia. This retrospective multi‐institutional study was conducted to clarify the characteristics of ACC in Japan. First, the histological ACC type cases treated between 1991 and 2015 were collected. A detailed analysis of the characteristics of anal canal squamous cell carcinoma (SCC) cases was then conducted. The results of the histological types revealed that of the 1781 ACC cases, 435 cases (24.4%) including seven cases of adenosquamous cell carcinomas were SCC and 1260 cases (70.7%) were adenocarcinoma. However, the most common histological type reported in the USA, Europe, and Australia is SCC. Most ACC cases are adenocarcinomas and there is a low incidence of SCC in Japan which is different from the above‐mentioned countries. Moreover, we reclassified T4 into the following two groups based on tumor size: T4a (tumor diameter of 5 cm or less) and T4b (tumor diameter of more than 5 cm). The results of the TNM classification of SCC revealed that the hazard ratio (HR) to T1 of T2, T3, T4a, and T4b was 2.45, 2.28, 2.89, and 4.97, respectively. As T4b cases had a worse prognosis than T4a cases, we propose that T4 for anal canal SCC in Japan be subclassified into T4a and T4b.

Decision-making in postoperative chemotherapy for ovarian metastasis from colorectal cancer: a retrospective single-center study

BACKGROUND

Ovarian metastases from colorectal cancer are relatively uncommon, and no consensus has been reached regarding resection of metastases or chemotherapy before and after surgery. We evaluated the clinicopathological characteristics of ovarian metastases from colorectal cancer and the impact of metastatic resection. We also performed a comparative analysis to clarify the prognostic impact of metastatic resection and the choice of chemotherapy before and after surgery.

METHODS

Between 2006 and 2014, 38 patients at our institution underwent resection of ovarian metastases from colorectal cancer. Clinicopathological data were extracted from the patients' records and evaluated with respect to the long-term outcome. For 15 patients with metachronous ovarian metastases who received chemotherapy until immediately before resection, we compared the prognosis with and without changes in the regimen after resection.

RESULTS

The 5-year overall survival rate was 19.9%, and the median survival duration was 27.2 months. The survival rate in the R0 resection group (n = 8) was significantly better than that in the R1/2 resection group (n = 30) (P = 0.0004). Patients without peritoneal dissemination (n = 15) or extra-ovarian metastases (n = 31) had a significantly better prognosis than those with peritoneal dissemination (n = 23) or extra-ovarian metastases (n = 7) (P = 0.040 and P = 0.0005, respectively). The progression-free survival and median survival times of patients who resumed chemotherapy after resection without a change in their preoperative regimen were 10.2 months and 26.2 months, respectively, while those among patients with a change in their regimen before resection versus after resection were 11.0 months and 18.1 months, respectively. The difference between the two groups was not statistically significant (progression-free survival time and median survival time: P = 0.52 and P = 0.48, respectively).

CONCLUSIONS

Patients who underwent R0 resection of ovarian metastases clearly had a better prognosis than those who underwent R1/2 resection. Additionally, a poor prognosis was associated with the presence of peritoneal dissemination and extra-ovarian metastases. The data also suggested that resumption of chemotherapy without changing the regimen after resection could preserve the next line of chemotherapy for future treatment and improve the prognosis.

Gut bacteria identified in colorectal cancer patients promote tumourigenesis via butyrate secretion

Emerging evidence is revealing that alterations in gut microbiota are associated with colorectal cancer (CRC). However, very little is currently known about whether and how gut microbiota alterations are causally associated with CRC development. Here we show that 12 faecal bacterial taxa are enriched in CRC patients in two independent cohort studies. Among them, 2 Porphyromonas species are capable of inducing cellular senescence, an oncogenic stress response, through the secretion of the bacterial metabolite, butyrate. Notably, the invasion of these bacteria is observed in the CRC tissues, coinciding with the elevation of butyrate levels and signs of senescence-associated inflammatory phenotypes. Moreover, although the administration of these bacteria into Apc^Δ14/+ mice accelerate the onset of colorectal tumours, this is not the case when bacterial butyrate-synthesis genes are disrupted. These results suggest a causal relationship between Porphyromonas species overgrowth and colorectal tumourigenesis which may be due to butyrate-induced senescence.

Several bacteria in the gut microbiota have been associated with colorectal cancer (CRC) but it is not completely clear whether they have a role in tumourigenesis. Here, the authors show enrichment of 12 bacterial taxa in two cohorts of CRC patients and that two Porphyromonas species accelerate CRC onset through butyrate secretion.

Oncologic impact of lateral lymph node metastasis at the distal lateral compartment in locally advanced low rectal cancer after neoadjuvant (chemo)radiotherapy

INTRODUCTION

The frequency and oncologic outcomes of lateral lymph node (LLN) metastasis at the most distal lateral compartment (DLC) among clinical stage II-III low rectal cancer patients treated with neoadjuvant (chemo)radiotherapy (nCRT) are poorly understood. The aim was to investigate the oncologic impact of LLN metastasis in the DLC versus the proximal lateral compartment (PLC).

MATERIALS AND METHODS

Consecutive patients with low rectal cancer treated with nCRT followed by total mesorectal excision and selective LLN dissection including the DLC were analyzed retrospectively. DLC was defined as the area distal to the infra-piriformis foramen on axial MRI images. Size and location of LLN metastasis on MRI, and survival were retrospectively assessed.

RESULTS

Of the 718 patients, 72 (10.0%) had pathological LLN metastasis. Thirty-two (44.4%) had metastasis in the DLC (DLC group), while 40 (55.6%) had metastasis in the PLC without metastasis in the DLC (PLC group). The proportion of ypN2 category tended to be lower in the DLC group (15.6% vs 35.0%, P = 0.105). The median number of metastatic LLN was similar (1 vs. 1, P = 0.691). The median short-axis size of metastatic LLN was smaller in the DLC group than in the PLC group on pre-treatment (P < 0.001) and re-staging (P = 0.004) MRI. By multivariable analysis, LLN metastasis in the DLC was predictive of better disease-free survival (HR, 0.412; 95% CI, 0.159-0.958, P = 0.039).

CONCLUSION

LLN metastasis in the DLC is frequent and has favorable oncologic outcomes after surgical dissection with nCRT.

Rumen microbiota and its relation to fermentation in lactose-fed calves

In our previous studies, we revealed the effect of lactose inclusion in calf starters on the growth performance and gut development of calves. We conducted the present study as a follow-up study to identify the shift in rumen microbiota and its relation to rumen fermentation when calves are fed a lactose-containing starter. Thirty Holstein bull calves were divided into 2 calf starter treatment groups: texturized calf starter (i.e., control; n = 15) or calf starter in which starch was replaced with lactose at 10% (i.e., LAC10; n = 15) on a dry matter basis. All calves were fed their respective treatment calf starter ad libitum from d 7, and kleingrass hay from d 35. Rumen digesta were collected on d 80 (i.e., 3 wk after weaning) and used to analyze rumen microbiota and fermentation products. There was no apparent effect of lactose feeding on the α-diversity and overall composition of rumen microbiota. Amplicon sequencing and real-time PCR quantification of the 16S rRNA gene confirmed that the abundance of butyrate-producing bacteria (i.e., Butyrivibrio group and Megasphaera elsdenii) did not differ between the control and LAC10 groups. Conversely, the relative abundance of Mitsuokella spp., which produce lactate, succinate, and acetate, was significantly higher in the rumen of calves that were fed lactose, whereas the lactate concentration did not differ between the control and LAC10 groups. These findings suggest that the lactate production can be elevated by an increase of Mitsuokella spp. and then converted into butyrate, not propionate, since the proportion of propionate was lower in lactose-fed calves. In addition, we observed a higher abundance of Coriobacteriaceae and Pseudoramibacter-Eubacterium in the LAC10 group. Both these bacterial taxa include acetate-producing bacteria, and a positive correlation between the acetate-to-propionate ratio and the abundance of Pseudoramibacter-Eubacterium was observed. Therefore, the higher abundance of Coriobacteriaceae, Mitsuokella spp., and Pseudoramibacter-Eubacterium in the rumen of lactose-fed calves partially explains the increase in the proportion of rumen acetate that was observed in our previous study.

Postoperative Nutritional Status is Predictive of the Survival Outcomes in Patients Undergoing Resection of Stage III Colorectal Cancer

BACKGROUND

Preoperative nutritional status is reportedly associated with the clinical outcomes in patients with colorectal cancer (CRC), although it remains inconclusive whether the preoperative nutritional status that may improve after surgery is truly predictive of the survival outcomes of patients with CRC.

METHODS

Clinical records of patients with stage III CRC (n = 821) in whom curative resection had been achieved were retrospectively reviewed and the prognostic impact of nutritional status, determined by the controlling nutritional status (CONUT) score, was analyzed.

RESULTS

The CONUT undernutrition grade was significantly associated with the overall survival rate (OS) in the original population (P < 0.0001). By adopting a cut-off value of CONUT score of ≥ 2 and adjustment for clinical variables using the inverse probability treatment weighting methods, the group with a preoperative CONUT score of ≥ 2 showed a worse OS as compared to the groups with a preoperative CONUT score of < 2 (P = 0.037). However, sub-analysis based on the dynamic changes in the CONUT score revealed that sustained malnutrition in the postoperative period was more frequent among patients with preoperative CONUT score of ≥ 2, and that the OS and recurrence-free survival rate (RFS) were significantly correlated with the "postoperative" nutritional status, irrespective of the preoperative nutritional status. Patients who showed improvements of the nutritional status after surgery showed a significantly longer OS and RFS.

CONCLUSIONS

Sustained undernutrition or worsening of the nutritional status after colectomy may be associated with a worse OS and RFS after curative resection in patients with stage III CRC.

Systemic Inflammatory Markers Combined with Tumor-Infiltrating Lymphocyte Density for the Improved Prediction of Response to Neoadjuvant Chemoradiotherapy in Rectal Cancer

BACKGROUND

Previous studies have reported the utility of systemic inflammatory markers and CD8+ tumor-infiltrating lymphocyte (TIL) separately in predicting response to chemoradiotherapy (CRT) in rectal cancer; however, the efficacy of combining these markers remains unclear.

OBJECTIVE

This study aimed to elucidate the predictive efficacy of systemic inflammatory markers combined with CD8+ TIL density on response to neoadjuvant CRT in locally advanced rectal cancer.

METHODS

Ten systemic inflammatory markers and CD8+ TIL density were assessed in 267 patients with rectal cancer using pretreatment clinical data and biopsy samples. Response to CRT was determined using the Dworak tumor regression grade (TRG), with good responders classified as TRG3-4.

RESULTS

Receiver operating characteristic curve analysis showed high areas under the curve for the lymphocyte-to-C-reactive protein ratio (LCR) and neutrophil × monocyte (N × M) value (0.58 and 0.62, respectively). In the multivariate analysis, LCR, N × M value, and CD8+ TIL density were independently associated with good responders (p = 0.016, 0.005, and 0.002, respectively). Stratified analysis with these three markers showed a positive correlation between TRG3-4 ratio and the number of positive predictive factors (8.2%, 20.0%, 34.2%, and 59.1% in patients with 0, 1, 2, and 3 predictors, respectively). Overall and disease-free survival were significantly worse in patients with zero factors present compared with those with one to three factors present.

CONCLUSIONS

LCR, N × M value, and CD8+ TIL density are independently associated with response to CRT. Assessing local TIL density along with systemic inflammatory markers may be useful for selecting a multimodal neoadjuvant approach in rectal cancer therapy.

Comparative Analysis of Patient-Matched PDOs Revealed a Reduction in OLFM4-Associated Clusters in Metastatic Lesions in Colorectal Cancer

Metastasis is the major cause of cancer-related death, but whether metastatic lesions exhibit the same cellular composition as primary tumors has yet to be elucidated. To investigate the cellular heterogeneity of metastatic colorectal cancer (CRC), we established 72 patient-derived organoids (PDOs) from 21 patients. Combined bulk transcriptomic and single-cell RNA-sequencing analysis revealed decreased gene expression of markers for differentiated cells in PDOs derived from metastatic lesions. Paradoxically, expression of potential intestinal stem cell markers was also decreased. We identified OLFM4 as the gene most strongly correlating with a stem-like cell cluster, and found OLFM4⁺ cells to be capable of initiating organoid culture growth and differentiation capacity in primary PDOs. These cells were required for the efficient growth of primary PDOs but dispensable for metastatic PDOs. These observations demonstrate that metastatic lesions have a cellular composition distinct from that of primary tumors; patient-matched PDOs are a useful resource for analyzing metastatic CRC.

•

Seventy-two PDOs were established from 21 stage IV CRC patients

•

Forty-one DEGs were identified between primary and corresponding metastatic PODs

•

scRNA-seq analysis identified OLFM4 as a potential cancer stem cell marker

•

Different roles of OLFM4⁺ cells in primary and metastatic PDOs were demonstrated

Improved oncologic outcomes with increase of laparoscopic surgery in modified complete mesocolic excision with D3 lymph node dissection for T3/4a colon cancer: results of 1191 consecutive patients during a 10-year period: a retrospective cohort study

BACKGROUND

Laparoscopic modified complete mesocolic excision (mCME) with D3 lymph node dissection has been performed with increasing frequency, but the oncological safety remains unclear. This study investigated the oncological safety of laparoscopic modified CME with D3 dissection for pT3/4a M0 colon cancer.

PATIENTS

Consecutive patients with pT3/4a M0 colon cancer undergoing curative colectomy at a comprehensive cancer center between 2004 and 2013 were included. Outcomes were compared between early (2004-2008, n = 450) and late (2009-2014, n = 741) periods. Prognostic factors were investigated by multivariate analysis.

RESULTS

A total of 1191 patients were eligible. Median follow-up was 57 months. Laparoscopic surgeries were more common in the late period (early vs late: 53.6% vs. 91.8%, p < 0.01). Patients in the late period showed lower blood loss (20 mL vs. 10 mL, p < 0.01), higher number of harvested lymph nodes (18.1 vs. 21.6, p < 0.01) and fewer patients with < 12 harvested nodes (13.6% vs. 5.8%, p < 0.01). Postoperative complication rates were similar between periods (2.7% vs. 2.7%, p = 0.97). Five-year relapse-free survival rate (RFS) (75.3% vs. 82.7%, p < 0.01) and overall survival rate (OS) (86.9% vs. 91.7%, p = 0.01) were higher in the late period. Multivariate analysis revealed laparoscopic surgery as an independent favorable prognostic factor for both RFS (hazard ratio (HR) = 0.73, 95% confidence interval (CI) 0.54-0.99, p = 0.03) and OS (HR = 0.56, 95% CI 0.37-0.83, p < 0.01).

CONCLUSION

Improved oncologic outcomes and more frequent laparoscopic surgery during the 10-year period of the study were demonstrated for modified CME with D3 dissection, suggesting the safety of this procedure performed by experienced surgeons for pT3/4a M0 colon cancer.

Impact on operative outcomes of laparoscopic simultaneous resection of colorectal cancer and synchronous liver metastases

INTRODUCTION

The efficacy of laparoscopic simultaneous resection of primary colorectal cancer and synchronous colorectal liver metastases (SCRLM) remains unclear.

METHODS

We retrospectively evaluated data from 258 patients who had undergone simultaneous curative resection of the primary tumor and SCRLM from 2006 to 2017. We compared surgical outcomes between open, hybrid (laparoscopic colorectal resection and open hepatectomy), and pure laparoscopic approaches. Surgical outcomes were also evaluated between the open hepatectomy (OH) group (ie, open/hybrid surgery) and the laparoscopic hepatectomy (LH) group (ie, pure laparoscopic surgery) in 141 patients later in the study period (2013-2017), when the clinical indications for laparoscopic hepatectomy were restricted to simple wedge resection and/or left lateral sectionectomy in our center.

RESULTS

The pure laparoscopic approach was associated with significantly less intraoperative blood loss and a significantly shorter postoperative hospital stay than the open and hybrid approaches. Late in the study period, operative outcomes in the LH group (n = 37) were more favorable than for the OH group (n = 104) in terms of intraoperative blood loss and postoperative hospital stay. In patients with rectal cancer, however, earlier postoperative recovery in the LH group did not differ significantly from the OH group.

CONCLUSION

Laparoscopic simultaneous resection of SCRLM with the primary tumor by simple hepatectomy is safe and may enhance patients' postoperative recovery, especially in patients with colon cancer.

Hybrid resection of massive rectal gastrointestinal stromal tumor using laparoscopic and transanal approaches

Rectal gastrointestinal stromal tumors (GISTs) are rare, and radical surgery such as abdominoperineal resection is necessary for large rectal GISTs to obtain tumor-free resection margins. Here, we describe a 77-year-old man with a locally advanced non-metastatic GIST in the left anterolateral wall of the lower rectum. Tumor size was estimated to be 73 mm, and invasion of the left seminal vesicle and prostate was suspected. Chemotherapy with imatinib mesylate reduced the tumor size, creating a slight gap between the tumor and anterior organs. Therefore, we performed sphincter-sparing partial rectal resection using a hybrid method of laparoscopic and transanal approaches. The postoperative course was uneventful, and the patient remains disease-free on adjuvant chemotherapy 12 months after surgery. This case suggests that a hybrid method of laparoscopic and transanal surgery allows oncological and function-preserving excision of large rectal GISTs.

Evaluation of the RAS signaling network in response to MEK inhibition using organoids derived from a familial adenomatous polyposis patient

RAS signaling is a promising target for colorectal cancer (CRC) therapy, and a variety of selective inhibitors have been developed. However, their use has often failed to demonstrate a significant benefit in CRC patients. Here, we used patient-derived organoids (PDOs) derived from a familial adenomatous polyposis (FAP) patient to analyze the response to chemotherapeutic agents targeting EGFR, BRAF and MEK. We found that PDOs carrying KRAS mutations were resistant to MEK inhibition, while those harboring the BRAF class 3 mutation were hypersensitive. We used a systematic approach to examine the phosphorylation of RAS effectors using reverse-phase protein array (RPPA) and found increased phosphorylation of MEK induced by binimetinib. A high basal level of ERK phosphorylation and its rebound activation after MEK inhibition were detected in KRAS-mutant PDOs. Notably, the phosphorylation of EGFR and AKT was more closely correlated with that of MEK than that of ERK. Transcriptome analysis identified MYC-mediated transcription and IFN signaling as significantly correlated gene sets in MEK inhibition. Our experiments demonstrated that RPPA analysis of PDOs, in combination with the genome and transcriptome, is a useful preclinical research platform to understand RAS signaling and provides clues for the development of chemotherapeutic strategies.

T-cell complexity and density are associated with sensitivity to neoadjuvant chemoradiotherapy in patients with rectal cancer

Emerging evidence suggests that an increased density of pre-treatment CD8⁺ tumor-infiltrating lymphocytes (TILs) is associated with good response to chemoradiotherapy (CRT) in patients with locally advanced rectal cancer. However, the significance of T-cell complexity in the clinical setting remains unknown. High-throughput T-cell receptor (TCR) β sequencing was applied to quantify the TCR repertoire of pre-treatment biopsies from 67 patients with advanced rectal cancer receiving preoperative CRT. Diversity index was used to represent the complexity of the TCR repertoire in a tumor. Pre-treatment CD8⁺ TIL densities were assessed by immunohistochemistry. Changes in TCR repertoire before and after CRT were also analysed in 23 patients. Diversity indices were significantly higher for good responders than for non-responders (P = 0.031). The multivariate analysis revealed that both CD8⁺ TIL density and TCR diversity index were independently associated with good response to CRT (P < 0.001 and P = 0.049, respectively). Patients who were high for both CD8⁺ TIL density and TCR diversity (double-high) had markedly better responses to CRT than double-low patients (84.2% vs 16.7%, P < 0.0001). Larger changes in TCR repertoires before and after CRT were correlated with better recurrence-free survival (P = 0.027). The complexity and dynamic change in the TCR repertoire might serve as a useful indicator of response to CRT in combination with CD8⁺ TIL density in patients with rectal cancer.

Radiomics Approach Outperforms Diameter Criteria for Predicting Pathological Lateral Lymph Node Metastasis After Neoadjuvant (Chemo)Radiotherapy in Advanced Low Rectal Cancer

BACKGROUND

Advanced low rectal cancer has a non-negligible risk of lateral pelvic lymph node (LPLN) metastasis (LPLNM) and lateral local recurrence (LR) after neoadjuvant (chemo)radiotherapy and total mesorectal excision. LPLN dissection (LPLND) reduces LR but increases postoperative complications and sexual/urinary dysfunction.

OBJECTIVE

The aim of this study was to develop a new radiomics-based prediction model for LPLNM in patients with rectal cancer.

METHODS

A total of 247 patients with rectal cancer and enlarged LPLNs treated by (chemo)radiotherapy and LPLND were enrolled in this retrospective, multicenter study. LPLN radiomic features were extracted from pretreatment portal venous-phase computed tomography images. A radiomics score of LPLN was constructed based on the least absolute shrinkage and selection operator regression in a primary cohort of 175 patients. Model performance was assessed in terms of discrimination, calibration, and decision curve analysis, and was externally validated in 72 patients.

RESULTS

The radiomics score showed significantly better discrimination compared with pretreatment short-axis diameter measurements in both the primary (area under the curve [AUC] 0.91 vs. 0.83, p = 0.0015) and validation (AUC 0.90 vs. 0.80, p = 0.0298) cohorts. Decision curve analysis also indicated the superiority of the radiomics score. In a subanalysis of patients with a short-axis diameter ≥ 7 mm, the radiomics nomogram, incorporating the radiomics score and LPLN shrinkage to ≤ 4 mm, had better discrimination compared with a model incorporating only LPLN shrinkage in both cohorts.

CONCLUSIONS

Radiomics-based prediction modeling provides individualized risk estimation of LPLNM in rectal cancer patients treated with (chemo)radiotherapy, and outperforms measurements of pretreatment LPLN diameter.

Clinical significance of clonal hematopoiesis in the interpretation of blood liquid biopsy

As the use of next-generation sequencing (NGS) for plasma cell-free DNA (cfDNA) continues to expand in clinical settings, accurate identification of circulating tumor DNA mutations is important to validate its use in the clinical management for cancer patients. Here, we aimed to characterize mutations including clonal hematopoiesis (CH)-related mutations in plasma cfDNA and tumor tissues using the same ultradeep NGS assay and evaluate the clinical significance of CH-related mutations on the interpretation of liquid biopsy results. Ultradeep targeted NGS using Oncomine Pan-Cancer Panel was performed on matched surgically resected tumor tissues, peripheral blood cells (PBCs), and 120 plasma cfDNA samples from 38 colorectal cancer patients. The clinical significance of the CH-related mutations in plasma cfDNA was evaluated by longitudinal monitoring of the postoperative plasma samples. Among the 38 patients, 74 nonsynonymous mutations were identified from tumor tissues and 64 mutations from the preoperative plasma samples. Eleven (17%) of the 64 mutations identified in plasma cfDNA were also detected in PBC DNA and were identified to be CH-related mutations. Overall, 11 of 38 (29%) patients in this cohort harbored at least one CH-related mutation in plasma cfDNA. These CH-related mutations were continuously detected in subsequent postoperative plasma samples from three patients which could be misinterpreted as the presence of residual disease or as lack of treatment response. Our results indicated that it is essential to integrate the mutational information of PBCs to differentiate tumor-derived from CH-related mutations in liquid biopsy analysis. This would prevent the misinterpretation of results to avoid misinformed clinical management for cancer patients.

Congestive ischemic colitis occurring after resection of left colon cancer: 4 case series

BACKGROUND

Ischemic colitis can occur after colectomy and is sometimes difficult to treat. We report 4 cases of refractory, delayed onset, regional congestive colitis occurring on the anal side of the anastomosis after laparoscopic left hemicolectomy.

CASE PRESENTATION

A total of 191 patients underwent surgery for left colon cancer (transverse, descending, and sigmoid colon cancer) at our hospital from January 2012 to December 2017. During the procedures, the left colic artery (LCA) or sigmoid colic artery (SA) was dissected, the superior rectal artery (SRA) was preserved, and the inferior mesenteric vein (IMV) was dissected at the inferior margin of the pancreas. Congestive ischemic colitis due to venous return dysfunction occurred in 4 cases (2.1%), 5 to 34 months postoperatively. The patients had diarrhea and blood in the stool. On computed tomography (CT), the patients exhibited continuous intestinal edema and high-density adipose tissue from the anastomosis site to the rectum. Contrast enhancement showed dilation of the vasa recti and arteries from the inferior mesenteric artery (IMA) to the SRA. Three patients improved with long-term intestinal rest; in 1 case, the stenosis did not improve and required colorectal resection.

CONCLUSION

Diagnoses were easy in these cases, but treatment was prolonged and surgery was necessary in 1 case. While this condition is rare, caution is warranted as it is difficult to treat.

Primary Tumor Histology Affects Oncological Outcomes Independently of the Anatomical Extent of Disease in Colorectal Liver Metastasis

Introduction

Growing evidence indicates the prognostic importance of the crosstalk between cancer cells and stroma through the induction of epithelial-mesenchymal transition (EMT). This study aimed to clarify the prognostic value of evaluating primary tumor histology with the anatomical extent of disease in patients with colorectal liver metastasis (CRLM).

Methods

Prognostic analyses were performed in 411 CRLM patients who underwent hepatectomy at two institutions. Tumors were graded into one of three histological categories based on integrated assessment of EMT-associated histology (Histology^EMT) in primary tumors, i.e., poorly differentiated clusters (PDCs) and desmoplastic reaction (DR).

Results

A prognostic grouping system for the anatomical extent of disease (N stage, liver metastasis number and size, and extrahepatic disease; Grade^anatomical) stratified patients into three groups with different five-year relapse-free survival (RFS) rates after hepatectomy: A, 31% (191 patients); B, 15% (124 patients); and C, 6% (96 patients; P < 0.0001). Histology^EMT (A, G1 PDC and mature-type DR; C, G3 PDC and immature-type DR; and B, others) identified 49, 120, and 242 patients with 46%, 5%, and 22% five-year RFS, respectively (P < 0.0001). Among prognostic factors, the Akaike information criterion was most favorable in Grade^anatomical, followed by Histology^EMT. Multivariate analysis demonstrated that these two factors independently impacted RFS; two-year RFS after hepatectomy in different patient groups had a wide range (10%-76%).

Conclusions

Histological assessment of dedifferentiation and the stromal environment of primary tumors contributed to effective risk stratification of early relapse after hepatectomy, which could be useful to determine clinical management for CRLM patients.

Transverse Single-Spin Asymmetry for Very Forward Neutral Pion Production in Polarized p+p Collisions at sqrt[s]=510 GeV

Transverse single-spin asymmetries of very forward neutral pions generated in polarized p+p collisions allow us to understand the production mechanism in terms of perturbative and nonperturbative strong interactions. During 2017, the RHICf Collaboration installed an electromagnetic calorimeter in the zero-degree region of the STAR detector at the Relativistic Heavy Ion Collider (RHIC) and measured neutral pions produced at pseudorapidity larger than 6 in polarized p+p collisions at sqrt[s]=510  GeV. The large nonzero asymmetries increasing both in longitudinal momentum fraction x_{F} and transverse momentum p_{T} have been observed at low transverse momentum p_{T}<1  GeV/c for the first time, at this collision energy. The asymmetries show an approximate x_{F} scaling in the p_{T} region where nonperturbative processes are expected to dominate. A non-negligible contribution from soft processes may be necessary to explain the nonzero neutral pion asymmetries.

Serial circulating tumour DNA analysis for locally advanced rectal cancer treated with preoperative therapy: prediction of pathological response and postoperative recurrence

BACKGROUND

The "watch-and-wait" approach is a common treatment option amongst patients with locally advanced rectal cancer (LARC). However, the diagnostic sensitivity of clinical modalities, such as colonoscopy and magnetic resonance imaging to determine pathological response, is not high. We analysed the clinical utility of circulating tumour DNA (ctDNA) of patients with LARC to predict response to preoperative therapy and postoperative recurrence.

METHODS

A serial ctDNA analysis of 222 plasma samples from 85 patients with LARC was performed using amplicon-based deep sequencing on a cell-free DNA panel covering 14 genes with over 240 hotspots.

RESULTS

ctDNA was detected in 57.6% and 22.3% of samples at baseline and after preoperative treatment, respectively, which was significantly different (P = 0.0003). Change in ctDNA was an independent predictor of complete response to preoperative therapy (P = 0.0276). In addition, postoperative ctDNA and carcinoembryonic antigen (CEA) were independent prognostic markers for risk of recurrence after surgery (ctDNA, P = 0.0127 and CEA, P = 0.0105), with a combined analysis having cumulative effects on recurrence-free survival (P = 1.0 × 10^-16).

CONCLUSIONS

Serial ctDNA analysis may offer clinically useful predictive and prognostic markers for response to preoperative therapy and postoperative recurrence in patients with LARC.

Prognostic nutritional index and postoperative outcomes in patients with colon cancer after laparoscopic surgery

PURPOSE

The prognostic nutritional index (PNI) is calculated using the serum albumin and peripheral lymphocyte counts. We sought to assess the correlation between the preoperative PNI and postoperative outcomes in patients with colon cancer treated with laparoscopic surgery.

METHODS

We included 896 colon cancer patients who underwent curative laparoscopic colectomy between January 2013 and March 2016. To identify any predictors of the postoperative outcomes, we compared the clinical characteristics and immunonutritional parameters, including the PNI, between patients classified as the Clavien-Dindo grade 2 or higher (n = 99) with those classified as grade 0 or 1 (n = 797).

RESULTS

A longer surgical time and a preoperative low PNI (< 49.8) (odds ratio; 1.913, p = 0.002) were independent predictors of postoperative complications according to a multivariate analysis. A preoperative low PNI was significantly associated with an older age, a lower performance status, a lower BMI, higher CEA levels, an advanced T status, lymph node metastasis, a longer operative time, a higher blood loss, a larger tumor size, treatment with a combined resection, a longer time to bowel recovery, a longer postoperative hospital stay, and a poor overall survival.

CONCLUSIONS

A preoperative low PNI was found to be significantly associated with the incidence of postoperative complications, an advanced tumor status, and a poor prognosis. Further research is needed to understand how to best clinically utilize this promising parameter.

Educational system for acquiring appropriate laparoscopic colorectal surgical skills: analysis in a Japanese high-volume cancer center

BACKGROUND

Acquiring appropriate laparoscopic technique is necessary to safely perform laparoscopic surgery. The Endoscopic Surgical Skill Qualification System of the Japanese Society of Endoscopic Surgery, which was established to improve the quality of laparoscopic surgery in Japan, provides training to become an expert laparoscopic surgeon. In this study, we describe our educational system, in a Japanese highest volume cancer center, and evaluate the system according to the pass rate for the Endoscopic Surgical Skill Qualification System examination.

METHODS

We assessed 14 residents who trained for more than 2 years from 2012 to 2018 in our department. All teaching surgeons, qualified by the Endoscopic Surgical Skill Qualification System, participated in all surgeries as supervisors. For the first 3 months, trainees learned as the scopist, then as the first assistant for 3 months, and then by performing laparoscopic surgery as an operator during ileocecal resection or sigmoidectomy. Trainees apply for this training in their second year of residency or later. All laparoscopic procedures in our department are standardized in detail.

RESULTS

The cumulative pass rate was 75% (12/16), and 87% (12/14) of the trainees eventually passed, while the general pass rate was approximately 30%. On average, those who passed in their second or third year had experienced 94 procedures as the surgeon, 177 as the first assistant, and 199 as the scopist. The number of laparoscopic procedures and the learning curves did not differ between successful and failed applicants.

CONCLUSIONS

Through our educational system, residents successfully acquired laparoscopic skills with a much higher pass rate in the Endoscopic Surgical Skill Qualification System examination than the general standard. Laparoscopic practice under supervision by experienced surgeons with standardized procedures and accurate understanding of the relevant anatomy is very helpful to achieving appropriate laparoscopic technique.

Abstract A46: Next-generation sequencing of circulating tumor DNA for detecting minimal residual disease and predicting recurrence in colorectal cancer patients

Background: Although the prognosis of colorectal cancer (CRC) has improved in the past decade, a subset of CRC patients may still suffer from relapse due to the progression from minimal residual disease (MRD) after surgical resection. A sensitive and noninvasive method to efficiently detect MRD is essential to further improve clinical prognosis. In this study, we have evaluated the feasibility of circulating tumor DNA (ctDNA) analysis in detecting MRD in CRC patients.

Methods: Plasma samples were prospectively collected from 38 CRC patients, ranging from stage I to IV, who underwent surgical resection. A preoperative blood sample was taken just before surgery and postoperative samples were collected on multiple time-points to monitor the changes of mutation profiles. The extracted nucleic acid from matched surgically resected tumor tissues, peripheral blood cells (PBCs), and plasma were subjected to ultradeep targeted next-generation sequencing (NGS) using Oncomine Pan-Cancer Panel.

Results: Cell-free DNA/RNA (cfDNA/RNA) was extracted from 208 preoperative and postoperative plasma samples with a median input of 20 ng for targeted-NGS (ranged from 8-20 ng). The median of sequencing depth, molecular coverage, and barcode tagging efficiency of the sequencing were 54,000x, 4,642x and 84%, respectively. 74 nonsynonymous mutations were identified from tumor tissues and 64 mutations from the preoperative plasma samples. 41 (64.1%) of the 64 mutations detected in plasma samples were concordantly identified from the tumor tissue DNA. Paired PBCs sequencing identified 11 of the mutations detected from plasma and 4 mutations detected from tumor tissues to be clonal hematopoiesis-related mutations. After the exclusion of clonal hematopoiesis-related mutations, 34 (89.5%) of the 38 patients harbor at least one preoperative mutation either from tumor tissue or plasma to be monitored postoperatively. Fourteen patients were detected with ctDNA mutations from postoperative plasma samples and to date, two of them have developed clinical recurrence. One patient was detected to carry TP53-G245D and KRAS-A146T from both the preoperative plasma and resected-tumor tissue. Both mutations were not detected from plasma during adjuvant chemotherapy. At 4.5 months after the completion of chemotherapy, both mutations were positively detected from plasma with no signs of radiologic or clinical evidence of recurrence. Clinical recurrence was confirmed by PET scan 3 months after the detection of molecular recurrence from ctDNA. Similarly, positive ctDNA mutations also preceded radiologic and clinical evidence of recurrence by 3.5 months in another patient who has developed recurrence.

Conclusions: Our current results indicate that ctDNA analysis allows the detection of MRD in CRC patients. The integration of ctDNA analysis with current standard monitoring guidelines holds great promise in early detection of recurrence to allow clinical intervention to be applied promptly.

Citation Format: Hiu Ting Chan, Satoshi Nagayama, Yoon Ming Chin, Masumi Otaki, Rie Hayashi, Kazuma Kiyotani, Yosuke Fukunaga, Masashi Ueno, Yusuke Nakamura, Siew-Kee Low. Next-generation sequencing of circulating tumor DNA for detecting minimal residual disease and predicting recurrence in colorectal cancer patients [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr A46.

The application of dynamic monitoring of circulating tumor DNA for detecting minimal residual disease and predicting recurrence in colorectal cancer patients

e15531

Background: Although the prognosis of colorectal cancer (CRC) has improved in the past decade, a subset of CRC patients may still suffer from relapse due to the progression from minimal residual disease (MRD) after surgical resection. A sensitive and non-invasive method to detect MRD and early diagnosis of recurrence disease is warranted to start therapeutic interventions at an earlier timing and improving the overall survival rate. In this study, we have evaluated the feasibility of circulating tumor DNA (ctDNA) analysis to detect MRD and early detection of recurrence in CRC patients. Methods: Plasma samples were collected prospectively from 38 CRC patients (stage I to IV), who underwent surgical resection. Preoperative blood samples were obtained just before surgery and post-operative samples were collected at multiple time-points to monitor the changes of tumor mutation profiles. Tumor-derived mutations were detected in preoperative blood samples as well as surgically resected-tumor tissues using ultradeep targeted next generation sequencing. Patient-paired peripheral blood cells (PBCs) were sequenced concurrently to exclude clonal hematopoiesis-related mutations. Results: Among the 38 patients, 74 non-synonymous mutations were identified in tumor tissues and 64 mutations in the preoperative plasma samples. Paired PBCs sequencing identified 11 mutations in plasma samples to be clonal hematopoiesis-related mutations. After the exclusion of clonal hematopoiesis-related mutations, 34 (89.5%) of the 38 patients harbors at least one somatic mutation either from tumor tissues or plasma samples to be monitored longitudinally. ctDNA was detectable in 5 of 14 (36%) post-surgical samples of patients who did not receive adjuvant chemotherapy and in 9 of 18 (50%) post-chemotherapy samples. Up to date, 6 patients have been detected with clinical recurrence and ctDNA analysis identified all 6 recurrences before imaging. Serial ctDNA analyses were able to detect disease recurrence up to 6 months before imaging tests. Furthermore, all patients that were ctDNA negative post-operative or post-chemotherapy showed no signs of clinical relapse. Conclusions: Our current results indicate that ctDNA analysis allows the detection of MRD in CRC patients. The integration of ctDNA analysis with current standard monitoring guidelines holds great promise in early detection of recurrence to allow clinical intervention to be applied promptly.

Impact of older age on clinicopathological and prognostic features of colon cancer in postmenopausal women

To clarify the clinicopathological features of colorectal cancer in older people, systematic studies considering age, sex, and the tumor locus is needed. We focused on colon cancer in postmenopausal women (<70 years, n = 68 vs. ≥70 years, n = 85), and examined the effect of age on clinicopathological features. Rates of medullary carcinoma /mucinous carcinoma were higher and pathological stages at diagnosis were less advanced in patients ≥70 years compared with <70 years. Matching pathological stages, no significant difference in disease-free interval was observed according to age; however, disease-specific survival (DSS) was poorer in patients ≥70 years than <70 years, being significantly different in stage IV cases. Regarding post-metastasis/recurrence (met/rec) cases, chemotherapy and surgery for metastasis were less frequent in those aged ≥70 years than <70 years. Post-met/rec DSS was poorer in ≥70 years, those with microsatellite instability, and those without surgery for met/rec than in each counterpart; however, post-met/rec chemotherapy exhibited no effect. Multivariate analyses revealed that an older age and no surgery for metastasis were independent predictors of disease-specific death. These findings remained after excluding stage IV cases. Older age was a potent risk factor of rapid disease-specific death after met/rec.

Needlescopic surgery for very low rectal cancer with no abdominal skin incision

INTRODUCTION

Needlescopic surgery (NS) is a minimally invasive operation beyond traditional laparoscopic surgery. This study aimed to describe NS for intersphincteric resection (ISR) and abdominoperineal resection (APR) for low rectal cancer without a small abdominal skin incision for extracting the specimen and to evaluate the safety and feasibility of the operation.

METHODS

From January 2011 to April 2016, 36 patients underwent NS for either ISR or APR. By definition, NS for ISR or APR at our institution uses three 3-mm ports and two 5-mm ports at the umbilicus and in the right lower quadrant. The specimen was extracted through the anus or the perineal wound. The feasibility of this operation was determined based on short-term outcomes and pathological findings.

RESULTS

No patients required conversion to open surgery. The mean operation time was 299 minutes, and the mean estimated blood loss was 30 mL. Postoperative complications higher than Clavien-Dindo grade III occurred in 2.8% of patients (n = 1). The median number of harvested lymph nodes was 16 (range, 0-30), and in no case was there a positive circumferential resection margin.

CONCLUSIONS

Needlescopic surgery for ISR or APR is technically safe and feasible for low rectal cancer based on the short-term outcomes and the oncological quality, particularly when compared to conventional laparoscopic surgery as described in previous reports.

Laparoscopic-endoscopic cooperative surgery for ileal lipoma: A case report

This is the first report of laparoscopic-endoscopic cooperative surgery (LECS) for an ileal tumor. A 50-year-old man was admitted to our hospital with a positive fecal occult blood test. Colonoscopy detected a submucosal tumor with intussusception located in the ileum, 10 cm oral from the Bauhin valve. On further examination, he was diagnosed with an ileal lipoma. There were no signs of malignancy. LECS was performed for the ileal tumor. After submucosal elevation by injecting saline solution, a mucosal incision was made circumferentially along the tumor. A full-thickness incision was created endoscopically and laparoscopically on the circumferential mucosal incisional line. The tumor was withdrawn intraluminally by endoscopy. The defect of the ileal wall was closed laparoscopically in an axial direction with linear staplers. Histologically, the tumor was a 25-mm ileal lipoma with negative resection margins and no malignancy.

Laparoscopic multivisceral resection for locally advanced colon cancer: a single-center analysis of short- and long-term outcomes

PURPOSE

We evaluated the technical and oncological safety of laparoscopic multivisceral resection (MVR) in selected patients with locally advanced colon cancer (LACC).

METHODS

We compared the clinical backgrounds, and short- and long-term outcomes of patients who underwent laparoscopic vs. those who underwent open MVR for LACC en bloc at our hospital.

RESULTS

Between January, 2004 and December, 2015, 140 patients underwent MVR of the primary tumor en bloc via laparoscopic surgery (laparoscopic group; LG, n = 69) or open surgery (open group; OG, n = 71). Laparoscopic surgery was selected mainly for tumors that invaded the bladder and abdominal wall. The LG patients had smaller tumors (60 vs. 80 mm, p < 0.001), less blood loss (30 vs. 181 g, p < 0.001), and shorter hospital stays (12 vs. 19 days, p < 0.001) than the OG patients. Open conversion was required for two patients. Postoperative complications and R0 resection were comparable between the groups. Local recurrence occurred in two LG patients and two OG patients. The 5-year cancer-specific survival, disease-free survival, and local disease-free survival of patients with pT4b disease were not significantly different between the LG and OG groups (90.3% vs. 75.2%, 71.2% vs. 67.6%, and 97.1% vs. 94.2%).

CONCLUSION

Although the LG included patients with lower risk, the short- and long-term outcomes were equivalent to those of the OG, which included patients with higher risk.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the management of patients with intermediate and advanced/relapsed hepatocellular carcinoma: a TOS-ESMO initiative endorsed by CSCO, ISMPO, JSMO, KSMO, MOS and SSO

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of hepatocellular carcinoma (HCC) was published in 2018, and covered the diagnosis, management, treatment and follow-up of early, intermediate and advanced disease. At the ESMO Asia Meeting in November 2018 it was decided by both the ESMO and the Taiwan Oncology Society (TOS) to convene a special guidelines meeting immediately after the Taiwan Joint Cancer Conference (TJCC) in May 2019 in Taipei. The aim was to adapt the ESMO 2018 guidelines to take into account both the ethnic and the geographic differences in practice associated with the treatment of HCC in Asian patients. These guidelines represent the consensus opinions reached by experts in the treatment of patients with intermediate and advanced/relapsed HCC representing the oncology societies of Taiwan (TOS), China (CSCO), India (ISMPO) Japan (JSMO), Korea (KSMO), Malaysia (MOS) and Singapore (SSO). The voting was based on scientific evidence, and was independent of the current treatment practices, the drug availability and reimbursement situations in the individual participating Asian countries.

Laparoscopic and robotic lateral lymph node dissection for rectal cancer

In the era of neoadjuvant chemoradiotherapy/radiotherapy and total mesorectal excision, overall oncological outcomes after curative resection of rectal cancer are excellent, with local recurrence rates as low as 5–10%. However, lateral nodal disease is a major cause of local recurrence after neoadjuvant chemoradiotherapy/radiotherapy and total mesorectal excision. Patients with lateral nodal disease have a local recurrence rate of up to 30%. The oncological benefits of lateral pelvic lymph node dissection (LPLND) in reducing local recurrence, particularly in the lateral compartment, have been demonstrated. Although LPLND is not standard in Western countries, technical improvements in minimally invasive surgery have resulted in rapid technical standardization of this complicated procedure. The feasibility and short- and long-term outcomes of laparoscopic and robotic LPLND have been reported widely. A minimally invasive approach has the advantages of less bleeding and providing a better surgical view of the deep pelvic anatomy than an open approach. With precise autonomic nerve preservation, postoperative genitourinary dysfunction has been reported to be minimal. We review recent evidence on the management of lateral nodal disease in rectal cancer and technical improvements of LPLND, focusing on laparoscopic and robotic LPLND.

A case of severe megacolon due to acquired isolated hypoganglionosis after low anterior resection for lower rectal cancer

Acquired isolated hypoganglionosis is a rare intestinal neurological disease, which presents in adulthood with the clinical symptoms of chronic constipation. A 39-year-old man underwent laparoscopic low anterior resection and covering ileostomy for locally advanced-rectal cancer. A 6-month course of postoperative adjuvant chemotherapy was completed, followed by closure of the ileostoma. After the closure, he developed severe colitis which required 1-month of hospitalization. Mucosal erosions and pseudo-membrane formation were evident on colonoscopy and severe mucosal damage characterized by infiltration of inflammatory cells and crypt degeneration were pathologically confirmed. Even after the remission of the colitis, he suffered from severe constipation and distention. At 4 years after the stoma closure, he decided to undergo laparoscopic total colectomy. Histopathologically, the nerve fibers and ganglion cells became gradually scarcer from the non-dilated to dilated regions. Immunohistochemical staining examination confirmed that the ganglion cells gradually decreased and became degenerated from the normal to dilated region, thereby arriving at the final diagnosis of isolated hypoganglionosis. The patient recovered without any complications and there has been no evidence of any relapse of the symptoms. We present a case of acquired isolated hypoganglionosis-related megacolon, which required laparoscopic total colectomy, due to severe enterocolitis following stoma closure.

Combination gemcitabine plus S-1 versus gemcitabine plus cisplatin for advanced/recurrent biliary tract cancer: the FUGA-BT (JCOG1113) randomized phase III clinical trial

BACKGROUND

Gemcitabine plus cisplatin (GC) is the standard treatment of advanced biliary tract cancer (BTC); however, it causes nausea, vomiting, and anorexia, and requires hydration. Gemcitabine plus S-1 (GS) reportedly has equal to, or better, efficacy and an acceptable toxicity profile. We aimed to confirm the non-inferiority of GS to GC for patients with advanced/recurrent BTC in terms of overall survival (OS).

PATIENTS AND METHODS

We undertook a phase III randomized trial in 33 institutions in Japan. Eligibility criteria included chemotherapy-naïve patients with recurrent or unresectable BTC, an Eastern Cooperative Oncology Group Performance Status of 0 - 1, and adequate organ function. The calculated sample size was 350 with a one-sided α of 5%, a power of 80%, and non-inferiority margin hazard ratio (HR) of 1.155. The primary end point was OS, while the secondary end points included progression-free survival (PFS), response rate (RR), adverse events (AEs), and clinically significant AEs defined as grade ≥2 fatigue, anorexia, nausea, vomiting, oral mucositis, or diarrhea.

RESULTS

Between May 2013 and March 2016, 354 patients were enrolled. GS was found to be non-inferior to GC [median OS: 13.4 months with GC and 15.1 months with GS, HR, 0.945; 90% confidence interval (CI), 0.78-1.15; P = 0.046 for non-inferiority]. The median PFS was 5.8 months with GC and 6.8 months with GS (HR 0.86; 95% CI 0.70-1.07). The RR was 32.4% with GC and 29.8% with GS. Both treatments were generally well-tolerated. Clinically significant AEs were observed in 35.1% of patients in the GC arm and 29.9% in the GS arm.

CONCLUSIONS

GS, which does not require hydration, should be considered a new, convenient standard of care option for patients with advanced/recurrent BTC.

CLINICAL TRIAL NUMBER

This trial has been registered with the UMIN Clinical Trials Registry (http://www.umin.ac.jp/ctr/index.htm), number UMIN000010667.

Comprehensive Comparative Analysis of Prognostic Value of Systemic Inflammatory Biomarkers for Patients with Stage II/III Colon Cancer

BACKGROUND

Among numerous systemic inflammatory biomarkers, it remains unclear which is the most prognostic for patients with stage II/III colon cancer. We aimed to compare the prognostic significance of systemic inflammatory biomarkers among patients with stage II/III colon cancer.

METHODS

We included 1303 patients with stage II/III colon cancer who underwent potentially curative resection from July 2004 to December 2013. Sixteen systemic inflammatory biomarkers-derived from combinations of neutrophils, lymphocytes, monocytes, platelets, C-reactive protein (CRP), and albumin-were compared to identify the biomarker most associated with overall survival (OS) and disease-free survival (DFS) using receiver operating characteristic (ROC) curve analysis.

RESULTS

Nine inflammatory biomarkers were predictive for OS, among which lymphocyte-to-CRP ratio (LCR), CRP-to-albumin ratio (CAR), neutrophil × CRP, monocyte × CRP, and platelet × CRP were also predictive for DFS. Among these five inflammatory biomarkers, the area under the curve (AUC) value was highest (0.630) for LCR, being significantly higher than that for neutrophil × CRP (P = 0.010), monocyte × CRP (P = 0.007), or platelet × CRP (P = 0.010) for OS. When the prognostic impact of LCR and CAR were analyzed by multivariate analysis, only LCR was an independent predictor of both OS [hazard ratio (HR), 1.77; 95% confidence interval (CI), 1.23-2.60; P = 0.002] and DFS (HR, 1.29; 95% CI, 1.00-1.66; P = 0.048).

CONCLUSIONS

LCR may be the most useful predictive factor for OS and DFS in patients with stage II or III colon cancer.