The effect of preoperative endoscopic tattooing using India ink on lymph node yield in laparoscopic colectomy for stage I right-sided colon cancer.

PURPOSE: The purpose of this study is to evaluate the effect of preoperative endoscopic tattooing using India ink (ETI) on the number of retrieved lymph nodes (LNs) dissected during laparoscopic surgery for stage I right-sided colon cancer (RCC). METHODS: This single-center, retrospective study included stage I RCC patients who underwent laparoscopic surgery between January 2010 and December 2021. The clinicopathological background and number of LNs retrieved were compared between patients managed with and without ETI. A multiple linear regression analysis was used to examine the effect of independent variables on the LN yield. RESULTS: A total of 169 patients were enrolled. Of these, 89 patients (52.7%) were classified into the ETI group, and 80 (47.3%) were classified into the no-ETI group. There were no significant differences in age, sex, body mass index, or tumor progression between the two groups. A univariate analysis showed that the number of LNs retrieved was significantly higher in female (26 vs. 24, p = 0.026), with tumor localization in the ascending or transverse colon (20 in the cecum, 26 in the ascending colon, 27 in the transverse colon, p < 0.001), and with preoperative ETI (28 vs. 21, p < 0.001). In a multivariate linear regression analysis, female sex (p = 0.0011), D3 lymphadenectomy (p = 0.046), and preoperative ETI (p = 0.012) were independently associated with the LN yield. CONCLUSION: In laparoscopic surgery for stage I RCC, preoperative ETI increased the number of LNs retrieved and allowed for appropriate staging.

The usefulness of indocyanine green fluorescence imaging for intestinal perfusion assessment of intracorporeal anastomosis in laparoscopic colon cancer surgery.

PURPOSE: The purpose of this study was to clarify the usefulness of indocyanine green fluorescence imaging (ICG-FI) in the assessment of intestinal vascular perfusion in patients who receive intracorporeal anastomosis (IA) in colon cancer surgery. METHODS: This was a single-center, retrospective study using propensity score matching. We compared the surgical outcomes of colon cancer patients who underwent laparoscopic colonic resection with IA or external anastomosis (EA) with the intraoperative evaluation of anastomotic perfusion using ICG-FI from January 2019 to July 2021. The detection rate of poor anastomotic perfusion by ICG-FI was examined. RESULTS: A total of 223 patients were enrolled. After matching, 69 patients each were classified into the IA and EA groups. There were no significant differences in age, sex, body mass index, tumor localization, or progression between the two groups. The operation time was similar (172 min vs. 171 min, p = 0.62) and the amount of bleeding was significantly lower (0 ml vs. 2 ml, p = 0.0023) in the IA group. The complication rates (grade ≥ 2) of the two groups were similar (14.5% vs. 11.6%, p = 0.59). ICG-FI identified four patients (5.8%) with poor anastomotic perfusion in the IA group, but none in the EA group (p = 0.046). All four patients with poor perfusion in the IA group underwent additional resection; none of these patients developed postoperative complications. CONCLUSION: Poor anastomotic perfusion was detected in 5.8% of cases who underwent laparoscopic colon cancer surgery with IA. ICG-FI is useful for evaluating anastomotic perfusion in IA in order to prevent AL.

Characteristics and clinical outcomes of patients with advanced gastric or gastroesophageal cancer treated in and out of randomized clinical trials of first-line immune checkpoint inhibitors.

BACKGROUND: Although several randomized trials (RCTs) showed survival benefits of immune checkpoint inhibitor (ICI) plus first-line chemotherapy for advanced gastric or gastroesophageal cancer (AGC), these trials could enroll patients who fulfilled the strict eligibility criteria or waited for certain screening period for central assessment of PD-L1 status. METHODS: We retrospectively compared characteristics and clinical outcomes of the patients with AGC who received first-line chemotherapy in control arm of RCTs with ICIs (control group) or clinical practice (practice group) at our institution from February 2016 to April 2019. RESULTS: The control group had a better baseline Eastern Cooperative Oncology Group performance status (PS0, 81.2% vs. 51.4%, p < 0.001) and a longer interval from first visit to first-line chemotherapy initiation (19 days vs. 9 days, p < 0.001) than the practice group. Median overall survival (OS) was 20.3 months in control group and 15.7 months in practice group, with a trend of longer OS in control group than that in practice group (hazard ratio, 0.71; p = 0.062). More patients in control group were treated with subsequent chemotherapy including ICIs. CONCLUSION: Patients with AGC in RCTs of ICIs had a better PS or a higher chance to receive subsequent chemotherapy, resulting in a better prognosis than those treated in clinical practice. This information should be considered when interpreting RCT results and applying new treatments into clinical practice.

Transcriptomic Profiling of MSI-H/dMMR Gastrointestinal Tumors to Identify Determinants of Responsiveness to Anti-PD-1 Therapy.

PURPOSE: Transcriptomic profiling was performed for microsatellite instability-high (MSI-H)/mismatch repair-deficient (dMMR) gastrointestinal tumors to determine the predictors of response to PD-1 blockade. EXPERIMENTAL DESIGN: Thirty-six patients with MSI-H/dMMR gastrointestinal tumors, including gastric cancer, colorectal cancer, cholangiocarcinoma, small intestine cancer, and pancreatic cancer, being treated with PD-1 blockade were analyzed. We conducted the transcriptomic analysis of gastrointestinal tumors using RNA sequencing data, including the consensus molecular subtypes (CMS) of colorectal cancer. RESULTS: Gene set enrichment analysis (GSEA) demonstrated that non-responders had upregulations of epithelial-mesenchymal transition, angiogenesis, hypoxia, mTORC1, TNF-α, KRAS, Wnt/ß-catenin, TGF-ß, and various metabolism-related signaling pathways. Meanwhile, the IFNγ pathway was enriched in responders. On the basis of the leading-edge analysis of GSEA, VEGF-A was significantly correlated with enriched pathways in non-responders. Patients with high VEGF-A expression, compared with those with low expression, had significantly shorter progression-free survival [PFS; median 4.8 months vs. not reached (NR), P = 0.032] and overall survival (median 11.1 months vs. NR, P = 0.045). Among 13 patients with colorectal cancer evaluable for CMS classification, the objective response rate was 100%, 0%, 0%, and 16.7% in CMS1, CMS2, CMS3, and CMS4, respectively. Patients with CMS1 had significantly longer PFS (NR vs. 4.8 months, P = 0.017) than those with CMS2, CMS3, or CMS4. CONCLUSIONS: Several transcriptomic features, including CMS classification and related genes, were associated with response to PD-1 blockade in MSI-H/dMMR gastrointestinal tumors. These findings can help develop predictive biomarkers or combination immunotherapies.

Ascites and resistance to immune checkpoint inhibition in dMMR/MSI-H metastatic colorectal and gastric cancers.

BACKGROUND: Despite unprecedented benefit from immune checkpoint inhibitors (ICIs) in patients with mismatch repair deficient (dMMR)/microsatellite instability high (MSI-H) advanced gastrointestinal cancers, a relevant proportion of patients shows primary resistance or short-term disease control. Since malignant effusions represent an immune-suppressed niche, we investigated whether peritoneal involvement with or without ascites is a poor prognostic factor in patients with dMMR/MSI-H metastatic colorectal cancer (mCRC) and gastric cancer (mGC) receiving ICIs. METHODS: We conducted a global multicohort study at Tertiary Cancer Centers and collected clinic-pathological data from a cohort of patients with dMMR/MSI-H mCRC treated with anti-PD-(L)1 ±anti-CTLA-4 agents at 12 institutions (developing set). A cohort of patients with dMMR/MSI-high mGC treated with anti-PD-1 agents±chemotherapy at five institutions was used as validating dataset. RESULTS: The mCRC cohort included 502 patients. After a median follow-up of 31.2 months, patients without peritoneal metastases and those with peritoneal metastases and no ascites had similar outcomes (adjusted HR (aHR) 1.15, 95% CI 0.85 to 1.56 for progression-free survival (PFS); aHR 0.96, 95% CI 0.65 to 1.42 for overall survival (OS)), whereas inferior outcomes were observed in patients with peritoneal metastases and ascites (aHR 2.90, 95% CI 1.70 to 4.94; aHR 3.33, 95% CI 1.88 to 5.91) compared with patients without peritoneal involvement. The mGC cohort included 59 patients. After a median follow-up of 17.4 months, inferior PFS and OS were reported in patients with peritoneal metastases and ascites (aHR 3.83, 95% CI 1.68 to 8.72; aHR 3.44, 95% CI 1.39 to 8.53, respectively), but not in patients with only peritoneal metastases (aHR 1.87, 95% CI 0.64 to 5.46; aHR 2.15, 95% CI 0.64 to 7.27) when compared with patients without peritoneal involvement. CONCLUSIONS: Patients with dMMR/MSI-H gastrointestinal cancers with peritoneal metastases and ascites should be considered as a peculiar subgroup with highly unfavorable outcomes to current ICI-based therapies. Novel strategies to target the immune-suppressive niche in malignant effusions should be investigated, as well as next-generation ICIs or intraperitoneal approaches.

Lactic acid promotes PD-1 expression in regulatory T cells in highly glycolytic tumor microenvironments.

The balance of programmed death-1 (PD-1)-expressing CD8+ T cells and regulatory T (Treg) cells in the tumor microenvironment (TME) determines the clinical efficacy of PD-1 blockade therapy through the competition of their reactivation. However, factors that determine this balance remain unknown. Here, we show that Treg cells gain higher PD-1 expression than effector T cells in highly glycolytic tumors, including MYC-amplified tumors and liver tumors. Under low-glucose environments via glucose consumption by tumor cells, Treg cells actively absorbed lactic acid (LA) through monocarboxylate transporter 1 (MCT1), promoting NFAT1 translocation into the nucleus, thereby enhancing the expression of PD-1, whereas PD-1 expression by effector T cells was dampened. PD-1 blockade invigorated the PD-1-expressing Treg cells, resulting in treatment failure. We propose that LA in the highly glycolytic TME is an active checkpoint for the function of Treg cells in the TME via upregulation of PD-1 expression.

HLA Class I Analysis Provides Insight Into the Genetic and Epigenetic Background of Immune Evasion in Colorectal Cancer With High Microsatellite Instability.

BACKGROUND & AIMS: A detailed understanding of antitumor immunity is essential for optimal cancer immune therapy. Although defective mutations in the B2M and HLA-ABC genes, which encode molecules essential for antigen presentation, have been reported in several studies, the effects of these defects on tumor immunity have not been quantitatively evaluated. METHODS: Mutations in HLA-ABC genes were analyzed in 114 microsatellite instability-high colorectal cancers using a long-read sequencer. The data were further analyzed in combination with whole-exome sequencing, transcriptome sequencing, DNA methylation array, and immunohistochemistry data. RESULTS: We detected 101 truncating mutations in 57 tumors (50%) and loss of 61 alleles in 21 tumors (18%). Based on the integrated analysis that enabled the immunologic subclassification of microsatellite instability-high colorectal cancers, we identified a subtype of tumors in which lymphocyte infiltration was reduced, partly due to reduced expression of HLA-ABC genes in the absence of apparent genetic alterations. Survival time of patients with such tumors was shorter than in patients with other tumor types. Paradoxically, tumor mutation burden was highest in the subtype, suggesting that the immunogenic effect of accumulating mutations was counterbalanced by mutations that weakened immunoreactivity. Various genetic and epigenetic alterations, including frameshift mutations in RFX5 and promoter methylation of PSMB8 and HLA-A, converged on reduced expression of HLA-ABC genes. CONCLUSIONS: Our detailed immunogenomic analysis provides information that will facilitate the improvement and development of cancer immunotherapy.

The Prognostic Impact of KRAS G12C Mutation in Patients with Metastatic Colorectal Cancer: A Multicenter Retrospective Observational Study.

BACKGROUND: KRAS is one of the most frequently mutated oncogenes in colorectal cancer (CRC). Recently, a novel therapy targeting KRAS G12C mutation has demonstrated promising activities for corresponding advanced solid tumors, including metastatic CRC (mCRC). However, the prognostic impact of the KRAS G12C mutation remains unclear in patients with mCRC. MATERIALS AND METHODS: We retrospectively reviewed medical records of patients with mCRC who received first-line chemotherapy between January 2005 and December 2017 at four large oncology facilities in Japan. Survival outcomes were compared between patients with KRAS G12C and those with non-G12C mutations. RESULTS: Among 2,457 patients with mCRC, 1,632 met selection criteria, and of these, 696 had KRAS exon 2 mutations, including 45 with KRAS G12C mutation tumors. Patient characteristics were not significantly different between the KRAS G12C and non-G12C groups. At a median follow-up of 64.8 months, patients with the KRAS G12C mutation showed significantly shorter first-line progression-free survival (PFS; median, 9.4 vs. 10.8 months; p = .015) and overall survival (OS; median, 21.1 vs. 27.3 months; p = .015) than those with non-G12C mutations. Multivariate analysis also showed that KRAS G12C mutation was significantly associated with shorter PFS (hazard ratio [HR], 1.43; 95% confidence interval [CI], 1.04-1.96, p = .030) and OS (HR, 1.42; 95% CI, 1.01-2.00; p = .044). CONCLUSION: We demonstrate that, compared with non-G12C mutations, KRAS G12C mutation is significantly correlated with shorter first-line PFS and OS. These findings indicate the relevance of a stratified treatment targeting KRAS G12C mutation in mCRC. IMPLICATIONS FOR PRACTICE: Among patients with KRAS exon 2 mutated metastatic colorectal cancer (mCRC), median progression-free survival (PFS) and overall survival (OS) were 9.4 and 21.1 months, respectively, for G12C mutation and 10.8 and 27.3 months, respectively, for patients with non-G12C mutations, indicating significantly shorter PFS (hazard ratio [HR], 1.47; 95% confidence interval [CI], 1.08-2.01; p = .015) and OS (HR, 1.50; 95% CI, 1.08-2.08; p = .015) in patients with G12C mutation than in those with non-G12C mutations. Furthermore, multivariate analysis showed that KRAS G12C mutation was independently associated with shorter first-line PFS and OS. Thus, these findings underscore the relevance of a stratified treatment targeting KRAS G12C mutation in mCRC.

Efficacy and safety of trifluridine/tipiracil plus bevacizumab and trifluridine/tipiracil or regorafenib monotherapy for chemorefractory metastatic colorectal cancer: a retrospective study.

BACKGROUND: The C-TASK-FORCE phase I/II and Danish randomized phase II trials reported the promising efficacy of trifluridine/tipiracil (TAS102) plus bevacizumab (BEV) in patients with chemorefractory metastatic colorectal cancer (mCRC). However, there had been no direct comparative phase III trial to compare the efficacy between TAS102 plus BEV and standard therapy with either TAS102 or regorafenib monotherapy. METHODS: We retrospectively reviewed the medical records of patients with mCRC who received TAS102 plus BEV, TAS102 monotherapy, or regorafenib monotherapy after standard chemotherapies during 2013-2019. RESULTS: Patients received TAS102 plus BEV (n = 139), TAS102 monotherapy (n = 153), or regorafenib monotherapy (n = 133). With a median follow-up of 25.3 months, median overall survival (OS) was 11.5 months [95% confidence interval (CI), 9.9-13.9] for TAS102 plus BEV, 8.1 months (95% CI, 6.8-9.2) for TAS102 monotherapy, and 6.8 months (95% CI, 5.7-8.5) for regorafenib monotherapy. The hazard ratios were 0.67 (95% CI, 0.51-0.88) for TAS102 plus BEV versus TAS102 monotherapy and 0.71 (95% CI, 0.54-0.94) for TAS102 plus BEV versus regorafenib monotherapy. Median progression-free survival (PFS) was 4.4 months (95% CI, 3.7-5.4) for TAS102 plus BEV, 2.5 months (95% CI, 1.6-2.3) for TAS102 monotherapy, and 2.1 months (95% CI, 1.6-2.3) for regorafenib monotherapy. The hazard ratios were 0.57 (95% CI, 0.45-0.73) for TAS102 plus BEV versus TAS102 monotherapy and 0.44 (95% CI, 0.34-0.58) for TAS102 plus BEV versus regorafenib monotherapy. On multivariate analysis, TAS102 plus BEV was independently correlated with better OS and PFS. No unexpected adverse events were observed in any group. CONCLUSION: Our study shows that OS and PFS are longer in patients treated with TAS102 plus BEV than in those treated with TAS102 or regorafenib monotherapy.

A Low Tumor Mutational Burden and PTEN Mutations Are Predictors of a Negative Response to PD-1 Blockade in MSI-H/dMMR Gastrointestinal Tumors.

PURPOSE: This study performed a comprehensive molecular characterization of microsatellite instability-high (MSI-H)/mismatch repair-deficient (dMMR) gastrointestinal (GI) tumors to elucidate predictors of response to PD-1 blockade. EXPERIMENTAL DESIGN: Forty-five patients with MSI-H/dMMR GI tumors, including gastric cancer, colorectal cancer, cholangiocarcinoma, small intestine cancer, pancreatic cancer, and duodenal cancer, receiving PD-1 blockade were analyzed. We conducted the genomic profiling of GI tumors by whole-exome sequencing or targeted next-generation sequencing. The tumor microenvironment was evaluated by transcriptomic analysis and multiplex fluorescence IHC. RESULTS: Patients with low tumor mutational burdens (TMBs) had lower objective response rates (ORRs; 0% vs. 48.8%) and a significantly shorter progression-free survival (PFS; 2.3 vs. 15.6 months; HR, 6.20; P = 0.002) than those with high TMBs. Among common gene alterations in GI tumors, only PTEN mutations, which were mutually exclusive with a low TMB, were significantly associated with a lower ORRs than wild-type PTEN (21.4 vs. 54.8%; odds, 4.45; P = 0.045). Compared with wild-type PTEN, PTEN mutations in the phosphatase domain were associated with significantly lower ORRs (12.5 vs. 54.8%; P = 0.049), shorter PFS (2.6 vs. 15.6 months; HR, 5.04; P < 0.001), lower intratumoral CD8+ T-cell levels, higher intratumoral CD204+ macrophage levels, and PI3K/AKT/mTOR pathway enrichment, whereas PTEN mutations in the C2 domain were not. CONCLUSIONS: Low TMBs and PTEN mutations, especially mutations in the phosphatase domain associated with an immunosuppressive environment, were mutually exclusive and might be negative predictors of PD-1 blockade responses in patients with MSI-H/dMMR GI tumors.

Survival Benefit of Crossover Administration of Regorafenib and Trifluridine/Tipiracil Hydrochloride for Patients With Metastatic Colorectal Cancer: Exploratory Analysis of a Japanese Society for Cancer of the Colon and Rectum Multicenter Observational Study (REGOTAS).

Background: The survival benefits of regorafenib (REG) and trifluridine/tipiracil hydrochloride (TFTD) have been demonstrated in chemorefractory patients with metastatic colorectal cancer (mCRC). However, the effects of crossover administration of REG and TFTD on patient survival remain unclear. The present study evaluated the association between exposure to REG and TFTD and overall survival (OS) in patients with mCRC using data from the REGOTAS study. Patients and Methods: We analyzed patients registered in the REGOTAS study, which retrospectively compared the efficacy and safety of use of REG or TFTD as later-line chemotherapy for chemorefractory mCRC patients. We compared the survival outcomes of cohort A (treated using both REG and TFTD) and cohort B (treated using either REG or TFTD). Results: A total of 550 patients (cohort A, n = 252; cohort B, n = 298) met the inclusion criteria. The median OS was significantly increased in cohort A compared with cohort B [9.6 months (95% confidence interval (CI), 8.9-10.9 months) vs. 5.2 months (95% CI, 4.4-6.0 months), P < 0.001]. Multivariate analysis revealed that cohort A was independently associated with a significant increase in OS [A vs. B: Hazard ratios (HR), 0.58; 95% CI, 0.47-0.72; P < 0.001]. Subgroup analysis adjusted using multivariate Cox model revealed a consistently better trend in most subgroups for cohort A compared with cohort B. Conclusions: Our study revealed prolonged survival in patients treated with REG and TFTD. Therefore, all active agents, including REG and TFTD, should be made available to mCRC patients.

A novel risk-scoring system for predicting lymph node metastasis of rectal neuroendocrine tumors.

AIM: Although rectal neuroendocrine tumors (NETs) are considered to be rare low-grade malignancies when lymph node metastasis (LNM) is present, their degree of malignancy is comparable to that of colorectal cancer (CRC). However, it remains unclear as to which patients require radical lymph node dissection. The aim of this study was to elucidate the risk factors for LNM and develop a risk-scoring system for LNM to help determine appropriate therapeutic approaches. METHODS: In this study, we examined 103 patients with rectal NETs who underwent local resection (n = 55) or radical resection with LN dissection (n = 48). We evaluated each pathological feature, including the depth of submucosal invasion (SM depth) and tumor budding grade. RESULTS: According to our univariate analyses and previous reports, the significant five risk factors for LNM were weighted with point values: 2 points for tumor size ≥ 15 mm and muscularis invasion, and 1 point each for SM depth ≥ 2000 µm, positive lymphovascular invasion, budding grade 3, and vertical margin. The area under the receiver operating curve for the scoring system was 0.899 (95% CI: 0.843-0.955). When a score of 2 was used as the cut-off value, the sensitivity and specificity for the prediction of LNM were 100% and 72.1%, respectively. CONCLUSIONS: The risk-scoring system for LNM of rectal NETs showed high diagnostic performance. Using this risk-scoring system, it is possible to predict the risk of LNM and thereby potentially avoid unnecessary surgery. Further prospective external validation studies should be performed. The study was registered in the Japanese Clinical Trials Registry as UMIN000036658.

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.

Spontaneous regression of transverse colon cancer: a case report.

Spontaneous regression (SR) of many malignant tumors has been well documented, with an approximate incidence of one per 60,000-100,000 cancer patients. However, SR of colorectal cancer (CRC) is very rare, accounting for less than 2% of such cases. We report a case of SR of transverse colon cancer in an 80-year-old man undergoing outpatient follow-up after surgical treatment of early gastric cancer. Colonoscopy (CS) revealed a Borrmann type II tumor in the transverse colon measuring 30 × 30 mm. Because the patient underwent anticoagulant therapy, we did not perform a biopsy at that time. A second CS was performed 1 week after the initial examination and revealed tumor shrinkage to a diameter of 20 mm and a shift to the Borrmann type III morphology. Biopsy revealed a poorly differentiated adenocarcinoma. One week after the second CS, we performed a partial resection of the transverse colon and D2 lymph node dissection. Histopathology revealed inflammatory cell infiltration and fibrosis from the submucosal to muscularis propria layers in the absence of cancer cells, leading to pathological staging of pStage 0 (T0N0). The patient had an uneventful recovery, and CS performed at 5 months postoperatively revealed the absence of a tumor in the colon and rectum. The patient continues to be followed up as an outpatient at 12 months postoperatively, and no recurrence has been observed.