Recurrence-free survival as a surrogate endpoint for overall survival after neoadjuvant chemotherapy and surgery for oesophageal squamous cell carcinoma.

BACKGROUND: Overall survival is considered as one of the most important endpoints of treatment efficacy but often requires long follow-up. This study aimed to determine the validity of recurrence-free survival as a surrogate endpoint for overall survival in patients with surgically resectable advanced oesophageal squamous cell carcinoma (OSCC). METHODS: Patients with OSCC who received neoadjuvant cisplatin and 5-fluorouracil, or docetaxel, cisplatin and 5-fluorouracil, at 58 Japanese oesophageal centres certified by the Japan Esophageal Society were reviewed retrospectively. The correlation between recurrence-free and overall survival was assessed using Kendall's τ. RESULTS: The study included 3154 patients. The 5-year overall and recurrence-free survival rates were 56.6 and 47.7% respectively. The primary analysis revealed a strong correlation between recurrence-free and overall survival (Kendall's τ 0.797, 95% c.i. 0.782 to 0.812) at the individual level. Subgroup analysis showed a positive relationship between a more favourable pathological response to neoadjuvant chemotherapy and a higher τ value. In the meta-regression model, the adjusted R2 value at the institutional level was 100 (95% c.i. 40.2 to 100)%. The surrogate threshold effect was 0.703. CONCLUSION: There was a strong correlation between recurrence-free and overall survival in patients with surgically resectable OSCC who underwent neoadjuvant chemotherapy, and this was more pronounced in patients with a better response to neoadjuvant chemotherapy.

Evaluation of the prognostic impact of pathologic tumor regression grade on patients with colorectal cancer after preoperative chemoradiotherapy.

BACKGROUND: The prognostic value of the pathological response to preoperative chemoradiotherapy (CRT) in rectal cancer (RC) remains unknown. OBJECTIVES: We aimed to assess the predictive value of the response to CRT that was derived from an evaluation of the histological findings (whole-section vs. representative-section sampling) and attempted to determine an objective cut-off value for the tumor regression grade (TRG). METHODS: We examined the association of the TRG with the outcomes (recurrence-free survival [RFS] and overall survival [OS]) of 78 patients with RC. Patients with RC treated with preoperative CRT were divided into development (30 cases) and validation (48 cases) cohorts. The TRG was classified as grades I (Ia, Ib), II, and III. The cut-off value was determined by receiver operating characteristic (ROC) curve analysis. RESULTS: The TRG determined from whole-section sampling versus representative-section sampling was more strongly correlated with patient survival. We found that in both cohorts, patients with a cut-off value of <73% had a poor prognosis. Finally, the cut-off value was found to be an independent predictive factor in both univariate and multivariate analysis. CONCLUSIONS: The TRG that was used to evaluate patients with RC who underwent preoperative CRT was an independent prognostic factor for outcome.

Biomarker-oriented chemo-immunotherapy for advanced gastric cancer.

The biomarker-oriented chemo-immunotherapy is useful and promising in the development of new anticancer agents, since the responders can be enriched by selecting patients with biomarkers. Compared to colorectal and lung cancers, the development of biomarker-driven molecular-targeted therapeutics for gastric cancers has been straggled. However, several new biomarkers in gastric cancers have been discovered and clinical trials in enrichment design with certain biomarkers have been conducted. Therefore, there are currently several treatment options to treat gastric cancer patients based on individual biomarker-oriented strategies. In the present review, we describe the useful biomarkers in gastric cancer, with focusing on HER2, PD-L1, and Claudin18.2, in relation to their clinical significance and associated targeted agents.

Prognostic impact and survival outcomes of colon perforation in patients with metastatic colorectal cancer: a multicenter retrospective cohort study.

BACKGROUND: Colon perforation caused by colorectal cancer (CRC) is a fatal condition requiring emergency intervention. For patients with metastatic lesions, surgeons face difficult decisions regarding whether to resect the primary and metastatic lesions. Moreover, there is currently no established treatment strategy for these patients. This study aimed to investigate the clinical practice and long-term outcomes of patients with metastatic CRC diagnosed with the onset of colon perforation. METHODS: We performed a population-based multicenter cohort study. Consecutive patients diagnosed with stage IV CRC between 2008 and 2015 at all designated cancer hospitals in Fukushima Prefecture, Japan, were enrolled in this study. We evaluated the impact of colon perforation on the survival outcomes of patients with metastatic CRC. The main outcome was the adjusted hazard ratio (aHR) of perforation for overall survival (OS). Survival time and HRs were estimated using Kaplan‒Meier and Cox proportional regression analyses. RESULTS: A total of 1258 patients were enrolled (perforation: n = 46; non-perforation: n = 1212). All but one of the patients with perforation underwent primary resection or colostomy and 25 cases were able to receive chemotherapy. The median OS for the perforation and non-perforation groups was 19.0 and 20.0 months, respectively (p = 0.96). Moreover, perforation was not an independent prognostic factor (aHR: 0.99; 95% confidence interval: 0.61-1.28). CONCLUSIONS: In metastatic CRC, perforation is not necessarily a poor prognostic factor. Patients with perforation who undergo primary tumor resection or colostomy and prompt initiation of systemic chemotherapy might be expected to have a survival time similar to that of patients with non-perforated colon.

The real-world data of immune-checkpoint inhibitor combination therapy for unresectable or metastatic esophageal cancer: a multi-institutional cohort study.

BACKGROUND: The real-world efficacy, feasibility, and prognostic factors of immune-checkpoint inhibitor combination therapy for unresectable or metastatic esophageal cancer are not fully established. METHODS: This multi-institutional retrospective cohort study evaluated 71 consecutive patients treated with immune-checkpoint inhibitor combination therapy for esophageal cancer between March 2021 and December 2022. We assessed tumor response, safety, and long-term survival. RESULTS: In patients with measurable lesions, the response rate was 58%, and the disease control rate for all enrolled patients was 80%. Five patients (7.0%) underwent successful conversion surgery. Grade 3 or higher immune-related adverse events occurred in 13% of patients, and one patient (1.4%) died due to cholangitis. Median progression-free survival was 9.7 (95% confidence interval: 6.5-not reached). C-reactive protein levels and performance status were identified as significant predictors of progression-free survival through Cox proportional hazards analysis. CONCLUSIONS: Immune-checkpoint inhibitor combination therapy for esophageal cancer demonstrated comparable tumor response, safety, and long-term survival to previous randomized clinical trials. Patients with good performance status and low C-reactive protein levels may be suitable candidates for this treatment.

TGFß-Responsive Stromal Activation Occurs Early in Serrated Colorectal Carcinogenesis.

Activated TGFß signaling in the tumor microenvironment, which occurs independently of epithelial cancer cells, has emerged as a key driver of tumor progression in late-stage colorectal cancer (CRC). This study aimed to elucidate the contribution of TGFß-activated stroma to serrated carcinogenesis, representing approximately 25% of CRCs and often characterized by oncogenic BRAF mutations. We used a transcriptional signature developed based on TGFß-responsive, stroma-specific genes to infer TGFß-dependent stromal activation and conducted in silico analyses in 3 single-cell RNA-seq datasets from a total of 39 CRC samples and 12 bulk transcriptomic datasets consisting of 2014 CRC and 416 precursor samples, of which 33 were serrated lesions. Single-cell analyses validated that the signature was expressed specifically by stromal cells, effectively excluding transcriptional signals derived from epithelial cells. We found that the signature was upregulated during malignant transformation and cancer progression, and it was particularly enriched in CRCs with mutant BRAF compared to wild-type counterparts. Furthermore, across four independent precursor datasets, serrated lesions exhibited significantly higher levels of TGFß-responsive stromal activation compared to conventional adenomas. This large-scale analysis suggests that TGFß-dependent stromal activation occurs early in serrated carcinogenesis. Our study provides novel insights into the molecular mechanisms underlying CRC development via the serrated pathway.

[365 Days in Newly Opened Cancer Treatment Center in Core Hospital of Mountainous Area].

The declining birthrate and aging population is one of the social issues in mountainous area in Japan. One regional core hospital at Aizu area in Fukushima prefecture opened cancer treatment center in these area in July, 2022. A high-performance radiation therapy system was newly installed and operated with the staff of Fukushima Medical University, and several supportive therapy for cancer chemotherapy including appearance care became possible in the center. The patients living in Aizu area can receive advanced treatments including radiation therapy without moving to long-distant bigger cities now. We report multiple preparations and several trials that we have made during one year since the opening of the center.

Outcomes of patients with esophageal squamous cell carcinoma who achieved a pathological complete response in the primary lesion by neoadjuvant treatment: a Japanese nationwide cohort study.

BACKGROUND: Minimal data was reported regarding the characteristics, risks of lymph node metastasis, and prognostic factors in esophageal cancer patients who achieved remarkable response in the primary lesion to neoadjuvant treatment (NAT). METHODS: This study evaluated the nationwide data of esophageal squamous cell carcinoma (ESCC) patients who underwent surgery following NAT in Japan. Of 4484 patients, 300 (6.7%) had ypT0 following NAT and curative esophagectomy. Factors associated with lymph node metastasis and prognosis were analyzed. RESULTS: Neoadjuvant chemotherapy (NAC) and neoadjuvant chemoradiotherapy (NACRT) were administered in 260 (86.2%) and 40 (13.8%) patients, respectively. Pathologically, 72 (24.0%) had lymph node metastasis (residual nodal disease; RND), and pretherapeutic lymph node metastasis was the independent risk factor for RND (odd ratio [OR]: 3.21; 95% confidence interval [CI]: 1.44-8.20; P = 0.008). The 5-year overall and relapse-free survivals were significantly longer in patients with pathological complete response (pCR) than in those with RND (both P < 0.001). Pretherapeutic cT3 or T4a tumors (hazard ratio [HR]: 1.71; 95% CI: 1.02-2.88; P = 0.043), RND (HR: 3.30; 95% CI: 1.98-5.50; P < 0.001), and operative blood loss (Liter, HR: 1.53; 95% CI: 1.07-2.19; P = 0.021) were independent risk factors affecting relapse-free survival in multivariable analysis. CONCLUSIONS: Of patients with ypT0 after NAT, 24.0% had RND, and pretherapeutic lymph node metastasis was the risk factor. In addition, pretherapeutic cT3, or T4a tumors, RND, and operative blood loss were the poor prognosticators in patients with ypT0 after NAT.

Comparison of proton-based definitive chemoradiotherapy and surgery-based therapy for esophageals cell carcinoma: a multi-center retrospective Japanese cohort study.

BACKGROUND: Proton-based, definitive chemoradiotherapy (P-CRT) for esophageal squamous cell carcinoma (ESCC) previously showed comparable survival outcomes with the surgery-based therapy, i.e., neoadjuvant chemotherapy followed by esophagectomy (NAC-S), in a single-institutional study. This study aimed to validate this message in a Japanese multicenter study. METHODS: Eleven Japanese esophageal cancer specialty hospitals have participated. A total of 518 cases with clinical Stage I-IVA ESCC between 2010 and 2019, including 168 P-CRT and 350 NAC-S patients, were enrolled and long-term outcomes were evaluated. Propensity-score weighting analyses with overlap weighting for confounding adjustment were used. RESULTS: The 3-year overall survival (OS) of the P-CRT group was equivalent to the NAC-S group (74.8% vs. 72.7%, hazard ratio [HR]: 0.87, 95% confidence interval [CI]: 0.61-1.25). Although, the 3-year P-CRT group progression-free survival (PFS) was inferior to the NAC-S group (51.4% vs. 59.6%, HR 1.39, 95% CI 1.04-1.85), the progression P-CRT group cases showed better survival than the NAC-S group (HR 0.58, 95% CI 0.38-0.88), largely because of salvage surgery or endoscopic submucosal dissection for local progression. The survival advantage of P-CRT over NAC-S was more pronounced in the cT1-2 (HR 0.61, 95% CI 0.29-1.26) and cStage I-II (HR 0.50, 95% CI 0.24-1.07) subgroups, although this trend was not evident in other populations, such as cT3-4 and cStage III-IVA. CONCLUSIONS: Proton-based CRT for ESCC showed equivalent OS to surgery-based therapy. Especially for patients with cT1-2 and cStage I-II disease, proton-based CRT has the potential to serve as a first-line treatment.

The tumor cell-intrinsic cGAS-STING pathway is associated with the high density of CD8+ T cells after chemotherapy in esophageal squamous cell carcinoma.

BACKGROUND: Chemotherapy has the potential to induce CD8+ T-cell infiltration in the tumor microenvironment (TME) and activate the anti-tumor immune response in several cancers including esophageal squamous cell carcinoma (ESCC). The tumor cell-intrinsic cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway has been known as a critical component for regulating immune cell activation in the TME. However, its effect on the infiltration of immune cells induced by chemotherapy in the ESCC TME has not been investigated. METHODS: We examined the effect of the tumor-cell intrinsic cGAS-STING pathway on the infiltration of CD8+ T cells induced by chemotherapy in ESCC using ESCC cell lines and surgically resected ESCC specimens from patients who received neoadjuvant chemotherapy (NAC). RESULTS: We found that chemotherapeutic agents, including 5-fluorouracil (5-FU) and cisplatin (CDDP), activated the cGAS-STING pathway, consequently inducing the expression of type I interferon and T-cell-attracting chemokines in ESCC cells. Moreover, the tumor cell-intrinsic expression of cGAS-STING was significantly and positively associated with the density of CD8+ T cells in ESCC after NAC. However, the tumor cell-intrinsic expression of cGAS-STING did not significantly impact clinical outcomes in patients with ESCC after NAC. CONCLUSION: Our findings suggest that the tumor cell-intrinsic cGAS-STING pathway might contribute to chemotherapy-induced immune cell activation in the ESCC TME.

M2 tumor-associated macrophages resist to oxidative stress through heme oxygenase-1 in the colorectal cancer tumor microenvironment.

M2 tumor-associated macrophages (M2-TAMs) promote cancer cell proliferation and metastasis in the TME. Our study aimed to elucidate the mechanism of increased frequency of M2-TAMs infiltration in the colorectal cancer (CRC)-TME, focusing on the resistance to oxidative stress through nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In this study, we evaluated the correlation between M2-TAM signature and mRNA expression of antioxidant related genes using public datasets, and the expression level of antioxidants in M2-TAMs by flow cytometry and the prevalence of M2-TAMs expressing antioxidants by immunofluorescence staining using surgically resected specimens of CRC (n = 34). Moreover, we generated M0 and M2 macrophages from peripheral blood monocytes and evaluated their resistance to oxidative stress using the in vitro viability assay. Analysis of GSE33113, GSE39582, and The Cancer Genome Atlas (TCGA) datasets indicated that mRNA expression of HMOX1 (heme oxygenase-1 (HO-1)) was significantly positively correlated with M2-TAM signature (r = 0.5283, r = 0.5826, r = 0.5833, respectively). The expression level of both Nrf2 and HO-1 significantly increased in M2-TAMs compared to M1- and M1/M2-TAMs in the tumor margin, and the number of Nrf2+ or HO-1+M2-TAMs in the tumor stroma significantly increased more than those in the normal mucosa stroma. Finally, generated M2 macrophages expressing HO-1 significantly resisted to oxidative stress induced by H2O2 in comparison with generated M0 macrophages. Taken together, our results suggested that an increased frequency of M2-TAMs infiltration in the CRC-TME is related to Nrf2-HO-1 axis mediated resistance to oxidative stress.

ARID1A deficiency is targetable by AKT inhibitors in HER2-negative gastric cancer.

BACKGROUND: The PI3K/AKT signaling pathway is frequently activated in gastric cancer (GC); however, AKT inhibitors are not effective in unselected GC patients in clinical trials. Mutations in AT-rich interactive domain 1A (ARID1A), which are found in approximately 30% of GC patients, activate PI3K/AKT signaling, suggesting that targeting the ARID1A deficiency-activated PI3K/AKT pathway is a therapeutic candidate for ARID1A-deficient GC. METHODS: The effect of AKT inhibitors was evaluated using cell viability and colony formation assays in ARID1A-deficient and ARID1A knockdown ARID1A-WT GC cells as well as in HER2-positive and HER2-negative GC. The Cancer Genome Atlas cBioPortal and Gene Expression Omnibus microarray databases were accessed to determine the extent of dependence of GC cell growth on the PI3K/AKT signaling pathway. RESULTS: AKT inhibitors decreased the viability of ARID1A-deficient cells and the inhibitory effect was greater in ARID1A-deficient/HER2-negative GC cells. Bioinformatics data suggested that PI3K/AKT signaling plays a greater role in proliferation and survival in ARID1A-deficient/HER2-negative GC cells than in ARID1A-deficient/HER2-positive cells, supporting the higher therapeutic efficacy of AKT inhibitors. CONCLUSIONS: The effect of AKT inhibitors on cell proliferation and survival is affected by HER2 status, providing a rationale for exploring targeted therapy using AKT inhibitors in ARID1A-deficient/HER2-negative GC.

Down-regulation of stimulator of interferon genes (STING) expression and CD8+ T-cell infiltration depending on HER2 heterogeneity in HER2-positive gastric cancer.

BACKGROUND: HER2 signaling might be involved in the regulation of immune cell activation in the tumor microenvironment (TME) of gastric cancer (GC). However, the relationship between HER2 status and immune cell condition in the HER2-positive GC TME is not clearly understood. METHODS: To investigate the effect of HER2 signaling on the activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway, which contributes to immune cell activation in the GC TME, we evaluated the associations among the expressions of HER2, cGAS-STING, and the number of CD8+ tumor-infiltrating lymphocytes (TIL) by considering HER2 heterogeneity in HER2-positive GC tissues. We also examined the effect of HER2 signaling on the activation of STING signaling in vitro using human HER2-positive GC cell lines. RESULTS: The expression of HER2 is highly heterogeneous in HER2-positive GC tissues, and we found that the number of CD8+ TIL in HER2 high areas was significantly lower than that in HER2 low areas in HER2-positive GC tissues. Intriguingly, the tumor cell-intrinsic expression of STING, but not cGAS, was also significantly lower in the HER2 high areas than the HER2 low areas in HER2-positive GC tissues. Moreover, in vitro experiments, we demonstrated that the blockade of HER2 signaling increased the expression of STING and its target genes, including IFNB1, CXCL9/10/11, and CCL5, in HER2-positive GC cell lines. CONCLUSIONS: Our results suggest that HER2 signaling might suppress immune cell activation in the GC TME by inhibiting STING signaling in tumor cells in HER2-positive GC.

Systemic inflammation score as a preoperative prognostic factor for patients with pT2-T4 resectable gastric cancer: a retrospective study.

BACKGROUND: Systemic inflammation has been reported to be associated with cancer progression and metastasis. Systemic inflammation score (SIS), calculated from preoperative serum albumin level and lymphocyte-to-monocyte ratio, has been shown to be a novel prognostic factor for several types of tumors. This study aimed to evaluate the prognostic value of the SIS in patients with pT2-4 resectable gastric cancer (GC). METHODS: Total 97 patients with pT2-4 GC who underwent curative surgery from 322 cases between 2009 and 2015 in Fukushima Medical University Hospital were included. We performed univariate and multivariate analyses to evaluate the usefulness of preoperative SIS and other prognostic factors for relapse-free survival (RFS) and overall survival (OS). RESULTS: The higher SIS score was associated with undifferentiated cancer and recurrence. Univariate analysis of RFS identified deeper tumor invasion and higher SIS were significant risk factors and multivariate analysis revealed that both of them were independent prognostic factors for RFS. As for OS, age, tumor invasion, SIS and LNR were significantly correlated with RFS. In multivariate analysis, tumor invasion, SIS and LNR were independent prognostic factors for OS. CONCLUSIONS: SIS was an independent prognostic factor for RFS and OS in pT2-4 resectable gastric cancer patients who underwent curative gastrectomy.

[The Potential of a Novel Therapeutic Strategy for Colorectal Cancer Targeting the cGAS-STING Pathway].

The cyclic GMP-AMP synthase(cGAS)-stimulator of interferon genes(STING)pathway is one of the important intracellular signaling pathways responsible for the recognition of exogenous DNA and subsequent induction of type Ⅰ interferon responses. Interestingly, in recent years, the importance of the cGAS-STING pathway in promoting anti-tumor immune responses has been highlighted. Decreased expression of cGAS-STING in tumor cells was reported in various cancers, including colorectal cancer(CRC), and it has been found to be involved in inhibiting the anti-tumor immune responses. In our recent investigation, we specifically examined the impact of tumor cell-intrinsic cGAS-STING pathway on the activation of immune cells within the CRC tumor microenvironment, focusing on mismatch repair deficient/microsatellite instability-high (dMMR/MSI-H)and mismatch repair proficient/microsatellite stable(pMMR/MSS)CRCs. We revealed that cGAS-STING expression in tumor cells was decreased in pMMR/MSS CRC compared to dMMR/MSI-H CRC, which correlated with the decreased infiltration of cytotoxic T cells. Here, we discuss the possibility of a novel therapeutic strategy for CRC targeting the tumor cell-intrinsic cGAS-STING pathway based on the findings from recent studies.

[An Abscopal Effect after Palliative Radiotherapy in a Patient with a Locally and Lymph Node Recurrent Gastric Cancer].

Radiotherapy is known to have a high local effect for cancer treatment. However, several reports that radiotherapy could stimulate the anti-tumor effect by releasing endogenous signals and cytokines, increasing the presentation of tumor associated antigens on dendritic cells, and proliferating tumor antigen-specific cytotoxic T lymphocytes have been shown. A tumor regression in both non-irradiated and irradiated fields have observed, which is called"abscopal effect". We report a case of the abscopal effect in adenocarcinoma of the stomach with locally and lymph node recurrence after surgery. A 59-year-old Japanese male was diagnosed with residual stomach cancer and underwent total gastrectomy and distal pancreatectomy. Three months after the surgery, a local recurrence and the involvement of para-aortic lymph node were diagnosed using computed tomography. The chemotherapy treatment(S-1, cisplatin, trastuzumab)was prescribed. However, the disease has progressed. Paclitaxel and ramucirumab were given for second-line, nivolumab for third-line and irinotecan for fourth-line. During that, tumor at local recurrent site invaded to the portal vein. The patients received 50 Gy in 25 fractions of radiotherapy. A remarkable reduction of the mass was shown. In addition to this, we observed that spontaneous shrinking of the para-aortic lymph node metastasis, which was located out of the radiation field. We observed a rare radiation-induced abscopal effect. Radiotherapy might represent a potential candidate for a combination with immunotherapy. A combination of immunotherapy as well as chemotherapy with radiotherapy represents a promising therapeutic strategy.

[Remodeling of the Tumor Microenvironment by Radiotherapy through the cGAS-STING Pathway in Esophageal Squamous Cell Carcinoma].

It has been reported that tumor cell-intrinsic cyclic GMP-AMP synthase(cGAS)-stimulator of interferon genes(STING) pathway is essential for radiotherapy(RT)-induced activation of anti-tumor immune responses. However, its role in the RT- induced remodeling of the tumor microenvironment(TME)in esophageal squamous cell carcinoma(ESCC), is largely unknown. In this study, we found that the tumor cell-intrinsic cGAS-STING pathway is a critical component for RT-induced activation of immune cells in the TME through the induction of type Ⅰ interferon and C-X-C motif chemokine ligand 10 in tumor cells in ESCC. However, at the same time, the tumor cell-intrinsic cGAS-STING pathway is also involved in RT-triggered infiltration and polarization of immunosuppressive CD163+ tumor-associated macrophages (TAM) through the induction of interleukin 34 (IL-34) in tumor cells in ESCC. Our findings suggest that targeting IL-34 to impede the infiltration and polarization of CD163+ TAM could potentially enhance the efficacy of RT-induced immune cell activation in ESCC TME.

[A Case of Perforation of the Duodenum during Chemotherapy with Ramucirumab plus Nab-Paclitaxel for Advanced Gastric Cancer].

A 70-year-old male patient was diagnosed with advanced gastric cancer with para-aortic lymph node metastasis. After diagnostic laparoscopy, the patient received 2 courses of neoadjuvant chemotherapy. Subsequently, distal gastrectomy, D2 plus para-aortic lymph node dissection, and Roux-en-Y reconstruction were performed. An enlarged lymph node(No. 16b2)was identified during surgery. The histopathological diagnosis revealed ypT4b, ypN3b, cM1(LYM; No. 16), Stage ⅣB. Chemotherapy with ramucirumab plus nab-paclitaxel was administered at 6 weeks postoperatively. However, after 2 courses of chemotherapy, the patient developed an abscess discharge from the wound, which was confirmed by an abdominal CT scan and diagnosed as an intra-abdominal abscess derived from duodenal perforation. The abscess was drained percutaneously. Subsequently, chemotherapy with nab-paclitaxel, nivolumab, and trifluridine/tipiracil hydrochloride was administered. After the appearance of brain metastases, the treatment was shifted to palliative care. The patient died 2 years and 7 months later from the primary disease.

[A Case of MSI-High Sigmoid Colon Cancer in Which Long-Term Survival Was Achieved by Pembrolizumab for Recurrent Lesions Resistant to Conventional Chemotherapy].

The patient underwent sigmoidectomy with D3 lymph node dissection and partial bladder resection for sigmoid colon cancer(cT4bN1M0, cStage Ⅲa), after preoperative chemotherapy with mFOLFOX plus panitumumab, and FOLFOXIRI plus bevacizumab. Postoperative adjuvant chemotherapy was performed by 8 courses of CAPOX. He relapsed hilar lymph nodes and peritoneal dissemination after 13 months after surgery, he underwent resection of the recurrent lesions. Four months after, he developed recurrence in liver and peritoneum. Although he was treated with FOLFIRI plus ramucirumab or aflibercept, resulted in progression of disease, then he received trifluridine tipiracil hydrochloride plus bevacizumab. At this point, the Japanese health insulance had started to cover pembrolizumab, this therapy was started as the fourth chemotherapy after the diagnosis of high frequency microsatellite instability(MSI), and then tumor markers rapidly declined. He underwent 38 courses of pembrolizumab, the recurrent lesions both liver and peritoneum disappeared. He had stoma closure, peritoneal dissemination disappeared not only intraoperatively but also in histologically from the peritoneal scar. He has received pembrolizumab for 4 years without another recurrence. Here, we report a case of MSI-high sigmoid colon cancer in which long-term survival was achieved by pembrolizumab for recurrent lesions resistant to conventional chemotherapy.

Prognostic impact of endoscopic response evaluation after neoadjuvant chemotherapy for esophageal squamous cell carcinoma: a nationwide validation study.

BACKGROUND: Our previous study reported the prognostic significance of endoscopic response (ER) evaluation, defined ER, and revealed ER as an independent prognostic factor of overall survival (OS) and recurrence-free survival (RFS) for esophageal squamous cell carcinoma (ESCC) treated with neoadjuvant chemotherapy (NAC) and surgery. The present study aimed to validate the prognostic impact of ER using a nationwide database from the authorized institute for board-certified esophageal surgeons by the Japan Esophageal Society. METHODS: This study retrospectively reviewed patients with ESCC who underwent subtotal esophagectomy at 85 authorized institutes for esophageal cancer from 2010 to 2015. Patients were classified as ER when the tumor size was markedly reduced post-NAC compared to pre-NAC. The correlation between OS and RFS was investigated. RESULTS: Of 4781 patients initially enrolled, 3636 were selected for subsequent analysis. Of them, 642 (17.7%) patients were classified as the ER group. Patients with ER showed significantly better OS and RFS. Subgroup analysis revealed the statistical difference in OS and RFS in cStage II and III, while the magnitude of survival difference between ER and non-ER was not evident in cStage I and IV. The percentage of ER varied from 46 to 87% among groups when institutions were classified into 3 subgroups based on the hospital volume, which would indicate the interinstitutional inconsistency. CONCLUSIONS: The prognostic impact of ER was validated using a nationwide database. Standardization of ER evaluation is required to improve the interinstitutional consistency and clinical validity of the ER evaluation.