Right-sided versus left-sided colorectal cancer in elderly patients: a sub-analysis of a large multicenter case-control study in Japan.

PURPOSE: This study investigated the impact of sidedness of colorectal cancer (CRC) in elderly patients on the prognosis. METHODS: In a sub-analysis of a multicenter case-control study of CRC patients who underwent surgery at ≥ 80 years old conducted in Japan between 2003 and 2007, both short- and long-term outcomes were compared between right-sided colon cancers (RCCs) and left-sided colorectal cancers (LCCs). RCCs were defined as those located from the cecum to the transverse colon. RESULTS: Among the 1680 patients who underwent curative surgery, 812 and 868 had RCCs and LCCs, respectively. RCCs were more frequent than LCCs in those who were female, had renal comorbidities, and had a history of abdominal surgery. Regarding tumor characteristics, RCCs were larger, invaded more deeply, and were diagnosed as either mucinous or signet ring-cell carcinoma more frequently than LCCs. Regarding the prognosis, patients with RCCs had a significantly longer cancer-specific survival (CS-S) and cancer-specific relapse-free survival (CS-RFS) than those with LCCs. Furthermore, sidedness was determined to be an independent prognostic factor for CS-S and CS-RFS. CONCLUSION: RCCs, which accounted for half of the cases in patients ≥ 80 years old, showed better long-term outcomes than LCCs.

Effect of body fat mass loss on prognosis of radical resection for pancreatic ductal adenocarcinoma based on bioelectrical impedance analysis.

BACKGROUND: Few reports have performed a prognostic analysis based on bioelectrical impedance analysis in patients with radical resection of pancreatic ductal adenocarcinoma (PDAC), and its usefulness in prognostic analysis remains unclear. This study aimed to evaluate body composition changes in patients undergoing radical resection for PDAC and analyze its impact on prognosis. METHODS: The medical records of radical resection for patients with PDAC were retrospectively reviewed, and the parameters of body composition, including body weight, skeletal muscle mass, body fat mass (BFM), and extracellular water-total body water ratio, from preoperatively to 12 months postoperatively, for each surgical procedure were measured based on direct segmental multifrequency bioelectrical impedance analysis with an InBody 770 (InBody Inc., Tokyo, Japan) device. The clinicopathological and prognostic factors were analyzed. RESULTS: Among 79 patients who underwent radical resection for PDAC, 36 (46%), 7 (8%), and 36 (46%) underwent pancreatoduodenectomy, total pancreatectomy, and distal pancreatectomy, respectively. The multivariate overall survival analysis demonstrated that BFM loss percentage at 1 month postoperatively ≧14% (p = 0.021), lymph node metastasis (p = 0.014), and non-adjuvant chemotherapy (p <  0.001) were independent poor prognostic factors. Multivariate analysis revealed that preoperative BFM < 12 kg and preoperative albumin < 3.5 g/dL were independently associated with BFM loss percentage at 1 month postoperatively ≧14% (p = 0.021 and p = 0.047, respectively). CONCLUSIONS: Loss of BFM in the early postoperative period may have a poor prognosis in radical resection of PDAC.

Analysis of Acquisition of COVID-2019 Neutralizing Antibodies in Organ Transplant Recipients.

BACKGROUND: This study confirmed the kinetics of antibodies acquired by SARS-CoV-2 vaccination in solid-organ transplant recipients and examined their association with the development of COVID-19 and immunosuppressive status in organ transplant recipients. METHODS: We measured COVID-19 neutralizing antibody titer in 21 organ transplant recipients vaccinated with the COVID-19 vaccine and 14 nontransplant recipients (control group) 3 times before and at 1 and 6 months after the third dose of vaccine. By confirming the kinetics of the acquired antibodies, we examined the relevance of the background characteristics of organ transplant recipients, such as the development of infectious diseases and immunosuppressive status. RESULTS: The proportion of patients with neutralizing antibodies was significantly higher in the nontransplant group than in the transplant group. Neutralizing antibody titers were significantly lower in transplant recipients when they were compared before the third dose and 1 month later. In the transplant recipient group, 11 patients were positive, and 10 were negative for neutralizing antibodies. When the causal relationship between the neutralizing antibody titer and background was examined, a positive correlation was found between the antibody titer and the number of years since transplantation, and a negative correlation was found between the tacrolimus trough values, amount of mycophenolate mofetil or steroids taken internally, and antibody titer. CONCLUSION: This study suggests that the effectiveness of vaccination in transplant recipients is associated with the post-transplant period before vaccination and the dose of immunosuppressive agents.

Clinical efficacy of Daikenchuto (DKT: TJ-100) for gastrointestinal symptoms in patients with a history of colon and rectosigmoid cancer surgery: a randomized crossover study.

PURPOSE: This randomized crossover trial investigated the effects of Daikenchuto (DKT: TJ-100) on gastrointestinal symptoms of patients after colon and rectosigmoid cancer surgery. METHODS: Among patients who had completed surgery for colon cancer, including rectosigmoid cancer, over 6 months ago, 20 who complained of gastrointestinal symptoms were enrolled. Subjects were randomly assigned to two sequences: sequences: A and B. In period 1, sequence A subjects were orally administered DKT, whereas sequence B subjects were untreated for 28 days. After a 5-day interval, in period 2, sequences A and B were reversed. Quality-of-life markers (GSRS and VAS), the Sitzmark transit study, the orocecal transit time (lactulose hydrogen breath test) and Gas volume score were evaluated before and after each period with findings compared between the presence of absence of DKT administration. RESULTS: Between sequences, there were no significant differences in clinicopathological characters or any evaluations before randomization. There was no carryover effect in this crossover trial. The administration of DKT significantly ameliorated the GSRS in total, indigestion, and diarrhea, although the planned number of subjects for inclusion in this trial was not reached. CONCLUSIONS: DKT may ameliorate subjective symptoms for postoperative patients who complain of gastrointestinal symptoms.

[Surgical Resection and Adjuvant Chemotherapy for Early Multiple Peritoneal Recurrence after Rejection of Hepatocellular Carcinoma-A Case Report].

Thus far, no consensus has been reached regarding the treatment of peritoneal dissemination of hepatocellular carcinoma (HCC). Here, we report a case of surgical resection and postoperative adjuvant chemotherapy for early multiple peritoneal recurrences of HCC. A 74-year-old man was found to have hepatic mass of 80 mm in size in S7 and 57 mm in S8, and was diagnosed with HCC. The patient underwent an open anterior segmentectomy and S7 subsegmentectomy of the liver. Peritoneal washing cytology revealed the presence of malignant cells. The tumor strongly adhered to the diaphragm, necessitating partial resection of the diaphragm. Six months after surgery, multiple disseminated recurrences were found on the CT scan. Atezolizumab plus bevacizumab combination therapy was initiated, but tumor size enlargement and elevation of tumor markers were observed after 3 courses. Resection of the dissemination(2 on the surface of the lung right lower lobe, 1 on the right renal superior retroperitoneum, 1 on the omentum, and 1 invading the jejunum)was performed. Considering the high risk of recurrence, postoperative adjuvant chemotherapy with lenvatinib was administered for 1 year. No recurrence has been found for 16 months after the resection. Although more cases are needed to conclude, this case report suggests that surgical resection and postoperative administration of lenvatinib may be effective in the treatment of disseminated HCC lesions at a high risk of recurrence.

[Unresectable Esophageal Cancer on the Elderly Woman Which Was Treated Effectively with Ipilimumab plus Nivolumab-A Case Report].

Until now, the standard treatment regimen was cisplatin plus 5-FU as the chemotherapy for unresectable advanced esophageal cancer. Immune checkpoint inhibitors have brought about changes to the cancer treatment. Ipilimumab plus nivolumab was approved in June 2022 for unresectable advanced esophageal cancer. An 86-year-old woman who was normal ADL and cognitive function was diagnosed with unresectable esophageal cancer with multiple lymph node metastasis. We thought surgery or chemotherapy is impossible because of her age and health status, so we treated with ipilimumab plus nivolumab. After 2 cycles, tumor became reduced in size on endoscopic examination and accumulation in primary lesion and lymph node metastases was decreased considerably on positron emission tomography/computed tomography(PET-CT). Though the cycle after initiation of chemotherapy was uneventful, tumor regrowth on the examinations at 5 months. The patient's condition of the disease was improved temporarily after change chemotherapy to paclitaxel as the second-line therapy, but she died due to disease progression at 11.4 months from initiation of treatment. Ipilimumab plus nivolumab can become one of the effective treatments for patients who are impossible to treat with conventional chemotherapy.

[A Case of Sclerosing Angiomatoid Nodular Transformation Resected for Suspected Relapse of Diffuse Large B-cell Lymphoma].

We report a case of sclerosing angiomatoid nodular transformation(SANT)5 years after remission of diffuse large B-cell lymphoma(DLBCL). A 64-year-old woman was diagnosed a nodular mass at the spleen by a contrast-enhanced CT scan 5 years after the relief for DLBCL. The mass showed accumulation of FDG. Because the possibility of the recurrence of malignant lymphoma could not be ruled out, laparoscopic splenectomy was performed for diagnosis and treatment. Immunohistologically, the resected mass revealed 3 different vascular components pattern(CD31, CD34 and CD8), so we diagnosed SANT. It is difficult to distinguish from malignant lymphoma or cancer even with various examination, so laparoscopic splenectomy is useful for diagnosis and treatment.

[A Case of Lynch Syndrome with Repeated Asynchronous Colorectal Cancer in a Short Period].

This case was a 73-year-old woman who previously underwent a partial colectomy for ascending colon cancer at the age of 70. She had a history of cancer of the uterus, descending colon, bladder, and left ureter. She had a family history of colorectal cancer and met the Amsterdam Ⅱ criteria for Lynch syndrome. She was diagnosed as Lynch syndrome with a MSH2 germline mutation by genetic analysis. One year later, a partial colectomy was performed for sigmoid colon cancer. Six months later, colonofiberscopy revealed early-stage cancer in the rectum, and EMR was performed. Despite adequate surveillance, she had frequent recurrences of advanced colorectal cancer within a short period of time. We report here risk factors of colorectal cancer in Lynch syndrome and indications for prophylactic total colectomy.

Utility of TMPRSS4 as a Prognostic Biomarker and Potential Therapeutic Target in Patients with Gastric Cancer.

BACKGROUND: Transmembrane serine protease 4 (TMPRSS4) belongs to the family of type II transmembrane serine proteases that are known to be upregulated in many malignant tumors. However, there is a paucity of studies documenting the clinical impact and biological effects of TMPRSS4 on gastric cancer (GC) patients who underwent surgery. METHODS: Tissues samples were obtained from 105 patients with GC who underwent gastrectomy followed by adjuvant chemotherapy, excluding those at stage I. The expression of TMPRSS4 was examined through immunohistochemical analysis. The association between TMPRSS4 expression and clinico-pathological features as well as prognosis was assessed. Moreover, the effects of TMPRSS4 expression on cell migration and sensitivity to 5-FU were investigated. RESULTS: The expression rate of TMPRSS4 was 56.3% (59/105) in GC cases. The expression of TMPRSS4 was positively correlated with the depth of tumor (T) and venous (V) invasion. The 5-year overall survival (OS) and recurrence-free survival (RFS) rates of the TMPRSS4-positive group was significantly lower than that of the TMPRSS4-negative group (p=0.0001 and p=0.005, respectively). Especially, there was significant differences in OS and RFS of patients with stage III cancer between the two groups (p=0.0064 and 0.012, respectively). Multivariate analysis demonstrated that TMPRSS4 expression and the stage of cancer were crucial prognostic factors for RFS. TMPRSS4-silenced GC cells exhibited increased sensitivity to 5-FU when compared with the non-specific control siRNA-transfected cells. CONCLUSION: TMPRSS4 can be considered as a potential prognostic biomarker, especially for stage III, and a promising therapeutic target for GC.

[A Case of Laparoscopic Surgery for Colon Metastasis of Renal Cancer].

A 67-year-old man underwent laparoscopic partial left nephrectomy for renal cell carcinoma 2.5 years ago. CT showed a well-defined 3 cm mass with contrast effect bordering on the descending colon, and PET-CT showed an accumulation of SUVmax 6.01 in the same area. Colonoscopy revealed a submucosal tumor-like mass in the descending colon. The patient was diagnosed with a local recurrence of renal cell carcinoma and invasion of the descending colon, and laparoscopic colectomy was performed. The excised specimen was a pale yellowish submucosal tumor measuring 4.5×3.8 cm, which was histologically diagnosed as metastasis of clear cell renal cell carcinoma. Surgical resections for metastases of renal carcinoma have been reported and expected prolong survival. We report a case of laparoscopic colon resection for recurrence of descending colon metastasis of renal cell carcinoma.

[A Case of Anal Canal Cancer with Pagetoid Spread and a Significant Response to Preoperative Chemoradiotherapy].

Perianal Pagetoid spread is a rare condition for which there is no proven therapy. We experienced a case of anal canal cancer with Pagetoid spread which exhibited a significant response to preoperative chemoradiotherapy(CRT). A 76-year-old man with anal stenosis was referred to our hospital. He was diagnosed with anal canal cancer with Pagetoid spread. No infiltration into the surrounding tissue was observed, but metastasis to the left inguinal lymph node was noted. The patient received preoperative CRT(oral S-1, 1.8 Gy×25 Fr, a total dose of 45 Gy)including the bilateral inguinal region. After CRT, the main tumor size was reduced and PET-CT showed disappearance of the abnormal accumulation in the left inguinal lymph nodes. Laparoscopic abdominoperineal resection and left inguinal trans lymphadenectomy were performed. The macroscopic findings of the surgical specimen confirmed no residual carcinoma or lymph node metastasis. Although more proof is needed, this case suggested that CRT may be effective for anal canal cancer with pagetoid spread.

Clinical complete response after nivolumab administered as a third-line treatment for unresectable advanced gastric cancer with peritoneal dissemination: A case report.

INTRODUCTION AND IMPORTANCE: Nivolumab, which is a fully human IgG4 PD-1 immune checkpoint inhibitor antibody, has been recommended as a third-line treatment based on the results of the ATTRACTION-2 study involving patients with unresectable advanced gastric cancer. CASE PRESENTATION: A 69 year-old woman was referred to our department with a diagnosis of gastric cancer based on an upper gastrointestinal endoscopy during a medical examination. The endoscopy, along with various tests, helped establish a diagnosis of unresectable advanced gastric cancer (cT4aN3aM1P1c, cStage IV) with peritoneal dissemination. The first and second-line chemotherapy administered was S-1 plus oxaliplatin followed by ramucirumab and nab-paclitaxel, respectively. In this case, the disease was evaluated as progressive disease due to increased peritoneal dissemination. Nivolumab was administered as the third-line treatment. The patient developed interstitial pneumonia after nine courses of nivolumab, for which chemotherapy was discontinued and prednisolone treatment was initiated. The patient had a complete response to treatment endoscopically, 9 months after the last administration of nivolumab. After that, there was no recurrence of the cancer, despite there being no treatment for 5 months. CLINICAL DISCUSSION: It was suggested that the therapeutic effect of nivolumab could be maintained for a long period after discontinuation of its administration. In addition, a correlation has been reported between the treatment efficacy and immune-related adverse events associated with nivolumab. CONCLUSIONS: The synergistic effect of the sustained effect of nivolumab and later-line treatment may contribute to the prolongation of survival after discontinuation of nivolumab in patients who are refractory or intolerant to treatment.

Peritoneal lavage with hydrogen-rich saline can be an effective and practical procedure for acute peritonitis.

PURPOSE: Acute peritonitis has remained a fatal disease despite of recent advances in care and treatment, including antibiotic and anticoagulant treatments. The cause of death is mostly sepsis-induced multiple organ failure. Oxidative stress can play an important role in this situation, but antioxidant therapy to capture any excessive reactive oxygen species has not yet been fully established. METHODS: Two experiments were performed. In the first experiment, we confirmed the effects of peritoneal lavage with hydrogen-rich saline (HRS) after a cecal ligation and puncture (CLP) operation in rats. In the second experiment, the changes in the hemodynamic state following this procedure were observed in a porcine model of abdominal sepsis to evaluate its safety and utility. RESULTS: Peritoneal lavage with HRS significantly improved the survival after CLP in rats, and it ameliorated the levels of sepsis-induced organ failure. Moreover, it showed anti-inflammatory and anti-apoptosis as well as antioxidant effects. The second experiment demonstrated the potential safety and feasibility of this procedure in a large animal model. CONCLUSION: This procedure can improve survival after sepsis through mitigating the sepsis-induced organ failure by inhibiting oxidative stress, apoptosis, and inflammatory pathways. Peritoneal lavage with HRS may therefore be an effective, safe, and practical therapy for patients with acute peritonitis.

Laparoscopic resection for a large gastrointestinal stromal tumor (GIST) with diaphragm invasion following preoperative imatinib treatment: A case report.

INTRODUCTION: Neoadjuvant imatinib for large GISTs may prevent tumor rupture and the need for extended surgery by reducing tumor size. In this study, we present a case of large gastric GIST with diaphragm invasion, due to the patient receiving laparoscopic resection following preoperative imatinib treatment. PRESENTATION OF CASE: A 72-year-old woman was hospitalized with left hypochondriac pain for a month. Examinations revealed a large heterogeneous gastric mass measuring 80 mm in size, arising from the greater curvature of the corpus. The mass invaded the left thoracic diaphragm. Treatment with imatinib at an initial dosage of 400 mg/day was initiated. After a further two months of follow-up, the lesion had sustained reduction to 50 mm in size, however, the invasion to the diaphragm remained. The patient eventually underwent laparoscopic partial gastrectomy and partial resection of the diaphragm with curative intent. Adjuvant chemotherapy was initiated at one month after the surgery, however, was discontinued due to nausea. After one-year follow-up, no recurrence was noted. DISCUSSION: Neoadjuvant imatinib may shrink tumor size remarkably and prevent tumor rupture during surgery, and thus lead to increased rates of complete resection. To date, several publications have directly compared the oncologic results between laparoscopic and open resection for GISTs. In the present case, the tumor was movable, and moderately fixed on diaphragm. It was favorable condition for laparoscopic surgery. CONCLUSIONS: This is the first report of a large gastric GIST invading the diaphragm that was successfully treated by laparoscopic resection after tumor reduction by neoadjuvant imatinib.

A case of Turcot's syndrome type 1 with loss of immunoexpression of MSH6 in colon cancer and liver metastasis due to secondary somatic mutation in coding mononucleotide (C)8 tract: a case report.

BACKGROUND: Lynch syndrome (LS), which is known as a hereditary cancer syndrome, is distinguished by microsatellite instability, represented by the altered number of repetitive sequences in the coding and/or non-coding region. Immunohistochemical staining (IHC) of DNA mismatch repair (MMR) proteins (e.g., MLH1, MSH2, MSH6, and PMS2) has been recognized as an useful technique for screening of LS. Previous study has shown that the assessment of IHC, however, requires specific caution due to variable staining patterns even without germline mutations in MMR genes. CASE PRESENTATION: A 48-year-old man, who had been treated for anaplastic astrocytoma, was referred to our department for the precise examination of progressing anemia. Whole-body examination revealed two advanced carcinomas in descending colon and stomach. A hypo-vascular mass lesion was detected in liver as well. Pathological diagnosis (on surgical specimens) was poorly differentiated adenocarcinoma in descending colon, moderately differentiated tubular adenocarcinoma in stomach, and liver metastasis, which is possibly from colon. It was suspected that this case would be Turcot's syndrome-type-1 due to its specific family history having two cases of colon cancer within the second relatives. Pathogenic frameshift mutations in codon 618 of MLH1 gene was identified. Immunohistochemical analyses (IHC) demonstrated complete loss of MLH1 immuno-expression as well as of PMS2 except for those in brain tumor. Although frameshift mutation was not found in MSH6 gene, histological expression of MSH6 was patchy in primary colon carcinoma and was completely lost in the metastatic site in liver. MSH6 expression in gastric carcinoma, a coincidental cancer in this case, was intact. An abnormal (C)8 region was identified by the cloned PCR of colon and liver tumors but not from gastric cancer. Frameshift mutation in a (C)8 tract in exon 5 of the MSH6 gene was also detected in liver metastasis. CONCLUSION: This case supports a plausible mechanism, proposed by a previous literature, for the reduced expression of MSH6 in a somatic mutation manner, which might preferentially happen in colon cancer rather than in stomach carcinoma in MLH1/PMS2-deficient type of Turcot's syndrome type 1.

Oncogenic mutation in RAS-RAF axis leads to increased expression of GREB1, resulting in tumor proliferation in colorectal cancer.

BRAFV600E mutation accounts for up to 90% of all BRAF mutations in human colorectal cancer (CRC), and constitutively activates the MEK-MAPK pathway. It is recognized that neutralizing mAbs for epidermal growth factor receptor alone are not effective for CRC with BRAFV600E mutation. Therefore, there is increasing interest in identification of the possible therapeutic targets in downstream of BRAF mutation in CRCs. To address this, we studied genome engineered mouse models for colonic neoplasia that has BrafV600E mutation on the basis of Apc inactivation, induced in 2 distinct Cre mouse models, CDX2P-G22Cre and CDX2P-CreERT2 mice. We carried out oligonucleotide microarray analysis for colonic neoplasia generated in these mouse models, and compared gene expression profiles among Kras/Braf WT, Kras-mutated, and Braf-mutated mouse colon tumors to seek new molecular targets corresponding to the KRAS-BRAF-MAPK axis. We found that the expression of the growth regulation by estrogen in breast cancer protein 1 (Greb1) was the most upregulated gene in Braf-mutated mouse tumors compared to Kras/Braf WT counterparts. The silencing of GREB1 significantly reduced the proliferation and tumorigenesis of CRC cell lines, whereas the overexpression of GREB1 promoted cell proliferation. Although GREB1 was first identified as a hormone-responsive gene mediating estrogen-stimulated cell proliferation in endometriosis, breast, and ovarian cancers, these results suggest that RAS-RAF-MAPK signaling upregulates GREB1 expression in CRC, resulting in cellular proliferation. Thus, GREB1 is a possible therapeutic target for CRCs with BrafV600E mutation.

[A Case of Sigmoid Colon Cancer Recurrence at the Hand-Sewn Anastomosis Site Originated from Tumor Implantation].

We report a case of anastomotic recurrence following laparoscopic sigmoidectomy with hand-sewn anastomosis, which was attributable to the implantation of exfoliated cancer cells. A 78-year-old man diagnosed with early colon cancer underwent endoscopic submucosal dissection(ESD); however, ESD was suspended due to infiltrated muscle fibers. Subsequently, he underwent laparoscopic sigmoidectomy with hand-sewn anastomosis, accompanied by D3 lymph node dissection. Histopathological findings revealed a well-differentiated tubular adenocarcinoma, pT2(MP), tub1>tub2>por2, ly0, v1, PM0, DM0, RM0, N0M0, pStage Ⅰ. The follow-up CT 6 months after surgery, showed enhanced wall thickening and irregular surface of the sigmoid colon. Colonoscopy revealed a type 2 tumor located on the anastomotic line. Based on the diagnosis of anastomotic recurrence, the patient underwent partial colectomy. Histopathological findings were similar to those of the primary tumor and suggested implantation of exfoliated cancer cells as the origin of anastomotic recurrence. Cancer cells had infiltrated all layers. In conclusion, we recommend the performance of appropriate operative procedures to prevent anastomotic recurrence, such as the cleaning of the anastomosed intestinal tract. Careful follow-up in colon cancer patients is of the utmost importance and the risk of anastomotic recurrence should always be considered.

The prognostic value of organ/space surgical site infection in stage I colorectal cancer recurrence.

PURPOSE: Evidence on risk factors for postoperative recurrence in patients with colorectal cancer (CRC) confined to pathological stage I is limited. Therefore, this study aimed to identify the risk factors for recurrence in patients with stage I CRC. METHODS: Data on clinicopathological factors and blood tests of patients diagnosed with pathological stage I CRC at Hiroshima University Hospital between April 1, 2010, and December 31, 2018, were retrospectively obtained. The statistical significance between the clinical factors and postoperative recurrence was also investigated. RESULTS: A total of 244 patients were included. The median observation period was 45 months. There were 17 patients (6.6%) with a postoperative recurrence (8 local and 9 distant recurrences). In the log-lank test, rectal cancer (p = 0.004), pT2 (p = 0.020) and organ/space surgical site infection (SSI) (p = 0.008) were significantly associated with postoperative recurrence. In a multivariate analysis, rectal cancer (hazard ratio [HR] 3.678, 95% confidence interval [CI] 1.184-11.425, p = 0.024) and organ/space SSI (HR 3.137, 95% CI 1.013-9.713, p = 0.047) were independently associated with a higher recurrence rate. Among 18 patients with organ/space SSI, 4 recurrences occurred, all of which were distant metastases. CONCLUSION: Organ/space SSI significantly affects the postoperative recurrence in patients with stage I CRC.

[MSI-H Small Bowel Cancer with Peritoneal Dissemination Successfully Treated with Pembrolizumab-A Case Report].

A 52-year-old man was diagnosed with small bowel adenocarcinoma(T4aN1M0, Stage ⅢA, according to the Japanese colorectal cancer classification)and treated with partial resection of the small bowel in June 2014. He also received adjuvant chemotherapy(XELOX: 8 courses)after surgery. Three and a half years after the operation, peritoneal dissemination recurred, and he received bevacizumab plus XELOX therapy. The regimen was adjusted to a total of 11 courses because of the disease progression. The primary lesion showed MSI-H. The patient was started on pembrolizumab therapy in April 2019. The tumor responded well to pembrolizumab(maximum therapeutic effect: PR, 31% reduction), but a new lesion appeared 6 months after the start of this regimen. He continued pembrolizumab therapy for 14 months without adverse events since it appeared to be clinically effective. Although MSI-H small bowel cancers are rare, accurate screening is essential to not miss the opportunity to administer pembrolizumab.

A Case of Advanced Gastric Cancer with Peritoneal Metastasis Treated Successfully with Nivolumab.

Peritoneal metastasis (PM) is detected in 14% of gastric cancers at the time of initial diagnosis, with a median survival time of 4 months. A 66-year-old woman diagnosed with cT4a(SE) N2M1(LYN) cStage IV was treated with three lines of chemotherapy for a year. During the third line of chemotherapy, computed tomography (CT) scan revealed a large amount of ascites, periportal collar sign, and bilateral ureteral stenosis owing to PM. The tumor biomarkers (CEA and CA 19-9) remained elevated similar to the initial levels. The patient was administered 3 mg/kg nivolumab intravenously biweekly as the fourth line of chemotherapy. Three months after the nivolumab treatment, gastroscopy revealed an extreme reduction of the tumor size, while CT scan revealed the absence of ascites and a well-controlled tumor. There was no immune-related adverse event with nivolumab during and after the treatment, and performance status improved to 0. The patient has been alive for about 2.5 years since her first visit with her sixth line of chemotherapy (docetaxel). We report a case of advanced gastric cancer with PM that was treated successfully with nivolumab.