Phase II Study of Intraperitoneal Administration of Paclitaxel Combined with S-1 and Cisplatin for Gastric Cancer with Peritoneal Metastasis.

BACKGROUND: Intraperitoneal chemotherapy is promising for gastric cancer with peritoneal metastasis. Although a phase III study failed to show a statistically significant superiority of intraperitoneal paclitaxel combined with S-1 and intravenous paclitaxel, the sensitivity analysis suggested clinical efficacy. Thus, attempts to combine intraperitoneal paclitaxel with other systemic therapies with higher efficacy have been warranted. We sought to explore the efficacy of intraperitoneal paclitaxel with S-1 and cisplatin. PATIENTS AND METHODS: Gastric cancer patients with peritoneal metastasis were enrolled in the phase II trial. In addition to the established S-1 and cisplatin regimen every 5 weeks, intraperitoneal paclitaxel was administered on days 1, 8, and 22 at a dose of 20 mg/m2. The primary endpoint was overall survival rate at 1 year after treatment initiation. Secondary endpoints were progression-free survival and toxicity. RESULTS: Fifty-three patients were enrolled and fully evaluated for efficacy and toxicity. The 1-year overall survival rate was 73.6% (95% confidence interval 59.5-83.4%), and the primary endpoint was met. The median survival time was 19.4 months (95% confidence interval, 16.1-24.6 months). The 1-year progression-free survival rate was 49.6% (95% confidence interval, 34.6-62.9%). The incidences of grade 3/4 hematological and non-hematological toxicities were 43% and 47%, respectively. The frequent grade 3/4 toxicities included neutropenia (25%), anemia (30%), diarrhea (13%), and anorexia (17%). Intraperitoneal catheter and implanted port-related complications were observed in four patients. There was one treatment-related death. CONCLUSIONS: Intraperitoneal paclitaxel combined with S-1 and cisplatin is well tolerated and active in gastric cancer patients with peritoneal metastasis.

Successful second conversion surgery after trastuzumab deruxtecan for recurrent HER2-positive gastric cancer.

A 65-year-old woman with HER2-positive gastric cancer with multiple liver metastases underwent first conversion surgery of gastrectomy with D2 lymph nodes dissection and three liver metastases after combination therapy with capecitabine, cisplatin, and trastuzumab. Two years later, she experienced multiple liver metastases that were refractory to combination therapy with paclitaxel albumin-bound nanoparticles and ramucirumab. She participated in the DESTINY-Gastric01 trial and received tri-weekly trastuzumab deruxtecan as third-line treatment for 26 cycles. The recurrent lesions markedly shrank, and this effect continued for 19 months. We then performed partial hepatectomy for the one remaining lesion. No adjuvant chemotherapy was given, and she remains alive without recurrence 18 months after the second conversion surgery. Trastuzumab deruxtecan may generate a notable tumor response and subsequent conversion surgery could be a treatment option for HER2-positive stage IV gastric cancer.

Adipocytes contribute to tumor progression and invasion of peritoneal metastasis by interacting with gastric cancer cells as cancer associated fibroblasts.

BACKGROUND: Peritoneal metastasis (PM) is one of the most common causes of noncurative surgery and the most frequent recurrence pattern in gastric cancer (GC). During the process of PM, GC cells detached from primary tumor interact with human peritoneal mesothelial cells (HPMC) overlapped with adipose tissues such as the omentum or mesentery. Although the interaction with HPMC promotes the malignancy of GC, the role of adipose tissues remains unclear. AIMS: We aimed to clarify how adipose tissue are affected by adjacent primary tumors during the expression of adipokines and to elucidate whether GC cells transform adipocytes into CAFs in vitro. In addition, we investigated whether GC cells are affected by adipocytes in their ability to infiltrate. METHODS: We investigated the phenotypic conversion of adipocytes during the malignant process of GC cells in vivo and in vitro. We evaluated the expression levels of adiponectin in the omental adipose tissue of gastric cancer patients by western blotting. Following adipocytes/gastric cancer cells coculture, adipocyte markers, adiponectin receptors, and inflammatory cytokine markers were detected by real-time PCR and/or western blotting in the single-cultured and co-cultured adipocytes; cancer-associated fibroblast (CAF) markers were detected by immunofluorescence and western blotting in the single-cultured and co-cultured adipocytes; invasion assays were performed in single cultured and co-cultured MKN45 and OCUM. RESULTS: In omental adipose tissues that are situated close to the primary tumors, the expression of adiponectin tended to decrease in patients with subserosal or serosal invasion. By co-culturing with GC cells, adipocytes were dedifferentiated and the expression levels of CAF marker FSP1 and inflammatory cytokines, PAI-1 and IL-6, significantly increased (p < 0.05). Furthermore, GC cells co-cultured with adipocytes showed enhanced invasion ability. CONCLUSION: Our findings suggest that the phenotypic conversion of adipocytes may promote the malignancy of GC in the construction of the cancer microenvironment of PM.

Hypoxia-Induced CD36 Expression in Gastric Cancer Cells Promotes Peritoneal Metastasis via Fatty Acid Uptake.

BACKGROUND: The lipid scavenger receptor cluster of differentiation 36 (CD36) has been shown to have a pro-metastatic function in several cancers. Adipose tissue, a favorable site for peritoneal metastasis (PM) from gastric cancer (GC), promotes this process by providing free fatty acids (FFAs); however, the role of CD36 in PM progression from GC remains to be elucidated. MATERIALS AND METHODS: We evaluated CD36 expression in the GC cells under various conditions. CD36 overexpressing (CD36OE) MKN45 cells were prepared and their migration and invasive properties were assessed. A PM mouse model was used to investigate the biological effects of palmitic acid (PA) and CD36. Furthermore, we examined the clinical role of CD36 expression in 82 human PM samples by immunohistochemical staining. RESULTS: Hypoxia markedly increased CD36 expression in GC cells. In normoxia, only CD36OE MKN45 cells treated with PA showed an increase in migration and invasion abilities. An increased expression of active Rac1 and Cdc42 was observed, which decreased following etomoxir treatment. Conversely, hypoxia increased those capacities of both vector and CD36OE MKN45 cells. In a mouse model transplanted with CD36OE MKN45 cells, more peritoneal tumors were observed in the high-fat diet group than those in the normal diet group. In clinical samples, 80% of PM lesions expressed CD36, consistent with hypoxic regions, indicating a significant association with prognosis. CONCLUSION: Our findings indicate that a hypoxia in the peritoneal cavity induces CD36 expression in GC cells, which contributes to PM through the uptake of FFAs.

Prognostic value of tumor-infiltrating CD163+macrophage in patients with metastatic gastric cancer undergoing multidisciplinary treatment.

BACKGROUND: The multidisciplinary treatment including induction chemotherapy plus conversion surgery (CS) has attracted attention as a new strategy to improve the outcome of metastatic gastric cancer (MGC). However, it is unclear which patients achieve a good response to chemotherapy and successful CS. Tumor-infiltrating immune cells (TIICs) have been reported to be both prognostic and predictive biomarkers not only in immunotherapy but also in chemotherapy in many cancer types. However, there have been no reports on the usefulness of TIICs as biomarkers in conversion surgery for MGC. The aim of the present study was to evaluate the association between the TIICs and treatment outcome for the multidisciplinary treatment in MGC. METHODS: We retrospectively analyzed 68 MGC patients who received docetaxel plus cisplatin plus S-1 (DCS) therapy between April 2006 and March 2019 in our institute. The number of tumor-infiltrating CD4+, CD8+, Foxp3+lymphocytes, CD68+, CD163+macrophages in pre-treatment endoscopic biopsy samples were evaluated to investigate their predictive value for multidisciplinary treatment. RESULTS: Fifty patients underwent CS following DCS therapy (CS group), whereas 18 patients underwent DCS therapy alone (non-CS group). The median survival time (MST) of CS group was 33.3 months, which was significantly longer than the MST of 9.0 months in non-CS group (p < 0.01). The number of CD163+macrophages was extracted as an independent prognostic factor for overall survival in all patients. There were more cases of high infiltration of CD163+macrophages in non-CS group than in CS group. Furthermore, in CS group, pathological responders to DCS therapy showed low infiltration of CD163+ macrophages, and high infiltration of CD8+lymphocyte. CD163 low group showed a significant prolonged survival compared with CD163 high group in patients who underwent CS (p = 0.02). CONCLUSIONS: The pre-treatment CD163+macrophages infiltration would be a pivotal biomarker for predicting prognosis and pathological response to multidisciplinary treatment among TIICs in MGC. Thus, for patients with low CD163+macrophage infiltration in pre-treatment biopsy sample, diagnostic imaging should be performed frequently during chemotherapy to avoid missing the optimal timing for CS, and CS should be aggressively considered as a treatment option if curative resection is deemed feasible.

Verification of Resectability Status for Pancreatic Cancer: Radiological and Pathological Analysis of Patients Undergoing Pancreatoduodenectomy With Combined Resection of the Superior Mesenteric Artery.

OBJECTIVES: Resectability status is considered an important indicator for progression of pancreatic cancer. We verified the superior mesenteric artery (SMA) factors of resectability status by radiological and pathological analysis in patients who underwent pancreatoduodenectomy with combined resection of the SMA. METHODS: We enrolled 22 patients who underwent pancreatoduodenectomy with combined resection of the SMA. Patients were divided into 3 groups according to the contact angle between the tumor and the SMA in preoperative computed tomography images (no contact, R-sma; contact within 180 degrees, BR-sma; contact more than 180 degrees, UR-sma). We pathologically evaluated cancer progression toward the SMA. RESULTS: There were 3 patients with R-sma, 12 with BR-sma, and 7 with UR-sma. The median distance (mm) between the cancer and the SMA was 7.0 with R-sma, 1.0 with BR-sma, and 0 with UR-sma (P = 0.0003). Invasion to the superior mesenteric nerve plexus was positive in none with R-sma, 11 with BR-sma, and 7 with UR-sma (P < 0.0001). Invasion to the SMA was positive in none with R-sma and BR-sma, and 7 with UR-sma (P < 0.0001). CONCLUSIONS: Superior mesenteric artery factors of resectability status are reliable indicator for cancer progression toward the SMA.

Crosstalk between cancer-associated fibroblasts and immune cells in peritoneal metastasis: inhibition in the migration of M2 macrophages and mast cells by Tranilast.

BACKGROUND: The role of tumor-stroma interactions in tumor immune microenvironment (TME) is attracting attention. We have previously reported that cancer-associated fibroblasts (CAFs) contribute to the progression of peritoneal metastasis (PM) in gastric cancer (GC), and M2 macrophages and mast cells also contribute to TME of PM. To elucidate the role of CAFs in TME, we established an immunocompetent mouse PM model with fibrosis, which reflects clinical features of TME. However, the involvement of CAFs in the immunosuppressive microenvironment remains unclear. In this study, we investigated the efficacy of Tranilast at modifying this immune tolerance by suppressing CAFs. METHODS: The interaction between mouse myofibroblast cell line LmcMF and mouse GC cell line YTN16 on M2 macrophage migration was investigated, and the inhibitory effect of Tranilast was examined in vitro. Using C57BL/6J mouse PM model established using YTN16 with co-inoculation of LmcMF, TME of resected PM treated with or without Tranilast was analyzed by immunohistochemistry. RESULTS: The addition of YTN16 cell-conditioned medium to LmcMF cells enhanced CXCL12 expression and stimulated M2 macrophage migration, whereas Tranilast inhibited the migration ability of M2 macrophages by suppressing CXCL12 secretion from LmcMF. In PM model, Tranilast inhibited tumor growth and fibrosis, M2 macrophage, and mast cell infiltration and significantly promoted CD8 + lymphocyte infiltration into the tumor, leading to apoptosis of cancer cells by an immune response. CONCLUSION: Tranilast improved the immunosuppressive microenvironment by inhibiting CAF function in a mouse PM model. Tranilast is thus a promising candidate for the treatment of PM.

Dynamic switch of immunity and antitumor effects of metformin in rat spontaneous esophageal carcinogenesis.

Chronic inflammation contributes to tumor development by creating a local microenvironment that facilitates neoplastic transformation and potentiates the progression of cancer. Esophageal cancer (EC) is an inflammation-associated malignancy with a poor prognosis. The nature of the switch between chronic inflammation of the esophagus and EC-related immunological changes remains unclear. Here, we examined the dynamic alterations of immune cells at different stages of chronic esophagitis, Barrett's esophagus (BE) and EC using an esophageal spontaneous carcinogenesis rat model. We also investigated the anticancer effects of metformin. To stimulate EC carcinogenesis, chronic gastroduodenal reflux esophagitis via esophagojejunostomy was induced in 120 rats in metformin-treated and non-treated (control) groups. After 40 weeks, BE and EC developed in 96.7% and 63.3% of the control group, and in 66.7% and 23.3% of the metformin-treated group, respectively. Flow cytometric analysis demonstrated that the balance of M1/M2-polarized or phospho-Stat3-positive macrophages, regulatory T, cytotoxic T, natural killer (NK), NK T cells, and Th17 T cells was dynamically changed at each stage of the disease and were resolved by metformin treatment. These findings clarify the immunity in esophageal carcinogenesis and suggest that metformin could suppress this disease by improving the immunosuppressive tumor microenvironment and immune evasion.

A case of primary malignant melanoma of the esophagogastric junction with abscopal effect after nivolumab administration.

BACKGROUND: The abscopal effect is a rare phenomenon in which local irradiation causes tumor regression outside the irradiated area. There have been no reports of abscopal effect in patients with gastrointestinal melanoma with metastasis. Here, we report a case of primary malignant melanoma of the esophagogastric junction with abscopal effect after long-term treatment with nivolumab. CASE PRESENTATION: A 75-year-old woman was referred to our hospital with a gastroesophageal lesion. Upper gastrointestinal endoscopy revealed a raised lesion on the posterior wall of the greater curvature of the cardia and tenderness in the lower esophagus. Immunostaining of the tumor biopsy showed positive staining for Melan-A, human melanoma black-45 (HMB45), and S-100, indicating malignant melanoma of the esophagogastric junction. Contrast-enhanced computed tomography (CT) of the abdomen showed a mildly stained lesion protruding into the cardiac part of stomach and enlarged surrounding lymph nodes. The patient was diagnosed with malignant melanoma of the esophagogastric junction and proximal gastrectomy with lower esophagus resection was performed. Histological examination showed large, round tumor cells with nuclear atypia. Immunostaining was positive for Melan A, HMB45, S-100 protein, and SRY-box transcription factor 10, and the final diagnosis was malignant melanoma of the esophagogastric junction, with regional lymph node metastases. Three months after surgery, follow-up CT indicated left pleural metastasis; therefore, the patient was administered nivolumab, an immune checkpoint inhibitor (ICI). Following three courses of nivolumab, the patient exhibited grade 3 renal dysfunction (Common Terminology Criteria for Adverse Events version 5.0). After that, we have not administered nivolumab treatment. Five months after the development of renal dysfunction, a CT scan demonstrated an unstained nodule within the pancreatic, and the patient was diagnosed with pancreatic metastasis; intensity-modulated radiotherapy was performed. Six months later, CT revealed pancreatic nodule and pleural metastasis was shrunk; after an additional 2 months, pleural metastasis and effusion had disappeared. The patient is alive with no additional lesions. CONCLUSIONS: We report a case of primary malignant melanoma of the esophagogastric junction with an abscopal effect following nivolumab treatment. The findings of this case report suggest that ICIs in combination with radiotherapy may be effective for treating metastatic or recurrent malignant melanoma of the gastrointestinal tract.

nPTD classification: an updated classification of gastric cancer location for function preserving gastrectomy based on physiological lymphatic flow.

BACKGROUND: The correlation between tumor location and lymphatic flow distribution in gastric cancer has been previously reported, and PTD (Proximal - Transitional - Distal) classification was proposed. Our group updated and developed the nPTD classification. METHOD: We retrospectively studied gastric cancer patients who underwent the dye method sentinel node biopsy from 1993 to 2020. The inclusion criteria were a single lesion type 0 cancer of ≤5 cm in the long axis, clinically node-negative, and invasion within the proper muscle layer pathologically. In this study, the distribution of dyed lymphatic flow was evaluated for each occupied area of the tumor. RESULTS: We included 416 patients in this study. The tumors located in the watershed of the right and left gastroepiploic arteries near greater curvature had extensive lymphatic flow; therefore, a newly circular region with a diameter of 5 cm is set on the watershed of the greater curvature between P and T zone as the 'n' zone. In addition, for cancers located in the lesser P curvature, lymphatic flow to the greater curvature was not observed. Therefore, the P zone was divided into two: the lesser curvature side (PL) and the greater curvature side (PG). CONCLUSIONS: The advantage of the nPTD classification is that it provides not only proper nodal dissection but also adequate function-preserving gastrectomy. If the tumor is localized within the PL, the proximal gastrectomy resection area can be further reduced. In contrast, for cancers located in the 'n' zone, near-total gastrectomy is required because of the extensive lymphatic flow.

[A Case of an Asymptomatic Coagulopathy after Peritoneovenous Shunt Placement for Malignant Ascites of Gastric Cancer].

The patient was a 61‒year‒old man who had an advanced gastric cancer with peritoneal dissemination. After chemotherapy, intraoperative findings during a total gastrectomy revealed the disappearance of the dissemination nodules. Although adjuvant chemotherapy was performed, the presence of massive ascites led to the recurrence of the peritoneal dissemination 5 months after the surgery. While the chemotherapy regimen was altered, we observed no reduction in malignant ascites. The patient complained of abdominal distention and was admitted to our hospital for symptom management. We performed a cell‒free and concentrated ascites reinfusion therapy(CART)several times. However, symptom management proved difficult; therefore, the patient underwent a peritoneovenous shunt(Denver shunt)placement. After the shunting, we observed no organ injury and improved abdominal distention; however, an asymptomatic coagulopathy was present in the course. Additionally, blood examinations showed increased FDP‒DD and thrombin‒antithrombin complex(TAT). However, 6 months after the shunting, coagulopathy improved and the patient reported the absence of abdominal distention. This report describes a patient with an asymptomatic coagulopathy after Denver shunt placement and evaluated the clinical course by using TAT values.

Gastrointestinal stromal tumor metastasis to the ovary: A case report.

Gastrointestinal stromal tumors are common mesenchymal tumors of the gastrointestinal tract. The major site of metastasis for gastrointestinal stromal tumors is the liver or peritoneum, while metastasis to the ovary is exceptionally rare. A 53-year-old woman visited the hospital for bloating and anorexia and was diagnosed with a huge gastric gastrointestinal stromal tumor and peritoneal metastasis in the pelvis on upper gastrointestinal endoscopy and abdominal enhanced computed tomography. After administration of imatinib, the tumor was significantly reduced, and we performed laparoscopic pelvic tumor resection and open proximal gastrectomy with transverse colectomy. Intraoperatively, the pelvic tumor was found to be an ovarian tumor. Microscopic examination confirmed a gastric gastrointestinal stromal tumor with ovarian metastasis. In conclusion, we experienced a rare case of gastric gastrointestinal stromal tumor with ovarian metastasis. Preoperative administration of imatinib was successful and radical resection was achieved. Although pelvic tumors are difficult to differentiate preoperatively, the possibility of ovarian metastasis from gastrointestinal stromal tumor should be considered.

[Four Cases of Surgical Treatment for Radiation Enteritis].

Although radiation therapy for pelvic cancer leads to improved outcomes, it may cause radiation enteritis. Radiation enteritis is classified as early and late reaction. Late reaction indicate progressive and irreversible changes caused by ischemic changes of the intestinal mucosa. Severe cases require a surgical treatment, which is challenging because of severe adhesions and a high risk of suture failure. In addition, the postoperative course may be unfavorable in some cases. We performed surgery for 4 radiation enteritis cases; however, the postoperative course was unfavorable in 2 cases because of impaired absorption and ileus of the remaining short bowel. These patients could not eat adequately after discharge; therefore, we needed to explain and make them understand the benefits and disadvantages of radiation therapy.

High CD8/CD33 ratio in peritoneal metastatic lesions is associated with favorable prognosis in gastric cancer.

BACKGROUND: Tumor-infiltrating lymphocytes (TILs) and other immune cells have been reported as a prognostic factor in several tumors, including gastric cancer, and they play an important role in antitumor effect at the primary site. There were few reports on the immune status in peritoneal metastatic lesions for gastric cancer. AIMS: The aims of this study were to assess the prognostic significance of TILs (CD4, CD8, CD19, regulatory T cells [Tregs]), and myeloid-derived suppressor cells (MDSCs) in peritoneal metastatic lesions. METHODS: We retrospectively investigated 60 patients for gastric cancer with peritoneal metastasis who were treated between 2009 and 2016 in our institute. Immunohistochemistry for CD4, CD8, CD19, FOXP3, and CD33 was performed in the peritoneal metastatic lesions. The absolute numbers of immune cells and ratios were evaluated, and the relationship between immune-related marker and overall survival (OS) was investigated. RESULTS: A high infiltration of CD8+ lymphocytes or high CD8/CD33 ratio was a better prognosis for OS in univariate analysis using all immunologic variables (P = .012, P = .001). In multivariate analysis for clinical and immunologic variables, high CD8/CD33 ratio was identified as an independent prognostic factor for OS (Hazard ratio: 0.291, 95% confidence interval: 0.126-0.670, P = .004). CONCLUSION: High CD8/CD33 ratio and high infiltration of CD8+ lymphocytes in peritoneal metastatic lesions were favorable prognoses for gastric cancer patients with peritoneal metastasis. It is necessary to modify the immune microenvironment result to increase the level of CD8+ lymphocytes in the peritoneal metastatic lesions.

[Laparoscopy Assisted Subtotal Gastrectomy(Billrothâ Reconstruction)for Gastric Cancer in the Upper Stomach-A Report of Three Cases].

We experienced 3 cases of upper gastric cancer who underwent BillrothⅠ reconstruction in laparoscopy assisted subtotal gastrectomy. Two cases were female and 1 was male. The postoperative course was uneventful in all cases without heartburn, and the surgical margin was negative. The body weight loss rate was 5.8-12.6%, and the short-term results were relatively acceptable. Although the number of cases in this study was small, reconstruction with BillrothⅠ/delta-shaped anastomosis after laparoscopy assisted subtotal gastrectomy were considered to be useful.

Current status of conversion surgery for stage IV gastric cancer.

Palliative chemotherapy with best supportive care is a mainstay for patients with gastric cancer (GC) and distant metastasis. However, with advances in GC chemotherapy, multimodal treatment, including perioperative chemotherapy plus conversion surgery, has attracted attention as a new strategy to improve the outcome of patients with stage IV disease. Conversion surgery is defined as surgical treatment aimed at R0 resection after a good response to induction chemotherapy for tumors originally considered unresectable or marginally resectable for technical and/or oncological reasons. Various biological characteristics differ, depending on each metastatic condition in stage IV GC. The main metastatic pathways of GC can be divided into three categories: lymphatic, hematogenous, and peritoneal. In each category, considerable historical data on conversion surgery have demonstrated the benefits of individualized approaches. However, owing to the diversity of these conditions, a common definition, including the choice of induction chemotherapy, optimal timing of resection, and eligibility for conversion surgery, has not been established among surgical oncologists. Thus, we explore the current and future treatment options by reviewing the literature on this controversial topic comprehensively.

Optimization of robot-assisted thoracoscopic esophagectomy in the lateral decubitus position.

BACKGROUND: On the introduction of robot-assisted thoracoscopic esophagectomy (RATE), we refined the robotic system application to enhance our surgical experience obtained through thoracoscopic esophagectomy (TE) in the lateral decubitus position (LDP). Herein, we evaluate our methods introduced to optimize RATE in the LDP. METHODS: We performed RATE in the LDP with camera rotation and manual hand control assignment to reproduce the surgical view and manipulation of open esophagectomy. Forty patients underwent RATE between July 2018 and August 2020. After the initial 30 cases (initial RATE group), we optimized the port arrangement and robot settings in the most recent ten cases (recent RATE group). The surgical results of RATE were compared with those of 30 patients underwent TE between April 2014 and May 2019 selected by propensity score-matched analysis based on cStage (TE group). RESULTS: Operative duration was significantly longer in the initial RATE group than the TE group and the recent RATE group. Thoracic blood loss was significantly less in the initial RATE group than the TE group. Console time was significantly shorter in the recent RATE group than the initial RATE group. There was no surgical mortality in RATE and the surgical morbidity rate was similar in the three groups. CONCLUSIONS: Camera rotation and manual hand control assignment during RATE in the LDP reproduced the surgical view and manipulation of open esophagectomy and TE in the LDP. The robotic platform enabled meticulous dissection and reduced blood loss, but was initially time-consuming. Optimization of the port arrangement minimized operative duration.