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.

Intraperitoneal paclitaxel combined with FOLFOX/CAPOX plus bevacizumab for colorectal cancer with peritoneal carcinomatosis (the iPac-02 trial): study protocol of a single arm, multicenter, phase 2 study.

BACKGROUND: The safety of intraperitoneally administrated paclitaxel (op PTX) was demonstrated in the phase I trial of ip PTX combined with conventional systemic chemotherapy for colorectal cancer with peritoneal carcinomatosis. Moreover, the median survival time was 29.3 months, which was longer than that observed in previous studies. Here, we planned the phase II trial of ip PTX: the iPac-02 trial. METHODS: This multicenter, open-label, single assignment interventional clinical study includes patients with colorectal cancer with unresectable peritoneal carcinomatosis. FOLFOX-bevacizumab or CAPOX-bevacizumab is administered concomitantly as systemic chemotherapy. PTX 20 mg/m2 is administered weekly through the peritoneal access port in addition to these conventional systemic chemotherapies. The response rate is the primary endpoint. Progression-free survival, overall survival, peritoneal cancer index improvement rate, rate of negative peritoneal lavage cytology, safety, and response rate to peritoneal metastases are the secondary endpoints. A total of 38 patients are included in the study. In the interim analysis, the study will continue to the second stage if at least 4 of the first 14 patients respond to the study treatment. The study has been registered at the Japan Registry of Clinical Trials (jRCT2031220110). RESULTS: We previously conducted phase I trial of ip PTX combined with conventional systemic chemotherapy for colorectal cancer with peritoneal carcinomatosis [1]. In the study, three patients underwent mFOLFOX, bevacizumab, and weekly ip PTX, and the other three patients underwent CAPOX, bevacizumab, and weekly ip PTX treatment. The dose of PTX was 20 mg/m [2]. The primary endpoint was the safety of the chemotherapy, and secondary endpoints were response rate, peritoneal cancer index improvement rate, rate of negative peritoneal lavage cytology, progression-free survival, and overall survival. Dose limiting toxicity was not observed, and the adverse events of ip PTX combined with oxaliplatin-based systemic chemotherapy were similar to those described in previous studies using systemic chemotherapy alone [3, 4]. The response rate was 25%, peritoneal cancer index improvement rate was 50%, and cytology in peritoneal lavage turned negative in all the cases. The progression-free survival was 8.8 months (range, 6.8-12 months), and median survival time was 29.3 months [5], which was longer than that observed in previous studies. CONCLUSION: Here, we planned the phase II trial of ip paclitaxel combined with conventional chemotherapy for colorectal cancer with peritoneal carcinomatosis: the iPac-02 trial.

A phase I study of intraperitoneal paclitaxel combined with gemcitabine plus nab-paclitaxel for pancreatic cancer with peritoneal metastasis.

PURPOSE: A phase I study of intraperitoneal paclitaxel (ip PTX) combined with gemcitabine (GEM) plus nab-paclitaxel (nab-PTX) (GnP) was conducted to determine the maximum tolerated dose (MTD) and the recommended dose (RD) in pancreatic cancer patients with peritoneal metastasis in first-line setting. METHODS: Based on the 3 + 3 dose-escalation model, ip PTX, GEM and nab-PTX were administered at doses of 20 or 30 mg/m2, 800 or 1000 mg/m2 and 100 or 125 mg/m2 (level 1, 2 and 3, respectively) on days 1, 8 and 15 in 4-week cycles. Dose-limiting toxicity (DLT) defined as severe adverse events was evaluated during the first cycle of the treatment. Safety and preliminary efficacy were also investigated. RESULTS: In total, 12 patients were enrolled. While 2 of the first 6 patients enrolled at level 1 experienced DLTs (grade 3 ip port dysfunction and grade 3 pneumonia), no DLT was observed in the next 6 patients enrolled at level 2 and 3. Therefore, we did not reach the MTD and the RD was determined to be level 3 (ip PTX of 30 mg/m2, GEM of 1000 mg/m2, and nab-PTX of 125 mg/m2). The major grade 3/4 adverse events included neutropenia (58%), anemia (33%), and ip port dysfunction (25%). The response rate was 25% and the median PFS was 5.4 (95% confidence interval; 2.4-16.0). The cytological status in peritoneal lavage turned negative in 8 patients (67%). CONCLUSIONS: Ip PTX combined with GnP was feasible and potentially effective in pancreatic cancer with peritoneal metastasis as a first-line treatment deserved further evaluations.

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

INTRODUCTION: Intraperitoneal (IP) chemotherapy is a promising treatment option for gastric cancer (GC) with peritoneal metastasis (PM). Recently, superiority of IP administration of paclitaxel (PTX) combined with S-1 and intravenous PTX over conventional systemic chemotherapy was suggested in a phase III study, although the difference in overall survival did not reach statistical significance in the primary analysis. Thus, attempts to combine IP PTX with other systemic therapies with higher efficacy are warranted. We designed a new regimen combining IP PTX with S-1 plus cisplatin (SP), which is regarded as the standard first-line treatment for metastatic GC in Japan, and subsequently carried out a dose-escalation study. METHODS: The combination was a 5-weekly regimen. IP PTX was to be administered on days 1, 8, and 22 with an initial dose of 15 mg/m2 at level 1 and 20 mg/m2 at level 2. S-1 was to be administered orally at a fixed dose of 80 mg/m2 b.i.d. for 21 days followed by a -14-day rest. Cisplatin was to be administered intravenously at a dose of 60 mg/m2 on day 8. Dose-limiting toxicities (DLTs) were defined as grade 4 leukopenia, grade 3 (G3) febrile neutropenia, G3 thrombocytopenia, and G3 nonhematological toxicity. RESULTS: A total of 9 patients with macroscopic PM were enrolled. No DLTs were observed among the 3 patients at level 1 and 6 patients at level 2. No adverse events or technical problems associated with the IP administration were observed. Consequently, the maximum-tolerated dose was not reached, and the dose for further clinical trials of IP PTX was determined as 20 mg/m2. As for efficacy, peritoneal lavage cytology turned negative after the first course in 4 of 7 patients who had positive cytology before treatment. CONCLUSION: The present study determined the dose for further clinical trials of IP PTX to be 20 mg/m2, when combined with the 5-weekly SP regimen.

Multicenter Phase II Study of Intravenous and Intraperitoneal Paclitaxel With S-1 for Pancreatic Ductal Adenocarcinoma Patients With Peritoneal Metastasis.

OBJECTIVE: To evaluate the clinical efficacy and tolerability of intravenous (i.v.) and intraperitoneal (i.p.) paclitaxel combined with S-1, "an oral fluoropyrimidine derivative containing tegafur, gimestat, and otastat potassium" in chemotherapy-naive pancreatic ductal adenocarcinoma (PDAC) patients with peritoneal metastasis. BACKGROUND: PDAC patients with peritoneal metastasis (peritoneal deposits and/or positive peritoneal cytology) have an extremely poor prognosis. An effective treatment strategy remains elusive. METHODS: Paclitaxel was administered i.v. at 50 mg/m and i.p. at 20 mg/m on days 1 and 8. S-1 was administered at 80 mg/m/d for 14 consecutive days, followed by 7 days of rest. The primary endpoint was 1-year overall survival (OS) rate. The secondary endpoints were antitumor effect and safety (UMIN000009446). RESULTS: Thirty-three patients who were pathologically diagnosed with the presence of peritoneal dissemination (n = 22) and/or positive peritoneal cytology (n = 11) without other organ metastasis were enrolled. The tumor was located at the pancreatic head in 7 patients and the body/tail in 26 patients. The median survival time was 16.3 (11.47-22.57) months, and the 1-year survival rate was 62%. The response rate and disease control rate in assessable patients were 36% and 82%, respectively. OS in 8 patients who underwent conversion surgery was significantly higher than that of nonsurgical patients (n = 25, P = 0.0062). Grade 3/4 hematologic toxicities occurred in 42% of the patients and nonhematologic adverse events in 18%. One patient died of thrombosis in the superior mesenteric artery. CONCLUSIONS: This regimen has shown promising clinical efficacy with acceptable tolerability in chemotherapy-naive PDAC patients with peritoneal metastasis.

Peritoneal Lavage CEA mRNA Levels Predict Conversion Gastrectomy Outcomes after Induction Chemotherapy with Intraperitoneal Paclitaxel in Gastric Cancer Patients with Peritoneal Metastasis.

BACKGROUND: The outcome of gastric cancer patients with peritoneal metastasis remains poor. We treated these patients with intraperitoneal and intravenous paclitaxel plus oral S-1 (tegafur/gimeracil/oteracil), followed by gastrectomy in responders. We evaluated the clinical significance of peritoneal lavage carcinoembryonic antigen (CEA) messenger RNA (mRNA) levels as a biomarker for indication of conversion gastrectomy. METHODS: The peritoneal lavage of 68 patients who received the above regimen as induction chemotherapy was repeatedly collected via intraperitoneal access ports. Gastrectomy was considered when improvement of peritoneal metastasis was confirmed by a second laparoscopic examination with negative peritoneal cytology. CEA and porphobilinogen deaminase mRNAs were chronologically quantified using the transcription reverse-transcription concerted reaction method. The CEA mRNA index (CmRI) was calculated as CEA mRNA/porphobilinogen deaminase mRNA × 10,000. RESULTS: Thirty-nine patients underwent gastrectomy and 29 patients did not (median survival time, 27.8 vs. 10.7 months, respectively; P < 0.001). In gastrectomy-positive patients, the outcome largely differed according to CmRI values immediately prior to surgery. Patients with a preoperative CmRI value <100 (n = 20) were associated with a significantly longer survival than those with a preoperative CmRI value >100 (n = 19) (41.8 vs. 20.1 months, respectively; P < 0.001). A preoperative CmRI value <100 was confirmed as an independent predictor of survival for gastrectomy-positive patients in the multivariate analysis. CONCLUSIONS: The CmRI reflects the response of peritoneal metastases to induction intraperitoneal chemotherapy. It may be a useful biomarker for indicating gastrectomy in gastric cancer patients with peritoneal metastasis.

Intraperitoneal Delivery of Cisplatin via a Hyaluronan-Based Nanogel/in Situ Cross-Linkable Hydrogel Hybrid System for Peritoneal Dissemination of Gastric Cancer.

Intraperitoneal administration of chemotherapeutics is expected for the treatment of peritoneally disseminated gastric cancer because of poor migration of the drugs from the systemic circulation to the peritoneal cavity. In this study, for intraperitoneal delivery of cisplatin (CDDP), we developed a hyaluronan (HA)-based hybrid system in which CDDP-loaded HA nanogels were either physically encapsulated in or chemically conjugated to injectable HA hydrogels. Physical encapsulation enabled sustained release of HA nanogels from the HA hydrogel matrix for over a week. This was a longer release period than that of encapsulated free CDDP, which released 80% of the drug in 2 days. The longer release was attributed to delayed diffusion of HA nanogels from the hydrogel matrix network. The release profile could be tuned by modifying the chemical conjugation of HA nanogels to the HA hydrogel matrix, as well as the type of chelating ligands used to load CDDP to the nanogel. Furthermore, intraperitoneally administered hybrid had significant antitumor activity in a mouse model of peritoneally disseminated gastric cancer, especially for nodules smaller than 1.0 mm.

Surgery after intraperitoneal and systemic chemotherapy for gastric cancer with peritoneal metastasis or positive peritoneal cytology findings.

BACKGROUND: Despite recent progress in systemic chemotherapy, the prognosis of gastric cancer patients with peritoneal metastasis (P1) or positive peritoneal cytology findings (CY1) is still poor. We developed a regimen combining intraperitoneal (IP) paclitaxel (PTX) with S-1 and PTX, which can produce notable efficacy with regard to peritoneal lesions. Surgery after response to combination chemotherapy is a promising option for P1 or CY1 gastric cancer. A retrospective study was performed to evaluate the safety and efficacy. METHODS: This study enrolled 100 primary P1 or CY1 gastric cancer patients treated with IP PTX plus S-1 and PTX at the University of Tokyo Hospital between 2005 and 2011. Radical gastrectomy was performed when peritoneal cytology findings became negative, and the disappearance or obvious shrinkage of peritoneal metastasis was confirmed by laparoscopy. The same chemotherapy regimen was restarted after surgery and repeated with appropriate dose reduction. RESULTS: Gastrectomy was performed in 64 (P1 56, P0CY1 8) of 100 (P1 90, P0CY1 10) patients. R0 resection was achieved in 44 patients (69%). The median survival time was 30.5 months [95% confidence interval (CI) 23.6-37.7 months] from the initiation of intraperitoneal chemotherapy and 34.6 months (95% CI 26.8-39.4 months) from the diagnosis of gastric cancer. Postoperative complications included anastomotic leakage and pancreatic fistula, each in two patients, which were cured conservatively. There were no treatment-related deaths. The median survival time of the 36 patients who did not undergo surgery was 14.3 months (95% CI 10.0-17.8 months). CONCLUSIONS: Surgery after response to intraperitoneal and systemic chemotherapy is safe and may prolong the survival of P1 and CY1 gastric cancer patients.

Port-site metastasis after laparoscopic surgery for gastrointestinal cancer.

Although the incidence of port-site metastasis after laparoscopic surgery for colorectal cancer has markedly decreased since laparoscopic colectomy was first reported in 1991, it still has not reached zero. In colorectal cancer, the safety of laparoscopic surgery, including the low incidence of port-site metastasis, has been proven in large, randomized trials. In gastric cancer, reports of port-site metastasis are extremely rare, but we should await the results of ongoing trials. This brief review summarizes the current knowledge regarding port-site metastasis after laparoscopic surgery for colorectal and gastric cancer.

Production of Cisplatin-Incorporating Hyaluronan Nanogels via Chelating Ligand-Metal Coordination.

Hyaluronan (HA) is a promising drug carrier for cancer therapy because of its CD44 targeting ability, good biocompatibility, and biodegradability. In this study, cisplatin (CDDP)-incorporating HA nanogels were fabricated through a chelating ligand-metal coordination cross-linking reaction. We conjugated chelating ligands, iminodiacetic acid or malonic acid, to HA and used them as a precursor polymer. By mixing the ligand-conjugated HA with CDDP, cross-linking occurred via coordination of the ligands with the platinum in CDDP, resulting in the spontaneous formation of CDDP-loaded HA nanogels. The nanogels showed pH-responsive release of CDDP, because the stability of the ligand-platinum complex decreases in an acidic environment. Cell viability assays for MKN45P human gastric cancer cells and Met-5A human mesothelial cells revealed that the HA nanogels selectively inhibited the growth of gastric cancer cells. In vivo experiments using a mouse model of peritoneal dissemination of gastric cancer demonstrated that HA nanogels specifically localized in peritoneal nodules after the intraperitoneal administration. Moreover, penetration assays using multicellular tumor spheroids indicated that HA nanogels had a significantly higher ability to penetrate tumors than conventional, linear HA. These results suggest that chelating-ligand conjugated HA nanogels will be useful for targeted cancer therapy.

Intravenous and intraperitoneal paclitaxel with S-1 for treatment of refractory pancreatic cancer with malignant ascites.

UNLABELLED: Objectives The aim of this study was to evaluate the safety and efficacy of intravenous and intraperitoneal paclitaxel (PTX) combined with S-1 for treatment of gemcitabine-refractory pancreatic cancer with malignant ascites. Methods After the feasibility of this regimen was first confirmed in an interim analysis in 10 patients, a total of 35 patients were enrolled between April 2011 and December 2014. PTX was administered intravenously (50 mg/m(2)) and intraperitoneally (20 mg/m(2)) on days 1 and 8, and 80 mg/m(2) S-1 was administered on days 1-14 every 3 weeks. The primary endpoint was overall survival (OS). The secondary endpoints were progression-free survival (PFS), the objective tumor response, efficacy against malignant ascites, and safety. Result In all 35 patients, the median OS and PFS were 4.8 (95 % confidence interval [CI], 2.1-5.3) months and 2.8 (95 % CI, 0.9-4.1) months, respectively. The 26 patients who were evaluable for efficacy achieved a response rate of 8 % and a disease control rate of 69 %. Malignant ascites had disappeared or decreased in 18 (69 %) patients, including complete resolution in 4 (15 %), and a negative change in cytological status was achieved in 8 (31 %) patients. The major grade 3/4 adverse events included neutropenia (34 %), anemia (31 %), nausea (9 %), and catheter-related infections (6 %). Conclusion Combination chemotherapy consisting of intravenous and intraperitoneal PTX with S-1 showed acceptable toxicity and favorable efficacy in pancreatic cancer patients with malignant ascites. ( CLINICAL TRIAL REGISTRATION NUMBER: UMIN000005306).

A case of disseminated carcinomatosis of the bone marrow originating from gastric cancer 3 years after intraperitoneal chemotherapy against peritoneal carcinomatosis.

BACKGROUND: Clinical studies of intraperitoneal chemotherapy with paclitaxel in patients of gastric cancer with peritoneal carcinomatosis is well tolerated and effective, and rare cases of metastasis and recurrence have experienced during the treatment. Disseminated carcinomatosis of the bone marrow is highly rare in gastric cancer and associated with a poor prognosis. CASE PRESENTATION: A 59-year-old woman of gastric cancer with peritoneal carcinomatosis received five courses of chemotherapy with intraperitoneal administration of paclitaxel, and laparoscopy showed disappearance of the peritoneal carcinomatosis. She subsequently underwent total gastrectomy, and the histopathological findings showed a complete response to the chemotherapy. Postoperatively, chemotherapy with intraperitoneal administration of paclitaxel was continued for 30 months, without apparent recurrence. However, the gastric cancer recurred as disseminated carcinomatosis of the bone marrow with disseminated intravascular coagulation, and we hence changed the chemotherapy regimen to weekly irinotecan. Remission was achieved, and she did not experience any major symptoms; however, she died 6 months after the diagnosis of disseminated carcinomatosis of the bone marrow. CONCLUSIONS: Since intraperitoneal paclitaxel administration can strongly suppress peritoneal carcinomatosis of gastric cancer, careful attention should be paid not only to peritoneal recurrence but also for rare site metastases, such as bone marrow metastases.

[Intraperitoneal Chemotherapy for Peritoneal Metastasis of Gastric Cancer].

Peritoneal metastasis of gastric cancer remains a refractory disease, and the standard treatment strategy is still unclear. Intraperitoneally administered paclitaxel(PTX)remains in the intraperitoneal(IP)cavity for a long time and directly infiltrates peritoneal metastatic nodules, thereby producing antitumor effects. We designed an IP chemotherapy regimen of S-1 combined with weekly intravenous(IV)and IP PTXadministration. In our phase I study, the recommended dose of IP PTXwas determined to be 20mg/m2. In our phase II study for patients with P1(macroscopic peritoneal metastasis-positive)or CY1 (cytology-positive)gastric cancer, the 1-year overall survival(OS)rate was 78%and the median survival time(MST)was 23.6 months. In another phase II study of patients with P1 gastric cancer, the 1-year OS rate was 77%and the MST was 17.1 months. A phase III PHOENIX-GC trial comparing IP chemotherapy to S-1 plus cisplatin has recently been completed. Phase II studies of the IP administration of docetaxel have also shown favorable results. Recently, the results of several clinical studies investigating the effects of S-1 combined with weekly IV and IP PTXadministration for peritoneal metastasis of pancreatic cancer have been published.

Clinical significance of cytological status of peritoneal lavage fluid during intraperitoneal chemotherapy for gastric cancer with overt peritoneal dissemination.

BACKGROUND: A positive cytology of peritoneal lavage fluid (CY1) is a poor prognostic factor in patients with gastric cancer (GC). We have recently reported that CY1 often changes to negative (CY0) following combination chemotherapy including intraperitoneal (IP) paclitaxel (PTX), which results in marked prolongation of survival in GC patients with peritoneal dissemination (P1). METHODS: A total of 95 P1 GC patients who received combination chemotherapy with S-1 and intravenous and IP PTX were enrolled. Peritoneal lavage fluid was periodically examined cytologically at the start of every cycle of chemotherapy, and the impact of CY status on patient outcome was retrospectively evaluated. RESULTS: Seventy-three (76.8%) of 95 patients were diagnosed as CY1 before initial treatment. Median survival time (MST) of the CY1 group was significantly shorter than that of the CY0 group (19.1 vs. 32.5 months, P = 0.033). Cytological status changed from CY1 to CY0 in 68 (93.2%) of 73 CY1 patients during the whole treatment period and MST of patients who showed a negative change was significantly longer than that of the unchanged group (20.0 vs. 13.0 months, P = 0.0017). In 64 patients who achieved CY0 by IP PTX regimen, the median time to achieve CY0 was 1.4 months, and patients who achieved a negative change within 1 month showed a particularly good outcome (MST = 26.1 months). CONCLUSIONS: Periodic cytological examination of peritoneal lavage fluid is clinically useful to evaluate the efficacy of treatment as well as to predict the outcome of patients with P1 GC.

Flow Cytometric Quantification of Intraperitoneal Free Tumor Cells is a Useful Biomarker in Gastric Cancer Patients with Peritoneal Metastasis.

BACKGROUND: The frequency of intraperitoneal free tumor cells (IPTC) is considered to reflect the severity of peritoneal metastasis (PM). We quantified the relative number of IPTC against leukocytes in peritoneal fluid and evaluated its clinical relevance in gastric cancer (GC) patients, particularly those with PM. METHODS: Cells recovered from ascites or peritoneal lavage fluid were immunostained with monoclonal antibodies (mAb) to CD45 and CD326 (EpCAM). Using flow cytometry (FACS), CD326(+) and CD45(+) cells were classified as either tumor cells (T) or leukocytes (L) and the T/L ratio (TLR) was calculated in a total of 506 samples obtained from 300 patients with GC and 33 patients with liver cirrhosis (LC). RESULTS: Median (M) of the TLR of the initial samples obtained from 199 patients with PM(+) GC was 1.32 % (0-1,868.44 %), which was significantly higher than that in patients with PM(-) GC (M = 0 %, 0-0.35 %; n = 101) or LC (M = 0 %, 0-0.031 %; n = 33). In 104 PM(+) patients who received combination chemotherapy including intraperitoneal paclitaxel, the TLR was repeatedly measured in peritoneal fluid obtained from the port. In these patients, the TLR showed a strong correlation with clinical features as well as cytological findings and carcinoembryonic antigen messenger RNA status. Finally, the median survival time of the 11 patients with initial TLR > 10 % was significantly shorter than that of the 52 patients with TLR < 10 % (271 vs. 627 days; p = 0.0002). CONCLUSION: The TLR excellently reflected tumor burden in the peritoneal cavity, and could be a reliable biomarker to determine the outcome, as well as the effectiveness, of chemotherapy in patients with PM(+) GC.

CD90(+)CD45(-) intraperitoneal mesothelial-like cells inhibit T cell activation by production of arginase I.

In this study, we analyzed intraperitoneal cells recovered from human samples and found that CD90(+)CD45(-) cells exist as a minor population but vigorously grow in culture, showing the morphological features of mesothelial cells (MC). Interestingly, the MC highly expressed arginase I and markedly suppressed T cell proliferation with the reduction of CD3 ζ chain expression in T cells stimulated by coated anti-CD3 mAb. The addition of nor-NOHA (500 µM), or L-arginine (1 mM) mostly restored the inhibitory effect of MC on T cell proliferation as well as the reduced expression of CD3 ζ chain. The expression level of CD3 ζ chain in T cells in the peritoneal cavity was significantly down-regulated from circulating T cells. These results suggest that intraperitoneal free MC have immunomodulatory functions through the control of L-arginine level, and thus may play significant roles in the pathogenesis of various diseases in the peritoneal cavity.

Salvage gastrectomy after intravenous and intraperitoneal paclitaxel (PTX) administration with oral S-1 for peritoneal dissemination of advanced gastric cancer with malignant ascites.

BACKGROUND: Peritoneal metastasis of gastric cancer has extremely poor clinical outcomes. Recently, we developed a combination chemotherapy that used intraperitoneal (IP) paclitaxel (PTX) and produced excellent antitumor effects against peritoneal lesions. However, no information is available about the benefit of gastrectomy in cases with malignant ascites. METHODS: A total of 64 patients with severe peritoneal metastasis and ascites received IP PTX at 20 mg/m(2) via implanted subcutaneous peritoneal access ports as well as intravenous (IV) PTX at 50 mg/m(2) on days 1 and 8. S-1 was administered at 80 mg/m(2) day for 14 consecutive days, followed by 7 days of rest. In all patients, investigative laparoscopy was performed around the combination chemotherapy, and gastrectomy was performed on patients who showed apparent shrinkage of their peritoneal nodules as well as negative peritoneal cytology at the second laparoscopy. RESULTS: Gastrectomy was performed in 34 patients. The median course of chemotherapy before surgery was 5 courses (range 2-16). R0 operation was achieved in 22 patients (65%), and grade 2 and 3 histological responses were obtained in 7 (21%) and 1 (3%) patient(s), respectively. The median survival time and 1-year overall survival of the gastrectomized patients were 26.4 months and 82%, and those of the 30 patients who did not receive gastrectomy were 12.1 months and 26%, respectively. Morbidity was minimal, and there was no mortality. CONCLUSIONS: Salvage gastrectomy after chemotherapy of S-1 with IV and IP PTX is promising, even for patients with highly advanced gastric cancer and severe peritoneal metastasis and malignant ascites.

Intraperitoneal administration of cisplatin via an in situ cross-linkable hyaluronic acid-based hydrogel for peritoneal dissemination of gastric cancer.

PURPOSE: To develop a drug-delivery system for the prolonged retention of intraperitoneally (i.p.) administered cisplatin (CDDP) to deliver intraperitoneal chemotherapy against peritoneal carcinomatosis effectively. METHODS: CDDP was encapsulated inside an in situ cross-linkable hyaluronic acid (HA)-based hydrogel. The gelation and degradation kinetics of the hydrogel and the release kinetics of CDDP were investigated in vitro, and the antitumor effect was investigated in a mouse model of peritoneal dissemination of human gastric cancer. RESULTS: The gelation time varied according to the concentration of two polymers: HA-adipic dihydrazide and HA-aldehyde. CDDP was released from the hydrogel for more than 4 days. A cell proliferation assay showed that the polymers themselves were not cytotoxic toward MKN45P, a human gastric cancer cell line. By mixing the two polymers in the peritoneum, in situ gelation was achieved. The weight of peritoneal nodules decreased in the hydrogel-conjugated CDDP group, whereas no significant antitumor effect was observed in the free CDDP group. CONCLUSIONS: In situ cross-linkable HA hydrogels represent a promising biomaterial to prolong the retention and sustain the release of intraperitoneally administered CDDP in the peritoneal cavity and to enhance its antitumor effects against peritoneal dissemination.