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.

Intraperitoneal Chemotherapy as Adjuvant or Perioperative Chemotherapy for Patients with Type 4 Scirrhous Gastric Cancer: PHOENIX-GC2 Trial.

The prognosis of patients with type 4 scirrhous gastric cancer remains poor due to a high risk of peritoneal metastasis. We have previously developed combined chemotherapy regimens of intraperitoneal (IP) paclitaxel (PTX) and systemic chemotherapy, and promising clinical efficacy was reported in gastric cancer with peritoneal metastasis. Herein, a randomized, phase III study is proposed to verify the efficacy of IP PTX to prevent peritoneal recurrence. Gastric cancer patients with type 4 tumors and without apparent distant metastasis, including peritoneal metastasis, will be randomized for standard systemic chemotherapy or combined IP and systemic chemotherapy based on peritoneal lavage cytology findings. Those with negative peritoneal cytology will receive radical gastrectomy and adjuvant chemotherapy of S-1 plus docetaxel (control arm), or S-1 plus intravenous and IP PTX (experimental arm). Those with positive peritoneal cytology will receive three courses of S-1 plus oxaliplatin (control arm), or S-1 plus oxaliplatin and IP PTX (experimental arm). Subsequently, they undergo gastrectomy and receive postoperative chemotherapy of S-1 plus docetaxel (control arm), or S-1 plus intravenous and IP PTX (experimental arm). The primary endpoint is disease free survival after a 3-year follow-up period. Secondary endpoints are overall survival, survival without peritoneal metastasis, safety, completion rate, curative resection rate, and histological response of preoperative chemotherapy. A total of 300 patients are to be enrolled.

Priorities, actions and risks in the COVID-19 pandemic: a flash SoMe survey among surgical oncologists.

OBJECTIVES: Corona virus-induced disease 19 (COVID-19) pandemic has globally affected the surgical treatment of cancer patients and has challenged the ethical principles of surgical oncologists around the world. Not only treatment but also diagnosis and follow-up have been disrupted. METHODS: An online survey was sent through Twitter and by the surgical societies worldwide. The survey consisted of 29 closed-ended questions and was conducted over a period of 24 days beginning in March 26, 2020. RESULTS: Overall, 394 surgical oncologists from 41 different countries answered the questionnaire. The predominant guiding principle was "saving lives" 240 (62%), and the different aspects of lock-down found hence large support (mean 7.1-9.3 out of 10). Shut-down of elective surgery and modification of cancer care found a mean support of 7.0 ± 3.0 and 5.8 ± 3.1, respectively. Modification of cancer care longer than two weeks was considered unacceptable to 114 (29%) responders. Hundred and fifty six (40%) and 138 (36%) expect "return to normal" beyond six months for surgical practice and cancer care, respectively. CONCLUSIONS: Surgical oncologists show strong and long-lasting support for lock-down measures aiming to save lives. The impact of the pandemic on surgical oncology is perceived controversially, but the majority was forced already now to accept what is inacceptable for many of their colleagues.

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.

Treatment of patients with peritoneal metastases from gastric cancer.

Despite recent advances in chemotherapy, outcomes of patients with peritoneal metastases (PM) from gastric cancer are still very poor and standard treatment has not been established. Although oral S-1 appears to be effective for patients with PM, the effects of systemic chemotherapy are limited. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) yield fewer benefits in patients with PM from gastric cancer than in patients with PM from other malignancies. In comparison, repeated intraperitoneal chemotherapy (RIPEC) with taxanes using an implantable peritoneal access port has a pharmacokinetic advantage for the control of peritoneal lesions and in combination with systemic chemotherapy can result in surprisingly long-term survival in patients with PM from gastric cancer. Herein, we review the results of recent clinical studies specifically targeting PM from gastric cancer and discuss future prospects for an intraperitoneal approach to the ideal treatment of patients with gastric cancer with peritoneal involvement.

Phase III Trial Comparing Intraperitoneal and Intravenous Paclitaxel Plus S-1 Versus Cisplatin Plus S-1 in Patients With Gastric Cancer With Peritoneal Metastasis: PHOENIX-GC Trial.

Purpose Intraperitoneal paclitaxel plus systemic chemotherapy demonstrated promising clinical effects in patients with gastric cancer with peritoneal metastasis. We aimed to verify its superiority over standard systemic chemotherapy in overall survival. Patients and Methods This randomized phase III trial enrolled patients with gastric cancer with peritoneal metastasis who had received no or short-term (< 2 months) chemotherapy. Patients were randomly assigned at a two-to-one ratio to receive intraperitoneal and intravenous paclitaxel plus S-1 (IP; intraperitoneal paclitaxel 20 mg/m2 and intravenous paclitaxel 50 mg/m2 on days 1 and 8 plus S-1 80 mg/m2 per day on days 1 to 14 for a 3-week cycle) or S-1 plus cisplatin (SP; S-1 80 mg/m2 per day on days 1 to 21 plus cisplatin 60 mg/m2 on day 8 for a 5-week cycle), stratified by center, previous chemotherapy, and extent of peritoneal metastasis. The primary end point was overall survival. Secondary end points were response rate, 3-year overall survival rate, and safety. Results We enrolled 183 patients and performed efficacy analyses in 164 eligible patients. Baseline characteristics were balanced between the arms, except that patients in the IP arm had significantly more ascites. The median survival times for the IP and SP arms were 17.7 and 15.2 months, respectively (hazard ratio, 0.72; 95% CI, 0.49 to 1.04; stratified log-rank P = .080). In the sensitivity analysis adjusted for baseline ascites, the hazard ratio was 0.59 (95% CI, 0.39 to 0.87; P = .008). The 3-year overall survival rate was 21.9% (95% CI, 14.9% to 29.9%) in the IP arm and 6.0% (95% CI, 1.6% to 14.9%) in the SP arm. Both regimens were well tolerated. Conclusion This trial failed to show statistical superiority of intraperitoneal paclitaxel plus systemic chemotherapy. However, the exploratory analyses suggested possible clinical benefits of intraperitoneal paclitaxel for gastric cancer.

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.

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.

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.

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.

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.

Optimal drug delivery for intraperitoneal paclitaxel (PTX) in murine model.

BACKGROUND: Repeated intraperitoneal (IP) administration of paclitaxel (PTX) with concurrent systemic chemotherapy is clinically effective for the treatment of peritoneal metastases (PM) from gastric cancer. However, it is unclear how biochemical modifications may affect the pharmacokinetics and bioavailability of IP administered PTX. METHODS: In a xenograft PM model using human gastric cancer cells, MKN45, fluorescein-conjugated PTX (OG-PTX) was given IP and the intra-tumor distribution of PTX examined with fluorescein microscopy. RESULTS: After IP injection, PTX was seen to directly infiltrate up to several hundred micrometers from the surface of the PM. Co-injection with 5 % non-animal stabilized hyaluronic acid increased PTX infiltration and suppressed the development of PM more efficiently than PTX alone. PTX solubilized with amphiphilic polymer composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) and n-butyl methacrylate (BMA) efficiently formed a micellar formation 50-100 nm in diameter. IP injection of the nanomicellar PTX (PTX-30W) also showed significantly enhanced tumor infiltration and further inhibition of the growth of PM compared with PTX solubilized with Cremophor-ethanol (PTX-Cre). Finally, IP administration of NK105, another nanomicellar PTX, inhibited the growth of subcutaneous tumors as well as PM, compared with conventional PTX-Cre in the same murine model. CONCLUSIONS: PTX administered IP directly infiltrates PM and are thus a useful strategy for the treatment of PM. Drug modification with nanotechnology may further enhance penetration of PM resulting in improved clinical efficacy.

[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.

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).

Intraperitoneal Mesenchymal Cells Promote the Development of Peritoneal Metastasis Partly by Supporting Long Migration of Disseminated Tumor Cells.

The human peritoneal cavity contains a small number of free cells of mesenchymal cell lineage. Intraperitoneal mesenchymal cells (PMC) play supportive roles in metastasis formation on the peritoneum. In this study, we found that PMC, when co-cultuerd with human gastric cancer cells, MKN45, enhanced the proliferation of MKN45 when cultured at low, but not high, cellular density. Also, PMC suppressed apoptotic cell death of MKN45 only under low density culture conditions. Time-lapse videoanalysis clearly demonstrated that PMC randomly migrated more vigorously than did MKN45, and strongly enhanced the migration behavior of co-cultured MKN45. In fact, the majority of MKN45 migrated together in direct physical contact with PMC, and the sum of migration lengths from original position of co-cultured MKN45 for 48 hours was approximately 10 times longer than that of MKN45 cultured alone. Our data suggest that enhanced migration can increase the chance of direct contact or positional proximity among sparcely distributed MKN45, which may bring survival advantages to tumor cells. This may be one of the important mechanisms of peritoneal metastasis, since only a small number of tumor cells are considered to be disseminated in the early step of metastasis formation on the peritoneum.