Microwave Scissors-Based Sutureless Laparoscopic Partial Nephrectomy Versus Conventional Open Partial Nephrectomy in a Porcine Model: Usefulness and Complications.

BACKGROUND: This study aimed to compare the benefits and safety of microwave scissors-based sutureless laparoscopic partial nephrectomy (MSLPN) with those of conventional open partial nephrectomy (cOPN). METHODS: Each kidney in nine pigs underwent MSLPN using microwave scissors (MWS) via transperitoneal laparoscopy or cOPN via retroperitoneal open laparotomy. The kidney's lower and upper poles were resected under temporary hilar-clamping. The renal calyces exposed during renal resections were sealed and transected using MWS in MSLPN and were sutured in cOPN. For MWS, the generator's power output was 60 W. Data on procedure time (PT), ischemic time (IT), blood loss (BL), normal nephron loss (NNL), and extravasation during retrograde pyelogram were compared between the two techniques. RESULTS: The authors successfully performed 22 MSLPNs and 10 cOPNs. Compared with cOPN, MSLPN was associated with significantly lower PT (median, 9.2 vs 13.0 min; p = 0.026), IT (median, 5.9 vs 9.0 min; p < 0.001), BL (median, 14.4 vs 38.3 mL; p = 0.043), and NNL (median, 7.6 vs 9.4 mm; p = 0.004). However, the extravasation rate was higher in the MSLPN group than in the cOPN group (54.5 % [n = 12] vs 30.0 % [n = 3]), albeit without a significant difference (p = 0.265). Pelvic stenosis occurred in one MSLPN procedure that involved deep lower pole resection near the kidney hilum. CONCLUSIONS: The study data show that MSLPN can improve intraoperative outcomes while reducing technical demands for selected patients with non-hilar-localized renal tumors. However, renal calyces, if violated, should be additionally sutured to prevent urine leakage.

Feasibility of Microwave Scissors-Based Off-Clamp Laparoscopic Partial Nephrectomy in a Porcine Model.

OBJECTIVES: To assess the feasibility of off-clamp laparoscopic partial nephrectomy using microwave scissors. METHODS: We performed transperitoneal laparoscopic partial nephrectomy, without hilar clamping or renorrhaphy, using only microwave scissors for renal resection in a porcine model. For each kidney, 2 types of procedures were performed: a middle pole resection excising an area of 2-cm diameter and approximately 1-cm depth and a lower pole resection at the level of the lower polar line. The renal calyces exposed during renal resection were sealed and transected using microwave scissors. After 3 days of follow-up, the pigs were reoperated to inspect for postoperative complications. Euthanasia was performed to collect the remaining kidneys for histopathological examination. RESULTS: Ten procedures were successfully performed, without hilar clamping or suturing of the renal calyces and parenchyma, in 5 kidneys from 3 pigs. The median resecting time, blood loss, and lateral thermal injury were 23.2 min, 47.1 mL, and 6.8 mm in the middle pole resection, and were 15.1 min, 26.5 mL, and 6.9 mm in the lower pole resection, respectively. No complications were noted during reoperation, such as postoperative hemorrhage and major urine leakage. Extravasation occurred in 2 middle pole resections and 3 lower pole resections during retrograde pyelogram. Hematoxylin and eosin staining revealed thermal injury characterized by tissue microwave fixation in the near zone and acute coagulative necrosis in the intermediate zone. CONCLUSIONS: Microwave scissors-based off-clamp laparoscopic partial nephrectomy is feasible in pigs and can be used for clinical applications.

Vessel-Sealing Capability of Novel Microwave Sealer: Experimental Study in Animal Models.

Background. Ultrasonically activated dissectors (UADs) and radiofrequency-based devices have been considered excellent surgical devices because of their reliability and flexibility. Meanwhile, microwave-based devices have demonstrated potential with their unique heating mechanism. This study aims to compare the sealing function of a newly invented forceps-like microwave sealer (MS) with that of currently available UADs. Materials and Methods. MS and 2 examples of UADs (Harmonic Focus+ [HF+] and Sonicision [SNC]) were employed to perform mesenterectomies (in vivo) and sealing sizable vessels (ex vivo). Vessel diameter, seal time, burst pressure (BP), sealing completion, and instrument sticking were recorded. The samples underwent histological investigation for thermal damage evaluation. Results. During mesenterectomies, MS required 3 seconds and 30 W to secure a complete seal. The BP achieved by the MS seal was higher than that of HF+ and SNC on arteries (851 ± 203.7 vs 682.4 ± 287.3, P < .05; vs 833.1 ± 251.2 mmHg, P = .4523, respectively) but was not statistically different on veins (324.9 ± 203.5 vs 460.1 ± 320.3 vs 508.3 ± 350.7 mmHg, P = .215). In all trials, MS caused less sticking but exhibited similar heat-induced alterations to UADs. MS's thermal spread was not statistically more extended than that of UADs on either arteries or veins. Conclusions. MS was capable of not only sealing tiny vessels but also achieving high-pressure endurance on sizable vessels. Its forceful grasping and synchronous heating process helped create solid stumps with an acceptable thermal spread.

Anti-endotoxin Properties of Polymyxin B-immobilized Fibers.

Polymyxin B is an antibiotic that shows strong bactericidal activity against Gram-negative bacteria, by binding to and inactivating endotoxin. Systemic administration of polymyxin B in humans is restricted because of its nephrotoxicity and neurotoxicity, and this compound was therefore considered a strong candidate ligand for the extracorporeal selective adsorption of circulating endotoxin in the blood. Toraymyxin® is a direct hemoperfusion column that uses polymyxin B attached to an insoluble carrier to bind endotoxin in the blood. In 1994, the Japanese National Health Insurance system approved the use of Toraymyxin for the treatment of endotoxemia and septic shock.In this chapter, we will review the development, clinical use, and efficacy of Toraymyxin, examine the structure of the Toraymyxin column, and comment on the current position of Toraymyxin in the treatment of severe sepsis and septic shock. We will also highlight some potential new applications of Toraymyxin for pulmonary diseases.

5-fluorouracil combined with cisplatin and mitomycin C as an optimized regimen for hyperthermic intraperitoneal chemotherapy in gastric cancer.

BACKGROUND AND OBJECTIVES: Optimized drug regimens for hyperthermic intraperitoneal chemotherapy (HIPEC) have not been standardized completely in patients with advanced gastric cancer (GC). We evaluated an optimized anti-tumor protocol comprising 5-fluorouracil (5-FU) combined with cisplatin (CDDP) and mitomycin C (MMC) in vitro for clinical use of HIPEC. METHODS: The sensitivities of 5-FU, CDDP, or MMC, alone or in combination, using different drug concentrations, exposure times, and hyperthermic conditions (42°C) were determined in vitro by the CD-DST method using 3 different differentiated GC cell lines. RESULTS: The tumor cell growth-inhibitory effect of 5-FU was concentration-dependent for all cell lines. In addition, 5-FU showed a hyperthermic sensitization effect at all drug concentrations for all cell lines. The appropriate concentration of each drug was 5-FU, 200 µg/mL; CDDP, 10 µg/mL; MMC, 2 µg/mL. Under hyperthermic conditions, most growth-inhibitory effects for each drug at 30 min was equivalent to 60 min of exposure; use of three drugs combined significantly inhibited growth compared with any of the drugs alone. CONCLUSION: An appropriate in vitro intraperitoneal chemotherapy regimen for GC was combined use of 5-FU, CDDP, and MMC at 42°C for 30 min.

The invention of microwave surgical scissors for seamless coagulation and cutting.

PURPOSE: We developed a microwave energy-based scissors device (MWCX) that is capable of performing cutting and coagulation using 2.45 GHz microwave energy. This paper aims to present the concept of the device and assess the basic functions including the hemostasis, cutting, and sealing abilities. METHODS: Seven beagle dogs were used in our experiments. In six dogs, we measured the coagulation time (CT), lateral thermal injury (LTI), bursting pressure (BP). The dogs were then subjected to re-laparotomy 1 week later to allow us to investigate the results. In one dog, the same factors and the quantities of smoke and mist emitted were compared to those observed when using a Harmonic Focus (HF) device. RESULTS: At 60 W, the MWCX could cut and seal small (5 s, diameter 1-2 mm) and medium-sized (10 s, 3-4 mm) vessels with complete hemostasis. The liver (length 2 cm) was cut for 30 s. Harvested vessels were sealed for 10 s (artery, 17 times; vein, six times). The mean BP was 887. 8 ± 41.5 mmHg in the medium arteries and 457.2 ± 118.0 mmHg in veins, with a mean diameter of 4.5 ± 1.3 mm. In a comparative study, the MWCX showed similar results to the HF with regard to the CT, BP and LTI, and emitted less smoke and mist. CONCLUSION: The MWCX showed similar levels of functionality and safety to HF, as well as the advantages offered by the use of microwave energy. Microwave devices might be used in the majority of applications for which traditional energy devices are used.

Feasibility and safety of hyperthermic intraperitoneal chemotherapy using 5-fluorouracil combined with cisplatin and mitomycin C in patients undergoing gastrectomy for advanced gastric cancer.

BACKGROUND AND OBJECTIVES: We conducted a dose-finding study for 5-fluorouracil (5-FU) administered with cisplatin (CDDP) and mitomycin C (MMC) to find an improved regimen for hyperthermic intraperitoneal chemotherapy (HIPEC) for advanced gastric cancer (GC). METHODS: The appropriate HIPEC regimen previously determined in vitro was 5-FU (200 µg/mL), MMC (2 µg/mL), and CDDP (10 µg/mL) at hyperthermic conditions (42°C) for 30 min. This was a clinical study to determine the recommended dose of 5-FU in combination with MMC and CDDP at 42°C for 30 min and to evaluate HIPEC safety in patients at high risk of developing peritoneal metastases following GC surgery. RESULTS: Twelve patients were treated with surgery plus HIPEC using 5-FU at 0, 500, 750, and 1000 mg combined with MMC (10 mg) and CDDP (50 mg) in the perfusate (5 L). Dose-limiting toxicities did not develop until 1000 mg 5-FU was reached. Four patients experienced grade 1 or 2 adverse events. The recommended dose was 1000 mg 5-FU/5 L perfusate. Eight (66.7%) patients demonstrated no recurrence of peritoneal metastases; 5-year overall survival rate was 83.3%. CONCLUSION: Gastrectomy and HIPEC with MMC, CDDP, and 5-FU is feasible, safe, and may protect against peritoneal metastasis following surgery for advanced GC.

Predictive detection areas for identifying additional MRI-detected breast lesions on second-look ultrasonography.

PURPOSE: Identifying an additional MRI-detected breast lesion on second-look ultrasonography (US) is technically challenging because of lesion displacement with the patient's position change. The aim of this study is to help identify MRI-detected lesions on second-look US by developing a probing area, called "the predictive detection area" (PDA), and by assessing the PDA. METHODS: We measured the nipple-to-lesion distances (NLDs) for 16 breast lesions on prone- and supine-position MRI sets and calculated the difference and angle between the two NLD vectors, representing the lesion displacement. The minimum and maximum differences and angles were chosen to form the PDA. Another 22 breast lesions, detected in the prone MRI, were identified on US by probing the PDA to evaluate the probability of existence. RESULTS: The width between the minimum and maximum differences in two NLDs and the angle to form the PDA for the upper-inner, upper-outer, and lower-outer quadrants were 23.0 mm and 95.0°, 29.0 mm and 41.0°, and 18.0 mm and 17.0°, respectively. The respective probabilities of existence were 100, 80, and 100%. CONCLUSIONS: The PDA had a high probability of existence and was acceptably accurate; therefore, the PDA in a second-look US has the potential to help operators to quickly identify additional MRI-detected lesions.

Viable Cancer Cells in the Remnant Stomach are a Potential Source of Peritoneal Metastasis after Curative Distal Gastrectomy for Gastric Cancer.

BACKGROUND: The mechanisms underlying peritoneal metastasis (PM) after curative gastrectomy for gastric cancer (GC) are not well elucidated. This study assessed whether viable cancer cells, including cancer stemlike cells (CSCs), were present in the remnant stomach immediately before gastrointestinal (GI) tract reconstruction because these could be a source of PM after gastrectomy. METHODS: Saline fluid used for remnant stomach lumen irrigation before GI reconstruction was prospectively collected from 142 consecutive patients undergoing distal gastrectomy for GC and cytologically examined. Proliferative activity (Ki67 staining) and stemness (expression of the CSC surface markers CD44s or CD44v6) were evaluated in detected cancer cells. RESULTS: Viable cancer cells were detected in 33 (23.2 %) of the 142 remnant stomachs. These cells formed clusters and stained positively for Ki67, indicating proliferation. Cancer cells in remnant stomachs and surface cancer cells in primary GCs from 10 (30.3 %) of these 33 cases also stained positively for CD44s or CD44v6. In a multiple logistic regression analysis, advanced cancer (odds ratio [OR], 4.65; 95 % confidence interval [CI], 1.32-16.4; P = 0.017), tumor size of 40 mm or larger (OR, 3.78; 95 % CI, 1.12-12.8; P = 0.033), and histologic differentiation (OR, 3.10; 95 % CI, 1.30-7.40; P = 0.011) were associated independently with the presence of cancer cells in the remnant stomach. CONCLUSION: Viable, proliferative, and clustered cancer cells, including CSCs, were found in remnant gastric lumens immediately before GI reconstruction, indicating a possible cellular source of PM after curative gastrectomy for GC. Dissemination of gastric contents into the peritoneal cavity should be avoided during GI reconstruction.

Mannan-binding protein, a C-type serum lectin, recognizes primary colorectal carcinomas through tumor-associated Lewis glycans.

Mannan (mannose)-binding protein (MBP) is a C-type serum lectin that plays a key role in innate immunity. MBP forms large multimers (200-600 kDa) and exhibits broad specificity for mannose, N-acetylglucosamine, and fucose. MBP exhibits high affinity for unique oligosaccharides that have been isolated from human colorectal carcinoma (SW1116) cells and characterized as highly fucosylated high m.w. type 1 Lewis glycans. In this study, we first demonstrated that MBP recognizes human primary colorectal carcinoma tissues through tumor-associated MBP ligands. We performed fluorescence-based histochemistry of MBP in human colorectal carcinoma tissues and showed that MBP clearly stained cancer mucosae in a Ca(2+)-dependent manner. Coincubation with plant (Aleuria aurantia) lectin, but not Con A, blocked MBP staining, indicating that fucose, rather than mannose, is involved in this interaction. The expression of MBP ligands was detected in 127 of 330 patients (38.5%), whereas, most significantly, there was no expression in 69 nonmalignant tissues. The MBP-staining pattern in cancer mucosae significantly overlapped with that of Lewis b [Fucα1-2Galß1-3(Fucα1-4)GlcNAc] staining, but the Lewis b staining in normal tissues was not associated with MBP staining. In addition, the MBP staining correlated inversely with the expression of CA19-9 Ag, and MBP stained 11 of 25 (44%) CA19-9 (sialyl Lewis a [NeuAc(α2-3)Galß1-3(Fucα1-4)GlcNAc])(-) colorectal carcinoma tissues. We found a favorable prognosis in patients with MBP ligand(+) tumors. These results suggest that selective recognition of cancer cells by endogenous MBP seems to be associated with an antitumor effect and that tissue staining with MBP in combination with CA19-9 may serve as a novel indicator of colorectal carcinoma tissues.

Pyomyositis at the surgical site in a patient with chronic myeloid leukemia: a case report and literature review.

BACKGROUND: Pyomyositis is a rare, subacute, deep pyogenic infection of the muscle tissue. This disease has been previously described in patients that were immunocompromised due to a hematological malignancy. CASE PRESENTATION: A 68-year-old man with a history of chronic myeloid leukemia was treated with imatinib. He was diagnosed with ascending colon cancer and underwent curative surgery. His postoperative course was uneventful, and he was healthy at 6 months after surgery, allowing for reinitiation of imatinib therapy. After the reinitiation of therapy, a computed tomography (CT) scan revealed a mass shadow in the right iliopsoas muscle. This lesion was clinically diagnosed as recurrent colon cancer with an abscess, which was resected surgically. A pathological examination uncovered both edema and inflammation. Two months after the second surgery, imatinib therapy was reinitiated; however, he again developed painful swelling and erythema in his right thigh. A CT scan revealed a similar shadow as described previously. He was then diagnosed with pyomyositis; he underwent incisional drainage and was administered linezolid. Following the treatment for pyomyositis, there was no cancer recurrence or evidence of any recurrent pyomyositis. CONCLUSIONS: Findings from this case suggest that both undergoing surgery and receiving imatinib therapy may modulate an individual's immune response, whereby the surgical site becomes more prone to infection and may predispose an individual to pyomyositis. The case report is followed by a discussion of the literature regarding this disease, including potential risk factors and the underlying pathogenesis.

Potential mechanisms mediating improved glycemic control after bariatric/metabolic surgery.

Conservative medical treatment for morbid obesity generally fails to sustain weight loss. On the other hand, surgical operations, so-called bariatric surgery, have evolved due to their long-term effects. The global increase in the overweight population and the introduction of laparoscopic surgery have resulted in the use of bariatric surgery spreading quickly worldwide in recent years. Recent clinical evidence suggests that bariatric surgery not only reduces body weight, but also improves secondary serious diseases, including type 2 diabetes mellitus, in so-called metabolic surgery. Moreover, several potential mechanisms mediating the improvement in glycemic control after bariatric/metabolic surgery have been proposed based on the animal and human studies. These mechanisms include changes in the levels of gastrointestinal hormones, bacterial flora, bile acids, intestinal gluconeogenesis and gastrointestinal motility as well as adipose tissue and inflammatory mediators after surgery. The mechanisms underlying improved glycemic control are expected to accelerate the promotion of both metabolic and bariatric surgery. This article describes the current status of bariatric surgery worldwide and in Japan, reviews the accumulated data for weight loss and diabetic improvements after surgery and discusses the potential mechanisms mediating improved glycemic control.

Minimally invasive surgery using the open magnetic resonance imaging system combined with video-assisted thoracoscopic surgery for synchronous hepatic and pulmonary metastases from colorectal cancer: report of four cases.

Simultaneous resection of hepatic and pulmonary metastases (HPM) from colorectal cancer (CRC) has been reported to be effective, but it is also considered invasive. We report the preliminary results of performing minimally invasive surgery using the open magnetic resonance (MR) imaging system to resect synchronous HPM from CRC in four patients. All four patients were referred for thoracoscopy-assisted interventional MR-guided microwave coagulation therapy (T-IVMR-MCT) combined with video-assisted thoracoscopic surgery (VATS). The median diameters of the HPM were 18.2 and 23.2 mm, respectively. The median duration of VATS and T-IVMR-MCT was 82.5 and 139 min, respectively. All patients were discharged without any major postoperative complications. One patient was still free of disease at 24 months and the others died of disease progression 13, 36, and 47 months without evidence of recurrence in the treated area. Thus, simultaneous VATS + T-IVMR-MCT appears to be an effective option as a minimally invasive treatment for synchronous HPM from CRC.

Initial experiences with MR Image-guided laparoscopic microwave coagulation therapy for hepatic tumors.

PURPOSE: Percutaneous thermal ablation is used for treating hepatic tumors. Recent advances in laparoscopy and imaging modalities have led to the development of a novel image-guided minimally invasive loco-regional treatment. The aim of this trial was to apply laparoscopic assistance to magnetic resonance (MR) image-guided thermoablation instead of ultrasonography, because of its various advantages. METHODS: Patients with hepatic tumors and liver cirrhosis underwent magnetic resonance (MR) image-guided laparoscopic microwave coagulation therapy using a borescope and endoscopic forceps. Six cases of laparoscopic microwave coagulation treatment using MR image guidance were successfully performed between January 2000 and December 2008. Tumors were detected, punctured, and ablated in an open-configured MR scanner. A total of nine hepatocellular carcinoma nodules were preoperatively identified in S3, S5 and S6 (mean diameter = 20.8 ± 5.4 mm). RESULTS: MR-guided microwave coagulation was laparoscopically achieved in all patients without any significant complications that required invasive treatment. The mean length of the operation was 275.3 ± 60.5 min, and the mean postsurgical hospital stay was 10.0 ± 2.3 days. Postoperative confirmation scanning was performed without moving the patients. CONCLUSION: MR-guided laparoscopic microwave coagulation therapy is an effective treatment for hepatic tumors adjacent to other organs, as it allows for more accurate detection of lesions and for tumors to be treated safely while avoiding adjacent organs. It is less invasive than conventional procedures, because the MR real-time guidance enabled continuous monitoring throughout the procedure.

Umbilical metastasis derived from breast cancer: report of a case.

Umbilical metastases mainly arise from malignancies of the digestive and gynecological systems, but rarely from breast cancer. A 64-year-old woman with a history of breast cancer was referred to us for investigation of a painful lesion in the umbilicus. Immunohistochemical staining of a specimen obtained by biopsy from the nodule showed umbilical metastasis of breast cancer. After a work up, she was successfully treated with a combination of surgery and endocrine therapy. We report this case to reinforce that not all periumbilical tumoral deposits are consistent.

Surgery-induced peritoneal cancer cells in patients who have undergone curative gastrectomy for gastric cancer.

BACKGROUND: Some patients who undergo curative gastrectomy with lymph node dissection (LND) for gastric cancer (GC) show subsequent peritoneal metastasis. The source of these metastatic cells remains unclear. METHODS: Curative gastrectomy with LND was performed in 102 patients with GC. Peritoneal washing was collected before and after gastrectomy. Cytology, reverse transcription-polymerase chain reaction, and cell culture were used to determine the presence of cancer cells. The proliferative potential of tumor cells was evaluated using Ki-67 staining. Tumorigenic capacity was assessed by cell injection into the peritoneal cavity of NOD/ShiJic-scid mice. Peritoneal recurrence-free survival (RFS) and peritoneal recurrence rate (RR) were examined to determine the clinical relevance of detected cancer cells. RESULTS: Of 102 peritoneal washing samples obtained before gastrectomy, 57 showed no CEA or CK20 mRNA amplification. After gastrectomy, CEA or CK20 mRNA was detected in 35 of these 57 samples, and viable cancer cells were identified in 24. The viable cancer cells in all 24 cases showed Ki-67 positivity, indicating proliferative activity. Cultured viable cancer cells generated peritoneal nodules after spilling over the peritoneal cavity in NOD/ShiJic-scid mice in 4 cases. The peritoneal RFS of patients with CEA or CK20 mRNA amplification after gastrectomy was significantly poorer than that of patients with negative amplification (p < .05). The 24 patients with viable cancer cells in the peritoneal cavity after gastrectomy showed higher peritoneal RR than those without them (p = .033). CONCLUSIONS: Viable tumorigenic cancer cells spilled into the peritoneal cavity during surgery, indicating that surgery induces peritoneal metastasis.

Cell transplantation therapy for a rat model of secondary lymphedema.

BACKGROUND: Although lymphedema is a progressive and lifelong condition, substantial advances in therapeutic intervention are limited. The development of a novel therapy for lymphedema is urgent for those patients suffering from it. The aim of this study was to investigate the usefulness of a new cell transplantation therapy in the rat tail model of secondary lymphedema. MATERIALS AND METHODS: We prepared two cell sources, human dermal microvascular endothelial cells (HDMECs) and lymphatic endothelial cells (LECs), which were collected from the resected normal dermis of patients with breast cancer. After the animal model of secondary lymphedema of the nude rats' tails was established, phosphate-buffered saline, purified LECs, or unpurified HDMECs were injected in the rats' tails five times for more than 14 d. The evaluations were performed by measuring the circumference, fluorescence lymphography, and histologic analysis of the rats' tails between each group. RESULTS: The isolated cells by the simple immunomagnetic sorting from HDMECs were positive for a pan-endothelial marker (CD31) and lymphatic-specific markers (podoplanin, lymphatic vessel endothelial hyaluronan receptor-1 [LYVE-1], and prospero homebox 1 [Prox-1]), and were considered to be LECs. In the cell transplantation group, which was injected with human LECs, the circumference, lymphatic flow, and thickness of the skin of the rat tail became thinner than the groups injected with unpurified HDMECs or phosphate-buffered saline. Immunohistochemistry of the rat tails showed that the number of own lymphatic vessels was increased in the purified LEC transplantation group compared with the other groups. Furthermore, in the LEC transplantation group, some vessels were immunopositive for human-podoplanin or -LYVE-1 and the areas adjacent to the vessels were rat-podoplanin or -LYVE-1 immunopositive. CONCLUSIONS: Our findings indicate that cell transplantation therapy using human LECs improved the secondary lymphedema in the nude rat tail. This therapeutic strategy may merit clinical investigation in patients with lymphedema.

Stratified phase II trial to establish the usefulness of the collagen gel droplet embedded culture-drug sensitivity test (CD-DST) for advanced gastric cancer.

BACKGROUND: We conducted a multicenter phase II trial to assess the suitability of three types of chemotherapy (docetaxel plus S-1, irinotecan plus S-1, or S-1 alone) for patients with advanced gastric cancer by means of the collagen gel droplet embedded culture-drug sensitivity test (CD-DST). To our knowledge, this is the first multicenter clinical trial that has employed CD-DST to choose anticancer agents for the treatment of advanced gastric cancer. METHODS: Subjects (n = 64) were patients with advanced or recurrent gastric cancer. Patients were allocated to one of the treatment regimens on the basis of CD-DST results. Outcome of the patients was compared between the groups deemed chemosensitive or chemoresistant by the CD-DST. RESULTS: Thirty-three patients showed high sensitivity (T/C ratio <60 %) to at least one type of anticancer agent (sensitive group), and 31 showed low sensitivity (T/C ratio ≥60 %) to all agents (resistant group). Specifically, the 1-year survival rate was significantly higher in the sensitive group (78.5 %; 95 % CI, 67.2-94.7 %) than in the resistant group (54.7 %; 95 % CI, 38.7-74.3 %; P = 0.019), whereas time to progression (TTP) was significantly longer in the sensitive group (59.8 %; 95 % CI, 48.2-81.7 %) than in the resistant group (30.0 %; 95 % CI 13.6-46.4 %; P = 0.023). Median survival time was also significantly longer in the sensitive group (15.5 months; 95 % CI, 12.8-18.2) than in the resistant group (12.5 months; 95 % CI, 10.2-14.9; P = 0.038). CONCLUSIONS: CD-DST predicts the outcome of patients undergoing chemotherapy for advanced gastric cancer, presumably through evaluating chemosensitivity.