The role of S-1 in the treatment of gastric cancer. Br J Cancer. 2008;98:1301-1304. [PMID: 18362933 DOI: 10.1038/sj.bjc.6604332]

Salvage Chemoradiotherapy for Loco-Regional Recurrence of Esophageal Squamous Cell Carcinoma After Esophagectomy

Background/Objectives: Loco-regional recurrence (LRR) of esophageal cancer following esophagectomy presents a significant therapeutic problem. This study aimed to evaluate the effectiveness of salvage concurrent chemoradiotherapy (CCRT) and to identify the prognostic factors influencing the survival outcomes in patients with an LRR of esophageal cancer. Methods: This retrospective study included 68 patients who underwent salvage CCRT for an LRR of esophageal squamous cell carcinoma between April 2008 and June 2024. Patients were treated with either 50.4 Gy in 28 fractions or 60 Gy in 30 fractions, along with concurrent fluoropyrimidine- and platinum-based chemotherapy. Prognostic factors were identified using univariate and multivariate Cox proportional hazards models. Results: The median overall survival (OS) was 30.1 months (95% confidence interval [CI]: 21.5-110.7 months), with a 2-year OS rate of 57.4%. The median progression-free survival (PFS) was 8.9 months (95% CI: 6.3-17.7 months). In the multivariate analysis, the significant prognostic factors for OS included the interval to recurrence (>1 year vs. ≤1 year, hazard ratio [HR] = 2.307, p = 0.024) and radiotherapy dose (60 Gy vs. 50.4 Gy, HR = 2.414, p = 0.040). For PFS, the interval to recurrence and radiotherapy dose remained significant predictors (p < 0.05). The 2-year OS rate was higher in the 60 Gy arm (62.7% vs. 42.0%, p = 0.285) and in patients with recurrence occurring >1 year after surgery (73.4% vs. 29.9%, p = 0.0054). The local control rate at 2 years was 71.9%, with better outcomes observed in the 60 Gy arm (93.5% vs. 76.5%, p = 0.0651). Conclusions: Salvage CCRT is a viable treatment option for LRR of esophageal cancer, achieving favorable survival outcomes, particularly in patients with late recurrence (>1 year) and in those receiving higher radiotherapy doses.

S-1 and 5-Fluorouracil-related adverse events in patients with advanced gastric cancer: A meta-analysis

OBJECTIVE

To assess S-1 and 5-fluorouracil (5-FU)-related adverse events in patients with advanced gastric cancer and provide focused health care approaches to improve patient compliance and quality of survival.

METHODS

The PubMed, Web of Science, Medline, Cochrane Library, EMbase, SinoMed, Wan Fang Data, CNKI, and VIP databases were searched, and relevant literature was screened from the database construction date through March 31, 2023. Review Manager 5.4.1 and Stata 12.0 were used to analyze the data and GRADEpro was used to assess the quality of the literature. Relative risk ratio (RR) and a 95% confidence interval (CI) were employed as markers to compare adverse events due to S-1 vs 5-FU.

RESULTS

Eight randomized controlled trials (RCT) were included, which contained 3,455 patients. The S-1 group had 1,804 patients, and the 5-FU group had 1,651 patients. There were 17 recorded adverse events in total. Stomatitis, hypokalemia, mucosal inflammation, and hypophosphatemia were more common in the 5-FU group than in the S-1 group (P < 0.001). No significant difference was observed between S-1 and 5-FU for other adverse events.

CONCLUSIONS

Although both S-1 and 5-FU cause a variety of side effects, 5-FU resulted in a higher incidence of stomatitis, hypokalemia, mucosal inflammation, and hypophosphatemia than S-1. Medical professionals should closely monitor the occurrence of adverse drug events and provide timely, rational guidance and nursing care to improve patient compliance and quality of life.

Postoperative Early Body Weight Loss Is a Risk Factor for Recurrence in Patients with pStage III Gastric Cancer

INTRODUCTION

The goal of this study was to determine whether postoperative early body weight loss (EWL) after radical gastrectomy is a risk factor for recurrence in patients with pathological stage III (pStage III) gastric cancer who received postoperative adjuvant chemotherapy, which included tegafur/gimeracil/oteracil (S-1).

METHODS

Patients who underwent gastrectomy for gastric cancer were identified from a prospectively managed gastric cancer database. We analyzed 58 consecutive patients who underwent radical gastrectomy with D2 lymph node dissection for confirmed pStage III gastric cancer treated postoperatively with adjuvant chemotherapy including S-1 between 2010 and 2019. Clinical and pathologic characteristics, baseline body mass index (BMI), and postoperative weights were extracted. Weight changes were evaluated from the preoperative period to the start of adjuvant chemotherapy. EWL was defined as % BMI change = (preoperative BMI - postoperative BMI at the start of adjuvant chemotherapy) × 100/preoperative BMI.

RESULTS

Of the 58 consecutive patients who underwent radical resection for gastric cancer, 72.4% were male, with a mean age of 65.5 years, and a mean preoperative BMI of 21.2 (range: 15.4-29.1) kg/m2. The degree of EWL was found to be closely correlated to compliance with adjuvant chemotherapy. Multivariate analysis by Cox proportional hazard analysis revealed that EWL was an independent factor for relapse-free survival (RFS), and patients with an EWL of 15.9% or more severe had poorer RFS.

CONCLUSION

EWL above a certain rate at the start of adjuvant chemotherapy was a predictor of poor compliance with adjuvant chemotherapy and a high risk of disease recurrence in patients with pStage III gastric cancer.

Association of dysbindin expression with individualized postoperative prognosis and chemotherapy benefit among patients with gastric adenocarcinoma

Background: The current model for predicting prognosis and chemotherapy response of patients with gastric adenocarcinoma is the TNM staging system, which may lack adequate accuracy and evaluations of molecular features at the individual level. We aimed to develop a prediction model to assess the individualized prognosis and responsiveness to fluorouracil-based adjuvant chemotherapy.

Method: This retrospective study concluded 2 independent cohorts of patients with GAC. The expression of dysbindin was quantified and evaluated the association with the overall survival for GAC patients. A prediction model for postoperative overall survival was generated and internally and externally validated. The interaction between dysbindin expression and PACT was detected in advanced GAC patients.

Results: Of the 637 patients enrolled in the study, 425 were men (66.7%) with a mean (SD) age of 59.79 (9.81) years. High levels of dysbindin expression predicted a poor prognosis in patients with GAC. Multivariate analysis demonstrated dysbindin expression was an independent prognostic predictor of overall survival in the test, validation and combined cohorts. A prognostic predictive model incorporating age, dysbindin expression, pathological differentiation, Lauren's classification and the TNM staging system was established. This model had better predictive accuracy for overall survival than the traditional TNM staging system and was internally and externally validated. More importantly, advanced GAC patients with low dysbindin expression were likely to benefit from fluorouracil-based PACT.

Conclusion: The risk stratification model incorporating dysbindin expression and TNM staging system showed better predictive accuracy. Advanced GAC patients with low dysbindin expression revealed better response of fluorouracil-based adjuvant chemotherapy.

The Combined Use of 5 or More Drugs Is a Factor Related to Lower Adherence to S-1 in S-1 and Oxaliplatin Treatment for Advanced Gastric Cancer

S-1 plus oxaliplatin (SOX) is an established treatment for advanced gastric cancer. S-1 adherence is the key to successful SOX treatment. This study focused on S-1 adherence by evaluating real-world adherence to S-1 and investigating factors related to decreased S-1 adherence. This study included cases treated between August 1, 2014 and October 12, 2016 at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research. The S-1 adherence rate per cycle was defined as the number of times a patient took S-1/28. In this study, adherence to S-1 was assessed through pill counts and by asking the patient about the reason for non-adherence at a pharmaceutical outpatient clinic. Univariate and multivariate analyses were performed to investigate factors influencing lower adherence. This analysis included 116 patients evaluated for adherence to S-1 on SOX treatment. The median rate of adherence to S-1 was 92.8% in the first cycle and 90.5% in the seventh cycle. The median relative dose intensity of S-1 was 84.6%. In terms of reasons for nonadherence, patients most commonly cited nausea/vomiting (43.7%), diarrhea (20.8%), missed dose (11.8%), and fever (8.1%). Logistic regression analysis was performed using the most appropriate regression equation, and a significant association was detected with 1 factor, number of combined drugs ≥5 (odds ratio (OR) = 2.50; 95% confidence interval (CI), 1.04-6.03, p = 0.04). Eliminating unnecessary concomitant medications helps maintain proper adherence to S-1 in SOX treatment.

High-throughput method to analyze tegafur and 5-fluorouracil in human tears and plasma using hydrophilic interaction liquid chromatography/tandem mass spectrometry

RATIONALE

We developed a new high-throughput method to analyze tegafur (FT) and 5-fluorouracil (5-FU) in tear and plasma samples using hydrophilic interaction liquid chromatography (HILIC)/tandem mass spectrometry (MS/MS).

METHODS

The tear samples (10 μL) spiked with FT, 5-FU, and 5-chlorouracil (internal standard) were diluted using 40 μL of 2 M ammonium acetate and 250 μL of acetonitrile with 2% formic acid; 20 μL of plasma spiked with the two drugs and internal standard was diluted with 80 μL of 2 M ammonium acetate and 500 μL of acetonitrile with 2% formic acid. After centrifugation, the clear supernatant extract (15 μL) was directly injected into the HILIC/MS/MS instrument, and each drug was separated on a Unison UK-Amino column (50 mm × 3 mm i.d., 3 μm particle size) with a linear gradient elution system composed of 10 mM ammonium acetate (pH 6.8) and acetonitrile at a flow rate of 0.7 mL/min. We performed quantification by multiple reaction monitoring (MRM) with negative-ion atmospheric-pressure chemical ionization.

RESULTS

Distinct peaks were observed for the drugs on each MRM channel within 2 min. The regression equations showed good linearity within the range 0.04-4.0 μg/mL for the tear and plasma samples with detection limits at 0.02-0.04 μg/mL. Recoveries for target analytes (FT and 5-FU) for the tear and plasma samples were in the 94-128% and 94-104% ranges, respectively. The intra- and inter-day coefficients of variation for the two drugs were lower than 10.8%. The accuracies of quantitation were 97-115% for both samples.

CONCLUSIONS

We established a high-throughput, reproducible, and practical procedure for analyzing FT and 5-FU in human tear and plasma samples using HILIC/MS/MS analysis with an aminopropyl-bonded mixed-mode separation column. This method can be applied to the high-throughput routines used in clinical analyses.

Taxanes in the Treatment of Advanced Gastric Cancer

Although rapid advances in treatment options have improved the prognosis of advanced gastric cancer (AGC), it remains a major public health problem and the second leading cause of cancer-related deaths in the world. Taxanes (paclitaxel and docetaxel) are microtubule stabilizing agents that inhibit the process of cell division, and have shown antitumor activity in the treatment of AGC as a single or combination chemotherapy. Accordingly, this review focuses on the efficacy and tolerability of taxanes in the first- or second-line chemotherapy setting for AGC.

Improvements of doxorubicin-induced antitumor activity and adverse reaction by combined citrulline

Citrulline is an amino acid with antioxidant activity. In this study, effects of citrulline on the adverse effects of doxorubicin (DOX) and DOX-induced antitumor activity were examined. Citrulline significantly inhibited DOX-induced increases in lipid peroxide (LPO) in the heart as adverse reaction. Combined treatment with DOX and citrulline increased DOX levels in tumor cells and enhanced cytotoxicity in vitro by significantly increasing DOX uptake compared with DOX treatment alone. In simultaneous in vivo treatments, combination treatment with DOX and citrulline decreased tumor weight and increased DOX concentrations in tumors. Promotion of DOX uptake by citrulline enhanced the antitumor activity of DOX through the action of energy-independent and Na(+)-independent transporters. This effect of citrulline on DOX influx is identical to that of S-(4-nitrobenzyl)-6-thioinosine, promoting DOX influx through the equilibrative nucleoside transporter 1. Therefore, it is anticipated that citrulline as a food component may enhance DOX efficacy.

S-1-based combination therapy vs S-1 monotherapy in advanced gastric cancer: a meta-analysis

AIM

To assess the efficacy and safety of combination therapy based on S-1, a novel oral fluoropyrimidine, vs S-1 monotherapy in advanced gastric cancer (AGC).

METHODS

We searched PubMed, EMBASE and the Cochrane Library for eligible studies published before March 2013. Our analysis identified four randomized controlled trials involving 790 participants with AGC. The outcome measures were overall survival (OS), progression-free survival (PFS), overall response rate (ORR) and grade 3-4 adverse events.

RESULTS

Meta-analysis showed that S-1-based combination therapy significantly improved OS (HR = 0.77, 95%CI: 0.66-0.91, P = 0.002), PFS (HR = 0.58, 95%CI: 0.46-0.72, P = 0.000) and ORR (OR = 2.23, 95%CI: 1.54-3.21, P = 0.000). Sensitivity analysis further confirmed this association. Lower incidence of grade 3-4 leucopenia (OR = 4.06, 95%CI: 2.11-7.81), neutropenia (OR = 3.94, 95%CI: 2.1-7.81) and diarrhea (OR = 2.41, 95%CI: 1.31-4.44) was observed in patients with S-1 monotherapy.

CONCLUSION

S-1-based combination therapy is superior to S-1 monotherapy in terms of OS, PFS and ORR. S-1 monotherapy is associated with less toxicity.

Economic evaluation of first-line adjuvant chemotherapies for resectable gastric cancer patients in China

Background

First-line postoperative adjuvant chemotherapies with S-1 and capecitabine and oxaliplatin (XELOX) were first recommended for resectable gastric cancer patients in the 2010 and 2011 Chinese NCCN Clinical Practice Guidelines in Oncology: Gastric Cancer; however, their economic impact in China is unknown.

Objective

The aim of this study was to compare the cost-effectiveness of adjuvant chemotherapy with XELOX, with S-1 and no treatment after a gastrectomy with extended (D2) lymph-node dissection among patients with stage II-IIIB gastric cancer.

Methods

A Markov model, based on data from two clinical phase III trials, was developed to analyse the cost-effectiveness of patients in the XELOX group, S-1 group and surgery only (SO) group. The costs were estimated from the perspective of Chinese healthcare system. The utilities were assumed on the basis of previously published reports. Costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICER) were calculated with a lifetime horizon. One-way and probabilistic sensitivity analyses were performed.

Results

For the base case, XELOX had the lowest total cost ($44,568) and cost-effectiveness ratio ($7,360/QALY). The relative scenario analyses showed that SO was dominated by XELOX and the ICERs of S-1 was $58,843/QALY compared with XELOX. The one-way sensitivity analysis showed that the most influential parameter was the utility of disease-free survival. The probabilistic sensitivity analysis predicted a 75.8% likelihood that the ICER for XELOX would be less than $13,527 compared with S-1. When ICER was more than $38,000, the likelihood of cost-effectiveness achieved by S-1 group was greater than 50%.

Conclusions

Our results suggest that for patients in China with resectable disease, first-line adjuvant chemotherapy with XELOX after a D2 gastrectomy is a best option comparing with S-1 and SO in view of our current study. In addition, S-1 might be a better choice, especially with a higher value of willingness-to-pay threshold.

Development and validation of a HPLC-MS/MS method with electrospray ionization for quantitation of potassium oxonate in human plasma: Application to a pharmacokinetic study

A rapid, sensitive and specific HPLC-MS/MS method was developed and validated for the quantification of potassium oxonate (Oxo) in human plasma using [¹³C₂,¹⁵N₃]-Oxo as an internal standard (IS). The target substance was separated from human plasma using the solid-phase extraction method. Chromatography separation was performed on a Waters:Atlantis dC¹⁸ column (150×4.6 mm, 5.0 μm) with a mobile phase consisting of H₂O with 0.1% formic acid in acetonitrile (90:10, v/v). The mass spectrometer works with electrospray ionization and multiple reaction monitoring in its negative ion mode, using target ions at [M–H]⁻ m/z 111.9 for Oxo and [M–H]⁻ m/z 117.0 for the IS. The mean standard curve was linear (r=0.9991) over the concentration range of 2.0–200.0 ng/ml and had good back-calculated accuracy and precision. The intra- and inter-day precision were <6.33% and the accuracy was >99.38%. The extraction recovery was >60.26%. The lower limit of quantification achieved with this method was 2.0 ng/ml. This assay method was demonstrated to be accurate, sensitive and simple and was successfully applied to a pharmacokinetic study following single oral administration of a 40-mg S-1 capsule in 12 tumor patients.

Metastatic gastric cancer treatment: a little slow but worthy progress

Metastatic gastric cancer is incurable and remains one of the leading causes of cancer-related deaths around the world. Despite the significant progress in its systemic treatment, metastatic gastric cancer is still a major therapeutic challenge for oncologists. Newer chemotherapy regimens and the addition of molecularly targeted agents to chemotherapy seem to provide better clinical outcomes for patients with metastatic gastric cancer. The objective of this article is to review the current treatment approach for this formidable disease.

Effect of linalool as a component of Humulus lupulus on doxorubicin-induced antitumor activity

As malignant neoplasm is a major public health problem, there is a need for the development of a novel modulator that enhances antitumor activity and reduces adverse reactions to antitumor agents. In this study, the effects of some volatile oil components in Humulus lupulus on doxorubicin (DOX) permeability in tumor cells and DOX-induced antitumor activity were examined. In vitro, DOX levels in tumor cells by combined linalool as its component significantly increased in the DOX influx system, and the increased effect by linalool on DOX cytotoxicity was shown. In vivo, the combination of DOX with linalool significantly decreased tumor weight compared with that of DOX alone treated group. The promotion of DOX influx level by combined linalool did not depend on energy, whereas it was suppressed by the absence of Na(+). This promoting effect was suppressed by the presence of S-(4-nitrobenzyl)-6-thioinosine and inhibited dependently on phlorizin concentration. It is considered that linalool promoted DOX influx in tumor cells because of its action on DOX transport through concentrative Na(+)-dependent nucleoside transporter 3, which increased DOX concentration in tumor cells and thus enhanced the antitumor activity of DOX. Therefore, linalool as a food component is anticipated to be an effective DOX modulator.

Cystoid macular edema associated with oral antineoplastic agent s-1 in a patient with diabetic retinopathy

A 60-year-old man with neovascular glaucoma due to diabetic retinopathy received an intravitreal injection of 1.25 mg bevacizumab (IVB) followed by extensive panretinal photocoagulation in the right eye. The anterior segment neovascularization regressed within 10 days after IVB. One and a half months later, the patient underwent gastrectomy for stage IIIb gastric cancer. Two months later, he was started on S-1 orally (100 mg/day for 48, 26, and 32 consecutive days in the first, second, and third treatment cycle, respectively). The interval between the first and second treatment cycle was 20 days and between the second and third cycle it was 24 days. The patient developed anemia and diarrhea. At the end of the second S-1 cycle, cystoid macular edema developed in the right eye, although diabetic retinopathy and neovascular glaucoma were stable. Macular edema persisted for 5 months despite another IVB, and disappeared 3 months after termination of S-1 therapy. The time course of the magnitude of macular edema correlated well with the severity of anemia. The macular edema was possibly associated with anemia, which is a major side effect of S-1. Further studies are warranted to investigate the relationship between anemia and macular edema in patients with diabetic retinopathy.

A comprehensive review of S-1 in the treatment of advanced gastric adenocarcinoma

Gastric cancer is the fourth most common malignancy worldwide with Japan, Korea, Taiwan, China, Mongolia and many countries in South America and eastern Europe, as well as parts of the Middle East, contributing to the majority of cases. In the USA, it was estimated that approximately 10,620 deaths would be caused by gastric cancer in 2010. Gastric cancer is often diagnosed in its advanced stages. Current first-line treatment for advanced gastric cancer (AGC) using triplet combination chemotherapy containing a platinum-based compound, a fluoropyrimidine with an anthracycline (frequently added in Europe) or a taxane (more often used in the USA and elsewhere) has resulted in higher response rates and modest improvement in overall survival compared with doublet combinations. However, triplet combinations can be associated with increased toxicity compared with the doublets and patient selection becomes important. A desirable research strategy is to improve outcomes of patients with AGC by identifying treatments that are effective, convenient and safe. The interest in oral agents compared with intravenous agents is mounting. One oral fluoropyrimidine, S-1, is novel as it combines tegafur, 5-chloro-2,4-dihydroxypyridine and potassium oxonate. S-1 is approved in Japan, China, Taiwan, Korea and Singapore for the treatment of patients with gastric cancer, and more recently has been approved in 27 European countries to treat AGC. Initial clinical trials in the USA and Europe observed diarrhea as the dose-limiting toxicity; however, initial Japanese studies reported myelosuppression as the dose-limiting toxicity. The differing dose tolerance in these two populations is likely due to polymorphisms in the CYP2A6 gene. Based on our review of Phase II and III studies, we conclude that S-1 is a convenient oral fluoropyrimidine that provides safety advantage over intravenous fluorouracil without compromising efficacy against AGC.

Pilot study of adjuvant chemotherapy with 3-week combination of S-1 and cisplatin for patients with stage II-IV (M0) gastric cancer

PURPOSE

The feasibility of a 3-week combination of S-1 and cisplatin as an adjuvant chemotherapy for patients with curatively resected gastric cancer was investigated.

EXPERIMENTAL DESIGN

Korean patients with stage II-IV (M0) gastric adenocarcinoma who underwent a gastrectomy with D2 lymph node resection were enrolled. The S-1 was administered orally at 80 mg/m(2) divided into two daily doses for 14 days, while the cisplatin was administered at 60 mg/m(2) intravenously over 2 h every 21 days. The patients received a maximum of six cycles.

RESULTS

From January 2006 to July 2010, 74 patients were included in this study. The median patient age was 56 years (range, 22-71), and 51.4% (38/74) of the patients had a performance status of 0. The median number of chemotherapy cycles administered was 6 (range, 1-6). The median relative dose intensity was 86.4% for S-1 and 80.0% for cisplatin. With a median follow-up duration of 13.9 months, the median relapse-free survival (RFS) and overall survival (OS) have not yet been reached. Fifteen relapses (20.3%) were documented. Plus, the estimated RFS rate was 60.5% at 3 years. The treatments were generally well tolerated. The most frequently observed grade 3-4 hematological toxicity was neutropenia (35.1%), and only 1 cycle of neutropenic fever occurred. The most frequently observed grade 3-4 non-hematological toxicities were nausea (4.1%) and asthenia (4.1%), and all the other grade 3-4 non-hematological toxicities were observed in less than 3% of the patients.

CONCLUSIONS

Postoperative adjuvant S-1 plus cisplatin for 18 weeks was found to be feasible for patients with stage II-IV (M0) gastric adenocarcinoma following complete surgical resection.

Calpain regulates thymidylate synthase-5-fluoro-dUMP complex levels associated with response to 5-fluorouracil in gastric cancer cells

Thymidylate synthase (TS) plays a major role in the response to 5-fluorouracil (5-FU) by binding directly to the 5-FU metabolite, 5-fluoro-dUMP (FdUMP). The change in the TS expression levels after 5-FU administration was examined in parallel to 5-FU responsiveness in six human gastric adenocarcinoma cell lines to elucidate the source of variability of 5-FU sensitivity. MKN-1, SH-10-TC and MKN-74 cells were more resistant to 5-FU than MKN-28, KATO III and MKN-45 cells. Western blotting analysis revealed that the 5-FU sensitivity of these cells did not correlate with the basal TS expression levels but did correlate with rapid detection of the TS-FdUMP complex after exposure to 5-FU. In 5-FU-resistant cells, very low levels of the TS-FdUMP complex early after 5-FU exposure were elevated by pretreatment with calpain inhibitors such as benzyloxycarbonyl-leucyl-leucinal (ZLLH), benzyloxycarbonyl-leucyl-leucyl-leucinal (ZLLLH) and ALLN, but not by other protease inhibitors. In contrast, ONO-3403, which causes calpain activation, stimulated downregulation of the TS-FdUMP complex in 5-FU-sensitive cells. The expression levels of calpastatin, an endogenous calpain inhibitor, were higher in 5-FU-sensitive cells than in 5-FU-resistant cells. ZLLH increased the 5-FU sensitivity of 5-FU-resistant cells, whereas ONO-3403 decreased the sensitivity of 5-FU-sensitive cells. In addition, knockdown of m-calpain by siRNA increased the 5-FU sensitivity in 5-FU-resistant cells, while knockdown of calpastatin reduced the sensitivity in 5-FU-sensitive cells. These results suggest that calpain might reduce the chemosensitivity of human gastric cancer cells to 5-FU possibly by rapid degradation of the TS-FdUMP complex, a finding that is considered to have novel therapeutic implications.

Chemotherapy in the treatment of metastatic gastric cancer: is there a global standard?

Gastric cancer remains one of the leading causes of cancer mortality worldwide even though its incidence has been decreasing in recent years. Despite remarkable advancements in chemotherapy, advanced gastric cancer has remained a therapeutic challenge for physicians as well as for patients. While early chemotherapeutic regimens succeeded in showing a modest but definite improvement over best supportive care, no single regimen stood out as superior. Most early trials failed to show survival benefit of combination regimens over single agent fluorouracil, but combination regimens were shown to have better response rates. Based on these data, the Japanese adopted single agent fluorouracil as a reference standard for further investigations, while the rest of the world used a doublet containing fluorouracil and platinum. As more clinical trials were conducted, the Japanese standard evolved into a doublet, while the Western countries adopted triplet combinations. There is no established global standard as yet, but with the introduction of newer targeted agents based on molecular assays and personalized approaches combined with conventional chemotherapy, multiple regimens are likely to emerge as global standards rather than one standard treatment for all.

S-1 and the treatment of gastric cancer with peritoneal dissemination

Peritoneal dissemination is the most common metastatic pattern of gastric cancer. We frequently face the necessity for gastrectomy in the event of gastric stenosis or gastric bleeding. However, the indication for palliative gastrectomy and the effectiveness of palliative chemotherapy are not clear. We retrospectively evaluated the prognostic factors after palliative gastrectomy in 121 gastric cancer patients with peritoneal dissemination. The expression of orotate phosphoribosyl transferase (OPRT) was examined immunohistochemically. The median survival time of all patients after palliative gastrectomy was 8.8 months. In the multivariate analyses, we adjusted the data of 82 patients without liver metastases for the background of 5-fluouracil (5-FU)-based chemotherapy regimen. The analysis revealed that the degree of peritoneal dissemination (multiple vs. a few metastases or cytology-positive; P= 0.01) and chemotherapy (S-1 vs. other 5-FU; P=0.01) were independent predictors of survival. Particularly, S-1 treatment was associated with a more favorable prognosis of the patients with high levels of OPRT expression compared to that of the patients with low expression. Patients with peritoneal dissemination are considered as terminal and inoperable. However, S-1 treatment may improve the survival after palliative gastrectomy in patients selected according to the degree of peritoneal dissemination and high OPRT expression.

The extent of lymph node dissection for gastric cancer: a critical appraisal

The extent of lymphadenectomy during therapeutic gastrectomy for gastric cancer remains a protracted and controversial issue. While traditionally extended lymphadenectomy is performed in Eastern Asia, limited lymphadenectomy is advocated by most western surgeons. Two large western randomized trials, meta-analyses and a recent systematic review were unable to demonstrate overall benefit from extended lymphadenectomy. In this review, the currently available data on this topic are critically evaluated, while ongoing studies and future perspective are discussed.

Determination of tegafur, 5-fluorouracil, gimeracil and oxonic acid in human plasma using liquid chromatography-tandem mass spectrometry

S-1 is an oral anticancer drug, which consists of tegafur (FT), gimeracil (CDHP) and potassium oxonate (Oxo) at a molar ratio of 1:0.4:1. Among these, tegafur is a prodrug, and is rapidly metabolized to the active drug, 5-fluorouracil (5-FU), in vivo. To evaluate the pharmacokinetics of S-1 in patients, LC-MS/MS methods were developed and validated for determination of FT, 5-FU, CDHP and Oxo in human plasma. FT, 5-FU and CDHP were extracted from plasma following protein precipitation, separated on a Synergi Hydro-RP column and simultaneously quantified by LC-MS/MS. The mobile phase consisted of methanol-water-ammonia-acetic acid (27:73:0.0018:0.018, v/v/v/v). The mass spectrometer was operated in negative mode using electrospray ionization. The calibration curves were linear in the range of 12.0-3000ng/mL for FT, and 2.00-500ng/mL for 5-FU and CDHP. The accuracy ranged from 93.1% to 110.7% and the precision ranged from 2.4% to 14.6% for each analyte. To determine Oxo in human plasma, an LC-MS/MS method employing pre-column derivatization was developed and validated. 4-Bromomethyl-7-methoxycoumarin was chosen as the derivatization reagent and [(13)C(2),(15)N(3)]-Oxo was used as the internal standard. The MS/MS detection was operated in positive mode using an APCI source. The calibration range was 2.00-150ng/mL. The accuracy and precision were within 95.9-99.1% and 4.4-10.0%, respectively. The validated methods were successfully applied to characterize the pharmacokinetic profiles of FT, 5-FU, CDHP and Oxo following oral administration of 60mg S-1 tablets to patients with solid gastrointestinal tract tumors.

Advances in the pharmacological treatment of gastro-oesophageal cancer

Despite a sharp decline in the incidence of gastric cancer during the second half of the 20th century, this malignancy remains the second leading cause of cancer mortality in the world. The incidence and mortality rate of gastric cancer increase with age; at present, the median ages at diagnosis are 67 years for men and 72 years for women in the US. This article reviews and discusses current medical treatment options for both the general population and elderly gastric cancer patients. Management of localized gastric cancer has changed significantly over recent years. Adjuvant chemoradiation is not generally recommended outside the US. After decades of trials of adjuvant chemotherapy with inconclusive results, a significant survival benefit for perioperative combination chemotherapy - as compared with surgery alone - in patients with resectable or locally advanced gastro-oesophageal cancer was recently demonstrated in the UK MAGIC trial. A further large, randomized trial from Japan demonstrated a significant survival benefit for adjuvant chemotherapy with S-1 after D2 resection for gastric cancer. However, both trials are applicable only to the population in which the trials were conducted. Specific data on elderly patients are missing. For patients with metastatic disease, oral fluoropyrimidines, such as capecitabine, have been developed. In Asian patients, treatment with the oral fluoropyrimidine S-1 is safe and effective. Docetaxel, oxaliplatin and irinotecan have demonstrated activity against gastric cancer in appropriately designed, randomized, phase III trials and have increased the available treatment options significantly. In addition, according to preliminary data, trastuzumab in combination with chemotherapy has significantly improved activity when compared to chemotherapy alone in patients with human epidermal receptor (HER)-2-positive gastric and gastro-oesophageal cancers. Thus, therapeutic decisions in patients with advanced gastric cancer may be adapted to the molecular subtype and co-morbidities of the individual patient. Data from retrospective analyses suggest that oxaliplatin seems to be better tolerated than cisplatin in elderly patients.

Pharmacokinetics of 5-fluorouracil in elderly Japanese patients with cancer treated with S-1 (a combination of tegafur and dihydropyrimidine dehydrogenase inhibitor 5-chloro-2,4-dihydroxypyridine)

S-1 is an oral anticancer agent that combines tegafur, a prodrug of 5-fluorouracil (5-FU), and 5-chloro-2,4-dihydroxypyridine (CDHP), an inhibitor of dihydropyrimidine dehydrogenase. We examined the effects of aging on the pharmacokinetics of the components of S-1. The median area under the concentration-time curve (AUC) of active 5-FU did not significantly differ between 10 patients 75 years or older and 53 patients younger than 75 years (P = 0.598, Mann-Whitney U test). It is interesting to note that the median oral clearance of tegafur in patients 75 years or older was significantly lower than that in patients younger than 75 years (P = 0.011). Furthermore, the median AUC of CDHP was significantly higher in patients 75 years or older than in those younger than 75 years (P = 0.004). This effect was caused by reduced renal function in the elderly, because CDHP is excreted in the urine by glomerular filtration. The opposing effects of aging on the oral clearance of tegafur and the AUC of CDHP may offset each other, leading to unchanged systemic exposure of 5-FU.

Fixed dosing and pharmacokinetics of S-1 in Japanese cancer patients with large body surface areas

BACKGROUND

S-1 is an oral anticancer agent that combines tegafur (FT) with 5-chloro-2,4-dihydroxypyridine (CDHP) and potassium oxonate. The recommended initial dose of S-1 is 120 mg/day for patients with a body surface area (BSA) of > or =1.5 m(2) in Japan.

METHODS

We examined the effects of using this fixed dose on the pharmacokinetics of FT, CDHP, and active 5-fluorouracil (5-FU) on the basis of actual BSA. The pharmacokinetics was compared between patients with a BSA of 1.5-1.75 m(2) and those with a BSA of > or =1.75 m(2).

RESULTS

The median areas under the time-concentration curves (AUCs) of 5-FU and CDHP were significantly lower in patients with a BSA of > or =1.75 m(2) than in those with a BSA of 1.5-1.75 m(2) (P = 0.005 and 0.006, respectively; Mann-Whitney U-test). There was no difference between the groups in the median AUC of FT.

CONCLUSION

Systemic exposure to 5-FU is significantly lower in Japanese cancer patients with a large BSA of >1.75 m(2) who received the recommended fixed dose of S-1.

Chemoradiotherapy for treatment of esophageal cancer in Japan: current status and perspectives

Radical surgery with extended lymph node dissection has been the main method used for treating patients with resectable esophageal cancer in Japan. Based on data from two phase III studies that compared surgery with or without pre- or postoperative chemotherapy, preoperative chemotherapy followed by surgery emerged as standard treatment for patients with stage II or III disease. Definitive chemoradiotherapy may be an alternative to surgery for those with unresectable as well as resectable esophageal cancer. Recent clinical trials in Japan showed that the survival after definitive chemoradiotherapy was comparable to survival following surgery in stage I disease, with a 5-year survival rate of 75%. However, the 5-year survival rate was worse for chemoradiotherapy (37%) and preoperative chemotherapy followed by radical surgery (60%) for stage II or III disease. In addition, salvage treatment following chemoradiotherapy appeared to be important for patients who did not achieve a complete response or who experienced recurrence. To improve the prognosis for esophageal cancer, a multimodality approach that includes more intensive induction chemotherapy prior to surgery, or possibly chemoradiotherapy containing molecular targeting agents, is preferred. Additional studies are necessary to further elucidate this multimodality approach. Current treatment strategies for esophageal cancer and research initiatives in Japan are reviewed.

Phase II trial of S-1 in combination with gemcitabine for chemo-naïve patients with locally advanced or metastatic pancreatic cancer

BACKGROUND

We performed a phase II study of combination chemotherapy with S-1 plus gemcitabine for treating chemo-naïve patients with unresectable pancreatic cancer to evaluate the efficacy and toxicity.

PATIENTS AND METHODS

Patients with histologically confirmed unresectable pancreatic cancer were eligible. The treatment consisted of S-1 (40 mg/m(2) p.o. b.i.d. from D1 to 14) and gemcitabine (1,250 mg/m(2) on D1 and 8), repeated every 3 weeks.

RESULTS

Thirty-two patients were enrolled between March 2005 and December 2007. No complete response was observed and a partial response was observed in 14 patients (44.0%), stable disease in eight patients (25.0%), and progressive disease in eight patients (25.0%). The median time to progression was 4.92 months (95% CI: 4.16-5.67 months), and the median overall survival was 7.89 months (95% CI: 5.96-9.82 months). The survival duration was significantly longer for the patients with a good performance status compared with that of the patients with a poor performance status. The major toxicities were grade 3-4 neutropenia (9, 28.1%), grade 3/4 thrombocytopenia (5, 15.6%), and grade 3 diarrhea (5, 15.6%).

CONCLUSION

The combination chemotherapy of S-1 and gemcitabine showed promising antitumor activity and manageable toxicities, and especially for the good performance status patients with unresectable pancreatic cancer.