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.

Rapamycin enhances chemotherapy-induced cytotoxicity by inhibiting the expressions of TS and ERK in gastric cancer cells

We have previously reported the synergistic cytotoxic effects of Docetaxel (TXT) and S-1 in gastric cancer in vitro and in vivo, and the combination regimen is now under phase III clinical trail. In this study, to elucidate whether the rapamycin, the inhibitor of the mTOR (mammalian target of rapamaycin), can enhance the potentiation of TXT and 5-fluorouracil (5-Fu) in gastric carcinoma cells. Rapamycin inhibited the growth of TMK-1, MKN-28, MKN-45 and MKN-74 cell lines by MTT assay, and it demonstrated the cytostatic effects as G1 arrest shown by flowcytometry. However, the cytotoxic effects of 5-Fu, TXT and cisplatin were enhanced by 2 to 4 times with the concomitant administration of rapamycin. To clarify the mechanism of the potentiation, the expression changes of the enzymes relating DNA metabolism and cell growth signal transduction pathways were examined by western blot analysis. Interestingly, the expression of thymidilate synthase was markedly decreased by the administration of rapamycin in TMK-1 cells in a time- and dose-dependent manner. Moreover, rapamycin decreased the phosphorylation of 4E-BP1, the phosphorylation of ERK1/2 and enhanced the phosphorylation of c-Jun NH2-terminal kinase, and the activation of caspase of apoptotic pathways in combination with TXT. These results strongly indicate that the mTOR inhibitor can enhance the potentiation of TXT and 5-Fu or S-1 and can serve as a new therapeutic tool for advanced and recurrent gastric cancer patients.

Successful treatment of duodenal adenocarcinoma with multiple liver metastases by S-1 + irinotecan (CPT-11)

Unresectable duodenal adenocarcinoma excluding the ampullary region is rare, and no standard chemotherapy has been defined for this disease. Although S-1-based chemotherapy is widely administered for advanced gastric cancer, few reports have described advanced duodenal cancer treated with S-1-based chemotherapy. We present herein a case of duodenal adenocarcinoma with liver metastases. The patient was a 72-year-old man with chief complaints of epigastralgia and fever. Gastroduodenal endoscopy revealed an ulcerative lesion on the upper wall of the duodenal bulb, and biopsy specimens showed well-differentiated adenocarcinoma. Computed tomography and ultrasonography showed multiple liver metastases. S-1 (80 mg/m(2) day(-1) on days 1-21) + irinotecan (80 mg/m(2) day(-1) on days 1 and 15) were administered in 4-week intervals as first-line chemotherapy. Tumor markers subsequently normalized, and liver metastases were diminished. The progression-free term was 6 months. Grade 3 neutropenia and diarrhea were observed as adverse events. S-1 + cisplatin and S-1 + docetaxel were administered as second- and third-line chemotherapies, respectively. The patient died due to hepatic failure, with an overall survival of 15 months. S-1-based regimens appear effective and well tolerated, and S-1 may thus represent a useful option for advanced duodenal cancer.

Upper gastrointestinal tumors: current status and future perspectives

Recent therapeutic developments that have provided new promising and successful approaches to the treatment of solid tumors are in large part due to the increasing understanding of their molecular biology. Despite this progress, these new therapies have provided minimal benefit in the treatment of upper gastrointestinal (GI) malignancies. Hence, the overall survival of patients with upper GI tumors remains dismal. These disappointing results are largely due to the lack of early detection strategies, inadequate medical treatments and the poor understanding of upper GI tumor biology. Clinically, the treatment paradigm has been evolving for these malignancies. Esophageal cancer is now commonly treated with preoperative chemoradiation in the USA, in both academic and community cancer centers, due to its theoretical advantages. Adjuvant chemotherapy and chemoradiation are also frequently used in patients with pancreatic cancer. Exciting prospects remain in the medical and surgical treatment of these malignancies with the inclusion of biologic agents in many protocols, newer chemotherapeutic agents (such as S-1 in the treatment of gastric cancer), and the use of minimally invasive procedures for the treatment of premalignant and, possibly, early malignant lesions of the esophagus and stomach. This review focuses on the current practice in the management of upper GI tumors and summarizes the recent advances in the field.

Challenge for a better combination with basic evidence

5-Fluorouracil (5-FU) has been the most widely accepted and studied chemotherapeutic agent, and many combination chemotherapeutic regimens have been reported. However, until recently, a standard regimen for metastatic gastric cancer had not been established. The combination of S-1 and cisplatin is a good candidate as a standard first-line regimen for metastatic gastric cancer. On the other hand, interest in biochemical modulation has become wide spread recently. The low level of dihydropyrimidine denhydrogenase (DPD), thymidylate synthase (TS) activities, and a high level of orotate phosphoribosyl-transferase (OPRT) activity enhance the antitumor effect of 5-FU and S-1. Docetaxel is one of the agents that modulate these enzyme expressions and activities. Moreover, the response rate of combination therapy of docetaxel and S-1 for metastatic gastric cancer was 56.3% and median survival time was 14.3 months in a phase II study, showing it to be a good candidate for a new standard regimen for gastric cancer. A phase III collaborative study, START (S-1 and Taxotere for advanced gastric cancer randomized phase III trial), is now under way in Japan and Korea.

Capecitabine in the treatment of advanced gastric cancer

Although the role of systemic chemotherapy has been established for the treatment of advanced gastric cancer, the prognosis of these patients remains poor, with a median overall survival of less than 1 year. Based on the results of several randomized Phase III trials, 5-fluorouracil continuous infusion plus cisplatin, with or without epirubicin, has become the global reference regimen for this patient population. However, treatment with fluorouracil infusion requires either frequent hospitalizations or the use of a central venous access device, harboring potential complications. Capecitabine, a tumor-activating oral prodrug of fluorouracil, may be more advantageous in terms of patient convenience, safety and efficacy. Two recent randomized Phase III trials have shown that capecitabine could replace infusional fluorouracil in cisplatin-based regimens. Furthermore, Phase II trials have shown that many other capecitabine-based doublet or triplet chemotherapy regimens incorporating newer cytotoxic agents are active and well tolerated. Many promising biological agents are now being tested in Phase III trials, incorporating capecitabine combinations as control arms, in patients with advanced gastric cancer.

Capecitabine in advanced gastric cancer

Since the routine introduction of chemotherapy for advanced gastric cancer in the early 1990 s, median survival for gastric cancer has improved from 3 months, with best supportive care alone, to > 11 months in recently reported Phase III trials of triplet chemotherapy. Capecitabine is an orally-active fluoropyrimidine, which is selectively metabolised to fluorouracil in tumour cells. The combinations of platinum compounds and capecitabine have been evaluated in two recent, large, Phase III trials demonstrating non-inferiority in efficacy compared with platinum plus continuous infusion fluorouracil. In view of the convenience and flexibility of patients in adjusting dosage when encountering toxicities, capecitabine is replacing continuous infusion fluorouracil as the backbone of combination chemotherapy in advanced gastric cancer patients. Future trials evaluating biologicals are now incorporating capecitabine combinations as control arms in both advanced disease and peri-operative settings in gastric cancer.

Medical treatment for advanced gastroesophageal adenocarcinoma

PURPOSE OF REVIEW

Gastroesophageal cancers continue to pose a significant health burden around the world. Advanced gastroesophageal cancer is an incurable condition and more research is desirable. Considerable new and important information, however, has become available.

RECENT FINDINGS

The number of phase III trials for patients with advanced gastroesophageal cancer is increasing and that is welcome news. Current results suggest that capecitabine can be substituted for 5-fluorouracil and oxaliplatin for cisplatin. Docetaxel, when combined with 5-fluorouracil and cisplatin, prolongs overall survival as well as improves safety, quality of life, and efficacy. S-1, a fourth generation oral fluoropyridine, is especially effective in combination with cisplatin. Dosing of S-1 is different between Western and Asian populations due to differences in metabolism by CYP2A6. Irinotecan should not be used as frontline therapy for advanced gastroesophageal cancer. Biologic agents are currently under investigation.

SUMMARY

Safer, more convenient, and more effective chemotherapy combinations are being developed for patients with advanced gastroesophageal cancer; however, considerable challenges exist to select the optimal therapy for an individual patient.