Bisphosphonates and evidence for association with esophageal and gastric cancer: a systematic review and meta-analysis.

OBJECTIVES: Concerns have been raised about a possible link between bisphosphonate use, and in particular alendronate, and upper gastrointestinal (UGI) cancer. A number of epidemiological studies have been published with conflicting results. We conducted a systematic review and meta-analysis of observational studies, to determine the risk of esophageal and gastric cancer in users of bisphosphonates compared with non-users. DESIGN: We searched PubMed, MEDLINE, EMBASE, Web of Knowledge and Cochrane Database of Systematic Reviews for studies investigating bisphosphonates and esophageal or gastric cancer. We calculated pooled ORs and 95% CIs for the risk of esophageal or gastric cancer in bisphosphonate users compared with non-users. We performed a sensitivity analysis of alendronate as this was the most common single drug studied and is also the most widely used in clinical practice. RESULTS: 11 studies (from 10 papers) examining bisphosphonate exposure and UGI cancer (gastric and esophageal), met our inclusion criteria. All studies were retrospective, 6/11 (55%) case-control and 5/11(45%) cohort, and carried out using data from 5 longitudinal clinical databases. Combining 5 studies (1 from each database), we found no increased risk, OR 1.11 (95% CI 0.97 to 1.27) of esophageal cancer in bisphosphonate users compared with non-users and no increased risk of gastric cancer in bisphosphonate users, OR 0.96 (95% CI 0.82 to 1.12). CONCLUSION: This is the fourth and most detailed meta-analysis on this topic. We have not identified any compelling evidence for a significantly raised risk of esophageal cancer or gastric cancer in male and female patients prescribed bisphosphonates.

Autocrine VEGF signaling promotes proliferation of neoplastic Barrett's epithelial cells through a PLC-dependent pathway.

BACKGROUND & AIMS: Tumor cells express vascular endothelial growth factor (VEGF), which induces angiogenesis. VEGF also activates VEGF receptors (VEGFRs) on or within tumor cells to promote their proliferation in an autocrine fashion. We studied the mechanisms of autocrine VEGF signaling in Barrett's esophagus cells. METHODS: Using Barrett's epithelial cell lines, we measured VEGF and VEGFR messenger RNA and protein, and studied the effects of VEGF signaling on cell proliferation and VEGF secretion. We studied the effects of inhibiting factors in this pathway on levels of phosphorylated phospholipase Cγ1 (PLCG1), protein kinase C, and extracellular signal-regulated kinases (ERK)1/2. We performed immunohistochemical analysis of phosphorylated VEGFR2 on esophageal adenocarcinoma tissues. We studied effects of sunitinib, a VEGFR2 inhibitor, on proliferation of neoplastic cells and growth of xenograft tumors in mice. RESULTS: Neoplastic and non-neoplastic Barrett's cells expressed VEGF and VEGFR2 messenger RNA and protein, with higher levels in neoplastic cells. Incubation with recombinant human VEGF significantly increased secretion of VEGF protein and cell number; knockdown of PLCG1 markedly reduced the recombinant human VEGF-stimulated increase in levels of phosphorylated PLCG1 and phosphorylated ERK1/2 in neoplastic cells. Esophageal adenocarcinoma tissues showed immunostaining for phosphorylated VEGFR2. Sunitinib inhibited VEGF signaling in neoplastic cells and reduced weight and volume of xenograft tumors in mice. CONCLUSIONS: Neoplastic and non-neoplastic Barrett's epithelial cells have autocrine VEGF signaling. In neoplastic Barrett's cells, VEGF activation of VEGFR2 initiates a PLCG1-protein kinase C-ERK pathway that promotes proliferation and is self-sustaining (by causing more VEGF production). Strategies to reduce autocrine VEGF signaling (eg, with sunitinib) might be used to prevent or treat cancer in patients with Barrett's esophagus.

Bisphosphonates and risk of upper gastrointestinal cancer--a case control study using the General Practice Research Database (GPRD).

BACKGROUND: Concerns have been raised as to the safety of bisphosphonates; in particular a possible link between bisphosphonate use and upper gastrointestinal (GI) cancer. Two published studies using different study populations but drawn from earlier versions of the same national UK database, reached differing conclusions: one finding no evidence for an increase in the risk of gastric or oesophageal cancer in bisphosphonate users and one finding a small but significantly increased risk of oesophageal cancer linked to duration of bisphosphonate use. METHODOLOGY/ PRINCIPAL FINDINGS: Design-A case control study comparing bisphosphonate prescribing in cases of upper GI cancer from 1995 to 2007 using UK primary care electronic health records (GPRD). Main Outcome Measure-Relative Risk (approximated to Odds Ratio for rare events) for oesophageal and gastric cancer development in bisphosphonate users compared to non-users. The odds of being a case of oesophageal cancer, adjusted for smoking status, were significantly increased in women who had had one or more bisphosphonate prescriptions, odds ratio 1.54 (95% CI 1.27-1.88) compared to non-users. There was no significant effect on gastric cancer in women, odds ratio adjusted for smoking status, 1.06 (95% CI 0.83-1.37) and also no apparent risk in men for either oesophageal or gastric cancer, odds ratio adjusted for smoking status 0.78 (95%CI 0.56-1.09) and 0.87 (95% CI 0.55-1.36) respectively. CONCLUSIONS/ SIGNIFICANCE: Our results support a small but significant increased risk of oesophageal cancer in women prescribed bisphosphonates and is based on the largest number of exposed cases to date in the UK.