Use of bisphosphonates and reduced risk of colorectal cancer

Adaptive Immune Receptor Distinctions Along the Colorectal Polyp-Tumor Timelapse

INTRODUCTION

Colorectal cancer (CRC) is the third-most common cancer diagnosed worldwide, with 1.85 million new cases per year. While mortality has significantly decreased due to preventive colonoscopy, only 5% of polyps identified progress to cancer. Studies have found that immunological alterations in other solid tumor microenvironments are associated with worse prognoses.

METHODS

We applied an immunogenomics approach to assess adaptive immune receptor gene expression changes that were associated with development of adenocarcinoma, utilizing 79 samples that represented normal, tubular, villous, and tumor colorectal tissue for 32 patients.

RESULTS

Results indicated that the number of productive TRD and TRG recombination reads, representing gamma-delta (γδ) T-cells, significantly decreased with progression from normal to tumor tissue. A further assessment of two independent CRC datasets was consistent with a decrease in TRD recombination reads with progression to CRC. Further, we identified three physicochemical parameters for immunoglobulin, complementarity determining region-3 (CDR3) amino acids associated with progression from normal to tumor tissue.

CONCLUSIONS

Overall, this study points towards a need for further investigation of γδ T-cells in relation to CRC development; and indicates immunoglobulin CDR3 physicochemical features as potential CRC biomarkers.

Anti-osteoporosis drugs reduce mortality in cancer patients: A national cohort study of elderly with vertebral fractures

Introduction

The most prevalent type of fragility fractures is osteoporotic vertebral fractures (OVFs). However, only a few studies have examined the relationship between anti-osteoporosis treatments and malignancy-related mortality following an OVF. The goal of this study is to determine the effect of anti-osteoporosis therapy on mortality in OVF patients with and without cancer.

Method

Data from older people over the age of 65 who were hospitalised for OVFs between 1 January 2003 and 31 December 2018 were analysed retrospectively. A total of 6139 persons getting osteoporosis treatment and 28,950 who did not receive treatment were analysed, together with 2 sets of patients, comprising cancer patients (794) and cancer-free patients (5342), using anti-osteoporosis medication or not, in 1:1 propensity score-matched analyses. The hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated.

Results

In all, 35,089 patients with OVFs were included in the population; 29,931 people (85.3%) were women, and the mean (standard deviation) age was 78.13 (9.27) years. Overall survival was considerably higher in those undergoing osteoporosis therapy. This was true both for those without cancer (adjusted HR 0.55; 95% CI 0.51-0.59; P<.0001) as well as those with cancer (adjusted HR 0.72; 95% CI 0.62-0.84; P<.0001). Even among cancer patients, those who received anti-osteoporotic drugs had a lower mortality rate than those who did not.

Conclusion

Our findings suggest that anti-osteoporosis therapy should be initiated regardless of the presence of cancer in the elderly, as it increases survival following OVFs.

Antiresorptive Medication Use Is not Associated With Acute Cardiovascular Risk: An Observational Study

CONTEXT

Bisphosphonates have been reported to be cardioprotective in some, but not all, studies. It is unknown whether denosumab (Dmab) use protects against cardiovascular events (CVEs).

OBJECTIVE

To determine whether oral bisphosphonate (oBP) or Dmab use is associated with CVEs in persons with incident fracture.

METHODS

Participants with an incident minimal trauma fracture from the Sax Institute's 45 and Up Study, a population-based cohort from NSW, Australia, were followed between 2005/2009 and 2017. Questionnaire data were linked to hospital admissions (Admitted Patients Data Collection [APDC]) by the Centre for Health Record Linkage). Medicare Benefit Schedule (MBS) and Pharmaceutical Benefits Scheme (PBS) data sets were provided by Services Australia. Data was stored in a secure computing environment (Secure Unified Research Environment). Fractures, CVEs, and comorbidities were identified from the APDC and oBP and Dmab medication from the PBS. oBP and Dmab users were matched to never users (NoRx) by propensity scores. The main outcome measures were association between oBP and Dmab with CVE (acute myocardial infarction, unstable angina, cerebrovascular accident, and transient ischemic attack) and were determined using a stratified Cox's proportional hazards model.

RESULTS

There were 880 pairs of oBP and NoRx (616 women) and 770 pairs of Dmab and NoRx (615 women) followed for ∼4.3 years. CVE risk was similar for oBP and NoRx Hazard Ratios (HR) women, 0.88 [95% CI 0.65-1.18]; men, 1.07 [95% CI 0.72-1.57]). Similar findings were obtained for Dmab (Hazard Ratios (HR) women, 1.08 [95% CI 0.78-1.50]; men, 1.55 [95% CI 0.96-2.48]).

CONCLUSION

oBP and Dmab use was not associated with CVEs.

Bisphosphonate treatment is associated with decreased mortality rates in patients after osteoporotic vertebral fracture

The aim of this study is to investigate the effect of bisphosphonate (BP) on mortality after osteoporotic vertebral fracture (OVF). BP medication (hazard ratios = 0.593; 95%CI: 0.361-0.976) was significantly associated with reduced all-cause mortality after OVF.

PURPOSE

Osteoporotic vertebral fracture (OVF) is the most common type of fragility fracture. Bisphosphonate (BP) medication was suggested to have positive effects on both fracture prevention and recovery outcomes. The aim of this study is to investigate the effect of BP on mortality after OVF.

METHODS

This cohort study involved 535 patients (170 males and 365 females), aged ≥ 65 years (mean age: 82.6 ± 7.0 years, mean follow-up periods: 33.0 ± 25.8 months) who were hospitalized after OVF from January 2011 to December 2019 at a public hospital. Patients treated with PTH (parathyroid hormone), PTH or PTHrp analogues, denosumab, and selective estrogen receptor modulators were excluded. Kaplan-Meier survival curves on mortality of patients with OVF with and without BP treatment were prepared, and log-rank tests were performed. Cox proportional hazards model was used to identify factors associated with mortality after OVF.

RESULTS

This study included 163 (30.5%) patients treated with BP. Kaplan-Meier survival curves showed that the mortality rate after OVF was significantly lower in patients treated with BP (P < 0.001). Cox proportional hazards model showed that older age (hazard ratios [HR] = 1.066; 95%CI:1.035-1.103), male sex (HR = 2.248; 95%CI:1.427-3.542), malnutrition (geriatric nutritional risk index < 92) (HR = 1.691; 95%CI:1.005-2.846), BP medication (HR = 0.593; 95%CI: 0.361-0.976), and Japanese Orthopaedic Association score at discharge (HR = 0.941; 95%CI: 0.892-0.993) were significantly associated with all-cause mortality after OVF.

CONCLUSIONS

BP medication is beneficial not only for fracture prevention but also for mortality after OVF.

A novel risk stratification for predicting prognosis of colorectal cancer patients with bone metastasis

Background

Our understanding in prognosis of bone metastasis (BM) from colorectal cancer (CRC) is limited. We aimed to establish a clinical risk stratification for individually predicting the survival of CRC patients with BM.

Methods

A total of 200 CRC patients with BM were included in this study. Survival time from BM diagnosis was estimated using the Kaplan-Meier method. The multivariable COX regression model identified the risk factors on cancer specific survival (CSS). Based on weighted scoring system, the stratification model was constructed to classify patients with BM according to prognostic risk. Discrimination power and calibration ability of risk stratification were measured.

Results

The median CSS time was 11 months after BM diagnosis. Lymph node metastasis, Carbohydrate antigen 199 (CA199) levels, bone involvement, Karnofsky Performance Status (KPS) scores, primary tumor resection, bisphosphonates therapy and radiotherapy were identified as predictors of CSS. Four risk groups were stratified according to weighted scoring system, including low risk, medium risk, medium-high risk and high risk group, with 35, 16, 9 and 5 months of median CSS, respectively (P=0.000). The risk stratification displayed good accuracy in predicting CSS, with acceptable discrimination and calibration.

Conclusions

This novel risk stratification predicts CSS in CRC patient with BM using easily accessible clinicopathologic factors, which is recommended for use in individualized clinical decision making in patient with BM.

Bisphosphonates and lifespan

Bisphosphonates are first line agents used to treat osteoporosis and reduce fracture rate. They bind to areas of exposed calcium in the skeleton and cause osteoclast apoptosis, thereby leading to a reduction in remodelling rates. They are also used to decrease skeletal complications of some cancers including a reduction in bone metastases. Following the landmark randomised controlled trial of zoledronate post hip fracture (HORIZON) in which an unexpected survival benefit was found, there has been increasing interest in their potential ability to increase lifespan. This review will consider the clinical evidence for their effect on mortality in both the osteoporosis and non-osteoporosis settings, the latter including studies in intensive care, cancer and cardiovascular disease. Where evidence exists, this review will briefly discuss some of the postulated mechanisms for this survival benefit.

Bisphosphonates and risk of cancers: a systematic review and meta-analysis

Background

It is unclear whether bisphosphonates are associated with risk of cancers. Therefore, this meta-analysis aimed to evaluate the effect of bisphosphonates on overall cancers.

Methods

A search in Pubmed, Embase, Cochrane Library and Web of Science databases was conducted, from the inception date of each resource to September 26, 2019. The summarised effect estimates with 95% CIs were calculated using a random-effect model. Heterogeneity and publication bias were explored.

Results

Thirty-four articles were included in this study (4,508,261 participants; 403,196 cases). The results revealed that bisphosphonates significantly decreased the risk of colorectal cancer (RR = 0.89, 95% CI: 0.81–0.98), breast cancer (RR = 0.87, 95% CI: 0.82–0.93) and endometrial cancer (RR = 0.75, 95% CI: 0.61–0.94), but no significant association was observed in all-cause cancer. Furthermore, nitrogen-containing bisphosphonates only had protective effects both on breast cancer (RR = 0.94, 95% CI: 0.90–0.99) and endometrial cancer (RR = 0.70, 95% CI: 0.54–0.92). Non-nitrogen-containing bisphosphonates tended to increase the risk of liver cancer (RR = 2.14, 95% CI: 1.23–3.72) and pancreas cancer (RR = 1.75, 95% CI: 1.32–2.33).

Conclusion

Bisphosphonates are significantly associated with risk reduction of colorectal, breast and endometrial cancer, especially nitrogen-containing bisphosphonates. It should be noted that non-nitrogen-containing bisphosphonates might increase the risk of liver and pancreas cancer. Large prospective cohort studies are needed to find the causal association between bisphosphonates and risk of cancers.

Beyond bone biology: Lessons from team science

Today, research in biomedicine often requires the knowledge and technologies in diverse fields. Therefore, there is an increasing need for collaborative team science that crosses traditional disciplines. Here, we discuss our own lessons from both interdisciplinary and transdisciplinary teams, which ultimately ushered us to expand our research realm beyond bone biology.

Bone metastases: a comprehensive review of the literature

The last report of the World Health Organization (WHO) stated that approximately four million people experience bone pain due to malignant diseases. Among them, metastatic bone pain is one of the most important sources of complaint. The estimated median survival in the presence of bone metastases ranks from 10 to 12 weeks. Bone represents a potential target of distant metastases for the majority of malignant tumours. However, the exact incidence of bone metastases is unknown. Bone metastases have an important socio-economic impact, and due to the enhancement of the overall survivorship, their incidence is increasing. Malignant neoplasms such as lung, thyroid, renal cancer, multiple myeloma, and melanoma often metastasize to the bone. Bone metastases commonly localize to the spinal column, pelvis, shoulder, and distal femur. The proper treatment for painful skeletal metastases is still unknown. Hence, the purpose of this review of the literature was to update current evidence concerning the aetiogenesis, biological behaviour, and treatment algorithms for painful skeletal metastases.

Use of metformin and risk of breast and colorectal cancer

BACKGROUND

Diabetes has been associated with increased risk of cancer, including breast cancer and colorectal cancer. Metformin, an oral hypoglycemic drug, but not other anti-diabetic drugs, has been associated with reduced risk of breast and of colon cancers in some, but not in other, studies.

METHODS

Data from two large-scale, population-based, case-control studies of breast and colorectal cancers etiology, conducted in Northern Israel since 1998 were analyzed to evaluate the association between regular use (>3 times) of metformin prior to diagnosis and risk of developing cancer. The multivariate analyses for both cancer sites included age, family history of breast/colorectal cancer, history of diabetes, sports participation, fruits/vegetables consumption, aspirin and statins use, and for breast cancer, also included use of oral contraceptives and postmenopausal hormones and number of pregnancies. Use of metformin and diabetes status were determined based on valid electronic medical records of the participants.

RESULTS

Metformin use prior to diagnosis of cancer was associated with a decrease in risk of both breast cancer (OR = 0.821, 0.726-0.928, p = 0.002) and colorectal cancer (OR = 0.754, 0.623-0.912, p = 0.004). An inverse association was not identified with use of other anti-diabetic medications. Diabetes was found to be associated with risk of colorectal cancer (OR = 1.204, 1.014-1.431, p = 0.034) but not of breast cancer. No dose response by years of use of metformin was found.

CONCLUSION

These analyses of large population-based studies provide evidence of a strong inverse association of metformin with breast and, even more so, with colorectal cancer risk.

Hormonal and reproductive factors and reduction in the risk of colorectal cancer

Females differ from males in incidence and clinical characteristics of colorectal cancer. Understanding the differences can lead to development of preventive approaches. To identify reproductive factors currently associated with the risk of colorectal cancer. Consecutively diagnosed female colorectal cancer cases and randomly chosen colorectal cancer-free controls matched on age/ethnicity/primary care clinic within the molecular epidemiology of colorectal cancer study, a population-based case-control study in Northern Israel, were included. A total of 2867 female cases and 2333 controls participated in this analysis. Participants were interviewed on reproductive history: ages at menarche, menopause, first birth, terminations of pregnancies, miscarriages, births, use of oral contraceptives. Among 5200 women, spontaneous miscarriages (odds ratio = 0.71, 0.61-0.83 for ever/never in Jews; odds ratio = 0.76, 0.53-1.08 in Arabs) and number of miscarriages, but not termination of pregnancies, as well as use, and duration of use, of oral contraceptives (Jews: odds ratio = 0.49, 0.39-0.62 for ever/never; Arabs: odds ratio = 0.14, 0.04-0.47) were strongly inversely associated with colorectal cancer risk. Up to 5 pregnancies were associated with increased risk while ages at menarche, at menopause and at first birth were not associated with colorectal cancer risk. Miscarriages but not terminations of pregnancy or full-term pregnancies, and use of oral contraceptives, were strongly associated with reduced odds of developing colorectal cancer suggesting unique hormonal influences on colorectal cancer.

Exposure to oral bisphosphonates and risk of gastrointestinal cancer

Few studies have explored the association of oral bisphosphonate exposure and gastrointestinal cancer within Asian populations. In this study, we investigated 45,397 Korean women from the nationwide population-based cohort from 2002 to 2013. Oral bisphosphonate exposure did not appear to be associated with elevated or reduced risk for gastrointestinal cancer.

INTRODUCTION

While several studies suggested increased risk in upper gastrointestinal (GI) cancer or reduced risk in colorectal cancer upon bisphosphonate exposure, the association is less explored within Asian populations. We investigated the effect of oral bisphosphonate exposure on the risk of GI cancers within a nationwide population-based cohort.

METHODS

This study used two separate cohorts. The first cohort included 45,397 women aged 60 years or older from the National Health Insurance Service-Health Screening Cohort during 2002-2013. Participants were classified into bisphosphonate users and non-users based on drug exposure during 2002-2007, and followed-up from the index date of January 1, 2008. The second cohort included 25,665 newly diagnosed osteoporosis patients who started taking oral bisphosphonate during 2003-2008. After 4 years of drug exposure period, patients were separated into quartiles based on cumulative oral bisphosphonate exposure. Participants were followed-up until December 31, 2013 for GI cancer, stomach cancer, and colorectal cancer. Cox proportional hazard regression models were used to assess the hazard ratios (HRs) and 95% confidence intervals (CIs) for the cancer risks.

RESULTS

Compared to bisphosphonate non-users, no significant risk difference was observed among bisphosphonate users on GI (HR 1.06; 95% CI 0.87-1.28), stomach (HR 1.11; 95% CI 0.85-1.47) and colorectal cancers (HR 1.04; 95% CI 0.79-1.37). Among bisphosphonate users, increasing doses of bisphosphonate exposure was not associated with elevated or reduced risk for GI cancer (p for trend 0.573).

CONCLUSION

Oral bisphosphonate use did not appear to be associated with elevated or reduced risk for GI cancers.

Bisphosphonates Zometa and Fosamax Synergize with Metformin to Prevent AOM-Induced Colon Cancer in F344 Rat Model

Recent observational studies suggest that bisphosphonates (BP) and antidiabetic drugs are associated with colorectal cancer risk reduction. Hence, we evaluated the colorectal cancer preventive effects of BPs (zometa and fosamax), individually and when combined with metformin, in azoxymethane-induced rat colon cancer model. Rat (30/group) were randomized and treated subcutaneously with azoxymethane to induce colorectal cancer. Dietary intervention with zometa or fosamax (0, 20, or 100 ppm) or metformin (1,000 ppm) or the combinations (zometa/fosamax 20 ppm plus metformin 1,000 ppm) began 4 weeks after azoxymethane treatment, at premalignant lesions stage. Rats were killed 40 weeks post drug intervention to assess colorectal cancer preventive efficacy. Dietary zometa (20 ppm) inhibited noninvasive adenocarcinomas multiplicity by 37% (P < 0.03) when compared with control diet fed group. Fosamax at 20 ppm and 100 ppm significantly reduced adenocarcinoma incidence (P < 0.005) and inhibited the noninvasive adenocarcinoma multiplicities by 43.8% (P < 0.009) and 60.8% (P < 0.004), respectively, compared with the group fed control diet. At 1,000 ppm dose, metformin failed to suppress colon adenocarcinoma formation. However, the lower dose combinations of zometa or fosamax with metformin resulted in significant inhibition of noninvasive adenocarcinoma by 48% (P < 0.006) and 64% (P < 0.0002), and invasive adenocarcinoma by 49% (P < 0.0005) and 38% (P < 0.006), respectively. Biomarker analysis of combination drug-treated tumors showed a decrease in cell proliferation with increased apoptosis when compared with untreated tumors. Overall, our results suggest that the combination of low doses of zometa or fosamax with metformin showed synergistic effect and significantly inhibited colon adenocarcinoma incidence and multiplicity.

Next Generation Lipophilic Bisphosphonate Shows Antitumor Effect in Colorectal Cancer In Vitro and In Vivo

Bisphosphonates, despite proven antitumor effect in vitro in many tumor types, are currently used only for treatment of osteoporosis and bone metastasis. Colorectal cancer is the third most commonly diagnosed type of cancer and lacks targeted therapy for RAS or RAF mutation carrying cases. A new lipophilic bisphosphonate showed promising results in lung cancer models, but their effect on colorectal cancer cells was not investigated excessively. Antitumor effects and impact on RAS-related signalization of zoledronic acid (ZA) and a lipophilic bisphosphonate (BPH1222) were investigated on 7 human colorectal cancer cell lines in vitro and in vivo. Furthermore, mutant KRAS dependent effect of prenylation inhibition was investigated using isogeneic cell lines. Both bisphosphonates reduced cell viability in vitro in a dose-dependent manner. Both compounds changed cell cycle distribution similarly by increasing the proportion of cells either in the S or in the subG1 phase or both. However, BPH1222 exerted higher inhibitory effect on spheroid growth than ZA. Interestingly, we found profound alterations in phosphorylation level of Erk and S6 proteins upon ZA or BPH1222 treatment. Furthermore, investigation of a mutant KRAS isogeneic model system suggests that the drugs interfere also with the mutant KRAS proteins. In vivo experiments with KRAS mutant xenograft model also revealed growth inhibitory potential of bisphosphonate treatment. Our results show that lipophilic bisphosphonates might extend the therapeutic spectrum of bisphosphonate drugs and could be considered as additional treatment approaches in colorectal cancer.

Risk of colorectal cancer in users of bisphosphonates: analysis of population-based electronic health records

The use of bisphosphonates has been associated with a decrease in the risk of colorectal cancer (CRC) in observational studies, but with controversial results and difficult to interpret because of routine concomitant use of calcium and vitamin D. We aimed to assess the association between CRC risk and outpatient exposure to antiosteoporotic drugs using a large cohort with prescription data in Catalonia. A case-control study was performed using the Information System for Development of Primary Care Research (SIDIAP) which is a primary care medical record database that has linked data on reimbursed medication. The study included 25,836 cases with an incident diagnosis of CRC between 2010 and 2015 and 129,117 matched controls by age (± 5 years), sex and healthcare region. A multivariable model was built adjusting for known risk factors and comorbidities that were significantly associated to CRC in the dataset, and a propensity score for bisphosphonates. Tests for interaction for multiple drug use and stratified analysis for tumour location were prospectively planned. Overall 18,230 individuals (11.5%) were users of bisphosphonates. A significant but modest protective effect on CRC was observed for bisphosphonates (OR 0.95, 95% CI 0.91-0.99), that was no longer significant when adjusted for calcium and vitamin D (OR 0.98, 95% CI 0.93-1.03). Bisphosphonates, however, showed a dose-response effect with duration of use even when adjusted for calcium and vitamin D (OR for use > 40 months: 0.90, 95% CI 0.81-1.00, P value for trend: 0.018). The use of bisphosphonates was associated with a modest decrease in the risk of CRC, but this effect was essentially explained by concomitant use of calcium or vitamin D. The observed protective effect was stronger for long durations of use, which deserves further study.

Oral bisphosphonate use and lung cancer incidence among postmenopausal women

Background

Bisphosphonates are common medications for the treatment of osteoporosis in older populations. Several studies, including the Women’s Health Initiative (WHI), have found inverse associations of bisphosphonate use with risk of breast and endometrial cancer, but little is known about its association with other common malignancies. The objective of this study was to evaluate the association of bisphosphonate use on the incidence of lung cancer in the WHI.

Patients and methods

The association between oral bisphosphonate use and lung cancer risk was examined in 151 432 postmenopausal women enrolled into the WHI in 1993–1998. At baseline and during follow-up, participants completed an inventory of regularly used medications including bisphosphonates.

Results

After a mean follow-up of 13.3 years, 2511 women were diagnosed with incident lung cancer. There was no evidence of a difference in lung cancer incidence between oral bisphosphonate users and never users (adjusted hazard ratio = 0.91; 95% confidence intervals, 0.80–1.04; P = 0.16). However, an inverse association was observed among those who were never smokers (hazard ratio = 0.57, 95% confidence interval, 0.39–0.84; P < 0.01).

Conclusion

In this large prospective cohort of postmenopausal women, oral bisphosphonate use was associated with significantly lower lung cancer risk among never smokers, suggesting bisphosphonates may have a protective effect against lung cancer. Additional studies are needed to confirm our findings.

A personalized platform identifies trametinib plus zoledronate for a patient with KRAS-mutant metastatic colorectal cancer

Colorectal cancer remains a leading source of cancer mortality worldwide. Initial response is often followed by emergent resistance that is poorly responsive to targeted therapies, reflecting currently undruggable cancer drivers such as KRAS and overall genomic complexity. Here, we report a novel approach to developing a personalized therapy for a patient with treatment-resistant metastatic KRAS-mutant colorectal cancer. An extensive genomic analysis of the tumor's genomic landscape identified nine key drivers. A transgenic model that altered orthologs of these nine genes in the Drosophila hindgut was developed; a robotics-based screen using this platform identified trametinib plus zoledronate as a candidate treatment combination. Treating the patient led to a significant response: Target and nontarget lesions displayed a strong partial response and remained stable for 11 months. By addressing a disease's genomic complexity, this personalized approach may provide an alternative treatment option for recalcitrant disease such as KRAS-mutant colorectal cancer.

Gene Expression Integration into Pathway Modules Reveals a Pan-Cancer Metabolic Landscape

Metabolic reprogramming plays an important role in cancer development and progression and is a well-established hallmark of cancer. Despite its inherent complexity, cellular metabolism can be decomposed into functional modules that represent fundamental metabolic processes. Here, we performed a pan-cancer study involving 9,428 samples from 25 cancer types to reveal metabolic modules whose individual or coordinated activity predict cancer type and outcome, in turn highlighting novel therapeutic opportunities. Integration of gene expression levels into metabolic modules suggests that the activity of specific modules differs between cancers and the corresponding tissues of origin. Some modules may cooperate, as indicated by the positive correlation of their activity across a range of tumors. The activity of many metabolic modules was significantly associated with prognosis at a stronger magnitude than any of their constituent genes. Thus, modules may be classified as tumor suppressors and oncomodules according to their potential impact on cancer progression. Using this modeling framework, we also propose novel potential therapeutic targets that constitute alternative ways of treating cancer by inhibiting their reprogrammed metabolism. Collectively, this study provides an extensive resource of predicted cancer metabolic profiles and dependencies.Significance: Combining gene expression with metabolic modules identifies molecular mechanisms of cancer undetected on an individual gene level and allows discovery of new potential therapeutic targets. Cancer Res; 78(21); 6059-72. ©2018 AACR.

Bone Metastases: An Overview

Bone is a frequent site of metastases and typically indicates a short-term prognosis in cancer patients. Once cancer has spread to the bones it can rarely be cured, but often it can still be treated to slow its growth. The majority of skeletal metastases are due to breast and prostate cancer. Bone metastasis is actually much more common than primary bone cancers, especially in adults. The diagnosis is based on signs, symptoms and imaging. New classes of drugs and new interventions are given a better quality of life to these patients and improved the expectancy of life. It is necessary a multidisciplinary approach to treat patients with bone metastasis. In this paper we review the types, clinical approach and treatment of bone metastases.

Oral bisphosphonates and colorectal cancer

Use of oral bisphosphonates has been associated with a decreased risk of colorectal cancer (CRC), but the association may be related to residual confounding by healthy lifestyle or body mass index (BMI). Therefore, we conducted a prospective nested case-control study within the Kaiser Permanente, Northern California health system cohort. In total, 12,505 CRC cases were individually matched to 599,534 controls. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using conditional logistic regression models with adjustment for important covariates extracted from the database. Participants who had ever used oral bisphosphonates were less likely than non-users to be diagnosed with CRC (OR 0.82; 95% CI: 0.74, 0.89). Colon and rectum site-specific associations were similar to the overall association. A stronger inverse association for ever use of bisphosphonates was observed for men (OR 0.63; 95% CI: 0.47, 0.85), however when stratified by previous lower endoscopy, the association was only observed in the participants who did not have a previous lower endoscopy (OR 0.73 (0.64, 0.83)). In conclusion, we found that oral bisphosphonate use was associated with a decreased odds of CRC, however this association may be due to residual confounding by BMI or another confounder.

Prevention of Colorectal Neoplasia

Colorectal cancer (CRC) is one of the leading causes of cancer-related morbidity and mortality worldwide. There are well-established screening protocols involving fecal testing, radiographic, and endoscopic evaluations that have led to decreased incidence and mortality of CRC in the United States. In addition to screening for CRC, there is interest in preventing colorectal neoplasia by targeting the signaling pathways that have been identified in the pathway of dysplasia progressing to carcinoma. This review will detail the efficacy of multiple potential preventative strategies including lifestyle changes (physical activity, alcohol use, smoking cessation, and obesity); dietary factors (dietary patterns, calcium, vitamin D, fiber, folate, and antioxidants and micronutrients); and chemopreventive agents (nonsteroidal anti-inflammatory drugs, statins, metformin, bisphosphonates, and postmenopausal hormonal therapy).

The Characteristics of Bone Metastasis in Patients with Colorectal Cancer: A Long-Term Report from a Single Institution

BACKGROUND

Bone metastasis in patients with colorectal cancer (CRC) is very rare, and data are extremely lacking. We aimed to evaluate the characteristics of bone metastasis in patients with CRC.

MATERIALS AND METHODS

We performed a chart review of 63 patients (1.1 %) with bone metastasis among 5479 patients who underwent surgery for CRC.

RESULTS

Most patients were stage 3 (17.5 %) or 4 (73.0 %), and 32 patients (50.8 %) were diagnosed with bone metastasis at initial diagnoses of CRC. Thirty-one patients developed bone metastasis during the follow-up period with median 10.1-month interval. PET-CT was most frequently used for the diagnosis of bone metastasis (71.4 %), and the spine was the most commonly involved site (77.8 %). Most patients had multiple bone metastases (73.0 %) and other metastases (87.3 %). Bone pain was the most common skeletal-related event (25.4 %), and patients were treated with radiation (25.4 %), surgery (14.3 %), or bisphosphonate (6.3 %). The median survival time was 17.8 months, and the 5-year survival rate was 5.7 %. In the multivariate analysis, the risk factors for survival included initial bone metastasis (hazard ratio [HR] 3.03; P < 0.001) and bone metastasis from colon cancer (HR 1.87; P = 0.04).

CONCLUSION

Bone metastasis in patients with CRC is extremely rare and shows poor prognosis.

Oral Bisphosphonates and Improved Survival of Breast Cancer

Purpose: Bisphosphonates are used for treatment or prevention of osteoporosis and of bone metastases. The use of oral bisphosphonates was suggested to be associated with reduced risk of developing breast cancer, and their positive influence on breast cancer survival was only demonstrated with third-generation bisphosphonates. We studied the association of use of oral bisphosphonates after breast cancer diagnosis on overall and breast cancer survival.Experimental Design: A nested case-control analysis was performed using data from the population-based Breast Cancer in Northern Israel Study (BCINIS). Participants were postmenopausal women with newly diagnosed breast cancer insured by Clalit. Use of second-generation bisphosphonates (alendronate and/or risedronate) was identified using computerized prescription records. The analysis was restricted to women who did not use bisphosphonates prior to diagnosis.Results: In a cohort of 3,731 postmenopausal women with breast cancer, followed up for an average of 70 months, there were 799 cases of death which were matched to 15,915 control periods of living breast cancer cases. Use of bisphosphonates after diagnosis for at least 18 months was significantly more common among survivors than among their matched controls who died, adjusted for tumor stage/grade (overall survival: OR = 0.63, 0.41-0.96, P = 0.03; breast cancer-specific survival: OR = 0.28, 0.09-0.91, P = 0.035). A similar advantageous effect, but statistically underpowered, was found in estrogen receptor (ER)-positive, ER-negative, and HER2neu-positive tumors.Conclusions: The use of oral bisphosphonates, by postmenopausal, probably osteoporotic, women initiated after diagnosis of breast cancer was associated with a significant improvement in overall and breast-specific odds of survival. Clin Cancer Res; 23(7); 1684-9. ©2016 AACR.

Oral bisphosphonates and colon cancer: an update

Bisphosphonates (BPs) are widely used as the main treatment for osteoporosis. In vitro and animal studies suggest that use of BPs may have a potential for colorectal cancer (CRC) prevention. Safety and efficacy in terms of osteoporosis prevention have only been evaluated in randomized controlled trials (RCTs) of relatively short duration (3-5 years), with smaller extension studies. The evidence for a benefit beyond 5 years is limited and intake of BPs has not shown any relationship with CRC in intervention studies. Observational studies and meta-analysis have shown unchanged or decreased risk of CRC. BPs used for treatment and prevention of osteoporosis should not be applied for prevention of CRC in clinical practice.

Repurposing of bisphosphonates for the prevention and therapy of nonsmall cell lung and breast cancer

A variety of human cancers, including nonsmall cell lung (NSCLC), breast, and colon cancers, are driven by the human epidermal growth factor receptor (HER) family of receptor tyrosine kinases. Having shown that bisphosphonates, a class of drugs used widely for the therapy of osteoporosis and metastatic bone disease, reduce cancer cell viability by targeting HER1, we explored their potential utility in the prevention and therapy of HER-driven cancers. We show that bisphosphonates inhibit colony formation by HER1(ΔE746-A750)-driven HCC827 NSCLCs and HER1(wt)-expressing MB231 triple negative breast cancers, but not by HER(low)-SW620 colon cancers. In parallel, oral gavage with bisphosphonates of mice xenografted with HCC827 or MB231 cells led to a significant reduction in tumor volume in both treatment and prevention protocols. This result was not seen with mice harboring HER(low) SW620 xenografts. We next explored whether bisphosphonates can serve as adjunctive therapies to tyrosine kinase inhibitors (TKIs), namely gefitinib and erlotinib, and whether the drugs can target TKI-resistant NSCLCs. In silico docking, together with molecular dynamics and anisotropic network modeling, showed that bisphosphonates bind to TKIs within the HER1 kinase domain. As predicted from this combinatorial binding, bisphosphonates enhanced the effects of TKIs in reducing cell viability and driving tumor regression in mice. Impressively, the drugs also overcame erlotinib resistance acquired through the gatekeeper mutation T790M, thus offering an option for TKI-resistant NSCLCs. We suggest that bisphosphonates can potentially be repurposed for the prevention and adjunctive therapy of HER1-driven cancers.

Bisphosphonates inactivate human EGFRs to exert antitumor actions

Bisphosphonates are the most commonly prescribed medicines for osteoporosis and skeletal metastases. The drugs have also been shown to reduce cancer progression, but only in certain patient subgroups, suggesting that there is a molecular entity that mediates bisphosphonate action on tumor cells. Using connectivity mapping, we identified human epidermal growth factor receptors (human EGFR or HER) as a potential new molecular entity for bisphosphonate action. Protein thermal shift and cell-free kinase assays, together with computational modeling, demonstrated that N-containing bisphosphonates directly bind to the kinase domain of HER1/2 to cause a global reduction in downstream signaling. By doing so, the drugs kill lung, breast, and colon cancer cells that are driven by activating mutations or overexpression of HER1. Knocking down HER isoforms thus abrogates cell killing by bisphosphonates, establishing complete HER dependence and ruling out a significant role for other receptor tyrosine kinases or the enzyme farnesyl pyrophosphate synthase. Consistent with this finding, colon cancer cells expressing low levels of HER do not respond to bisphosphonates. The results suggest that bisphosphonates can potentially be repurposed for the prevention and therapy of HER family-driven cancers.

Primary prevention of colorectal cancer: Myth or reality?

Colorectal cancer incidence has been rising strongly in parallel with economic development. In the past few decades, much has been learned about the lifestyle, dietary and medication risk factors for this malignancy. With respect to lifestyle, compelling evidence indicates that prevention of weight gain and maintenance of a reasonable level of physical activity can positively influence in lowering the risk. Although there is controversy about the role of specific nutritional factors, consideration of dietary pattern as a whole appears useful for formulating recommendations. Though quite often recommended, the role for many supplements, including omega-3, vitamin D, folate, and vitamin B6, remains unsettled. Only calcium and vitamin D supplementation appear to add a modest benefit, particularly in those with a low daily intake. With regard to chemoprevention, medications such as aspirin and nonsteroidal anti-inflammatory drugs, and postmenopausal hormonal replacement for women might be associated with substantial reductions in colorectal cancer risk, though their utility is affected by their side effect profile. However, the role of agents such as statins, bisphosphonates and antioxidants have yet to be determined. Ultimately, primary prevention strategies focusing on modifying environmental, lifestyle risk factors, and chemopreventive drugs are options that have already been tested, and may impact on colon cancer incidence.

Long-term risks of bisphosphonate therapy

The objective this study was to summarize long-term risks associated with bisphosphonate therapy. Search of relevant medical publications for data from clinical trials, trial extensions, observational studies and post-marketing reports. Trial extensions and modifications did not reveal significant long-term safety issues. Observational data suggest at least as many benefits as risks. Post-marketing reports of musculoskeletal pain, osteonecrosis of the jaw and atypical femur fractures have been widely circulated in the lay press. Most focus on long-terms risks has been on osteonecrosis of the jaw and atypical femur fractures which occur in patients who have not received bisphosphonate therapy but may be more frequent (though still uncommon) in patients who have been on treatment for 5 years or longer. Lower-risk patients may be able to stop treatment after 3-5 years for a “drug holiday,” which mitigates these long-term risks; for higher risk patients, therapy through 6-10 years appears to be advisable and offers more benefits than risks.

Exposure to bisphosphonates and risk of colorectal cancer

Animal and in vitro studies suggest that the use of bisphosphonates (BPs) may be associated with reduced risk for colorectal cancer (CRC). However, results from these studies have been inconsistent. The aim of our study was to review and summarize the evidence provided by longitudinal studies on the association between BP use and CRC risk A comprehensive literature search for articles published up to October 2012 was performed. Prior to performing a meta-analysis, the studies were evaluated for publication bias and heterogeneity. Relative risks (RRs) or odds ratios were calculated. Six reports (four case-control studies and two cohort studies) published between 2010 and 2012 were identified. There was evidence of an association between any use of BPs and CRC risk using a fixed-effects model (RR = 0.80, 95% confidence interval = 0.74, 0.85) and a random-effects model (RR = 0.80, 95% confidence interval = 0.71, 0.90). However, we did not observe any evidence of a trend with increasing duration of use. Our findings indicate that there is evidence of an association between any use of BP and reduced CRC risk. However, this subject deserves further investigation.

Bisphosphonate use and risk of colorectal cancer: a systematic review and meta-analysis

AIM

A growing body of evidence suggests that bisphosphonates may have chemopreventive potential against colorectal cancer. Our aim was to examine this association through a meta-analysis of observational studies.

METHODS

A comprehensive search for relevant articles published up to October 2012 was performed, reviews of each study were conducted and data were abstracted. Prior to meta-analysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were calculated using the random effects and the fixed effects models. Subgroup and sensitivity analyses were also performed.

RESULTS

Eight large population-based epidemiological studies (one case-control, two nested case-control analyses within a cohort and five cohort studies), involving more than 630 000 participants, contributed to the analysis. We found no evidence of publication bias. However, significant heterogeneity was detected among the cohort studies. The analysis revealed a significant protective association between bisphosphonate use and colorectal cancer risk (fixed RR = 0.85, 95% CI 0.80, 0.90, random RR = 0.85, 95% CI 0.75, 0.96). When the analysis was stratified into subgroups according to study design, the association was inverse in both case-control and cohort studies, but only in the former was it statistically significant. The sensitivity analysis confirmed the stability of our results. Furthermore, we found evidence for a dose effect; Long term bisphosphonate use was associated with a 27% decrease in the risk of developing colorectal cancer as compared with non-use (RR = 0.73, 95% CI 0.57, 0.93).

CONCLUSION

Our findings support a protective effect of bisphosphonates against colorectal cancer. However, further evidence is warranted.

The effect of bisphosphonates on the risk of endometrial and ovarian malignancies

OBJECTIVE

The use of bisphosphonates has been associated with reduced risk and improved survival of breast and colorectal malignancies. This study was aimed at studying the effects of bisphosphonates on gynecological cancers.

METHODS

The Cancer in the Ovary and Uterus Study (CITOUS) is a case-control study of newly diagnosed cases of gynecological malignancies and age/clinic/ethnic-group matched population controls. The use of bisphosphonates prior to, and following, diagnosis was assessed in 424 cases of ovarian and endometrial cancers and 341 controls, all postmenopausal at recruitment, enrolled in Clalit Health Services (CHS), using pharmacy records.

RESULTS

The use of bisphosphonates for more than 1 year prior to diagnosis was associated with a significantly reduced risk of ovarian cancer (OR=0.49, 95% CI: 0.26-0.93) and endometrial cancer (OR=0.39, 95% CI: 0.24-0.63). The association with endometrial cancer (OR=0.48, 0.27-0.84) remained statistically significant after adjustment for a variety of putative effect modifiers (RR=0.48, 0.26-0.89). The association with ovarian cancer remained significant when adjusted to statin use (0.46, 0.23-0.90) but not for other modifiers (0.58, 0.29-1.18). A strong negative association was found in an adjusted model for the use of either bisphosphonates or statins for more than 1 year (0.40, 0.23-0.68).

CONCLUSION

The use of bisphosphonates, with or without statins, for more than 1 year before diagnosis was associated with reduced risk of endometrial and ovarian cancers.

Beyond aspirin-cancer prevention with statins, metformin and bisphosphonates

Cancer risk reduction using pharmacological means is an attractive modern preventive approach that supplements the classical behavioural prevention recommendations. Medications that are commonly used by large populations to treat a variety of common, non-cancer-related, medical situations are an attractive candidate pool. This Review discusses three pharmacological agents with the most evidence for their potential as cancer chemopreventive agents: anti-hypercholesterolaemia medications (statins), an antidiabetic agent (metformin) and antiosteoporosis drugs (bisphosphonates). Data are accumulating to support a significant negative association of certain statins with cancer occurrence or survival in several major tumour sites (mostly gastrointestinal tumours and breast cancer), with an augmented combined effect with aspirin or other non-steroidal anti-inflammatory drugs. Metformin, but not other hypoglycaemic drugs, also seems to have some antitumour growth activity, but the amount of evidence in human studies, mainly in breast cancer, is still limited. Experimental and observational data have identified bisphosphonates as a pharmacological group that could have significant impact on incidence and mortality of more than one subsite of malignancy. At the current level of evidence these potential chemopreventive drugs should be considered in high-risk situations or using the personalized approach of maximizing individual benefits and minimizing the potential for adverse effects with the aid of pharmacogenetic indicators.

Acute phase response after zoledronic acid is associated with long-term effects on white blood cells

We have recently reported a long-lasting decrease in circulating γδ T cells in osteoporotic patients on oral amino-bisphosphonates (N-BPs). Here we verify whether these changes are associated with the occurrence of acute phase response (APR) to intravenous (IV) zoledronic acid (ZOL) or changes of other circulating white blood cells (WBC). WBC count was obtained before and 1 year after a single IV administration of 5 mg ZOL in 36 osteoporotic patients (mean age 72 ± 9, range 45-86 years) without other relevant diseases; 12 of 36 patients developed the classical APR. After 1 year in the patients who experienced an APR, but not in the others, a significant decrease not only of γδ T cells (-30 %), but also of total lymphocytes (-11 %) and eosinophils (-27 %), was observed. The mechanism leading to the observed decrease of circulating lymphocytes and eosinophils remains unclear, but our observation opens a new frontier for the understanding of the immunoeffects of N-BPs.

Oral bisphosphonate use and colorectal cancer incidence in the Women's Health Initiative

Bisphosphonates are widely prescribed to increase bone density in postmenopausal women with osteopenia or osteoporosis. Aminobisphosphonates have numerous anticancer properties and reduce bone metastases in cancer patients. Several studies, including the Women's Health Initiative (WHI), have found that use of oral bisphosphonates is associated with reduced risk of developing breast cancer, but less is known about associations with other common malignancies in women such as colorectal cancer (CRC). A few case-control and retrospective cohort studies have reported decreased risk of CRC among bisphosphonate users. In contrast, a prospective cohort study found no association. We evaluated the association between oral bisphosphonate use and CRC incidence in 156,826 postmenopausal women, ages 50 to 79 years, who participated in WHI clinical trials and observational study. A detailed health interview was conducted at baseline, and bisphosphonate use was ascertained from an inventory of regularly used medications at baseline and over follow-up. A total of 1931 women were diagnosed with incident invasive CRC during a median follow-up of 12 years. Alendronate was the most commonly used bisphosphonate, accounting for >90% of the total person-years of use. The association between oral bisphosphonate use and CRC risk did not reach statistical significance (hazard ratio [HR] from multivariable-adjusted models = 0.88; 95% confidence interval [CI] 0.72-1.07; p = 0.19). Furthermore, we did not observe greater risk reductions for women with longer duration of use. Uncontrolled confounding may explain why previous studies have observed an association.

The invisible arm of immunity in common cancer chemoprevention agents

Immunoprevention refers to a strategy of preventing pathogen-associated and spontaneous cancers through the use of vaccines, antibodies, and immune modulators. Immune modulators function by enhancing the endogenous ability of the immune system to monitor for malignancy, so-called "immunosurveillance." There is growing evidence that many of the most promising cancer chemoprevention agents including aspirin, COX-2 inhibitors, aromatase inhibitors, and bisphosphonates mediate their effects, in part, by enhancing immunosurveillance and reversing the immune evasive mechanisms that premalignant lesions use. In the following review, we introduce critical components of the human immune surveillance system-dendritic cells, T cells, and immune suppressive cells-and discuss the emerging data suggesting that common chemoprevention agents may modulate the function of these immunologic cells.

Bisphosphonates are associated with reduced risk of colorectal cancer: a systematic review and meta-analysis

BACKGROUND & AIMS

Colorectal cancer (CRC) is the third most common cancer worldwide. Several preclinical and observational studies have shown that bisphosphonates may have chemopreventive effects against CRC. We performed a systematic review and meta-analysis of all studies evaluating the effect of bisphosphonates on the risk of CRC.

METHODS

We conducted a systematic search of Medline, Embase, and Web of Science through August 2012 and manually reviewed the literature. Studies were included if they met the following criteria: (1) evaluated and clearly defined exposure to bisphosphonates, (2) reported CRC outcomes, and (3) reported relative risks or odds ratio (OR) or provided sufficient data for their estimation. Summary OR estimates with 95% confidence intervals (CIs) were estimated using the random-effects model. Statistical heterogeneity was assessed with the Cochran's Q and I(2) statistic.

RESULTS

We analyzed data from 6 population-based observational studies reporting 20,001 cases of CRC in 392,106 patients. A meta-analysis of these studies showed a statistically significant 17% reduction in CRC incidence with bisphosphonate use (unadjusted OR, 0.83; 95% CI, 0.76-0.90), with borderline heterogeneity across studies (Cochran's Q, P = .16; I(2) = 37%). This effect persisted after correcting for multiple covariates in individual studies (adjusted OR, 0.85; 95% CI, 0.74-0.98). When the analysis was restricted to women only, use of bisphosphonates was associated with a 16% reduction in CRC incidence, which bordered on statistical significance (n = 5 studies; adjusted OR, 0.84; 95% CI, 0.70-1.01). This chemopreventive effect of bisphosphonates was observed for proximal and distal colon cancers, as well as rectal cancer, independently.

CONCLUSIONS

Based on meta-analysis, bisphosphonate use is associated with a modest, but statistically significant, reduction in CRC risk.

Exposure to bisphosphonates and risk of gastrointestinal cancers: series of nested case-control studies with QResearch and CPRD data

OBJECTIVE

To investigate the association between use of bisphosphonates estimated from prescription information and risk of gastrointestinal cancers.

DESIGN

Series of nested case-control studies.

SETTING

General practices in the United Kingdom contributing to the QResearch primary care database (660) and the Clinical Practice Research Datalink (CPRD) (643).

PARTICIPANTS

Patients aged ≥ 50 with a diagnosis of a primary gastrointestinal cancer in 1997-2011, each matched with up to five controls by age, sex, practice, and calendar year.

MAIN OUTCOME MEASURES

Odds ratios for incident gastrointestinal cancers (colorectal, oesophageal, gastric) and use of bisphosphonates, adjusted for smoking status, ethnicity, comorbidities, and use of other drugs.

RESULTS

20,106 and 19,035 cases of colorectal cancer cases, 5364 and 5135 cases of oesophageal cancer cases, and 3155 and 3157 cases of gastric cancer were identified from QResearch and CPRD, respectively. Overall bisphosphonate use (at least one prescription) was not associated with risk of colorectal, oesophageal, or gastric cancers in either database. Adjusted odds ratios (95% confidence interval) for QResearch and CPRD were 0.97 (0.79 to 1.18) and 1.18 (0.97 to 1.43) for oesophageal cancer; 1.12 (0.87 to 1.44) and 0.79 (0.62 to 1.01) for gastric cancer; and 1.03 (0.94 to 1.14) and 1.10 (1.00 to 1.22) for colorectal cancer. Additional analyses showed no difference between types of bisphosphonate for risk of oesophageal and colorectal cancers. For gastric cancer, alendronate use was associated with an increased risk (1.47, 1.11 to 1.95; P=0.008), but only in data from the QResearch database and without any association with duration and with no definitive confirmation from sensitivity analysis.

CONCLUSIONS

In this series of population based case-control studies in two large primary care databases, exposure to bisphosphonates was not associated with an increased risk of common gastrointestinal cancers.

Reduced risk of colorectal cancer with use of oral bisphosphonates: a systematic review and meta-analysis

PURPOSE

The association between oral bisphosphonate (BP) intake and colorectal cancer (CRC) risk has been investigated in several recent studies with conflicting results. We summarized the evidence from the published studies in a categorical, dose-response meta-analysis.

METHODS

Relevant studies were identified by a search of MEDLINE and EMBASE databases through January 15, 2012. We included studies that reported effect size estimates with 95% CIs for the association between exposure to oral BPs and risk of CRC.

RESULTS

Three case-control studies with a total of 16,998 CRC cases and 108,197 controls and one cohort study with 94,405 individuals exposed to BPs and 283,181 unexposed to BPs were included in meta-analysis. The random effect model meta-analysis suggested reduced risk of CRC with exposure to oral BPs with pooled odds ratio (OR) of 0.87 (95% CI, 0.78 to 0.97). Significant inverse relationship was noted for 10 or more prescriptions categories, with pooled ORs of 0.71 (95% CI, 0.58 to 0.87). Similarly, the analysis for 1 to 3 years of use and more than 3 years of use of BPs suggested a significant inverse relationship, with pooled ORs of 0.76 (95% CI, 0.68 to 0.85) and 0.78 (95% CI, 0.61 to 0.99), respectively.

CONCLUSION

This meta-analysis suggests that the use of oral BPs at a dose of 10 or more prescriptions or 1 or more years of duration is associated with reduced risk of CRC. Further randomized controlled trials are needed to prove this association.

Long-term effects of amino-bisphosphonates on circulating γδ T cells

The aim of this study was to explore whether desensitization to the occurrence of the acute-phase response (APR) in patients previously treated with amino-bisphosphonates (N-BPs) is due to a long-lasting reduction in the number of circulating γδ T cells. Circulating lymphocyte subpopulation counts were obtained from 63 patients with postmenopausal or senile osteoporosis at baseline and after 2 days and 12 months of the first intravenous (IV) 5 mg zoledronic acid (ZOL) infusion. At baseline both the proportion and absolute number of circulating γδ T cells were significantly higher in patients who had never used N-BPs vs. previous users, either oral or IV. A typical APR was observed in none of the patients given IV ZOL a year earlier, in 6 (22 %) of the patients previously treated with oral N-BPs, and in 13 (57 %) of the patients naive to any N-BP treatment. In patients naive to N-BPs, a significant reduction in both total lymphocytes and their subsets was observed 2 days after ZOL infusion; all these changes returned to baseline values 1 year later with the exception of γδ T cells, which remained significantly lower in terms of both proportion and absolute number. These results indicate for the first time that both IV and oral N-BP treatments are associated with a long-lasting decrease in circulating γδ T cells, and this may explain the lower incidence of APR in patients previously exposed to N-BPs. Other clinical implications of this sustained effect of N-BPs on immune-regulatory cells might be important.

Reduced colon cancer incidence and mortality in postmenopausal women treated with an oral bisphosphonate--Danish National Register Based Cohort Study

In this Danish national register-based cohort study, we examined the effects of alendronate on the development of colon cancers and survival. The incidence of colon cancer and mortality rate, once colon cancer had been diagnosed, were lower in patients treated with alendronate, posing the question whether alendronate acts as chemopreventive.

INTRODUCTION

When bisphosphonates are given by mouth, around 99% remains non-absorbed in the intestine. Based on their biochemical actions, we predicted that oral bisphosphonates might prevent colon cancers.

METHODS

This is a Danish national register-based cohort study. We identified 30,606 women aged 50+, mean age 71.9 years, who had not previously taken treatments for osteoporosis, who began to take alendronate in 1996-2005, and assigned 124,424 individually age- and gender-matched control subjects. The main outcome measure was colorectal cancers incidence and post-diagnosis survival in patients taking oral alendronate for osteoporosis.

RESULTS

Cox proportional hazards analysis of death due to colon cancer showed lower risk in alendronate users, crude hazard ratio (HR) 0.69 (95% CI 0.59-0.81) with an adjusted HR of 0.62 (95% CI 0.52-0.72). The reduction in risk comprised both a lower incidence of colon cancer-adjusted HR 0.69 (95% CI 0.60-0.79) and a lower mortality once colon cancer had been diagnosed, adjusted HR 0.82 (95% CI 0.70-0.97). Weekly alendronate was associated with a greater risk reduction than daily alendronate. The main findings were unaffected by excluding patients from the analysis who had pulmonary disease, a major co-morbid condition in users of alendronate and an important cause of death.

CONCLUSIONS

The risk of overall deaths from cancer and in particular death caused by colon cancer was significantly and substantially decreased (40%) in patients treated with alendronate, with survival curves deviating progressively after 2 years. Also, the incidence of colon cancer was lower in those patients.

Bisphosphonate use and gastrointestinal tract cancer risk: Meta-analysis of observational studies

AIM: To perform a meta-analysis of observational studies to further elucidate the relationship between oral bisphosphonate use and gastrointestinal cancer risk.

METHODS: Systematic literature search was conducted in MEDLINE, EMBASE, and the Cochrane Library to identify studies through January 2011. Search terms were “bisphosphonates” or trade names of the drugs, and “observational studies” or “cohort studies” or “case-control studies”. Two evaluators reviewed and selected articles on the basis of predetermined selection criteria as followed: (1) observational studies (case-control or cohort studies) on bisphosphonate use; (2) with at least 2 years of follow-up; and (3) reported data on the incidence of cancer diagnosis. The DerSimonian and Laird random effects model were used to calculate the pooled relative risk (RR) with 95% confidence interval (CI). Two-by-two contingency table was used to calculate the outcomes not suitable for meta-analysis. Subgroup meta-analyses were conducted for the type of cancer (esophageal, gastric and colorectal cancers). Sensitivity analyses were performed to examine the effect sizes when only studies with long-term follow-up (mean 5 years; subgroup 3 years) were included.

RESULTS: Of 740 screened articles, 3 cohort studies and 3 case-control studies were included in the analyses. At first, 4 cohort studies and 3 case-control studies were selected for the analyses but one cohort study was excluded because the cancer outcomes were not categorized by type of gastrointestinal cancer. More than 124 686 subjects participated in the 3 cohort studies. The mean follow-up time in all of the cohort studies combined was approximately 3.88 years. The 3 case-control studies reported 3070 esophageal cancer cases and 15 417 controls, 2018 gastric cancer cases and 10 007 controls, and 11 574 colorectal cancer cases and 53 955 controls. The percentage of study participants who used bisphosphonate was 2.8% among the cases and 2.9% among the controls. The meta-analysis of all the studies found no significant association between bisphosphonate use and gastrointestinal cancer. Also no statistically significant association was found in a meta-analysis of long-term follow-up studies. There was no negative association between bisphosphonate use and the incidence of esophageal cancer in the overall analysis (RR 0.96, 95% CI: 0.65-1.42, I² = 52.8%, P = 0.076) and no statistically significant association with long-term follow-up (RR 1.74, 95% CI: 0.97-3.10, I² = 58.8%, P = 0.119). No negative association was found in the studies reporting the risk of gastric cancer (RR 0.89, 95% CI: 0.71-1.13, I² = 0.0%, P = 0.472). In case of colorectal cancer, there was no association between colorectal cancer and bisphosphonate use (RR 0.62, 95% CI: 0.30-1.29, I² = 88.0%, P = 0.004) and also in the analysis with long-term follow-up (RR 0.61, 95% CI: 0.28-1.35, I² = 84.6%, P = 0.011).

CONCLUSION: Oral bisphosphonate use had no significant effect on gastrointestinal cancer risk. However, this finding should be validated in randomized controlled trials with long-term follow-up.