Does warfarin therapy influence the risk of bladder cancer?

The impact of warfarin on overall survival in cancer patients

Venous thromboembolism (VTE) is a common complication in patients with cancer. Warfarin has largely been replaced by low-molecular-weight heparin (LMWHs) and direct oral anticoagulants (DOACs) as the standard of care in cancer-associated VTE. The survival benefit of these anticoagulants over warfarin in the cancer population was not demonstrated in clinical trials, possibly due to insufficient sample size and limited follow-up duration. There are emerging population-based studies suggesting that warfarin may be associated with improved overall survival in cancers and may have a protective effect against certain types of cancers. Warfarin may exert its anti-neoplastic properties through both coagulation pathway -dependent and -independent mechanisms, the latter of which are mediated by inhibition of the Gas6-AXL signaling pathway. Further research should emphasize on identifying clinical and laboratory predictors of beneficial effects of warfarin. In this review article, we summarize and update the current evidence regarding the potential impact of warfarin on the overall survival of cancer patients and incidence of cancer, as well as review the potential mechanism of such effect and future perspectives.

Retrospective evaluation of the impact of non-oncologic chronic drug therapy on the survival in patients with bladder cancer

Background Chronic drug therapy may impact recurrence and survival of patients with bladder cancer and thus be of concern regarding drug choice and treatment decisions. Currently, data are conflicting for some drug classes and missing for others. Objective To analyze the impact of common non-oncologic chronic drug intake on survival in patients with bladder cancer and radical cystectomy. Setting. Patients with bladder cancer and radical cystectomy (2004–2018) at the University Hospital Munich. Method Data from an established internal database with patients with bladder cancer and radical cystectomy were included in a retrospective study. Drug therapy at the time of radical cystectomy and survival data were assessed and follow-up performed 3 months after radical cystectomy and yearly until death or present. Impact on survival was analyzed for antihypertensive, antidiabetic, anti-gout, antithrombotic drugs and statins, using the Kaplan–Meier method, log-rank test and Cox-regression models. Main outcome measure Recurrence free survival, cancer specific survival and overall survival for users versus non-users of predefined drug classes. Results Medication and survival data were available in 972 patients. Median follow-up time was 22 months (IQR 7–61). In the univariate analysis, a significant negative impact among users on recurrence free survival (n = 93; p = 0.038), cancer specific survival (n = 116; p < 0.001) and overall survival (n = 116; p < 0.001) was found for calcium-channel blockers, whereas angiotensin-receptor-blockers negatively influenced overall survival (n = 96; p = 0.020), but not recurrence free survival (n = 73; p = 0.696) and cancer specific survival (n = 96; p = 0.406). No effect of angiotensin-receptor-blockers and calcium-channel blockers was seen in the multivariate analysis. None of the other studied drugs had an impact on survival. Conclusion There was no impact on bladder cancer recurrence and survival for any of the analyzed drugs. Considering our results and the controverse findings in the literature, there is currently no evidence to withhold indicated drugs or choose specific drug classes among the evaluated non-oncologic chronic drug therapies. Thus, prospective studies are required for further insight. Trail registration This is part of the trial DRKS00017080, registered 11.10.2019.

Association of Vitamin K and Non-Vitamin K Oral Anticoagulant Use and Cancer Incidence in Atrial Fibrillation Patients

The association between the use of vitamin K antagonists (VKAs) and cancer risk reduction remains unclear. We aimed to assess the association between the use of VKAs or direct oral anticoagulants (DOACs) and the incidence of cancer in a large cohort of patients with atrial fibrillation (AF) by means of a population‐based, propensity‐weighted cohort study using population‐wide databases including patients diagnosed with nonvalvular AF (NVAF) followed for up of 5 years (median 2.94 years). We created two cohorts based on the initiation therapy (VKA or DOAC). Initiation with VKA or DOAC was defined as filling a prescription with no previous exposure in the preceding 12 months. Cancer diagnoses of any type and for specific tumors (lung, colon, prostate, bladder, and breast). We included 39,989 patients, 31,200 (78.0%) in the VKA cohort. Incidence rate for any cancer was 12.45 per 1,000 person‐year in the DOAC cohort vs. 14.55 in the VKA cohort (adjusted hazard ratio (HR): 1.16, 95% confidence interval (CI): 1.02–1.32). In secondary outcomes, no differences were found for specific types of cancer, such as lung (HR: 1.28, CI: 0.89–1.83), colon (HR: 0.84, CI: 0.62–1.13), prostate (HR: 1.40, CI: 0.94–2.10), bladder (HR: 1.07, CI: 0.76–1.52), and breast (HR: 1.05, CI: 0.66–1.69). Sensitivity analyses yielded similar results. Subgroup analyses also produced consistent findings, except for men, for whom VKA was associated with a lower risk of colon cancer (HR: 0.68, 95% CI: 0.48–0.96). Our results do not confirm a chemoprotective effect of VKA when compared with DOAC in a large, real‐world cohort of patients with NVAF followed for up to 5 years.

The Association between Oral Anticoagulants and Cancer Incidence among Individuals with Nonvalvular Atrial Fibrillation

Objective Existing evidence on the association between vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs) and cancer is limited and contradictory. No observational studies have been conducted to simultaneously address the cancer safety of VKAs and DOACs. The objective of this study was to determine whether use of VKAs and DOACs, separately, when compared with nonuse, is associated with cancer overall and prespecified site-specific incidence.

Methods Using the United Kingdom Clinical Practice Research Datalink, we identified patients newly diagnosed with nonvalvular atrial fibrillation (NVAF) between 2011 and 2017. Using a time-varying exposure definition, each person-day of follow-up was classified as use of (1) VKAs, (2) DOACs, (3) VKAs and DOACs (drug switchers), and (4) nonuse of anticoagulants (reference). We also conducted a head-to-head comparison of new users of DOACs versus VKAs using propensity score fine stratification weighting. Hazard ratios (HRs) with 95% confidence intervals (CIs) for cancer overall and prespecified subtypes were estimated using Cox proportional hazards models.

Results Compared with nonuse, use of VKAs was not associated with cancer overall (HR: 1.05, 95% CI: 0.91–1.22) or cancer subtypes. Similarly, use of DOACs was not associated with cancer overall (HR: 1.13, 95% CI: 0.93–1.37), but an association was observed for colorectal cancer (HR: 1.73, 95% CI: 1.01–2.99), and pancreatic cancer generated an elevated, though nonsignificant HR (HR: 2.15, 95% CI: 0.72–6.44). Results were consistent in the head-to-head comparison.

Conclusion Use of oral anticoagulants is not associated with the incidence of cancer overall among patients with NVAF. Possible associations between DOACs and colorectal and pancreatic cancer warrant further study.

Mechanistic Investigation of the Androgen Receptor DNA-Binding Domain Inhibitor Pyrvinium

Pyrvinium was identified as the first small molecule inhibitor of the androgen receptor (AR) DNA-binding domain (DBD). It was also among the first small molecules shown to directly inhibit the activity of AR splice variants (ARVs), which has important clinical implications in the treatment of castration-resistant prostate cancer. Important questions about pyrvinium's mechanism of action remain. Here, we demonstrate through mutational analysis that amino acids 609 and 612 are important for pyrvinium action. Nuclear magnetic resonance demonstrates a specific interaction between a soluble pyrvinium derivative and the AR DBD homodimer-DNA complex. Chromatin immunoprecipitation and electrophoretic mobility shift assay experiments demonstrate that, despite an interaction with this complex, pyrvinium does not alter the DNA-binding kinetics in either assay. AR immunoprecipitation followed by mass spectrometry was used to identify proteins whose interaction with AR is altered by pyrvinium. Several splicing factors, including DDX17, had reduced interactions with AR in the presence of pyrvinium. RNA sequencing of prostate cancer cells treated with pyrvinium demonstrated changes in splicing, as well as in several other pathways. However, pyrvinium did not alter the levels of ARVs in several prostate cancer cell lines. Taken together, our new data pinpoint the direct interaction between pyrvinium and AR DBD and shed light on the mechanism by which it inhibits AR transcriptional activity.

Effects of warfarin on biological processes other than haemostasis: A review

Warfarin is the world's most widely used anticoagulant drug. Its anticoagulant activity is based on the inhibition of the vitamin K-dependent (VKD) step in the complete synthesis of a number of blood coagulation factors that are required for normal blood coagulation. Warfarin also affects synthesis of VKD proteins not related to haemostasis including those involved in bone growth and vascular calcification. Antithrombotic activity of warfarin is considered responsible for some aspects of its anti-tumour activity of warfarin. Some aspects of activities against tumours seem not to be related to haemostasis and included effects of warfarin on non-haemostatic VKD proteins as well as those not related to VKD proteins. Inflammatory/immunomodulatory effects of warfarin indicate much broader potential of action of this drug both in physiological and pathological processes. This review provides an overview of the published data dealing with the effects of warfarin on biological processes other than haemostasis.

Association of Warfarin Use With Lower Overall Cancer Incidence Among Patients Older Than 50 Years

IMPORTANCE

In cancer models, warfarin inhibits AXL receptor tyrosine kinase-dependent tumorigenesis and enhances antitumor immune responses at doses not reaching anticoagulation levels. This study investigates the association between warfarin use and cancer incidence in a large, unselected population-based cohort.

OBJECTIVE

To examine the association between warfarin use and cancer incidence.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study with subgroup analysis used the Norwegian National Registry coupled with the Norwegian Prescription Database and the Cancer Registry of Norway. The cohort comprised all persons (N = 1 256 725) born between January 1, 1924, and December 31, 1954, who were residing in Norway from January 1, 2006, through December 31, 2012. The cohort was divided into 2 groups-warfarin users and nonusers; persons taking warfarin for atrial fibrillation or atrial flutter were the subgroup. Data were collected from January 1, 2004, to December 31, 2012. Data analysis was conducted from October 15, 2016, to January 31, 2017.

EXPOSURES

Warfarin use was defined as taking at least 6 months of a prescription and at least 2 years from first prescription to any cancer diagnosis. If warfarin treatment started after January 1, 2006, each person contributed person-time in the nonuser group until the warfarin user criteria were fulfilled.

MAIN OUTCOMES AND MEASURES

Cancer diagnosis of any type during the 7-year observation period (January 1, 2006, through December 31, 2012).

RESULTS

Of the 1 256 725 persons in the cohort, 607 350 (48.3%) were male, 649 375 (51.7%) were female, 132 687 (10.6%) had cancer, 92 942 (7.4%) were classified as warfarin users, and 1 163 783 (92.6%) were classified as nonusers. Warfarin users were older, with a mean (SD) age of 70.2 (8.2) years, and were predominantly men (57 370 [61.7%]) as compared with nonusers, who had a mean (SD) age of 63.9 (8.6) years and were mostly women (613 803 [52.7%]). Among warfarin users and compared with nonusers, there was a significantly lower age- and sex-adjusted incidence rate ratio (IRR) in all cancer sites (IRR, 0.84; 95% CI, 0.82-0.86) and in prevalent organ-specific sites (lung, 0.80 [95% CI, 0.75-0.86]; prostate, 0.69 [95% CI, 0.65-0.72]; and breast, 0.90 [95% CI, 0.82-1.00]). There was no observed significant effect in colon cancer (IRR, 0.99; 95% CI, 0.93-1.06). In a subgroup analysis of patients with atrial fibrillation or atrial flutter, the IRR was lower in all cancer sites (IRR, 0.62; 95% CI, 0.59-0.65) and in prevalent sites (lung, 0.39 [95% CI, 0.33-0.46]; prostate, 0.60 [95% CI, 0.55-0.66]; breast, 0.72 [95% CI, 0.59-0.87]; and colon, 0.71 [95% CI, 0.63-0.81]).

CONCLUSIONS AND RELEVANCE

Warfarin use may have broad anticancer potential in a large, population-based cohort of persons older than 50 years. This finding could have important implications for the selection of medications for patients needing anticoagulation.

Risk of cancer after anticoagulation in patients with unprovoked venous thromboembolism: an observational cohort study

Essentials Data on long-term cancer risk are controversial in patients with venous thromboembolism (VTE). We assessed long-term rates and risk factors of cancer in patients with VTE. Cancer risk after anticoagulation is not higher in VTE patients than in the general population. VTE recurrence is not predictive of a future cancer diagnosis.

SUMMARY

Background Patients with venous thromboembolism (VTE) are at risk of having a subsequent cancer diagnosis. The risk is highest during the first 6 months. Reports on cancer rates thereafter are controversial. We aimed to assess long-term rates and risk factors of cancer in patients with VTE. Methods and Results We followed patients with a first unprovoked VTE after discontinuation of anticoagulation, and excluded those receiving long-term antithrombotic therapy or with major thrombophilia. The study endpoint was the occurrence of cancer. Sixty-two (5.2%) of 1188 patients developed cancer during a median follow-up of 98 months. The cumulative incidence rates of cancer were 0.7% (95% confidence interval [CI] 0.2-1.2%), 3.1% (95% CI 2.0-4.1%) and 9% (95% CI 6.5-11.5) after 1, 5 and 15 years; these were not significantly different from those in the matched general population (0.6%, 3.4%, and 12.2%, respectively). The corresponding standardized incidence ratios (ratio of the observed cancer cases and the number of cases based on national cancer incidence rates) of 1.1 (95% CI 0.5-2.5), 1.0 (95% CI 0.6-1.4) and 0.9 (95% CI 0.7-1.2) did not indicate a difference in cancer incidence between our cohort and the general population. Advancing age (hazard ratio [HR] per decade 1.5, 95% CI 1.2-2.0) and shorter duration of anticoagulation (HR per 1-month decrease 1.3, 95% CI 1.1-1.6) were associated with an increased cancer risk, whereas VTE recurrence was not (HR 1.17, 95% CI 0.66-2.07). Conclusions Asymptomatic patients with unprovoked VTE who have completed anticoagulation therapy do not have a higher cancer risk. The inverse association between the duration of anticoagulation and the incidence of cancer warrants further investigation.

Vitamin K and its analogs: Potential avenues for prostate cancer management

Epidemiological studies have demonstrated a relationship between cancer incidence and dietary habits. Especially intake of certain essential nutrients like vitamins has been shown to be beneficial in experimental studies and some clinical trials. Vitamin K (VK) is an essential nutrient involved in the blood clotting cascade, and there are considerable experimental data demonstrating its potential anticancer activity in several cancer types including prostate cancer. Previous in vitro and in vivo studies have focused mainly on anti-oxidative effects as the underlying anticancer mechanism of VK. However, recent studies reveal that VK inhibits the growth of cancer cells through other mechanisms, including apoptosis, cell cycle arrest, autophagy, and modulation of various transcription factors such as Myc and Fos. In the present review, we focus on the anticancer effect of dietary VK and its analogs on prostate cancer, with an emphasis on the signaling pathways that are activated following exposure to these compounds. This review also highlights the potential of VK and its derivatives as an adjuvant treatment in combination with other vitamins or with chemotherapeutic drugs. Based on our recent results and a review of the existing literature, we present evidence that VK and its derivatives can potentially be explored as cancer therapy, especially for prostate cancer.

Clinical Significance of Hematuria in Atrial Fibrillation With Oral Anticoagulation Therapy

BACKGROUND

Hematuria is a common and important complication in atrial fibrillation (AF) patients on oral anticoagulation therapy (OAT). This study evaluated the clinical significance of hematuria and its relationship with genitourinary disease in AF patients receiving OAT.Methods and Results:Among 20,456 consecutive AF patients who visited a tertiary hospital from January 2005 to April 2015, 5,833 had hematuria. Of these 5,833 patients, 3,798 were on OAT (OAT(+) group) and 2,035 were not (OAT(-) group). A total of 1,785 patients from each group were then matched on propensity score analysis. The prevalence of cancer and other diseases in the genitourinary tract was evaluated. While there was no difference in the prevalence of genitourinary stones or urinary tract infection, genitourinary cancer was significantly more common in the OAT(+) group than in the OAT(-) group (1.6% vs. 0.7%, P=0.011). Bladder cancer was the most common genitourinary malignancy, and it was significantly more common in the OAT(+) group (1.2% vs. 0.5%, P=0.019). Subjects on warfarin were more likely to have bladder cancers of lower pathologic grade (63.6% vs. 33.3%, P=0.124).

CONCLUSIONS

OAT was associated with a higher prevalence and early detection of genitourinary cancer in AF patients with hematuria. Meticulous evaluation of the cause of hematuria is necessary in AF patients with hematuria receiving OAT.

Cancer risk in long-term users of vitamin K antagonists: a population-based case-control study

Some evidence suggests that long-term use of vitamin K antagonists (VKAs) has a cancer chemopreventive effect. Such an effect would have considerable implications in terms of understanding tumor biology. To evaluate if long-term VKA treatment influences the risk of developing cancer, we performed a matched case-control analysis. We used data from four Danish nationwide registers. Cases were all Danish individuals with a first-time cancer diagnosis (except nonmelanoma skin cancer) between 2000 and 2009. For each case, eight controls, matched by birth year and gender, were selected from the source population by risk-set sampling. Long-term VKA use was defined as exposure to VKA for a period of 3 or more years. Conditional logistic regression was used to compute odds ratios (ORs) for cancer associated with long-term VKA exposure, adjusting for potential confounders. Prespecified subanalyses were performed for selected cancer sites, subgroups and measures of exposure. A total of 238,196 cases and 1,713,176 controls were included. The adjusted OR for cancer associated with long-term VKA exposure was 0.99 (95% CI: 0.95-1.02). Long-term VKA use was associated with increased ORs for alcohol- or obesity-related cancer sites, whereas we observed a decreased risk of prostate cancer (OR: 0.86; 95% CI: 0.78-0.95). Our study does not support a general chemopreventive effect of VKA drugs. However, in accordance with findings from previous studies, we found an inverse association between use of VKA and prostate cancer.

The association between vitamin K antagonist therapy and site-specific cancer incidence estimated by using heart valve replacement as an instrumental variable

Earlier studies suggest a protective association between vitamin K antagonist (VKA) anticoagulants and the incidence of cancer. The authors examined the associations between VKA therapy and incidence of 24 site-specific cancers with a Danish population-based cohort study, using heart valve replacement as an instrumental variable. The authors enrolled 9,727 Danish residents who received a replacement heart valve between 1989 and 2006. The heart valve recipients were matched with 95,481 unexposed individuals on age and sex. The authors used the heart valve replacement instrument to estimate rate ratios associating VKA therapy with incidence of the 24 site-specific cancers using Poisson regression models. Direct associations between VKA therapy and incidence of the 24 cancers were estimated in a prescription validation subset. The instrumental variable associations were plotted according to the inverse normal of rank percentile and subjected to semi-Bayes shrinkage adjustment for multiple comparisons. The pattern of associations was consistent with a null-centered Gaussian distribution. No individual cancer site showed a substantial positive or negative association with VKA therapy in the prescription validation subset, the instrumental variable analysis, or the analysis with semi-Bayes adjustment. These results do not support the existing hypothesis that VKA therapy is associated with reduced cancer risk.

Long-term use of vitamin K antagonists and incidence of cancer: a population-based study

Whether long-term use of vitamin K antagonists (VKAs) might affect the incidence of cancer is a longstanding hypothesis. We conducted a population-based study including all cancer- and thromboembolism-free patients of our health area; study groups were defined according to chronic anticoagulant use to VKA-exposed and control groups. Cancer incidence and cancer-related and overall mortality was assessed in both groups. 76 008 patients (3231 VKA-exposed and 72 777 control subjects) were followed-up for 8.2 (± 3.2) years. After adjusting for age, sex, and time-to-event, the hazard ratio of newly diagnosed cancer in the exposed group was 0.88 (95% confidence interval [95% CI] 0.80-0.98; P < .015). VKA-exposed patients were less likely to develop prostate cancer, 0.69 (95% CI 0.50-0.97; P = .008). The adjusted hazard ratio for cancer-related and overall mortality was 1.07 (95% CI 0.92-1.24) and 1.12 (95% CI 1.05-1.19), respectively. These results support the hypothesis that anticoagulation might have a protective effect on cancer development, especially prostate cancer.

Cancer prevention and vitamin K antagonists: an overview

The relation of cancer to thromboembolism has been described since the mid 1800s. Different studies in animal and in vitro models have confirmed the link between the haemostatic system and both tumor stroma formation and metastasis. Although the mechanisms of warfarin effects on cancer are not elucidated, but are based on hypothesis, various studies have reported interesting results in this setting. But does warfarin added to recommended anti-tumour therapy improve survival of cancer patients? For the time being it is difficult to answer this question. Data from the literature are few and sometimes contradictory. Trials are characterized by important differences in studied cohorts, histological types of cancers evaluated, and in the treatment protocols. Most studies show that there is benefit from the addition of warfarin to chemotherapy in the tumour development, expansion and on the patient survival, especially in particular types of cancers. These data, although fascinating, do not rationalize the use of anticoagulation in the routine prophylaxis of cancer, however, they call for efforts in preparing large scale randomized trials to elucidate the effect of anticoagulation in the setting of neoplastic disease.

Does antithrombotic therapy improve survival in cancer patients?

Venous thromboembolism (VTE) is a common complication of malignancy, and is associated with significant morbidity and mortality. Anticoagulant therapy, in the form of heparin and warfarin, plays an important role in the prevention of recurrent VTE. Recent studies have demonstrated that long-term therapy with low molecular weight heparin (LMWH) is more effective than warfarin in patients with cancer. In addition, accumulating clinical evidence suggests that LMWH significantly improves overall survival in cancer patients without VTE. Intriguingly, however, this improved survival cannot simply be explained by a reduction in fatal pulmonary embolism. Furthermore, the beneficial effects persist long after the LMWH has been discontinued, suggesting that LMWH can directly influence tumour cell biology. This hypothesis is entirely plausible, given the complex feedback mechanisms that exist between tumour cells, coagulation proteases, and vascular endothelial cells. Furthermore, an accumulating body of in vitro experimental evidence suggests that both heparin and warfarin have direct antineoplastic effects. Further large randomized controlled trials will be required in order to validate these exciting preliminary data, and to define whether anticoagulant therapy may constitute a useful adjunctive therapy in the management of cancer patients without VTE.

Use of warfarin and risk of urogenital cancer: a population-based, nested case-control study

BACKGROUND

Indirect evidence suggests that prolonged treatment with warfarin might be associated with a decreased incidence of urogenital cancer. We aimed to assess this association in a large population-based study.

METHODS

Beneficiaries of Saskatchewan Health who were eligible for prescription drug benefits and aged 50 years or over with no history of cancer since 1967 were enrolled into a nested, matched case-control study. 19 412 new cases of urogenital cancer diagnosed between Jan 1, 1981, and Dec 31, 2002, were identified by use of information from the Saskatchewan Cancer Agency registry. For each case, six controls, totalling 116 470, who were matched for age, sex, and time of diagnosis were selected randomly. Conditional logistic regression analysis was used to calculate adjusted incidence rates of urogenital cancer in relation to warfarin use.

FINDINGS

Compared with men who never used warfarin, men with 4 years of warfarin use had an adjusted incidence rate of 0.80 (95% CI [0.65-0.99]). For warfarin use 76-100% of the time, the adjusted rate ratios were 0.80 (0.66-0.96) during year 2 preceding diagnosis of prostate cancer, 0.76 (0.62-0.94) during year 3, and 0.67 (0.53-0.86) during year 4. No significant association was found between warfarin and risk of other urogenital cancers.

INTERPRETATION

Our results suggest that warfarin has an antitumour effect that is specific to prostate cancer. Further investigation, with more complete assessment of confounders and that addresses the effect of warfarin on mortality of prostate cancer, is warranted.

The effect of anticoagulants on cancer risk and survival: systematic review

OBJECTIVES

Several in vitro and in vivo studies have shown that low molecular weight heparin and warfarin may directly inhibit tumour cell growth and prevent metastatic spread. However, the clinical evidence in support of an anti-cancer effect is less conclusive. We summarize the evidence from clinical studies that examine the effect of these anticoagulants on cancer development and briefly describe the current understanding of the potential mechanisms by which anticoagulants may exert an anti-cancer effect.

METHODS

English-language articles reporting on warfarin, coumarin or low molecular weight heparin for the treatment or prevention of cancer were selected from PUBMED. All randomized clinical trials, case-control studies, cohort studies, and meta-analyses were retrieved. Detailed data review and abstraction was performed according to pre-specified criteria.

RESULTS

Of ninety-nine articles retrieved, 12 warfarin and 17 low molecular weight heparin articles were included in the review. We found no consistent evidence that warfarin may improve cancer survival, though there is indirect evidence that prolonged warfarin use may decrease the risk of urogenital cancer. Low molecular weight heparin may improve survival of patients with small cell lung cancer and those with advanced malignancy who have more favorable prognoses.

CONCLUSION

Clinical evidence exists in support of an anti-neoplastic effect of anticoagulants. However, more research is needed to further define which cancer type and stage would most benefit from low molecular weight heparin, as well as to explore the role of warfarin in urogenital tumour development.