Medication use among women with breast cancer in the Netherlands : Pharmacoepidemiological studies based on data from the Eindhoven Cancer Registry-PHARMO linkage

In the Netherlands, breast cancer is the most frequent (30%) of all cancers in women. In 2008, around 13,000 women were newly diagnosed with the disease. Worldwide, breast cancer accounted for almost 1.4 million new cancer patients in 20082. Incidence rates of breast cancer have been increasing in the Netherlands since 1960. This increase can be explained by several factors: the increased detection of (early) breast cancer due to the introduction and increased use of mammography and cytology since the 1980s, the implementation of the mass breast cancer screening program between 1991 and 1996, and a change in adverse way of the risk factors for breast cancer over the years. Many known risk factors are related to endogenous hormones: young age at menarche, higher age at menopause, high age at first childbirth, lower parity, shorter lactation and obesity. Changes in adverse way of these reproductive patterns and other lifestyle factors, such as physical activity, have almost certainly played an important role in the increase of breast cancer incidence. In 2008, 3,300 patients died of breast cancer in the Netherlands, making it, together with lung cancer, the most important cause of cancer death among women. However, breast cancer survival has improved for several decades: in the 1970s 5-year relative survival was less than 50%, while for patients diagnosed in 2000-2002 this was 80%. Factors related to the increased survival are, among other things, early detection through breast cancer awareness and screening, resulting in a more favourable stage distribution, and improved (adjuvant) treatment. With the incidence rates of breast cancer increasing and survival rates improving, the number of prevalent breast cancer patients will continue to rise. In 2005 it was estimated that 119,000 patients in the Netherlands were ever diagnosed with breast cancer6. Breast cancer prevalence rises with approximately 5% annually, and in 2015 the number of (ex-)breast cancer patients might increase to about 194,000. This number is expected to continue to rise also due to demographic developments (age distribution skewed toward old age). A large proportion of these women will still require some form of health care, either for diagnosis and treatment, surveillance during follow-up, or because of recurrences, metastases or new primary malignancies. Breast cancer survivors are at high risk of developing subsequent primary cancers either in the breast or in another organ

The effect of aspirin and nonsteroidal anti-inflammatory drug use after diagnosis on survival of oesophageal cancer patients

Background:Aspirin use has been shown to lower incidence and mortality in cancer patients. The aim of this population-based study was to determine the effect of postdiagnosis low-dose aspirin use on survival of patients with oesophageal cancer.Methods:Patients with oesophageal cancer (1998-2010) were selected from the Eindhoven Cancer Registry and linked with outpatient pharmacy data regarding aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs). Users were subdivided into both prediagnosis and postdiagnosis or only postdiagnosis users. Parametric survival models with an exponential (Poisson) distribution were used with non-specific death as endpoint.Results:In this study 560 patients were included. Overall, 157 patients (28.0%) were non-users, 293 patients (52.3%) pre-and postdiagnosis (89 aspirin and 204 NSAID users) and 110 patients (19.6%) only postdiagnosis users (16 aspirin and 94 NSAID users). Postdiagnosis aspirin use was associated with overall survival (RR 0.45 (95% CI 0.34-0.60; P<0.001); adjusted rat

The influence of BRAF and KRAS mutation status on the association between aspirin use and survival after colon cancer diagnosis

Background: Use of aspirin after diagnosis of colon cancer has been associated with improved survival. Identification of cancer subtypes that respond to aspirin treatment may help develop personalized treatment regimens. The aim of this study was to investigate the influence of BRAF and KRAS mutation status on the association between aspirin use and overall survival after colon cancer diagnosis. Methods: A random selection of 599 patients with colon cancer were analyzed, selected from the Eindhoven Cancer Registry, and BRAF and KRAS mutation status was determined. Data on aspirin use (80 mg) were obtained from the PHARMO Database Network. Parametric survival models with exponential (Poisson) distribution were used. Results: Aspirin use after colon cancer diagnosis was associated with improved overall survival in wild-type BRAF tumors, adjusted rate ratio (RR) of 0.60 (95% CI 0.44-0.83). In contrast, aspirin use in BRAF mutated tumors was not associated with an improved survival (RR 1.11, 95% CI 0.57-2.16). P-value for interaction was non-significant. KRAS mutational status did not differentiate in the association between aspirin use and survival. Conclusion: Low-dose aspirin use after colon cancer diagnosis was associated with improved survival in BRAF wild-type tumors only. However, the large confidence interval of the rate ratio for the use of aspirin in patients with BRAF mutation does not rule out a possible benefit. These results preclude BRAF and KRAS mutation status to be used as a marker for individualized treatment with aspirin, if aspirin becomes regular adjuvant treatment for colon cancer patients in the future

Lower risk of cancer in patients on metformin in comparison with those on sulfonylurea derivatives: Results from a large population-based follow-up study

OBJECTIVE - Numerous studies have suggested a decreased risk of cancer in patients with diabetes on metformin. Because different comparison groups were used, the effect magnitude is difficult to estimate. Therefore, the objective of this study was to further analyze whether, and to what extent, use of metformin is associated with a decreased risk of cancer in a cohort of incident users of metformin compared with users of sulfonylurea derivatives. RESEARCH DESIGN AND METHODS - Data for this study were obtained from dispensing records from community pharmacies individually linked to hospital discharge records from 2.5 million individuals in the Netherlands. The association between the risk of cancer in those using metformin compared with those using sulfonylurea derivatives was analyzed using Cox proportional hazard models with cumulative duration of drug use as a time-varying determinant. RESULTS - Use of metformin was associated with a lower risk of cancer in general (hazard ratio 0.90 [95% CI 0.88-0.91]) compared with use of sulfonylurea derivatives. When specific cancers were used as end points, similar estimates were found. Dosage-response relations were identified for users of metformin but not for users of sulfonylurea derivatives. CONCLUSIONS - In our study, cumulative exposure to metformin was associated with a lower risk of specific cancers and cancer in general, compared with cumulative exposure to sulfonylurea derivatives. However, whether this should indeed be seen as a decreased risk of cancer for the use of metformin or as an increased risk of cancer for the use sulfonylurea derivatives remains to be elucidated