Changes in glucose-lowering drug use before and after cancer diagnosis in patients with diabetes.

AIM: This study explores the changes in glucose-lowering drug (GLD) use before and after cancer diagnosis among patients with diabetes. METHODS: New GLD users (1998-2011) living in the Dutch ECR-PHARMO catchment area were selected from the PHARMO Database Network (n=52,228). Those with a primary cancer diagnosis were considered cases (n=3281) and matched with eligible controls (n=12,891) without cancer during follow-up. Conditional logistic regression analysis was used to assess changes in GLD use, such as treatment add-ons, treatments drops and initiation of insulin, for cases compared with controls associated with specific cancer types in four time windows (6-3 and 0-3months before cancer diagnosis; 0-3 and 3-6months after cancer diagnosis). RESULTS: In the 3months before cancer diagnosis, patients with upper gastrointestinal (GI) cancers (oesophageal, stomach, pancreatic, liver cancers) had higher odds of initiating insulin (OR: 9.3; 95% CI: 3.6-24.1); to a lesser extent, this was also observed in the 3months prior to that (at 6months, OR: 3.9; 95% CI: 1.3-12.1). Diagnosis of colorectal (OR: 3.4; 95% CI: 1.4-8.4), pulmonary (OR: 2.5; 95% CI: 1.1-5.4) and upper GI (OR: 13.6; 95% CI: 5.0-36.9) cancers was associated with increased odds of initiating insulin in the 3months after cancer diagnosis. During all study time windows, the odds of treatment drops were higher for patients with upper GI cancers whereas, for most other cancers, these odds were higher only after a diagnosis of cancer. CONCLUSION: The greater odds of initiating insulin during the 6months prior to diagnosis of upper GI cancers suggest reverse causation. After cancer diagnosis, drops in use of GLDs was commonly seen.

Impact of detection bias on the risk of gastrointestinal cancer and its subsites in type 2 diabetes mellitus.

BACKGROUND: Type 2 diabetes mellitus (T2DM) may be a risk factor for gastrointestinal (GI) cancers, but variations in study designs of observational studies may have yielded biased results due to detection bias. Furthermore, differences in risk for GI cancer subsites have not been extensively evaluated. We aimed to determine the risk of GI cancer and its subsites in patients with T2DM and how it is affected by detection bias. METHODS: A matched cohort study was performed using the NCR-PHARMO database. New-users of ≥1 non-insulin anti-diabetic drug during 1998-2011 were matched with non-diabetic controls by year of birth, sex, and time between database entry and index. Cox regression analyses were performed with and without lag-period to estimate hazard ratios (HRs) for GI cancer and its subsites. Covariables included age, sex, use of other drugs and history of hospitalisation. RESULTS: An increased risk of GI cancer was observed in T2DM patients (HR 1.5, 95% confidence interval [CI] 1.3-1.7) compared with controls, which was attenuated in the 1-year lagged analysis (HR 1.4, 95% CI 1.2-1.7). Stratified by subsite, statistically significant increased risks of pancreatic (HR 4.7, 95% CI 3.1-7.2), extrahepatic bile duct (HR 4.2, 95% CI 1.5-11.8) and distal colon cancer (HR 1.5, 95% CI 1.1-2.1) were found, which remained statistically significantly increased in the lagged analysis. CONCLUSIONS: T2DM patients had a 40% increased risk of GI cancer. Increased GI cancer risks tended to be weaker when reducing detection bias by applying a 1-year lag-period. Future observational studies should therefore include sensitivity analyses in which this bias is minimised.

The difference in association between aspirin use and other thrombocyte aggregation inhibitors and survival in patients with colorectal cancer.

BACKGROUND: Several studies have suggested that the association between aspirin and improved cancer survival is mediated through the mechanism of aspirin as thrombocyte aggregation inhibitors (TAI). The aim of this study was to provide epidemiological evidence for this mechanism assessing the association between overall survival and the use of aspirin and non-aspirin TAI in patients with colorectal cancer. METHODS: In this observational study, data from the Netherlands Comprehensive Cancer Organisation were linked to PHARMO Database Network. Patients using aspirin or aspirin in combination with non-aspirin TAI (dual users) were selected and compared with non-users. The association between overall survival and the use of (non-)aspirin TAI was analysed using Cox regression models with the use of (non-)aspirin TAI as a time-varying covariate. RESULTS: In total, 9196 patients were identified with colorectal cancer and 1766 patients used TAI after diagnosis. Non-aspirin TAI were mostly clopidogrel and dipyridamole. Aspirin use was associated with a significant increased overall survival and hazard ratio (HR) 0.41 (95% confidence interval [CI] 0.37-0.47), and the use of non-aspirin TAI was not associated with survival of HR 0.92 (95% CI 0.70-1.22). Dual users did not have an improved overall survival when compared with patients using solely aspirin. CONCLUSIONS: Aspirin use after diagnosis of colorectal cancer was associated with significantly lower mortality rates and this effect remained significant after adjusting for potential confounders. No additional survival benefit was observed in patients using both aspirin and another TAI.

Chemotherapy for ovarian cancer in the Netherlands: a population-based study on treatment patterns and outcomes.

Information on treatment patterns for ovarian cancer (OC) is limited. The aim of this study was to describe current patterns of chemotherapy and other systemic treatments for OC in the Netherlands and evaluate survival outcomes following subsequent lines of treatment. Data from the Eindhoven Cancer Registry, including on newly diagnosed cancer patients, were linked to the PHARMO Database Network, including information on in- and out-patient drug use. Patients diagnosed with OC between January 2000 and December 2010 were selected. An algorithm was used to identify separate lines of treatment. Data were studied descriptively. Detailed data on systemic drug use were available for 261 patients (17%) with OC. In first-line treatment, 87% of the patients (227/261) received platinum-based chemotherapy. Of the 161 patients receiving second-line treatment, 101 patients (63%) received platinum-based chemotherapy. In third line, this was 51% (53/103). The median number of treatment lines received by patients was two (interquartile range 1-3), and eight or more lines of chemotherapy were identified for 12 patients. Median survival from diagnosis onwards was 47 months from the end of first-line treatment, median survival was 32 months, and from the end of second-line treatment, it was 14 months. Predominantly beyond second-line treatment, there is much variety in treatment patterns with chemotherapy for OC. Although uncertainty remains regarding the desirability of this observed treatment variation, there seems a need for detailed clinical guidance, assuring that physicians can properly choose the most suitable treatment for each patient.

Effect of low-dose aspirin use on survival of patients with gastrointestinal malignancies; an observational study.

BACKGROUND: Previous studies suggested a relationship between aspirin use and mortality reduction. The mechanism for the effect of aspirin on cancer outcomes remains unclear. The aim of this study was to evaluate aspirin use and survival in patients with gastrointestinal tract cancer. METHODS: Patients with gastrointestinal tract cancer diagnosed between 1998 and 2011 were included. The population-based Eindhoven Cancer Registry was linked to drug-dispensing data from the PHARMO Database Network. The association between aspirin use after diagnosis and overall survival was analysed using Cox regression models. RESULTS: In total, 13 715 patients were diagnosed with gastrointestinal cancer. A total of 1008 patients were identified as aspirin users, and 8278 patients were identified as nonusers. The adjusted hazard ratio for aspirin users vs nonusers was 0.52 (95% CI 0.44-0.63). A significant association between aspirin use and survival was observed for patients with oesophageal, hepatobiliary and colorectal cancer. CONCLUSIONS: Post-diagnosis use of aspirin in patients with gastrointestinal tract malignancies is associated with increased survival in cancers with different sites of origin and biology. This adds weight to the hypothesis that the anti-cancer effects of aspirin are not tumour-site specific and may be modulated through the tumour micro-environment.

Are metformin, statin and aspirin use still associated with overall mortality among colorectal cancer patients with diabetes if adjusted for one another?

BACKGROUND: Metformin, statin and aspirin use seem associated with decreased mortality in cancer patients, though, without adjusting for one another. Independent associations of these drugs with overall mortality after colorectal cancer (CRC) diagnosis within glucose-lowering drugs (GLDs) users were assessed. METHODS: Patients starting GLDs before CRC diagnosis (1998-2011) were selected from the Eindhoven Cancer Registry linked with the PHARMO Database Network. The Cox regression model, with time since CRC diagnosis, included time-dependent variables of cumulative exposure to metformin, statins and aspirin after cancer diagnosis and time-dependent ever-never terms for drug exposure. RESULTS: A total of 1043 patients used GLDs before CRC diagnosis; 666 (64%) used metformin, 639 (61%) used statins and 490 (47%) used aspirin after CRC diagnosis. Multivariable analyses revealed that longer cumulative exposure to metformin was not associated with overall mortality (HRCumulative exposure/6 months 1.02; 95% CI 0.97-1.07), whereas the favourable effect of statins increased with cumulative exposure (HRCumulative exposure/6 months 0.93; 95% CI 0.89-0.98). No association between aspirin use and overall mortality was seen (HRCumulative exposure/6 months 0.98; 95% CI 0.93-1.03). CONCLUSIONS: No independent association between cumulative exposure to metformin, aspirin and overall mortality was found. Cumulative exposure to statins after CRC diagnosis was associated with lower overall mortality, supporting a drug effect of statins among GLDs users.

Metachronous peritoneal carcinomatosis after curative treatment of colorectal cancer.

INTRODUCTION: Population-based data on metachronous peritoneal carcinomatosis (PC) after curative resection of colorectal origin are scarce. The aim of this study was to investigate the incidence of and risk factors for developing metachronous PC from colorectal cancer as well as survival since diagnosis of PC. METHODS: Data on metachronous metastases were collected between 2010 and 2011 for all patients diagnosed with M0 colorectal cancer between 2003 and 2008 in the Dutch Eindhoven Cancer Registry. Median follow-up was 5.0 years. Survival was defined as time from metastases diagnosis to death. RESULTS: Of the 5671 colorectal cancer patients, 1042 (18%) were diagnosed with metachronous metastases of whom 197 (19%) developed metachronous PC. The peritoneal surface was the only site of metastasis in 81 (41%) patients while 116 (59%) patients were diagnosed with both PC and metastases elsewhere. Median survival after diagnosis of PC was 6 months compared to 15 months for patients with distant metastases in other organs. Patients with an advanced primary tumour stage, positive lymph nodes at initial diagnosis, primary mucinous adenocarcinoma, positive resection margin and a primary tumour located in the colon were at increased risk of developing metachronous PC. CONCLUSION: Of the colorectal cancer patients who developed metachronous metastases, approximately one fifth is diagnosed with PC. Prognosis of these patients is poor with a median survival of 6 months after diagnosis. Identifying patients at high risk for developing metachronous PC is important as it may contribute to more accurate patient information, tailor-made follow-up schemes, and more adequate treatment.

ß-Blocker use and all-cause mortality of melanoma patients: results from a population-based Dutch cohort study.

BACKGROUND: Results from preclinical and observational studies suggest that ß-adrenoreceptor inhibition might influence disease progression of melanoma. PATIENTS AND METHODS: Patients ⩾18years with cutaneous melanoma (Breslow thickness >1mm) registered in the Eindhoven Cancer Registry between January 1, 1998 and December 31, 2010, who were also registered with PHARMO record linkage system (RLS), were eligible. Randomly selected patients using ß-blockers from PHARMO record linkage system (RLS) matched on age and gender served as a control cohort. Adjusted time-dependent and time-fixed Cox proportional hazard models were employed to estimate the hazard ratio of all-cause mortality. Five-year relative survival rates for all-cause mortality were calculated to estimate disease specific survival. RESULTS: 203 of 709 eligible patients used ß-blockers after melanoma diagnosis. The use of ß-blockers was not associated with the risk of dying (adjusted hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.55-1.24). Neither duration of exposure nor ß-blocker dosage showed significant influence on survival. Five-year relative survival for ß-blocker users was lower than in non-users amongst melanoma patients (80.9% and 83.7%, respectively) but higher among the ß-blocker control group compared to the general population (101.4%). CONCLUSION: Our results do not show a statistically significant impact of ß-blocker exposure on overall survival of melanoma patients, regardless of the timing, duration or dosage of ß-blocker use.

Use of aspirin postdiagnosis improves survival for colon cancer patients.

BACKGROUND: The preventive role of non-steroid anti-inflammatory drugs (NSAIDs) and aspirin, in particular, on colorectal cancer is well established. More recently, it has been suggested that aspirin may also have a therapeutic role. Aim of the present observational population-based study was to assess the therapeutic effect on overall survival of aspirin/NSAIDs as adjuvant treatment used after the diagnosis of colorectal cancer patients. METHODS: Data concerning prescriptions were obtained from PHARMO record linkage systems and all patients diagnosed with colorectal cancer (1998-2007) were selected from the Eindhoven Cancer Registry (population-based cancer registry). Aspirin/NSAID use was classified as none, prediagnosis and postdiagnosis and only postdiagnosis. Patients were defined as non-user of aspirin/NSAIDs from the date of diagnosis of the colorectal cancer to the date of first use of aspirin or NSAIDs and user from first use to the end of follow-up. Poisson regression was performed with user status as time-varying exposure. RESULTS: In total, 1176 (26%) patients were non-users, 2086 (47%) were prediagnosis and postdiagnosis users and 1219 (27%) were only postdiagnosis users (total n=4481). Compared with non-users, a survival gain was observed for aspirin users; the adjusted rate ratio (RR) was 0.77 (95% confidence interval (CI) 0.63-0.95; P=0.015). Stratified for colon and rectal, the survival gain was only present in colon cancer (adjusted RR 0.65 (95%CI 0.50-0.84; P=0.001)). For frequent users survival gain was larger (adjusted RR 0.61 (95%CI 0.46-0.81; P=0.001). In rectal cancer, aspirin use was not associated with survival (adjusted RR 1.10 (95%CI 0.79-1.54; P=0.6). The NSAIDs use was associated with decreased survival (adjusted RR 1.93 (95%CI 1.70-2.20; P<0.001). CONCLUSION: Aspirin use initiated or continued after diagnosis of colon cancer is associated with a lower risk of overall mortality. These findings strongly support initiation of a placebo-controlled trial that investigates the role of aspirin as adjuvant treatment in colon cancer patients.

Risk of cancer in patients on insulin glargine and other insulin analogues in comparison with those on human insulin: results from a large population-based follow-up study.

AIMS/HYPOTHESIS: Several publications suggest an association between certain types of insulin and cancer, but with conflicting results. We investigated whether insulin glargine (A21Gly,B31Arg,B32Arg human insulin) is associated with an increased risk of cancer in a large population-based cohort study. 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. In a cohort of incident users of insulin, the association between insulin glargine and other insulin analogues, respectively, and cancer was analysed in comparison with human insulin using Cox proportional hazard models with cumulative duration of drug use as a time-varying determinant. The first hospital admission with a primary diagnosis of cancer was considered as the main outcome; secondary analyses were performed with specific cancers as outcomes. RESULTS: Of the 19,337 incident insulin users enrolled, 878 developed cancer. Use of insulin glargine was associated with a lower risk of malignancies in general in comparison with human insulin (HR 0.75, 95% CI 0.71, 0.80). In contrast, an increased risk was found for breast cancer (HR 1.58, 95% CI 1.22, 2.05). Dose-response relationships could not be identified. CONCLUSION/INTERPRETATION: Users of insulin glargine and users of other insulin analogues had a lower risk of cancer in general than those using human insulin. Both associations might be a consequence of residual confounding, lack of adherence or competing risk. However, as in previous studies, we demonstrated an increased risk of breast cancer in users of insulin glargine in comparison with users of human insulin.