Weight-lowering Effects of Glucagon-like Peptide-1 Receptor Agonists and Detection of Breast Cancer Among Obese Women with Diabetes.

BACKGROUND: It has been proposed that the weight loss associated with glucagon-like peptide-1 receptor agonists (GLP-1 RAs) may improve detection of breast cancer in patients undergoing this treatment. We aimed to determine whether the weight-lowering effects of GLP-1 RAs are associated with an increased detection of breast cancer among obese women with type 2 diabetes. METHODS: Using the UK Clinical Practice Research Datalink, we conducted a propensity score-matched cohort study among female obese patients with type 2 diabetes newly treated with antidiabetic drugs between 1 January 2007 and 31 January 2018. New users of GLP-1 RAs (n = 5,510) were matched to new users of second- to third-line noninsulin antidiabetic drugs (n = 5,510). We used time-dependent Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of breast cancer associated with different GLP-1 RA maximal weight loss categories (<5%, 5%-10%, >10%). RESULTS: Breast cancer incidence gradually increased with GLP-1 RA maximal weight loss categories, with the highest HR observed for patients achieving at least 10% weight loss (HR = 1.8, 95% CI = 1.1, 2.8). In secondary analyses, the HR for >10% weight loss was highest in the 2-3 years since treatment initiation (HR = 2.9, 95% CI = 1.2, 6.9). CONCLUSIONS: In this population-based study, the detection of breast cancer gradually increased with GLP-1 RA weight loss categories, particularly among those achieving >10% weight loss. These results are consistent with the hypothesis that substantial weight loss with GLP-1 RAs may improve detection of breast cancer among obese patients with type 2 diabetes.

The Risk of Cardiovascular Disease in Prostate Cancer Patients Receiving Androgen Deprivation Therapies.

BACKGROUND: Androgen deprivation therapy (ADT), with a proven role in prostate cancer management, has been associated with various cardiovascular diseases. However, few studies have investigated these associations by type of ADT, particularly for newer ADTs such as the gonadotropin-releasing hormone (GnRH) antagonist degarelix. We investigated the risk of cardiovascular disease by type of ADT in a real-world setting. METHODS: We identified men newly diagnosed with prostate cancer, from 2009 to 2015, from the Scottish Cancer Registry and ADTs from the nationwide Prescribing Information System. Cardiovascular events were based upon hospitalization (from hospital records) or death from cardiovascular disease (from death records). We used Cox regression to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for cardiovascular events with time-varying ADT exposure, comparing ADT users with untreated patients, after adjusting for potential confounders, including prior cardiovascular disease. RESULTS: The cohort contained 20,216 prostate cancer patients, followed for 73,570 person-years, during which there were 3,853 cardiovascular events. ADT was associated with a 30% increase in cardiovascular events (adjusted HR = 1.3; 95% CI = 1.2, 1.4). This reflected increases in cardiovascular events associated with GnRH agonists (adjusted HR = 1.3; 95% CI = 1.2, 1.4), degarelix (adjusted HR = 1.5; 95% CI = 1.2, 1.9), but not bicalutamide monotherapy (adjusted HR = 1.0; 95% CI = 0.82, 1.3). CONCLUSIONS: There were increased risks of cardiovascular disease with the use of GnRH agonists and degarelix, but not with bicalutamide monotherapy. This is the first study to observe increased cardiovascular risks with degarelix, but the cause of this association is unclear and merits further investigation.

Post-diagnostic antipsychotic use and cancer mortality: a population based cohort study.

BACKGROUND: Many antipsychotics elevate prolactin, a hormone implicated in breast cancer aetiology however no studies have investigated antipsychotic use in patients with breast cancer. This study investigated if antipsychotic use is associated with an increased risk of cancer-specific mortality among breast cancer patients. METHODS: A cohort of 23,695 women newly diagnosed with a primary breast cancer between 1st January 1998 and 31st December 2012 was identified from the UK Clinical Practice Research Datalink linked to English cancer-registries and followed for until 30th September 2015. Time-dependent Cox proportional hazards models were used to calculate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of breast cancer-specific mortality comparing use of antipsychotics with non-use, overall, and by prolactin elevating activitiy. Analyses were repeated restricting to patients with a history of severe mental illness to control for potential confounding by indication. RESULTS: In total 848 patients were prescribed an antipsychotic and of which 162 died due to their breast cancer. Compared with non-use, antipsychotic use was associated with an increased risk of breast-cancer specific mortality (HR 2.25, 95%CI 1.90-2.67), but this did not follow a dose response relation. Restricting the cohort to patients with severe mental illness attenuated the association between antipsychotic use and breast cancer-specific mortality (HR 1.11, 95%CI 0.58-2.14). CONCLUSIONS: In this population-based cohort of breast cancer patients, while the use of antipsychotics was associated with increased breast cancer-specific mortality, there was a lack of a dose response, and importantly null associations were observed in patients with severe mental illness, suggesting the observed association is likely a result of confounding by indication. This study provides an exemplar of confounding by indication, highlighting the importance of consideration of this important bias in studies of drug effects in cancer patients.

Prognosis following surgical resection versus local excision of stage pT1 colorectal cancer: A population-based cohort study.

AIMS: To evaluate patient management following stage pT1 colorectal cancer (CRC) diagnosis, and to determine if surgical resection improved outcome compared with local excision, within a population-based study. METHODS: Data were collected from the Northern Ireland Cancer Registry. Cases of stage pT1 CRC diagnosed from 2007 to 2012 were identified. Analyses were conducted using Cox proportional hazard models to calculate hazard ratios (HR) and 95% confidence intervals (CI) for cancer-specific and all-cause mortality for individuals undergoing formal surgery versus local excision. RESULTS: 394 patients with pT1 CRC were included. Of these, 37.1% were treated by local resection, 36.8% had biopsy followed by surgery and 26.1% had local excision followed by surgery. There were 60 deaths over a mean 4.8 years of follow-up, including 10 CRC-specific deaths. An additional 12 patients had a CRC recurrence or metastases during follow-up. Of the CRC-specific deaths or recurrences, 27.3% had local excision only. Individuals treated by formal surgery did not have a reduced risk of CRC-specific death (adjusted HR = 1.51, 95% CI 0.29, 7.89), but did have a reduced risk of all-cause mortality (adjusted HR = 0.51 95% CI 0.30, 0.87) compared with those undergoing local excision only. CONCLUSIONS: Patients with stage pT1 CRC undergoing formal surgery had a reduced risk of all-cause mortality compared with those treated by local excision only. However, this was not explained by a reduced risk of recurrence/disease-free survival or CRC death, and suggests that the observed benefits may simply reflect selection of a healthier patient population in the formal surgery group.

Metformin and the incidence of viral associated cancers in patients with type 2 diabetes.

Limited studies have associated metformin with a reduced risk of viral associated cancers, however these had a number of methodological shortcomings. This study investigated whether the use of metformin is associated with a reduced risk of viral associated cancers in patients with type 2 diabetes. A cohort of 137,754 patients newly-prescribed non-insulin antidiabetic drugs between January 1, 1988 and March 31, 2016 was identified from the UK Clinical Practice Research Datalink and followed until a first-ever diagnosis of a viral associated cancer, death from any cause, end of registration with the practice, or March 31, 2016. Time-varying use of metformin was compared with use of other antidiabetic drugs, with exposures lagged by one year for latency purposes. Time-dependent Cox proportional hazards models were used to estimate adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) of incident viral associated cancer with use of metformin overall, by cumulative duration of use and viral etiology. Overall, there were 424 viral associated cancers during 759,810 person-years of follow-up (crude rate of 5.6 per 10,000 person-years). Metformin was not associated with a decreased rate of viral associated cancer (HR: 0.93, 95% CI: 0.65-1.32). There was no evidence of a duration-response relationship in terms of cumulative duration of use (p trend = 0.69), including with use of metformin for more than 10 years (HR 1.02, 95% CI: 0.52-1.99), or by viral etiology. In this large population-based cohort study, the use of metformin was not associated with a reduced risk of viral associated cancer.

Androgen deprivation therapy for prostate cancer and the risk of hospitalisation for community-acquired pneumonia.

BACKGROUND: Androgens have been shown to influence both the immune system and lung tissue, raising the hypothesis that androgen deprivation therapy (ADT) for prostate cancer may increase the risk of pneumonia. Thus, the aim of this study was to determine whether ADT is associated with an increased risk of hospitalisation for community-acquired pneumonia in patients with prostate cancer. METHODS: This was a population-based cohort study using the United Kingdom Clinical Practice Research Datalink linked to the Hospital Episode Statistics repository. The cohort consisted of 20 310 men newly diagnosed with non-metastatic prostate cancer between 1 April 1998 and 31 March 2015. Time-dependent Cox proportional hazards models were used to estimate adjusted HRs and 95% CIs for hospitalisation for community-acquired pneumonia associated with current and past use of ADT compared with non-use. RESULTS: During a mean follow-up of 4.3 years, there were 621 incident hospitalisations for community-acquired pneumonia (incidence rate: 7.2/1000 person-years). Current ADT use was associated with an 81% increased risk of hospitalisation for community-acquired pneumonia (12.1 vs 3.8 per 1000 person-years, respectively; HR 1.81, 95% CI 1.47 to 2.23). The association was observed within the first six months of use (HR 1.73, 95% CI 1.23 to 2.42) and remained elevated with increasing durations of use (≥25 months; HR 1.79, 95% CI 1.39 to 2.30). In contrast, past ADT use was not associated with an increased risk (HR 1.23, 95% CI 0.95 to 1.60). CONCLUSIONS: The use of ADT is associated with an increased risk of hospitalisation for community-acquired pneumonia in men with prostate cancer.

Androgen Deprivation Therapy and the Risk of Anemia in Men with Prostate Cancer.

BACKGROUND: The use of androgen deprivation therapy in prostate cancer may be associated with an increased risk of anemia, but the evidence remains limited. This study aimed to determine if androgen deprivation is associated with increased risk of anemia in patients newly diagnosed with prostate cancer. METHODS: This was a population-based cohort study using the United Kingdom Clinical Practice Research Datalink linked to the Hospital Episode Statistics repository. The cohort consisted of 10,364 men newly diagnosed with nonmetastatic prostate cancer between 1 April 1998 and 30 September 2015. We used time-dependent Cox proportional hazards models to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for anemia (hemoglobin <130 g/L) associated with current and past use of androgen deprivation therapy, compared with nonuse. RESULTS: There were 3,651 incident anemia events during 31,574 person-years of follow-up (rate: 11.6/100 person-years). Current androgen deprivation therapy use was associated with a nearly three-fold increased hazard of anemia, compared with nonuse (23.5 vs. 5.9 per 100 person-years, respectively; HR: 2.90, 95% CI: 2.67, 3.16). The HR was elevated in the first 6 months of use (HR: 2.20, 95% CI: 1.95, 2.48) and continued to be elevated with longer durations of use. Past androgen deprivation therapy use was associated with a lower estimate (HR: 1.27, 95% CI: 1.12, 1.43), which returned closer to the null ≥25 months after treatment discontinuation (HR: 0.95, 95% CI: 0.79, 1.15). CONCLUSIONS: The use of androgen deprivation therapy is associated with increased risk of anemia, which reverses upon treatment discontinuation.

Adenocarcinoma risk in gastric atrophy and intestinal metaplasia: a systematic review.

BACKGROUND: Gastric cancer (GC) has a poor prognosis with wide variation in survival rates across the world. Several studies have shown premalignant lesions gastric atrophy (GA) and intestinal metaplasia (IM) influence gastric cancer risk. This systematic review examines all available evidence of the risk of GC in patients with GA or IM and explores the geographical variation between countries. METHODS: EMBASE, MEDLINE, Web of Science and the Cochrane Library were searched for relevant articles published to June 2016 investigating the risk of GC in individuals with GA or IM. Analysis was performed to determine variation based on geographical location. Study quality was assessed using the Newcastle-Ottawa Scale and heterogeneity between studies was also evaluated. RESULTS: Fifteen relevant articles were identified, in which there were eight studies of GC incidence in GA and nine in IM cohorts (two articles investigated both GA and IM). The incidence rate of GC in patients with GA ranged from 0.53 to 15.24 per 1000 person years, whereas there was more variation in GC incidence in patients with IM (0.38 to 17.08 per 1000 person years). The greatest GC incidence rates were in Asian countries, for patients with GA, and the USA for those with IM (15.24 and 17.08 per 1000 person years, respectively). The largest studies (four over 25,000 person years) had an incidence rate range of 1.0-2.5 per 1000 person years, however, in general, study quality was poor and there was marked heterogeneity. CONCLUSION: Overall there is a wide variation in annual incidence rate of GC from premalignant lesions. With the recent introduction of surveillance guidelines for gastric atrophy and intestinal metaplasia in the Western world, future assessment of this risk should be performed. Furthermore, substantial heterogeneity supports the need for more robust studies in order to pool results and determine the overall incidence rate of gastric cancer for patients with these premalignant lesions.

Statin use after diagnosis of breast cancer and survival: a population-based cohort study.

BACKGROUND: Preclinical studies have shown that statins, particularly simvastatin, can prevent growth in breast cancer cell lines and animal models. We investigated whether statins used after breast cancer diagnosis reduced the risk of breast cancer-specific, or all-cause, mortality in a large cohort of breast cancer patients. METHODS: A cohort of 17,880 breast cancer patients, newly diagnosed between 1998 and 2009, was identified from English cancer registries (from the National Cancer Data Repository). This cohort was linked to the UK Clinical Practice Research Datalink, providing prescription records, and to the Office of National Statistics mortality data (up to 2013), identifying 3694 deaths, including 1469 deaths attributable to breast cancer. Unadjusted and adjusted hazard ratios (HRs) for breast cancer-specific, and all-cause, mortality in statin users after breast cancer diagnosis were calculated using time-dependent Cox regression models. Sensitivity analyses were conducted using multiple imputation methods, propensity score methods and a case-control approach. RESULTS: There was some evidence that statin use after a diagnosis of breast cancer had reduced mortality due to breast cancer and all causes (fully adjusted HR = 0.84 [95% confidence interval = 0.68-1.04] and 0.84 [0.72-0.97], respectively). These associations were more marked for simvastatin 0.79 (0.63-1.00) and 0.81 (0.70-0.95), respectively. CONCLUSIONS: In this large population-based breast cancer cohort, there was some evidence of reduced mortality in statin users after breast cancer diagnosis. However, these associations were weak in magnitude and were attenuated in some sensitivity analyses.

Clopidogrel use and cancer-specific mortality: a population-based cohort study of colorectal, breast and prostate cancer patients.

PURPOSE: Concerns were raised about the safety of antiplatelet thienopyridine derivatives after a randomized control trial reported increased risks of cancer and cancer deaths in prasugrel users. We investigate whether clopidogrel, a widely used thienopyridine derivative, was associated with increased risk of cancer-specific or all-cause mortality in cancer patients. METHODS: Colorectal, breast and prostate cancer patients, newly diagnosed from 1998 to 2009, were identified from the National Cancer Data Repository. Cohorts were linked to the UK Clinical Practice Research Datalink, providing prescription records, and to the Office of National Statistics mortality data (up to 2012). Unadjusted and adjusted hazard ratios (HRs) for cancer-specific and all-cause mortality in post-diagnostic clopidogrel users were calculated using time-dependent Cox regression models. RESULTS: The analysis included 10 359 colorectal, 17 889 breast and 13 155 prostate cancer patients. There was no evidence of an increase in cancer-specific mortality in clopidogrel users with colorectal (HR = 0.98 95% confidence interval (CI) 0.77, 1.24) or prostate cancer (HR = 1.03 95%CI 0.82, 1.28). There was limited evidence of an increase in breast cancer patients (HR = 1.22 95%CI 0.90, 1.65); however, this was attenuated when removing prescriptions in the year prior to death. CONCLUSIONS: This novel study of large population-based cohorts of colorectal, breast and prostate cancer patients found no evidence of an increased risk of cancer-specific mortality among colorectal, breast and prostate cancer patients using clopidogrel.

Drugs affecting the renin-angiotensin system and survival from cancer: a population based study of breast, colorectal and prostate cancer patient cohorts.

BACKGROUND: Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) are commonly prescribed to the growing number of cancer patients (more than two million in the UK alone) often to treat hypertension. However, increased fatal cancer in ARB users in a randomized trial and increased breast cancer recurrence rates in ACEI users in a recent observational study have raised concerns about their safety in cancer patients. We investigated whether ACEI or ARB use after breast, colorectal or prostate cancer diagnosis was associated with increased risk of cancer-specific mortality. METHODS: Population-based cohorts of 9,814 breast, 4,762 colorectal and 6,339 prostate cancer patients newly diagnosed from 1998 to 2006 were identified in the UK Clinical Practice Research Datalink and confirmed by cancer registry linkage. Cancer-specific and all-cause mortality were identified from Office of National Statistics mortality data in 2011 (allowing up to 13 years of follow-up). A nested case-control analysis was conducted to compare ACEI/ARB use (from general practitioner prescription records) in cancer patients dying from cancer with up to five controls (not dying from cancer). Conditional logistic regression estimated the risk of cancer-specific, and all-cause, death in ACEI/ARB users compared with non-users. RESULTS: The main analysis included 1,435 breast, 1,511 colorectal and 1,184 prostate cancer-specific deaths (and 7,106 breast, 7,291 colorectal and 5,849 prostate cancer controls). There was no increase in cancer-specific mortality in patients using ARBs after diagnosis of breast (adjusted odds ratio (OR) = 1.06 95% confidence interval (CI) 0.84, 1.35), colorectal (adjusted OR = 0.82 95% CI 0.64, 1.07) or prostate cancer (adjusted OR = 0.79 95% CI 0.61, 1.03). There was also no evidence of increases in cancer-specific mortality with ACEI use for breast (adjusted OR = 1.06 95% CI 0.89, 1.27), colorectal (adjusted OR = 0.78 95% CI 0.66, 0.92) or prostate cancer (adjusted OR = 0.78 95% CI 0.66, 0.92). CONCLUSIONS: Overall, we found no evidence of increased risks of cancer-specific mortality in breast, colorectal or prostate cancer patients who used ACEI or ARBs after diagnosis. These results provide some reassurance that these medications are safe in patients diagnosed with these cancers.

Patterns of first-line targeted therapy utilization and adherence among older adults diagnosed with metastatic renal cell carcinoma.

BACKGROUND: Despite the rapid approval of targeted therapies for metastatic renal cell carcinoma (mRCC) evidence on real world treatment patterns remains limited. This study evaluated patterns of first-line targeted therapy utilization and adherence in older adults, a population with a high burden of RCC. METHODS: 2093 patients aged ≥66 years with a primary diagnosis of mRCC were identified from United States (US)-based cancer registry and administrative claims data (2007-2015). We included only patients with de novo disease. We assessed the initiation of first-line targeted therapy within four months of diagnosis and persistence and adherence to targeted therapy, using the proportion of days covered (PDC). Multivariable logistic regression yielded adjusted odds ratios (ORs) and 95% confidence intervals (CIs) to describe characteristics associated with targeted therapy versus no targeted therapy initiation and for high (≥80% PDC) versus low adherence. RESULTS: 28.8% of patients received first-line targeted therapy within four months of diagnosis, with the proportion of patients receiving targeted therapy increasing over time. Older age (one-year increment OR:0.95 95%CI 0.93, 0.97), high comorbidity burden (OR:0.65 95%CI0.46, 0.93) and clear cell histology (OR:1.54 95%CI 1.19, 2.00) were associated with targeted therapy initiation. 48.2% of patients exhibited a high PDC to oral targeted therapy at 120 days, which was attenuated with inclusion of patients who died during the time period (34.2% PDC ≥80%). CONCLUSION: Increasing age, high comorbidity burden and non-clear cell histology were associated with decreased targeted therapy initiation among patients with de novo mRCC. Our findings suggest adherence to oral therapies was low; future research exploring the mechanisms and impact of low adherence in this older patient population is warranted.

Hormone therapy use and the risk of acute kidney injury in patients with prostate cancer: a population-based cohort study.

BACKGROUND: Hormone therapy is widely used in prostate cancer. However, studies have raised concerns that hormone therapy, particularly the use of gonadotropin-releasing hormone agonists, could increase the risk of acute kidney injury. METHODS: Men newly diagnosed with non-metastatic prostate cancer, from 2012 to 2017, were identified from the Scottish Cancer Registry. A matched comparison cohort of prostate cancer-free men was also identified. Hormone therapy use was determined from the Prescribing Information System in Scotland. The primary outcome was hospitalisations with acute kidney injury taken from Scottish hospital records (SMR01) up to June 2019. Time-dependent Cox regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for acute kidney injury by hormone therapy use. RESULTS: The prostate cancer cohort contained 10,751 patients followed for 41,997 person years, during which there were 618 hospitalisations with acute kidney injury. Prostate cancer patients had higher rates of acute kidney injury compared with cancer-free controls (adjusted HR = 1.47 95% CI 1.29, 1.69). However, prostate cancer patients currently using hormone therapy (adjusted HR = 1.14 95% CI 0.92, 1.41), including gonadotropin-releasing hormone (GnRH) agonists (adjusted HR = 1.13 95% CI 0.90, 1.40), did not appear to have a marked increase in acute kidney injury compared with prostate cancer patients not using hormone therapy after adjusting for potential confounders. CONCLUSIONS: In our cohort, there was little evidence that gonadotropin-releasing hormone agonists were associated with marked increases in acute kidney injury.

Angiotensin converting enzyme inhibitors and risk of lung cancer: population based cohort study.

OBJECTIVE: To determine whether the use of angiotensin converting enzyme inhibitors (ACEIs), compared with use of angiotensin receptor blockers, is associated with an increased risk of lung cancer. DESIGN: Population based cohort study. SETTING: United Kingdom Clinical Practice Research Datalink. PARTICIPANTS: A cohort of 992 061 patients newly treated with antihypertensive drugs between 1 January 1995 and 31 December 2015 was identified and followed until 31 December 2016. MAIN OUTCOME MEASURES: Cox proportional hazards models were used to estimate adjusted hazard ratios with 95% confidence intervals of incident lung cancer associated with the time varying use of ACEIs, compared with use of angiotensin receptor blockers, overall, by cumulative duration of use, and by time since initiation. RESULTS: The cohort was followed for a mean of 6.4 (SD 4.7) years, generating 7952 incident lung cancer events (crude incidence 1.3 (95% confidence interval 1.2 to 1.3) per 1000 person years). Overall, use of ACEIs was associated with an increased risk of lung cancer (incidence rate 1.6 v 1.2 per 1000 person years; hazard ratio 1.14, 95% confidence interval 1.01 to 1.29), compared with use of angiotensin receptor blockers. Hazard ratios gradually increased with longer durations of use, with an association evident after five years of use (hazard ratio 1.22, 1.06 to 1.40) and peaking after more than 10 years of use (1.31, 1.08 to 1.59). Similar findings were observed with time since initiation. CONCLUSIONS: In this population based cohort study, the use of ACEIs was associated with an increased risk of lung cancer. The association was particularly elevated among people using ACEIs for more than five years. Additional studies, with long term follow-up, are needed to investigate the effects of these drugs on incidence of lung cancer.

Glucagon-like peptide-1 analogues and risk of breast cancer in women with type 2 diabetes: population based cohort study using the UK Clinical Practice Research Datalink.

OBJECTIVE:  To determine whether the use of glucagon-like peptide-1 (GLP-1) analogues, compared with the use of dipeptidylpeptidase-4 (DPP-4) inhibitors, is associated with an increased risk of incident breast cancer in patients with type 2 diabetes. DESIGN:  Population based cohort study. SETTING:  Clinical Practice Research Datalink, UK. PARTICIPANTS:  44 984 women aged at least 40 years, who were newly treated with glucose lowering drugs between 1 January 2007 and 31 March 2015, with follow-up until 31 March 2016. MAIN OUTCOMES AND MEASURES:  Time varying use of GLP-1 analogues compared with use of DPP-4 inhibitors, with exposures lagged by one year for latency purposes. Time dependent Cox proportional hazards models were used to estimate adjusted hazard ratios with 95% confidence intervals of incident breast cancer associated with use of GLP-1 analogues overall, by cumulative duration of use, and time since initiation. RESULTS:  The cohort was followed for a mean of 3.5 years (standard deviation 2.2), with 549 incident events of breast cancer recorded (crude incidence 3.5 (95% confidence interval 3.3 to 3.8) per 1000 person years). Overall, compared with use of DPP-4 inhibitors, use of GLP-1 analogues was not associated with an increased risk of breast cancer (incidence 4.4 v 3.4 per 1000 person years; hazard ratio 1.40 (95% confidence interval 0.91 to 2.16)). Hazard ratios gradually increased with longer durations of use, with a peak between two to three years of GLP-1 use (2.66 (95% confidence interval 1.32 to 5.38)), and returned closer to the null after more than three years of use (0.98 (0.24 to 4.03)). A similar pattern was observed with time since initiation of GLP-1 analogues. CONCLUSIONS:  In this population based cohort study, use of GLP-1 analogues was not associated with an overall increased risk of breast cancer. Although it is not possible to rule out a tumour promoter effect, the observed duration-response associations are likely the result of a transient increase in detection of breast cancers in GLP-1 analogue users.

Statin use after colorectal cancer diagnosis and survival: a population-based cohort study.

PURPOSE: To investigate whether statins used after colorectal cancer diagnosis reduce the risk of colorectal cancer-specific mortality in a cohort of patients with colorectal cancer. PATIENTS AND METHODS: A cohort of 7,657 patients with newly diagnosed stage I to III colorectal cancer were identified from 1998 to 2009 from the National Cancer Data Repository (comprising English cancer registry data). This cohort was linked to the United Kingdom Clinical Practice Research Datalink, which provided prescription records, and to mortality data from the Office of National Statistics (up to 2012) to identify 1,647 colorectal cancer-specific deaths. Time-dependent Cox regression models were used to calculate hazard ratios (HR) for cancer-specific mortality and 95% CIs by postdiagnostic statin use and to adjust these HRs for potential confounders. RESULTS: Overall, statin use after a diagnosis of colorectal cancer was associated with reduced colorectal cancer-specific mortality (fully adjusted HR, 0.71; 95% CI, 0.61 to 0.84). A dose-response association was apparent; for example, a more marked reduction was apparent in colorectal cancer patients using statins for more than 1 year (adjusted HR, 0.64; 95% CI, 0.53 to 0.79). A reduction in all-cause mortality was also apparent in statin users after colorectal cancer diagnosis (fully adjusted HR, 0.75; 95% CI, 0.66 to 0.84). CONCLUSION: In this large population-based cohort, statin use after diagnosis of colorectal cancer was associated with longer rates of survival.