TNM stage in the Nordic Cancer Registries 2004-2016: Registration and availability

BACKGROUND AND PURPOSE

Stage at cancer diagnosis is an important predictor of cancer survival. TNM stage is constructed for anatomic solid cancer diagnoses from tumor size (T), nodal spread (N) and distant metastasis (M) and categorized in groups 0-I, II, II and IV. TNM stage is imperative in cancer diagnosis, management and control, and of high value in cancer surveillance, for example, monitoring of stage distributions. This study yields an overview of TNM availability and trends in stage distribution in the Nordic countries for future use in monitoring and epidemiologic studies.

MATERIAL AND METHODS

TNM information was acquired from the cancer registries in Denmark, Norway, Sweden, and Iceland during 2004-2016 for 26 cancer sites in the three former countries and four in Iceland. We studied availability, comparability, and distribution of TNM stage in three periods: 2004-2008, 2009-2013, and 2014-2016, applying a previously validated algorithm of 'N0M0 for NXMX'. For cancers of colon, rectum, lung, breast, and kidney, we examined TNM stage-specific 1-year relative survival to evaluate the quality in registration of TNM between countries.

RESULTS

Denmark, Sweden, and Iceland exhibited available TNM stage proportions of 75-95% while proportions were lower in Norway. Proportions increased in Sweden over time but decreased in Denmark. One-year relative survival differed substantially more between TNM stages than between countries emphasizing that TNM stage is an important predictor for survival and that stage recording is performed similarly in the Nordic countries.

INTERPRETATION

Assessment and registration of TNM stage is an imperative tool in evaluations of trends in cancer survival between the Nordic countries.

Have the recent advancements in cancer therapy and survival benefitted patients of all age groups across the Nordic countries? NORDCAN survival analyses 2002-2021

BACKGROUND

Since the early 2000s, overall and site-specific cancer survival have improved substantially in the Nordic countries. We evaluated whether the improvements have been similar across countries, major cancer types, and age groups.

MATERIAL AND METHODS

Using population-based data from the five Nordic cancer registries recorded in the NORDCAN database, we included a cohort of 1,525,854 men and 1,378,470 women diagnosed with cancer (except non-melanoma skin cancer) during 2002-2021, and followed for death until 2021. We estimated 5-year relative survival (RS) in 5-year calendar periods, and percentage points (pp) differences in 5-year RS from 2002-2006 until 2017-2021. Separate analyses were performed for eight cancer sites (i.e. colorectum, pancreas, lung, breast, cervix uteri, kidney, prostate, and melanoma of skin).

RESULTS

Five-year RS improved across nearly all cancer sites in all countries (except Iceland), with absolute differences across age groups ranging from 1 to 21 pp (all cancer sites), 2 to 20 pp (colorectum), -1 to 36 pp (pancreas), 2 to 28 pp (lung), 0 to 9 pp (breast), -11 to 26 pp (cervix uteri), 2 to 44 pp (kidney), -2 to 23 pp (prostate) and -3 to 30 pp (skin melanoma). The oldest patients (80-89 years) exhibited lower survival across all countries and sites, although with varying improvements over time.

INTERPRETATION

Nordic cancer patients have generally experienced substantial improvements in cancer survival during the last two decades, including major cancer sites and age groups. Although survival has improved over time, older patients remain at a lower cancer survival compared to younger patients.

Long-term aspirin use and cancer risk: a 20-year cohort study

BACKGROUND

Long-term use of aspirin has been shown to reduce colorectal cancer risk, but the association remains inconclusive for individual noncolorectal cancers. We examined the association between long-term aspirin use and cancer risk in Denmark.

METHODS

Using nationwide registries, we followed individuals aged 40-70 years at baseline (January 1, 1997) for cancer diagnoses through 2018. We assessed low-dose (75-150 mg) aspirin use according to continuity, duration, and cumulative amount. In addition, we explored associations with consistent high-dose (500 mg) aspirin use. Using Cox regression, we estimated multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) with aspirin use for overall and site-specific cancer.

RESULTS

Among 1 909 531 individuals, 422 778 were diagnosed with cancer during mean follow-up of 18.2 years. Low-dose aspirin use did not reduce the hazard ratio for cancer overall irrespective of continuity and duration of use (continuous use: HR = 1.04, 95% CI = 1.03 to 1.06). However, long-term (≥5 or ≥10 years) use was associated with at least 10% reductions in hazard ratios for several cancer sites: colon, rectum, esophagus, stomach, liver, pancreas, small intestine, head and neck, brain tumors, meningioma, melanoma, thyroid, non-Hodgkin lymphoma, and leukemia. Substantially elevated hazard ratios were found for lung and bladder cancer. In secondary analyses, consistent high-dose aspirin use was associated with reduced hazard ratios for cancer overall (HR = 0.89, 95% CI = 0.85 to 0.93) and for several cancer sites.

CONCLUSION

Long-term low-dose aspirin use was associated with slight to moderately reduced risks for several cancers but not for cancer overall owing to increased risk for some common cancers. Similar or slightly stronger inverse associations were observed for consistent use of high-dose aspirin.

Menopausal hormone therapy and central nervous system tumors: Danish nested case-control study

BACKGROUND

Use of estrogen-containing menopausal hormone therapy has been shown to influence the risk of central nervous system (CNS) tumors. However, it is unknown how the progestin-component affects the risk and whether continuous versus cyclic treatment regimens influence the risk differently.

METHODS AND FINDINGS

Nested case-control studies within a nationwide cohort of Danish women followed for 19 years from 2000 to 2018. The cohort comprised 789,901 women aged 50 to 60 years during follow-up, without prior CNS tumor diagnosis, cancer, or contraindication for treatment with menopausal hormone therapy. Information on cumulative exposure to female hormonal drugs was based on filled prescriptions. Statistical analysis included educational level, use of antihistamines, and use of anti-asthma drugs as covariates. During follow-up, 1,595 women were diagnosed with meningioma and 1,167 with glioma. The median (first-third quartile) follow-up time of individuals in the full cohort was 10.8 years (5.0 years to 17.5 years). Compared to never-use, exposure to estrogen-progestin or progestin-only were both associated with increased risk of meningioma, hazard ratio (HR) 1.21; (95% confidence interval (CI) [1.06, 1.37] p = 0.005) and HR 1.28; (95% CI [1.05, 1.54] p = 0.012), respectively. Corresponding HRs for glioma were HR 1.00; (95% CI [0.86, 1.16] p = 0.982) and HR 1.20; (95% CI [0.95, 1.51] p = 0.117). Continuous estrogen-progestin exhibited higher HR of meningioma 1.34; (95% CI [1.08, 1.66] p = 0.008) than cyclic treatment 1.13; (95% CI [0.94, 1.34] p = 0.185). Previous use of estrogen-progestin 5 to 10 years prior to diagnosis yielded the strongest association with meningioma, HR 1.26; (95% CI [1.01, 1.57] p = 0.044), whereas current/recent use of progestin-only yielded the highest HRs for both meningioma 1.64; (95% CI [0.90, 2.98] p = 0.104) and glioma 1.83; (95% CI [0.98, 3.41] p = 0.057). Being an observational study, residual confounding could occur.

CONCLUSIONS

Use of continuous, but not cyclic estrogen-progestin was associated with increased meningioma risk. There was no evidence of increased glioma risk with estrogen-progestin use. Use of progestin-only was associated with increased risk of meningioma and potentially glioma. Further studies are warranted to evaluate our findings and investigate the influence of long-term progestin-only regimens on CNS tumor risk.

Potential preventive properties of GLP-1 receptor agonists against prostate cancer: a nationwide cohort study

AIMS/HYPOTHESIS

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have been suggested to possess antineoplastic properties against prostate cancer. We examined the association between GLP-1RA use and prostate cancer risk in a real-world setting.

METHODS

We performed a nationwide register-based cohort study using an active-comparator, new-user design. We included all men in Denmark aged ≥50 years who commenced use of GLP-1RAs or basal insulin during 2007-2019. HRs and 95% CIs for incident prostate cancer were estimated using multivariable Cox regression in 'intention-to-treat' (ITT)- and 'per-protocol'-like analyses.

RESULTS

Among 14,206 initiators of GLP-1RAs and 21,756 initiators of basal insulin, we identified 697 patients with prostate cancer during a mean follow-up period of about 5 years from initiation of the study drugs. In comparison with basal insulin use, GLP-1RA use was associated with an adjusted HR of 0.91 (95% CI 0.73, 1.14) in the 'ITT' analysis and 0.80 (95% CI 0.64, 1.01) in the 'per-protocol' analysis. Stronger inverse associations were seen among older men (≥70 years) ('ITT' HR 0.56; 95% CI 0.38, 0.82; 'per-protocol' HR 0.47; 95% CI 0.30, 0.74), and in patients with CVD ('ITT' HR 0.75; 95% CI 0.53, 1.06; 'per-protocol' HR 0.60; 95% CI 0.39, 0.91).

CONCLUSIONS/INTERPRETATION

GLP-1RA use was inversely associated with prostate cancer risk compared with use of basal insulin in the 'per-protocol' analysis. Older men and patients with CVD exhibited stronger inverse associations in both the 'ITT' and 'per-protocol' analyses. Our results may indicate that GLP-1RA use could protect against prostate cancer.

Central nervous system tumours among users of vaginal oestradiol tablets: A nationwide population-based study

BACKGROUND AND PURPOSE

It is currently unknown whether vaginal oestradiol is associated with development of meningioma and glioma. The aim of this study was to examine associations between cumulative use and treatment intensity of vaginally administered oestradiol tablets and incidence of meningioma and glioma in a nationwide, population-based study.

METHODS

We conducted a nested case-control study within a nationwide cohort of Danish women followed from 2000 to 2018. The cohort consisted of 590,676 women aged 50-60 years at study start, without prior cancer diagnosis or use of systemic hormone therapy. Information on cumulative dose, duration, and intensity of vaginal oestradiol tablet use was assessed from filled prescriptions. Conditional logistic regression provided adjusted hazard ratios (HRs) for the association between vaginal oestradiol use and diagnosis of meningioma or glioma.

RESULTS

We identified 1108 women with meningioma and 835 with glioma. Of these, 19.8% and 14.0% used vaginal oestradiol tablets, respectively. The HRs in those with ever-use of vaginal oestradiol tablets was 1.14 (95% confidence interval [CI] 0.97-1.34) for meningioma and 0.90 (95% CI 0.73-1.11) for glioma. The corresponding HRs for new users exclusively were 1.18 (95% CI 0.99-1.40) for meningioma and 0.89 (95% CI 0.71-1.13) for glioma. Intensity of vaginal oestradiol tablet use according to duration and user status yielded slightly elevated HRs for meningioma without an apparent dose-response pattern, while the HRs for glioma were generally below unity. Among new users, the HR with high intensity of current or recent vaginal oestradiol tablet use for 2+ years was 1.66 (95% CI 1.09-2.55) for meningioma and 0.77 (95% CI 0.41-1.44) for glioma.

CONCLUSION

Use of vaginal oestradiol tablets was associated with a slightly increased incidence of meningioma but not of glioma. Owing to the observational nature of the study, residual bias cannot be ruled out.

A Comparative Study on the Lysosomal Cation Channel TMEM175 Using Automated Whole-Cell Patch-Clamp, Lysosomal Patch-Clamp, and Solid Supported Membrane-Based Electrophysiology: Functional Characterization and High-Throughput Screening Assay Development

The lysosomal cation channel TMEM175 is a Parkinson's disease-related protein and a promising drug target. Unlike whole-cell automated patch-clamp (APC), lysosomal patch-clamp (LPC) facilitates physiological conditions, but is not yet suitable for high-throughput screening (HTS) applications. Here, we apply solid supported membrane-based electrophysiology (SSME), which enables both direct access to lysosomes and high-throughput electrophysiological recordings. In SSME, ion translocation mediated by TMEM175 is stimulated using a concentration gradient at a resting potential of 0 mV. The concentration-dependent K+ response exhibited an I/c curve with two distinct slopes, indicating the existence of two conducting states. We measured H+ fluxes with a permeability ratio of PH/PK = 48,500, which matches literature findings from patch-clamp studies, validating the SSME approach. Additionally, TMEM175 displayed a high pH dependence. Decreasing cytosolic pH inhibited both K+ and H+ conductivity of TMEM175. Conversely, lysosomal pH and pH gradients did not have major effects on TMEM175. Finally, we developed HTS assays for drug screening and evaluated tool compounds (4-AP, Zn as inhibitors; DCPIB, arachidonic acid, SC-79 as enhancers) using SSME and APC. Additionally, we recorded EC50 data for eight blinded TMEM175 enhancers and compared the results across all three assay technologies, including LPC, discussing their advantages and disadvantages.

Were cancer patients worse off than the general population during the COVID-19 pandemic? A population-based study from Norway, Denmark and Iceland during the pre-vaccination era

Background

In a population-based setting, we investigated the risks of testing positive for SARS-CoV-2 and developing severe COVID-19 outcomes among cancer patients compared with the general population.

Methods

In nationwide cohorts, we identified all individuals in Norway, Denmark and Iceland who tested positive for SARS-CoV-2 or had a severe COVID-19 outcome (hospitalisation, intensive care, and death) from March until December 2020, using data from national health registries. We estimated standardised incidence ratios (SIRs) with 95% confidence intervals (CIs) comparing cancer patients with the general population.

Findings

During the first wave of the pandemic, cancer patients in Norway and Denmark had higher risks of testing SARS-CoV-2 positive compared to the general population. Throughout 2020, recently treated cancer patients were more likely to test SARS-CoV-2 positive. In Iceland, cancer patients experienced no increased risk of testing positive. The risk of COVID-19-related hospitalisation was higher among cancer patients diagnosed within one year of hospitalisation (Norway: SIR = 2.43, 95% CI 1.89-3.09; Denmark: 2.23, 1.96-2.54) and within five years (Norway: 1.58, 1.35-1.83; Denmark: 1.54, 1.42-1.66). Risks were higher in recently treated cancer patients and in those diagnosed with haematologic malignancies, colorectal or lung cancer. Risks of COVID-19-related intensive care and death were higher among cancer patients.

Interpretation

Cancer patients were at increased risk of testing positive for SARS-CoV-2 during the first pandemic wave when testing availability was limited, while relative risks of severe COVID-19 outcomes remained increased in cancer patients throughout 2020. Recent cancer treatment and haematologic malignancy were the strongest risk factors.

Funding

Nordic Cancer Union.

Increased mortality in patients with hematologic malignancies treated with proton pump inhibitors: a nationwide cohort study

Proton Pump inhibitors (PPIs) are frequently prescribed to cancer patients to prevent gastric mucosal damage. Post-diagnostic PPI use in patients with solid tumors may be associated with increased cancer mortality. However, the hazardous impact of PPIs in patients with hematologic malignancies remains unknown. This association was investigated in a large, retrospective cohort study using data from the Danish nationwide health registries. The outcomes were cancer-specific or non-cancer deaths. We identified 15,320 patients with hematologic malignancies and of these 1811 were identified as post-diagnostic PPI users. PPI users had significantly increased HRs for cancer-specific mortality (HR 1.31; 95% CI, 1.18-1.44) and 1-year cancer-specific mortality (HR 1.50, 95% CI 1.29-1.74) as compared to nonusers. The association between PPI use and increased cancer-specific mortality in Danish patients with hematologic malignancies supports the raised concerns regarding the frequent use of PPIs in cancer patients.

Influence of various assumptions for the individual TNM components on the TNM stage using Nordic cancer registry data

BACKGROUND

The stage at diagnosis is one of the most important predictors for cancer survival. TNM stage is constructed from T (tumor size), N (nodal spread), and M (distant metastasis) components. In many notifications to cancer registries, TNM information is incomplete with unknown N and/or M. We aimed to evaluate the influence of various assumptions for recoding missing N (NX) and M (MX) as N0 and M0 on the proportion with available TNM stage, stage-distribution, and stage-specific relative survival.

MATERIAL AND METHODS

We identified 140,201 patients diagnosed with incident cancer of the colon, rectum, lung, breast, or kidney during 2014-2016 in Denmark, Norway, Sweden, or Iceland. Information on TNM were obtained from cancer registry records used for an update of the Nordic cancer statistics database NORDCAN. Patients were followed for death or emigration through 2017. We calculated proportions of available TNM stage, stage distribution, and stage-specific relative survival under different approaches for each cancer site and country.

RESULTS

Application of the assumptions yielded higher numbers of cases with available TNM stage for stages 0-I, II, and III. We observed only minor differences in stage-specific one-year relative survival when applying N0M0 for missing N and M, especially for high completeness of TNM registrations, whereas relative survival for remaining cases with missing TNM stage declined substantially.

CONCLUSION

We found no major changes in stage-specific one-year relative survival applying N0M0 for NXMX. We conclude that complete TNM information is preferable to making assumptions, but it seems reasonable to consider assuming N0M0 for missing N and M in future studies based on the Nordic cancer registries. An automatic algorithm, though, is not recommended without considering potential area-specific reasons for frequent use of NX and MX. Clinicians should be urged to report complete TNM information to improve surveillance of the TNM stage.

Abstract P4-03-02: Low-dose aspirin prescriptions and breast cancer recurrence: a Danish nationwide cohort study with up to 23 years of follow-up

Background Low-dose aspirin irreversibly inhibits the cyclooxygenase enzymes COX-1 and COX-2, which catalyze the formation of prostaglandins and thromboxanes, inhibiting platelet aggregation. Platelets are thought to play a role in tumorigenesis. As such, aspirin may have a beneficial effect on breast cancer prognosis, but results to date are conflicting. Objectives To evaluate the association between aspirin use and breast cancer recurrence up to 23 years after primary diagnosis. Methods We included all women diagnosed with non-metastatic breast cancer during 1996-2004 registered in the Danish Breast Cancer Group (DBCG) clinical database. We obtained information on aspirin prescriptions (>= 2 prescriptions filled between cancer diagnosis and the landmark) from the Danish National Prescription Registry. Information on early and late (>10 years after primary diagnosis) recurrence was obtained using the DBCG database (for recurrence within the first 10 years after diagnosis) and for late recurrence via a previously described and validated algorithm, drawing on data from the Danish National Patient Registry, the Danish Pathology Registry, the Danish Cancer Registry and a contralateral breast cancer database. We used Cox regression to compute crude and adjusted hazard ratios (HRs) with 95% confidence intervals (CI) employing landmark analyses starting follow-up at years 5, 10, 15, and 20 after primary diagnosis. We adjusted for potential confounders including calendar year of diagnosis, menopausal status, comorbidities, estrogen receptor status, clinical stage, grade, surgery type, chemo- and endocrine therapy, diagnostic codes for alcoholism and obesity, as well as co-medications (angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, statins, bisphosphonates, metformin, digoxin, hormone replacement therapy, non-steroidal anti-inflammatory drugs, and vitamin K antagonists). We followed patients until recurrence, death, second cancer, loss to follow-up, or 31 December 2018. Results Among 21,684 women with non-metastatic breast cancer, 4,902 experienced recurrence during 242,427 person-years of follow-up. Our landmark analyses showed a reduced hazard of recurrence in the 5-, 10-, and 15-year landmark cohorts (5-year landmark adjusted HR = 0.80, 95% CI = 0.68, 0.94; 10-year landmark adjusted HR = 0.84, 95% CI = 0.71, 1.00, 15-year landmark adjusted HR = 0.83, 95% CI = 0.61, 1.14). The 20-year landmark analysis revealed an adjusted HR of 1.09 (95% CI = 0.49, 2.46). Conclusions The potential anti-cancer effect of aspirin appears most pronounced in the first 15 years after breast cancer diagnosis. Funding Elisabeth Solmunde is funded by the Danish Cancer Society (R320-A18464-B5768) and the Independent Research Fund Denmark (1149-00013B). This work was supported by grants to Deirdre Cronin-Fenton from the Danish Cancer Society (“Knæk Cancer” R147-A10100).

Citation Format: Elisabeth Solmunde, Rikke N Pedersen, Mette Nørgaard, Lene Mellemkjær, Søren Friis, Bent Ejlertsen, Thomas P. Ahern, Deirdre Cronin-Fenton. Low-dose aspirin prescriptions and breast cancer recurrence: a Danish nationwide cohort study with up to 23 years of follow-up [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-03-02.

There is no F in APC: Using physiological fluoride-free solutions for high throughput automated patch clamp experiments

Fluoride has been used in the internal recording solution for manual and automated patch clamp experiments for decades because it helps to improve the seal resistance and promotes longer lasting recordings. In manual patch clamp, fluoride has been used to record voltage-gated Na (NaV) channels where seal resistance and access resistance are critical for good voltage control. In automated patch clamp, suction is applied from underneath the patch clamp chip to attract a cell to the hole and obtain a good seal. Since the patch clamp aperture cannot be moved to improve the seal like the patch clamp pipette in manual patch clamp, automated patch clamp manufacturers use internal fluoride to improve the success rate for obtaining GΩ seals. However, internal fluoride can affect voltage-dependence of activation and inactivation, as well as affecting internal second messenger systems and therefore, it is desirable to have the option to perform experiments using physiological, fluoride-free internal solution. We have developed an approach for high throughput fluoride-free recordings on a 384-well based automated patch clamp system with success rates >40% for GΩ seals. We demonstrate this method using hERG expressed in HEK cells, as well as NaV1.5, NaV1.7, and KCa3.1 expressed in CHO cells. We describe the advantages and disadvantages of using fluoride and provide examples of where fluoride can be used, where caution should be exerted and where fluoride-free solutions provide an advantage over fluoride-containing solutions.

Prescription rates for drugs used in treatment of benign prostatic hyperplasia and erectile dysfunction before and after prostate cancer diagnosis

BACKGROUND

Symptoms and treatment of benign prostatic hyperplasia (BPH) or erectile dysfunction (ED) may lead to prostate cancer workup, and patterns of prescriptions before diagnosis may affect findings of pharmacoepidemiological studies. Usage of BPH and ED drugs after diagnosis may be related to prostate cancer treatment. We investigated differences in prescription rates of BPH and ED drugs among prostate cancer patients and cancer-free comparisons and between patients with localized and non-localized disease.

MATERIAL AND METHODS

A nationwide register-based study, including all Danish men aged 50-85 years diagnosed with prostate cancer during 1998-2015 and an age-matched comparison cohort without cancer. We calculated rates of new and total prescriptions in 1-month intervals from 3 years before to 3 years after cancer diagnosis for drugs used to treat BPH and ED, overall and stratified by clinical stage.

RESULTS

We identified 54,286 men with prostate cancer and a comparison cohort of 249,645 age-matched men. The new prescription rate for BPH drugs increased for men with prostate cancer in the year before diagnosis and peaked 1 month before diagnosis with an 18-fold higher rate. Men with prostate cancer had a higher total prescription rate of BPH drugs 3 years before diagnosis, notably among men with localized disease. Before diagnosis, the new prescription rates for ED drugs were similar among men with prostate cancer and comparisons. After diagnosis, men with prostate cancer had a 7-fold higher rate of new prescriptions for ED drugs. Among men with localized disease, the total prescription rate of ED drugs increased in the months following diagnosis.

CONCLUSION

Differences in prescription rates suggest increased prostate cancer surveillance among men receiving BPH drugs, whereas the post-diagnostic increase in ED drugs among men with localized disease is compatible with the increased risk of ED following prostate cancer treatment.

Hormonal contraception use before and after breast cancer diagnosis: A nationwide drug utilization study

PURPOSE

To describe the use of hormonal contraceptives in Danish breast cancer patients.

METHODS

Nationwide drug utilization study in Danish women diagnosed with breast cancer at ages 13-50 years during 2000-2015. User proportions were estimated in 6-months intervals from 2 years before to 2 years after diagnosis.

RESULTS

Use of hormonal contraceptives declined sharply after breast cancer diagnosis. Still, 7% of patients aged 13-39 years filled hormonal contraceptive prescriptions within 6 months after the diagnosis.

CONCLUSIONS

The majority of premenopausal breast cancer patients discontinues hormonal contraception at diagnosis. All prescribers of hormonal contraceptives should acknowledge that hormonal contraception is contraindicated for breast cancer patients.

PLAIN LANGUAGE SUMMARY

Use of hormonal contraception is contraindicated among women with breast cancer. In this nationwide study, we assessed the use of hormonal contraceptives among all Danish premenopausal women diagnosed with breast cancer during 2000-2015. Hormonal contraceptive use was assessed within 2 years before and 2 years after breast cancer diagnosis. The majority of patients discontinued hormonal contraception at breast cancer diagnosis. However, 7% of patients aged 13-39 years filled hormonal contraceptive prescriptions within 6 months after the diagnosis.

Identification of Drug-Cancer Associations: A Nationwide Screening Study

The main tool in drug safety monitoring, spontaneous reporting of adverse effects, is unlikely to detect delayed adverse drug effects including cancer. Hypothesis-free screening studies based on administrative data could improve ongoing drug safety monitoring. Using Danish health registries, we conducted a series of case-control studies by identifying individuals with incident cancer in Denmark from 2001 to 2018, matching each case with 10 population controls on age, sex, and calendar time. ORs were estimated using conditional logistic regression accounting for matching factors, educational level, and selected comorbidities. A total of 13,577 drug-cancer associations were examined for individual drugs and 8,996 for drug classes. We reviewed 274 drug-cancer pairs where an association with high use and a cumulative dose-response pattern was present. We classified 65 associations as not readily attributable to bias of which 20 were established as carcinogens by the International Agency for Research on Cancer and the remaining 45 associations may warrant further study. The screening program identified drugs with known carcinogenic effects and highlighted a number of drugs that were not established as carcinogens and warrant further study. The effect estimates in this study should be interpreted cautiously and will need confirmation targeted epidemiologic and translational studies.

Significance

This study provides a screening tool for drug carcinogenicity aimed at hypothesis generation and explorative purposes. As such, the study may help to identify drugs with unknown carcinogenic effects and, ultimately, improve drug safety as part of the ongoing safety monitoring of drugs.

Use of beta-blockers and risk of contralateral breast cancer

Beta-blockers have shown antineoplastic effects in laboratory studies but epidemiologic evidence in relation to contralateral breast cancer (CBC) is sparse. We investigated postdiagnosis beta-blocker use and risk of CBC in a cohort of 52 723 women with breast cancer by using nationwide Danish health registers and the Danish Breast Cancer Group database. We defined postdiagnosis beta-blocker use as a time-varying covariate starting 1 year after a second prescription was redeemed. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for CBC associated with beta-blocker use compared to nonuse. We identified 1444 women with CBC of whom 209 women were beta-blocker users. We found an overall HR of 1.08 (95% CI: 0.93-1.27) for beta-blocker use and risk of CBC with no substantial variation according to cumulative amount, intensity or selectivity of beta-blocker use. Hence, our cohort study of women with breast cancer did not sustain a protective effect of beta-blocker use on risk of CBC, irrespective of beta-blocker type.

The impact of the COVID-19 pandemic on cancer diagnosis based on pathology notifications: A comparison across the Nordic countries during 2020

The severity of the COVID-19 pandemic and subsequent mitigation strategies have varied across the Nordic countries. In a joint Nordic population-based effort, we compared patterns of new cancer cases and notifications between the Nordic countries during 2020. We used pathology notifications to cancer registries in Denmark, the Faroe Islands, Finland, Iceland, Norway and Sweden to determine monthly numbers of pathology notifications of malignant and in-situ tumors from January to December 2020 compared to 2019 (2017-2019 for Iceland and the Faroe Islands). We compared new cancer cases per month based on unique individuals with pathology notifications. In April and May 2020, the numbers of new malignant cases declined in all Nordic countries, except the Faroe Islands, compared to previous year(s). The largest reduction was observed in Sweden (May: -31.2%, 95% CI -33.9, -28.3), followed by significant declines in Finland, Denmark and Norway, and a non-significant decline in Iceland. In Denmark, Norway, Sweden and Finland the reporting rates during the second half of 2020 rose to almost the same level as in 2019. However, in Sweden and Finland, the increase did not compensate for the spring decline (annual reduction -6.2% and -3.6%, respectively). Overall, similar patterns were observed for in-situ tumors. The COVID-19 pandemic led to a decline in rates of new cancer cases in Sweden, Finland, Denmark and Norway, with the most pronounced reduction in Sweden. Possible explanations include the severity of the pandemic, temporary halting of screening activities and changes in healthcare seeking behaviour.

Updated fraction of cancer attributable to lifestyle and environmental factors in Denmark in 2018

Environmental exposures and avoidable risk factors account for a large proportion of cancer burden. Exposures and lifestyle vary over time and between populations, which calls for updated and population-specific quantification of how various avoidable risk factors influence cancer risk to plan and design rational and targeted prevention initiatives. The study considered 12 risk-factor groups categorized as class I carcinogens by IARC/WCRF. Exposure data was derived from national studies and surveys and were linked to cancer incidence in 2018 based on the nationwide Danish Cancer Registry. In 2018, 23,078 men and 21,196 women were diagnosed with cancer excluding non-melanoma skin cancer, in Denmark. Of these, 14,235 (32.2%) were estimated to be attributable to avoidable class I carcinogens. Tobacco smoking accounted for 14.6% of total cancers, followed by UV-radiation that accounted for 5.8%. Based on exposure data from 2008, one-third of the cancers in Denmark in 2018 are estimated to be caused by class I carcinogens with tobacco use being the main contributor followed by UV-radiation. Our results should be integrated with public health policies to effectively increase awareness and promote strategies to decrease risk factor exposures at population level.

Prescription rates for commonly used drugs before and after a prostate cancer diagnosis

PURPOSE

To investigate differences in prescription rates of commonly used drugs among prostate cancer patients and cancer-free comparisons and between patients diagnosed with localized and non-localized disease.

METHODS

We conducted a register-based study including all men aged 50-85 years diagnosed with prostate cancer in Denmark from 1998 to 2015 and an age-matched cancer-free comparison cohort. We calculated the number of new and total prescriptions from three years before to three years after the date of diagnosis of the case for selected drug classes divided by the number of person-months and stratified by stage at diagnosis.

RESULTS

We included 54,286 prostate cancer patients and 249,645 matched comparisons. 30,712 patients were diagnosed with localized disease and 12,884 with non-localized disease. The rates of new prescriptions increased considerably among patients within the year before the diagnosis. Hereafter the rates varied between drug classes. For most drug classes, total prescription rates for patients and comparisons increased similarly in the study period. Total prescription rates varied between men with localized and non-localized disease for all drug classes apart from statins.

CONCLUSION

Our findings indicate that a large proportion of prostate cancer cases are likely diagnosed during medical work-up for other reasons than prostate cancer. Increased rates occur within the last year before diagnosis and future studies on the interaction between drug use and prostate cancer should at least include a one year pre-diagnostic lag-time. Post-diagnostic prescription rates demonstrated an increased use of drugs most likely associated with the consequences of the disease.

The M1 and pre-M1 segments contribute differently to ion selectivity in ASICs and ENaCs

The ability to discriminate between different ionic species, termed ion selectivity, is a key feature of ion channels and forms the basis for their physiological function. Members of the degenerin/epithelial sodium channel (DEG/ENaC) superfamily of trimeric ion channels are typically sodium selective, but to a surprisingly variable degree. While acid-sensing ion channels (ASICs) are weakly sodium selective (sodium:potassium ratio ∼10:1), ENaCs show a remarkably high preference for sodium over potassium (>500:1). This discrepancy may be expected to originate from differences in the pore-lining second transmembrane segment (M2). However, these show a relatively high degree of sequence conservation between ASICs and ENaCs, and previous functional and structural studies could not unequivocally establish that differences in M2 alone can account for the disparate degrees of ion selectivity. By contrast, surprisingly little is known about the contributions of the first transmembrane segment (M1) and the preceding pre-M1 region. In this study, we used conventional and noncanonical amino acid-based mutagenesis in combination with a variety of electrophysiological approaches to show that the pre-M1 and M1 regions of mASIC1a channels are major determinants of ion selectivity. Mutational investigations of the corresponding regions in hENaC show that these regions contribute less to ion selectivity, despite affecting ion conductance. In conclusion, our work suggests that the remarkably different degrees of sodium selectivity in ASICs and ENaCs are achieved through different mechanisms. These results further highlight how M1 and pre-M1 are likely to differentially affect pore structure in these related channels.

The suitability of high throughput automated patch clamp for physiological applications

Although automated patch clamp (APC) devices have been around for many years and have become an integral part of many aspects of drug discovery, high throughput instruments with gigaohm seal data quality are relatively new. Experiments where a large number of compounds are screened against ion channels are ideally suited to high throughput APC, particularly when the amount of compound available is low. Here we evaluate different APC approaches using a variety of ion channels and screening settings. We have performed a screen of 1920 compounds on GluN1/GluN2A NMDA receptors for negative allosteric modulation using both the SyncroPatch 384 and FLIPR. Additionally, we tested the effect of 36 arthropod venoms on Na_V 1.9 using a single 384-well plate on the SyncroPatch 384. As an example for mutant screening, a range of acid-sensing ion channel variants were tested and the success rate increased through fluorescence-activated cell sorting (FACS) prior to APC experiments. Gigaohm seal data quality makes the 384-format accessible to recording of primary and stem cell-derived cells on the SyncroPatch 384. We show recordings in voltage and current clamp modes of stem cell-derived cardiomyocytes. In addition, the option of intracellular solution exchange enabled investigations into the effects of intracellular Ca²⁺ and cAMP on TRPC5 and HCN2 currents, respectively. Together, these data highlight the broad applicability and versatility of APC platforms and also outlines some limitations of the approach. KEY POINTS: High throughput automated patch clamp (APC) can be used for a variety of applications involving ion channels. Lower false positive rates were achieved using automated patch clamp versus a fluorometric imaging plate reader (FLIPR) in a high throughput compound screen against NMDA receptors.  Genetic variants and mutations can be screened on a single 384-well plate to reduce variability of experimental parameters. Intracellular solution can be perfused to investigate effects of ions and second messenger systems without the need for excised patches. Primary cells and stem cell-derived cells can be used on high throughput APC with reasonable success rates for cell capture, voltage clamp measurements and action potential recordings in current clamp mode.

Use of antidepressants and endometrial-cancer risk: a nationwide nested case-control study

BACKGROUND

Preclinical studies have suggested that antidepressant drugs may possess antineoplastic properties. In a nationwide case-control study, we examined the association between use of antidepressants and endometrial-cancer risk with a particular focus on selective serotonin reuptake inhibitors (SSRIs).

METHODS

From the Danish Cancer Registry, we identified all women with a histologically verified diagnosis of endometrial cancer between 2000 and 2016, and, for each woman, 15 age-matched controls. We obtained information on use of SSRIs, tricyclic antidepressants (TCAs) and other antidepressants based on records of filled prescriptions from the National Prescription Register. Using conditional logistic regression, we calculated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for associations between use of antidepressants and endometrial-cancer risk compared with non-use. In active comparator analyses, SSRI use was compared with TCA use.

RESULTS

The study population comprised 8164 cases and 122 432 controls. Compared with non-use, SSRI use was associated with an OR of 0.88 (95% CI 0.82-0.96) for endometrial cancer, whereas the association with TCA use was close to unity (OR 1.05, 95% CI 0.90-1.22). Use of other antidepressants yielded an OR of 0.86 (95% CI 0.71-1.03). We observed no apparent trends in associations according to cumulative amount. The inverse association with SSRI use persisted when compared with TCA use (OR 0.81, 95% CI 0.66-0.99).

CONCLUSIONS

Use of SSRIs was associated with a decreased risk of endometrial cancer, whereas no inverse association appeared with use of TCAs. The antineoplastic potential of SSRIs should be investigated in future studies.

Low-dose aspirin use and mortality risk in patients with head and neck cancer: A nationwide cohort study of 10 770 patients

Several recent observational studies have linked low-dose aspirin use to improved survival in patients with head and neck cancer. However, studies of patterns of aspirin use and risk of cancer-specific mortality are lacking. This nationwide cohort study included all patients in the Danish Cancer Registry with a primary diagnosis of head and neck squamous cell cancer (HNSCC) during 2000 to 2016, aged 30 to 84 years, without prior cancer (except nonmelanoma skin cancer) and alive 1 year after diagnosis. Nationwide registries provided information on filled prescriptions, mortality and potential confounding factors. For a subpopulation, a clinical database provided additional information, including human papillomavirus (HPV) tumor status. We used Cox proportional hazards regression models to estimate adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for the association between postdiagnostic low-dose aspirin use (≥1 prescription within first year after diagnosis) and risk of cancer-specific mortality. We identified 10 770 patients with HNSCC during a median follow-up of 3.9 years. Of these, 1799 (16.7%) were low-dose aspirin users. Postdiagnostic use of low-dose aspirin was associated with a HR of 0.97 (95% CI 0.82-1.15) for cancer-specific mortality. Similar neutral associations were found according to patterns of aspirin use. No apparent trends emerged according to age, sex, topography or stage. A tendency towards a decreased cancer-specific mortality risk with low-dose aspirin use was observed among HPV-positive patients; however, the statistical precision was low. In conclusion, we did not observe an association between postdiagnostic low-dose aspirin use and cancer-specific mortality in a nationwide cohort of patients with HNSCC.

The Validity of Danish Prescription Data to Measure Use of Aspirin and Other Non-Steroidal Anti-Inflammatory Drugs and Quantification of Bias Due to Non-Prescription Drug Use

Purpose

To evaluate the potential of Danish prescription registries to capture aspirin and non-aspirin non-steroidal anti-inflammatory drug (NSAID) use and to quantitatively evaluate the magnitude of bias from misclassification of true NSAID and aspirin use as apparent non-use in drug outcome studies.

Patients and Methods

In a population-based cohort study, we retrieved sales statistics for NSAIDs and aspirins based on nationwide data from the Danish Health Data Authority and the Danish National Prescription Registry. We estimated prevalence of recorded and non-recorded NSAID use in the prescription registry and resulting proportions of true NSAID and aspirin use misclassified as apparent non-use from 1999 to 2019 at population and patient levels.

Results

The prevalence of true use misclassified as non-use (mainly due to over-the-counter use) peaked at 4.7% in 2012 for NSAIDs overall, 5.5% in 2012 for ibuprofen, and at 5.9% in 2002 for high-dose aspirin. Misclassification of other individual NSAIDs was near null. Misclassification of true low-dose aspirin use as non-use declined during the study period but remained around 1% since 2005. In subgroups of cardiac patients, the highest prevalence of true NSAID use misclassified as non-use was 5.0% in 2002 and 4.3% in 2017. Quantitative bias analyses showed how such misclassification of true NSAID and aspirin use as non-use remained minimal both at population and patient levels. In hypothetical examples simulating real study populations with differing exposure prevalence and prevalence of true NSAID and aspirin use misclassified as apparent non-use, the approximate percentage change due to misclassification of use as non-use did not exceed 5% and in most scenarios stayed around 1%.

Conclusion

The Danish prescription registries are valid data sources for assessing the effects of aspirin and NSAID use. The influence of non-recorded NSAID and aspirin use on estimates of association is virtually negligible.