Text analysis framework for identifying mutations among non-small cell lung cancer patients from laboratory data

BACKGROUND

Laboratory data can provide great value to support research aimed at reducing the incidence, prolonging survival and enhancing outcomes of cancer. Data is characterized by the information it carries and the format it holds. Data captured in Alberta's biomarker laboratory repository is free text, cluttered and rouge. Such data format limits its utility and prohibits broader adoption and research development. Text analysis for information extraction of unstructured data can change this and lead to more complete analyses. Previous work on extracting relevant information from free text, unstructured data employed Natural Language Processing (NLP), Machine Learning (ML), rule-based Information Extraction (IE) methods, or a hybrid combination between them.

METHODS

In our study, text analysis was performed on Alberta Precision Laboratories data which consisted of 95,854 entries from the Southern Alberta Dataset (SAD) and 6944 entries from the Northern Alberta Dataset (NAD). The data covers all of Alberta and is completely population-based. Our proposed framework is built around rule-based IE methods. It incorporates topics such as Syntax and Lexical analyses to achieve deterministic extraction of data from biomarker laboratory data (i.e., Epidermal Growth Factor Receptor (EGFR) test results). Lexical analysis compromises of data cleaning and pre-processing, Rich Text Format text conversion into readable plain text format, and normalization and tokenization of text. The framework then passes the text into the Syntax analysis stage which includes the rule-based method of extracting relevant data. Rule-based patterns of the test result are identified, and a Context Free Grammar then generates the rules of information extraction. Finally, the results are linked with the Alberta Cancer Registry to support real-world cancer research studies.

RESULTS

Of the original 5512 entries in the SAD dataset and 5017 entries in the NAD dataset which were filtered for EGFR, the framework yielded 5129 and 3388 extracted EGFR test results from the SAD and NAD datasets, respectively. An accuracy of 97.5% was achieved on a random sample of 362 tests.

CONCLUSIONS

We presented a text analysis framework to extract specific information from unstructured clinical data. Our proposed framework has shown that it can successfully extract relevant information from EGFR test results.

Association between treatment and improvements in overall survival of patients with advanced/metastatic non-small cell lung cancer since 2011: A study in the United States, Canada, and Germany using retrospective real-world databases

BACKGROUND

This study aimed to describe treatment patterns and overall survival (OS) in patients with advanced non-small cell lung cancer (aNSCLC) in three countries between 2011 and 2020.

METHODS

Three databases (US, Canada, Germany) were used to identify incident aNSCLC patients. OS was assessed from the date of incident aNSCLC diagnosis and, for patients who received at least a first line of therapy (1LOT), from the date of 1LOT initiation. In multivariable analyses, we analyzed the influence of index year and type of prescribed treatment on OS.

FINDINGS

We included 51,318 patients with an incident aNSCLC diagnosis. The percentage of patients treated with a 1LOT differed substantially between countries, whereas the number of patients receiving immunotherapies/targeted treatments increased over time in all three countries. Median OS from the date of incident diagnosis was 9.9 months in the United States vs. 4.1 months in Canada. When measured from the start of 1LOT, patients had a median OS of 10.7 months in the United States, 10.9 months in Canada, and 10.9 months in Germany. OS from the start of 1LOT improved in all three countries from 2011 to 2020 by approximately 3 to 4 months.

CONCLUSIONS

Observed continuous improvement in OS among patients receiving at least a 1LOT from 2011 to 2020 was likely driven by improved care and changes in the treatment landscape. The difference in the proportion of patients receiving a 1LOT in the observed countries requires further investigation.

The association between neighborhood-level income and cancer stage at diagnosis and survival in Alberta

BACKGROUND

Socioeconomic status (SES) is associated with a range of health outcomes, including cancer diagnosis and survival. However, the evidence for this association is inconsistent between countries with and without single-payer health care systems. In this study, the relationships between neighborhood-level income, cancer stage at diagnosis, and cancer-specific mortality in Alberta, Canada, were evaluated.

METHODS

The Alberta Cancer Registry was used to identify all primary cancer diagnoses between 2010 and 2020. Average neighborhood income was determined by linking the Canadian census to postal codes and was categorized into quintiles on the basis of income distribution in Alberta. Multivariable multinomial logistic regression was used to model the association between income quintile and stage at diagnosis, and the Fine-Gray proportional subdistribution hazards model was used to estimate the association between SES and cancer-specific mortality.

RESULTS

Out of the 143,818 patients with cancer included in the study, those in lower income quintiles were significantly more likely to be diagnosed at stage III (odds ratio [OR], 1.07; 95% CI [confidence interval], 1.06-1.09) or IV (OR, 1.12; 95% CI, 1.11-1.14) after adjusting for age and sex. Lower income quintiles also had significantly worse cancer-specific survival for breast, colorectal, liver, lung, non-Hodgkin lymphoma, oral cavity, pancreas, and prostate cancers.

CONCLUSIONS

Disparities were observed in cancer outcomes across neighborhood-level income groups in Alberta, which demonstrates that health inequities by SES exist in countries with single-payer health care systems. Further research is needed to better understand the underlying causes and to develop strategies to mitigate these disparities.

Real-world impact of patient-reported outcome measurement on overall survival, healthcare use and treatment discontinuation in cancer patients

Aim: The purpose of this retrospective, population-based, observational cohort analysis was to assess whether routine patient-reported outcomes (PRO) monitoring alone has an impact on real-world overall survival (OS) and hospitalizations among individuals diagnosed with lung, breast or colorectal cancer. The importance of follow-up care in post-PRO data collection was also discussed. Patients & methods: Administrative databases covering 17 cancer centers from Alberta, Canada were queried and individuals ≥18 years old and diagnosed with lung, breast or colorectal cancer from 1 January 2016 to 31 December 2019 were included and followed until 31 December 2020. Patients were stratified by whether they received routine PRO monitoring initiated within 120 days of diagnosis and matched 1:1 with use of propensity scores based on baseline characteristics. OS was assessed from the index date to death, and the respective Kaplan-Meier curves were estimated along with hazard ratios from Cox Proportional Hazard Models. Linear and logistic regression models were used to estimate mean differences and odds ratios (OR) respectively for healthcare resource utilization events including cancer physician visits, emergency department visits and outpatient ambulatory care encounters. Results: 4800 patients were included in each matched cohort. There was no statistically significant difference between PRO monitoring and non-monitoring cohorts in OS (HR = 1.01; 95% CI: 0.93-1.09; p = 0.836) and treatment discontinuation (OR = 0.98; 95% CI: 0.85-1.12; p = 0.75). Median OS was 51.5 months for unmonitored cohort (95% CI: 47.5-NA) versus 50.6 months for monitored cohort (95% CI: 47.6-55.7). Compared with PRO-monitored patients, unmonitored patients were associated with lower hospitalization risks (OR = 1.12; 95% CI: 1.03-1.22; p = 0.01). However, PRO-monitored patients experienced significantly fewer physician visits in comparison to unmonitored patients (MD = -1.036; 95% CI: -1.288 to -0.784, p < 0.001). Conclusion: Our results show that capturing patient-reported symptoms alone reduced the number of physician visits but neither reduced hospitalizations nor improved OS in this real-world cancer population. To drive more meaningful clinical impact, PRO monitoring programs must be met with rigorous follow-up response to the identified symptoms.

Time spent in the sun and the risk of developing non-Hodgkin lymphoma: a Canadian cohort study

PURPOSE

The objective was to explore the relationship of sun behavior patterns with the risk of developing non-Hodgkin lymphoma (NHL).

METHODS

Sun behavior information from Alberta's Tomorrow Project, CARTaGENE, and Ontario Health Study were utilized. The relationship between time in the sun during summer months and risk of NHL was assessed using Cox proportional hazard models with age as the time scale and adjustment for confounders. Cohorts were analyzed separately and hazard ratios (HR) pooled with random effects meta-analysis. Joint effects of time in the sun and use of sun protection were examined. Patterns of exposure were explored via combinations of weekday and weekend time in the sun.

RESULTS

During an average follow-up of 7.6 years, 205 NHL cases occurred among study participants (n = 79,803). Compared to < 30 min daily in the sun, we observed HRs of 0.84 (95% CI 0.55-1.28) for 30-59 min, 0.63 (95% CI 0.40-0.98) for 1-2 h, and 0.91 (95% CI 0.61-1.36) for > 2 h. There was suggestive evidence that > 2 h was protective against NHL with use of sun protection, but not without it. Compared to < 30 min daily, moderate exposure (30 min to 2 h on weekdays or weekend) was associated with a lower risk of NHL (HR 0.63, 95% CI 0.43-0.92), while intermittent (< 30 min on weekdays and > 2 h on weekends) and chronic (> 2 h daily) were not.

CONCLUSION

This study provides evidence of a protective effect of moderate time spent in the sun on NHL risk.

Impact of the COVID-19 pandemic on cancer diagnoses, stage and survival in Alberta

BACKGROUND

The COVID-19 pandemic is suspected to have affected cancer care and outcomes among patients in Canada. In this study, we evaluated the impact of the state of emergency period during the COVID-19 pandemic (Mar. 17 to June 15, 2020) on cancer diagnoses, stage at diagnosis and 1-year survival in Alberta.

METHODS

We included new diagnoses of the 10 most prevalent cancer types from Jan. 1, 2018, to Dec. 31, 2020. We followed patients up to Dec. 31, 2021. We used interrupted time series analysis to examine the impact of the first COVID-19-related state of emergency in Alberta on the number of cancer diagnoses. We used multivariable Cox regression to compare 1-year survival of the patients who received a diagnosis during 2020 after the state of emergency with those who received a diagnosis during 2018 and 2019. We also performed stage-specific analyses.

RESULTS

We observed significant reductions in diagnoses of breast cancer (incidence rate ratio [IRR] 0.67, 95% confidence interval [CI] 0.59-0.76), prostate cancer (IRR 0.64, 95% CI 0.56-0.73) and colorectal cancer (IRR 0.64, 95% CI 0.56- 0.74) and melanoma (IRR 0.57, 95% CI 0.47-0.69) during the state of emergency period compared with the period before it. These decreases largely occurred among early-stage rather than late-stage diagnoses. Patients who received a diagnosis of colorectal cancer, non-Hodgkin lymphoma and uterine cancer in 2020 had lower 1-year survival than those diagnosed in 2018; no other cancer sites had lower survival.

INTERPRETATION

The results from our analyses suggest that health care disruptions during the COVID-19 pandemic in Alberta considerably affected cancer outcomes. Given that the largest impact was observed among early-stage cancers and those with organized screening programs, additional system capacity may be needed to mitigate future impact.

Understanding Real-World Treatment Patterns and Clinical Outcomes among Metastatic Melanoma Patients in Alberta, Canada

Immunotherapy and targeted therapies have been shown to considerably improve long-term survival outcomes in metastatic melanoma patients. Real-world evidence on the uptake of novel therapies and outcomes for this patient population in Canada are limited. We conducted a population-based retrospective cohort study of all metastatic melanoma patients diagnosed in Alberta, Canada (2015-2018) using electronic medical records and administrative data. Information on BRAF testing for patients diagnosed in 2017 or 2018 was obtained through chart abstraction. In total, 434 metastatic melanoma patients were included, of which 110 (25.3%) were de novo metastatic cases. The median age at diagnosis was 66 years (IQR: 57-76) and 70.0% were men. BRAF testing was completed for the majority of patients (88.7%). Among all patients, 60.4%, 19.1%, and 6.0% initiated first-line, second-line, and third-line systemic therapy. The most common therapies were anti-PD-1 and targeted therapies. The two-year survival probability from first-line therapy, second-line therapy, and third-line therapy was 0.50 (95% CI: 0.44-0.57), 0.26 (95% CI: 0.17-0.40), and 0.14 (95% CI: 0.40-0.46), respectively. In the first-line setting, survival was highest for patients that received ipilimumab or ipilimumab plus nivolumab, while targeted therapy had the highest survival in the second-line setting. This study indicates that novel therapies improve survival in the real world but a considerable proportion of patients do not receive treatment with systemic therapy.

The Association between Early-Onset Diagnosis and Clinical Outcomes in Triple-Negative Breast Cancer: A Systematic Review and Meta-Analysis

Early-onset diagnosis, defined by age <40 years, has historically been associated with inferior outcomes in breast cancer. Recent evidence suggests that this association is modified by molecular subtype. We performed a systematic review and meta-analysis of the literature to synthesize evidence on the association between early-onset diagnosis and clinical outcomes in triple-negative breast cancer (TNBC). Studies comparing the risk of clinical outcomes in non-metastatic TNBC between early-onset patients and later-onset patients (≥40 years) were queried in Medline and EMBASE from inception to February 2023. Separate meta-analyses were performed for breast cancer specific survival (BCSS), overall survival (OS), and disease-free survival (DFS), locoregional recurrence-free survival (LRRFS), distant recurrence-free survival (DRFS), and pathological complete response (pCR). In total, 7581 unique records were identified, and 36 studies satisfied inclusion criteria. The pooled risk of any recurrence was significantly greater in early-onset patients compared to later-onset patients. Better BCSS and OS were observed in early-onset patients relative to later-onset patients aged >60 years. The pooled odds of achieving pCR were significantly higher in early-onset patients. Future studies should evaluate the role of locoregional management of TNBC and the implementation of novel therapies such as PARP inhibitors in real-world settings, and whether they improve outcomes.

Patient-Reported Symptom Burden and Supportive Care Needs of Patients With Stage II-III Colorectal Cancer During and After Adjuvant Systemic Treatment: A Real-World Evidence Study

PURPOSE

Patients with colorectal cancer (CRC) experience a range of physical and psychologic symptoms, and supportive care needs throughout the illness trajectory. We used patient-reported outcomes and administrative health data to describe symptom burden and supportive care needs during and after adjuvant treatment and determine factors associated with changes to symptom burden.

METHODS

A retrospective population-based cohort study of patients who were newly diagnosed with stage II-III CRC in Alberta, Canada, between January 1, 2016, and January 31, 2019. Adults age 18 years or older who completed a patient-reported outcomes survey (Edmonton Symptom Assessment System) and supportive care needs (Canadian Problem Checklist) within 3 months after starting adjuvant treatment (during treatment) and > 7 months after starting treatment (after treatment) were included. Changes to symptom severity were stratified as stable, improved, or deteriorated. Multivariable logistic regression was used to evaluate factors associated with these changes.

RESULTS

We included 303 patients (median age 60 years, 62% male, 84.5% stage III, 51.2% rectal v colon). Prevalent symptoms included tiredness (80.5%), pain (50.8%), and poor well-being (50%) during treatment, and tiredness (71.3%), pain (44.2%), and poor well-being (62.1%) after treatment. The results were heterogeneous with respect to improvements, stability, or deterioration. Pain worsened for 25% of the cohort, tiredness for 28%, and depression, anxiety, and well-being for 21%, 22%, and 31%, respectively. Deterioration of some symptoms was associated with older age, stage II, comorbidities, rural setting, and higher income.

CONCLUSION

We demonstrated symptom severity was generally low and most symptoms remained stable or improved after treatment. Particular groups of patients were at greater risk for more severe and/or more persistent symptoms. Ongoing assessments and interventions to address physical and psychologic symptoms, and supportive care needs in patients with CRC during and after treatment are needed.

Practice patterns and predictors of treatment intensification in patients with metastatic castration-sensitive prostate cancer

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Background: In recent years, treatment intensification beyond androgen deprivation therapy (ADT) with several novel therapies have shown survival benefit in patients with metastatic castration-sensitive prostate cancer (mCSPC). Given the rapidly evolving landscape in mCSPC treatment, there is a need to better understand how treatment strategies fit in real-world clinical practice and are combined/sequenced with other available therapies. Methods: Using electronic medical records and administrative data, a population-based retrospective cohort study was conducted. Patients aged ≥18 years of age who were newly diagnosed with de novo mCSPC and initiated ADT post-diagnosis between 2010 to 2020 in Alberta, Canada, were included. Treatment intensification was defined as the receipt of apalutamide, abiraterone acetate, enzalutamide, or chemotherapy (e.g. docetaxel) within 180 days of ADT initiation. Results: A total of 2,515 de novo mCSPC were identified during study period with 2,098 (83%) patients initiating ADT post-diagnosis. Of those, 525 (25%) received intensification beyond ADT. The percentage of patients who were intensified was 3% in 2010-2013 and gradually increased to 67% in 2020. Between 2014-2017, docetaxel was the most common therapy for intensification, but its use decreased considerably in 2018-2020 with abiraterone acetate, apalutamide and enzalutamide becoming increasingly available in the mCSPC setting. Upon progression, 46% and 22% in the intensified group versus 38% and 13% in the ADT-alone group initiated one and two-lines of subsequent therapies respectively. Abiraterone acetate and enzalutamide were the most common subsequent therapy for both the intensified (32% and 31% respectively) and the ADT-alone (56% and 38% respectively) groups. Docetaxel (24%) was used as subsequent therapy among mCSPC patients who were intensified with oral systemic agents. In multivariable logistic regression analyses of patients diagnosed in 2014-2020, significant predictors of intensification were younger age at diagnosis, lower Charlson comorbidity index, greater number of metastatic sites, shorter time to ADT initiation, referral to a specialists/cancer centres, surgery or radiation prior to ADT, and more recent year of diagnosis (all p<0.05). Conclusions: In Alberta, Canada, there has been a considerable increase in the utilization of ADT intensification therapies that correspond with the timing of clinical trial data and approvals of novel agents. Early referral to specialists/cancer centres is warranted to intensify mCSPC treatment beyond ADT and to improve patients’ outcomes. [Table: see text]

Evaluating Multiple Next-Generation Sequencing-Derived Tumor Features to Accurately Predict DNA Mismatch Repair Status

Identifying tumor DNA mismatch repair deficiency (dMMR) is important for precision medicine. Tumor features, individually and in combination, derived from whole-exome sequenced (WES) colorectal cancers (CRCs) and panel-sequenced CRCs, endometrial cancers (ECs), and sebaceous skin tumors (SSTs) were assessed for their accuracy in detecting dMMR. CRCs (n = 300) with WES, where mismatch repair status was determined by immunohistochemistry, were assessed for microsatellite instability (MSMuTect, MANTIS, MSIseq, and MSISensor), Catalogue of Somatic Mutations in Cancer tumor mutational signatures, and somatic mutation counts. A 10-fold cross-validation approach (100 repeats) evaluated the dMMR prediction accuracy for i) individual features, ii) Lasso statistical model, and iii) an additive feature combination approach. Panel-sequenced tumors (29 CRCs, 22 ECs, and 20 SSTs) were assessed for the top performing dMMR predicting features/models using these three approaches. For WES CRCs, 10 features provided >80% dMMR prediction accuracy, with MSMuTect, MSIseq, and MANTIS achieving ≥99% accuracy. The Lasso model achieved 98.3% accuracy. The additive feature approach, with three or more of six of MSMuTect, MANTIS, MSIseq, MSISensor, insertion-deletion count, or tumor mutational signature small insertion/deletion 2 + small insertion/deletion 7 achieved 99.7% accuracy. For the panel-sequenced tumors, the additive feature combination approach of three or more of six achieved accuracies of 100%, 95.5%, and 100% for CRCs, ECs, and SSTs, respectively. The microsatellite instability calling tools performed well in WES CRCs; however, an approach combining tumor features may improve dMMR prediction in both WES and panel-sequenced data across tissue types.

Lung Immune Therapy Evaluation (LITE) Risk, a Novel Prognostic Model for Patients With Advanced Non-Small Cell Lung Cancer Treated With Immune Checkpoint Blockade

INTRODUCTION/BACKGROUND

Immune checkpoint inhibitors (ICI) have revolutionized non-small cell lung cancer (NSCLC). We aimed to identify baseline characteristics, that are prognostic factors for overall survival (OS) in patients with NSCLC treated with ICI monotherapy, in order to derive the Lung Immune Therapy Evaluation (LITE) risk, a prognostic model.

MATERIALS AND METHODS

Multi-center observational cohort study of patients with advanced NSCLC that received ≥1 dose of ICI monotherapy. The training set (n=342) consisted of patients with NSCLC who received first line ICI. The test set (n=153) used for external validation was a discrete cohort of patients who received second line ICI. 20 candidate prognostic factors were examined. Penalized Cox regression was used for variable selection. Multiple imputation was used to address missingness.

RESULTS

Three baseline characteristics populated the final model: ECOG (0, 1 or ≥2), lactate dehydrogenase>upper limit of normal, and derived neutrophil to lymphocyte ratio ≥3. Patients were parsed into 3 risk groups; favorable (n=146, risk score 0-1), intermediate (n=101, risk score 2) and poor (n=95, risk score ≥3). The c-statistic of the training cohort was 0.702 and 0.694 after bootstrapping. The test cohort c-statistic was 0.664. The median OS for favorable, intermediate and poor LITE risk were; 28.3 months, 9.1 months and 2.1 months respectively. Improving LITE risk group was associated with improved OS, intermediate vs favorable HR 2.08 (95%CI 1.46-2.97, P < .001); poor vs favorable HR 5.21 (95%CI 3.69-7.34, P < .001).

CONCLUSION

A simple prognostic model, utilizing accessible clinical data, can discriminate survival outcomes in patients with advanced NSCLC.

The impact of population-based EGFR testing in non-squamous metastatic non-small cell lung cancer in Alberta, Canada

OBJECTIVES

While Epidermal Growth Factor Receptor (EGFR) Tyrosine Kinase Inhibitors have been shown to be effective in phase III randomized trials, the value of targeted therapies has been challenging to evaluate at the population-level. We examined the impact of population-level EGFR testing and treatment on survival outcomes among non-squamous metastatic Non-Small Cell Lung Cancer (NSCLC) patients.

MATERIALS AND METHODS

Real-world, population-level data were collected from all de novo non-squamous metastatic NSCLC patients in Alberta, Canada from 2004 to 2020. EGFR testing data were collected through Alberta Precision Laboratories. Differences in survival rates and overall survival (OS) pre (2004-2012) and post initiation (post) (2013-2019) testing periods were evaluated using interrupted time series analyses. The impact of testing and subsequent treatment was evaluated using multivariable Cox Proportional Hazards models.

RESULTS

In total, 4,578 non-squamous metastatic NSCLC patients were diagnosed pre-EGFR testing and 4,457 patients were diagnosed post-EGFR testing (2013-2019). Among patients diagnosed in the pre-EGFR testing period, the 6-month, 1-year, and 2-year survival probabilities were 0.39 (95 % CI: 0.38-0.41), 0.22 (95 % CI: 0.21-0.23), and 0.09 (95 % CI: 0.08-0.10), while the survival probabilities for patients diagnosed in the post-EGFR testing period were 0.45 (95 % CI: 0.43-0.46), 0.29 (95 % CI: 0.27-0.30), and 0.16 (95 % CI: 0.15-0.17), respectively. After adjusting for baseline patient and clinical characteristics, OS in the post-EGFR period was significantly improved compared to the pre-EGFR period (HR: 0.81; 95 % CI: 0.78-0.85). Among patients who were treated with systemic therapy, those tested for an EGFR mutation had significantly greater survival than patients who were not tested HR of 0.81 (95 % CI: 0.70-0.95).

CONCLUSION

These results show the considerable impact of population-based molecular testing and subsequent targeted therapies on survival among metastatic NSCLC patients. The estimates here can be used in future studies to evaluate the population-level cost-effectiveness of testing and treatment.

The association between medical cannabis and prescription opioid medication use in patients with early-stage cancer: A population-based study

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Background: Medical cannabis (MC) and prescription opioid medication (POM) use is common among cancer patients. There is conflicting evidence on the association of cannabis with POM as to whether cannabis can help decrease/ cease opioid use. In this population-based study, we examine the association between MC authorization and cessation or reduction in POM use among patients with early stage cancer. Methods: This is a retrospective, population-based study of patients with early stage (stage I-III) cancer diagnosed between January 1, 2014 and December 31, 2018 in the province of Alberta, Canada. Cases were identified from the Alberta Cancer Registry (ACR) and linked to the provincial pharmacy information network (PIN) and the database from the College of Physician and Surgeons of Alberta (CPSA). Patient and treatment characteristic were used to identify a comparable non-MC group with prior POM use via probabilistic modelling. Descriptive statistics were used to describe differences between patients with and without a MC authorization. Modified Poisson regression was used to compare the likelihood of opioid cessation and reduction among groups. Results: We identified 8,801 patients of whom 326 (3.7%) had a MC authorization. Patients with a MC authorization were younger, had higher stage disease, underwent radiation and/or systemic therapy and had a higher total oral morphine equivalent (OME) use at baseline (p < 0.01). Patients with a MC authorization were less likely to cease POM at 9-12 months post MC authorization (RR 0.63, 95% CI 0.57-0.70), and less likely to reduce their POM dose by 25% (RR 0.79, 95% CI 0.74-0.85) and 50%. (RR 0.73, 95% CI 0.67-0.79). Conclusions: Patients with early stage, non-metastatic cancer with a MC authorization have higher rates of baseline POM use and are less likely to cease or reduce their POM use up to 1 year after MC authorization. Further study is required to understand the harms of concomitant MC and POM use and the impact on survivorship care.

Long-term Use of Hormone Replacement Therapy is Associated With a Lower Risk of Developing High-risk Serrated Polyps in Women

GOALS/BACKGROUND

Hormone replacement therapy (HRT) and parity have been suggested protective factors against the development of colorectal polyps. However, there are a limited number of studies that have examined the relationship of these factors with high-risk adenomatous polyps (HRAP) or high-risk serrated polyps (HRSP), which may have different causes and therefore implications for screening programs.

STUDY

Data from a cross-sectional study of 1384 women undergoing screening-related colonoscopy between 2008 and 2016 were analyzed. Modified Poisson regression models with robust error variance were used to determine the relative risk of developing adenomatous polyps, serrated polyps, HRAPs, and HRSPs associated with pregnancy, menopausal status, and the use of HRT (duration and type).

RESULTS

Women that used HRT for ≥6 years were at a significantly lower risk of developing a HRSP [risk ratios (RR): 0.53; 95% confidence interval (CI): 0.29-0.97]. Irrespective of the duration of use, the use of HRT that included progesterone alone or with estrogen was associated with a significantly lower risk of developing a HRSP (RR: 0.54; 95% CI: 0.30-0.95). The use HRT with progesterone for ≥6 years was associated with a nonsignificant lower risk of developing a HRSP (RR: 0.42; 95% CI: 0.17-1.04). None of the reproductive factors assessed or HRT were associated with the development of adenomatous polyps or HRAPs.

CONCLUSIONS

The results of this study suggests that the long-term use of HRT, and therapies that include progesterone are associated with a lower risk of developing HRSPs. These results could have implications for targeted screening for serrated polyps among women.

The efficacy of chemopreventive agents on the incidence of colorectal adenomas: A systematic review and network meta-analysis

Colorectal cancer (CRC) is the fourth most common cancer and third leading cause of cancer-related death worldwide. Use of chemopreventive agents (CPAs) to reduce the incidence of precursor colorectal adenomas could lower the future burden of CRC. Many classes of potential CPAs have been investigated. To identify the most effective CPAs, we conducted a systematic review and a network meta-analysis (NMA). An electronic search was performed through August 2020 to identify all randomized controlled trials (RCTs) assessing the efficacy of CPAs in reducing the incidence of colorectal adenomas at the time of surveillance colonoscopy among patients who had previously undergone polypectomy during an index colonoscopy. In total, 33 RCTs were included in the NMA, which was conducted under a Bayesian inference framework. Random effects models were used with adjustment for follow-up length and control group event rates to yield relative risks (RRs) and 95% credible intervals (CrIs). Our full network consisted of 13 interventions in addition to a placebo arm. Of 20,925 included patients, 7766 had an adenoma. Compared to placebo, the combination of difluoromethylornithine (DFMO) + Sulindac (RR 0.24, CrI 0.10-0.55) demonstrated a protective effect, while aspirin had a RR of 0.77 (CrI 0.60-1.00), celecoxib 800 mg had a RR of 0.56 (CrI 0.31-1.01) and metformin had a RR of 0.56 (CrI 0.22-1.39). Our results suggest that select CPAs may be efficacious in preventing the development of adenomas. Further studies are needed to identify those patients most likely to benefit and the minimum effective dosages of CPAs.

Stage migration of testicular germ cell tumours in Alberta, Canada, during the COVID-19 pandemic: a retrospective cohort study

BACKGROUND

An absence of screening recommendations and the rapid progression of testicular germ cell tumours (TGCTs) offer a perspective on the potential impact of the COVID-19 pandemic on cancer presentations. We evaluated the presenting cancer stages of TGCTs in a real-world population before and during the pandemic to assess stage migration.

METHODS

We performed a retrospective review of all new patients with TGCT diagnoses in Alberta, Canada, from Dec. 31, 2018, to Apr. 30, 2021, using the Alberta Cancer Registry. Because potential changes in staging should not occur instantaneously, we used a 6-month lag time from Apr. 1, 2020, for seminomas, and a 3-month lag time for nonseminomas, to compare initial cancer stages at presentation before and during the pandemic. We evaluated monthly rates of presentation by stage and histology. Exploratory outcomes included the largest tumour dimension, tumour markers and, for advanced disease, risk category and treatment setting.

RESULTS

Of 335 patients with TGCTs, 231 were diagnosed before the pandemic and 104 during the pandemic (using a lag time). In total, 18 (7.8%) patients diagnosed before the pandemic presented with stage III disease, compared to 16 (15.4%) diagnosed during the pandemic (relative risk 1.97, 95% confidence interval [CI] 1.05-3.72). We observed no significant differences for secondary outcomes. Without a lag time, the rate ratio for a stage II presentation decreased significantly during the pandemic (0.40, 95% CI 0.21-0.72).

INTERPRETATION

We observed signs of TGCT stage migration during the COVID-19 pandemic, driven by a decline in stage II disease and a potential rise in stage III disease. Management of TGCTs should remain a priority, even during a global pandemic.

Treatment patterns and survival outcomes of early-onset colorectal cancer patients in Alberta, Canada: a population-based study

BACKGROUND

The incidence of early-onset (<50) colorectal cancer (eoCRC) has been increasing in Canada. Little is known about treatment patterns and outcomes among this patient population in Canada.

PATIENTS AND METHODS

We conducted a retrospective population-based cohort study of CRC patients in Alberta (2010-2018) using electronic medical records and administrative claims data. Treatment patterns and CRC-specific mortality were compared between early-onset age groups (<40 and 40-49) and average age-at-onset (60-70) (aoCRC) patients with multivariable logistic regression and cox proportional hazard models.

RESULTS

There were 334 and 935 patients in the early-onset groups and 4606 in the aoCRC group. Compared with aoCRC, patients <40 were more likely to receive chemotherapy in stage II colon (OR 3.41, CI 1.75-6.47) and stage III rectal (OR 3.01, CI 1.18-10.21), and to receive systemic therapy (OR 2.40, CI 1.46-4.12) and radiation in stage IV CRC (OR 2.70, CI 1.48-4.92). The 40-49 age group was more likely to receive chemotherapy in stage II colon (OR 2.13, CI 1.25-3.56), and chemoradiation in stage II rectal (OR 2.16, CI 1.25-3.80) and stage III rectal (OR 1.63, CI 1.13-2.40), as well as systemic therapy in stage IV CRC (OR 2.46, CI 1.75-3.52). Survival did not differ between <40 and 60-70 age groups. Survival was significantly higher for the 40-49 age group, but only in stage IV (HR 0.79, CI 0.67-0.94).

CONCLUSIONS

EoCRC patients tended to receive more therapy than average age CRC patients with minimal survival gains. Additional research to identify optimal treatment strategies for eoCRC patients is required.

Understanding patient characteristics, treatment patterns, and clinical outcomes for advanced and recurrent endometrial cancer in Alberta, Canada

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Background: Endometrial cancer (EC) incidence in Canada is steadily increasing and a paucity of real-world data exists. This study aimed to examine treatment (tx) patterns and clinical outcomes for patients (pts) with advanced and recurrent (A/R) EC in Canada. Methods: A retrospective observational cohort study was conducted among pts with primary advanced EC (de novo stage IIIB, IIIC, IV) or recurrent EC (progression from de novo stage I, II, IIIA) between 2010 and 2018 in Alberta, Canada. Health administrative data were used to describe baseline characteristics, time to next tx (TTNT), and overall survival (OS). Using Kaplan-Meier methods, TTNT was defined from tx initiation to initiation of subsequent tx or death from any cause, and OS was examined from tx initiation until death from any cause. Outcomes were stratified by pt type (A/R) and tx. Results: 1,053 pts were included: 620 (58.9%) advanced and 433 (41.1%) recurrent pts. 713 (67.7%) pts received first-line (1L) systemic therapy; this differed by pt type (75.2% of advanced and 57.0% of recurrent pts). Advanced pts who received chemotherapy were more likely to have prior surgery (p < 0.001), radiotherapy (p = 0.01), were younger (p < 0.001), and had fewer comorbidities (p < 0.001) than those without chemotherapy. Platinum-based chemotherapy (PBCT) was the most common 1L regimen (78.6%), differing by pt type (96.1% for advanced and 45.4% for recurrent pts). Hormone therapy in 1L was higher for recurrent compared to advanced pts (27.9% vs 3.2%). Median TTNT and OS from 1L systemic therapy was 19.9 months (95% confidence interval [CI]: 17.5–23.5) and 35.9 months (95% CI: 31.5–53.5), differing by therapy (p < 0.05). Median OS from 1L ranged from 8.5 months (95% CI: 6.2–20.0; platinum monotherapy) to 62.5 months (95% CI: 59.2–NA; hormone therapy). 257 pts received second-line (2L) chemotherapy, with a median TTNT of 7.0 months (95% CI: 6.1–8.2) and median OS of 12.6 months (95% CI: 10.0–14.6). Outcomes differed by tx (p < 0.05), with median OS ranging from 8.0 months (95% CI: 5.9–13.2; non-platinum monotherapy) to 17.1 months (95% CI: 12.7–NA; non-platinum combination). Among pts who received a 1L PBCT, median OS from 2L chemotherapy (N = 187) was 10.4 months (95% CI: 8.9–13.3) and was significantly higher for those rechallenged with PBCT compared to no rechallenge (13.3 months [95% CI: 11.2–20.9] vs 6.4 months [95% CI: 4.6–10.4]). Median OS in third-line (N = 71) and fourth-line (N = 26) chemotherapy was 11.0 months (95% CI: 8.2–13.5) and 12.0 months (95% CI: 7.5–NA), respectively. Outcomes did not differ significantly by pt type (A/R; p≥0.05). Conclusions: Outcomes for pts with A/R EC in Alberta, Canada are poor, particularly following 1L therapy where tx options are limited. Novel therapies with proven efficacy could address this unmet need and improve pt outcomes. Funding: GSK (216962; diana.d.martins@gsk.com).

Trends and disparities in the treatment of older adults with colon cancer

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Background: Adults aged ≥70 years represent approximately half of all patients diagnosed with colon cancer (CC), but undertreatment in this population persists. Recent guidelines have aimed to reduce age-related biases in the treatment of CC and emphasized the importance of personalizing management with comprehensive geriatric assessments (CGAs). Therefore, we hypothesized that age-related disparities in the curative-intent treatment of CC would improve over time. Methods: This was a retrospective, population-based cohort study of adults diagnosed with CC between 2010 and 2018 in Alberta, Canada. The study data included patient demographics and clinical characteristics collected through the Alberta Cancer Registry and electronic medical records. Patients were stratified by age: < 70 and ≥70 years. Cox proportional hazard models (CPHM) were generated to evaluate the associations and interaction between age groups and treatment status on disease-specific survival (DSS), after adjusting for important covariates. Multivariable logistic regression was used to identify time trends and predictors of treatment receipt. Results: A total of 10,838 patients were included, of whom 5,176 (48%) were aged ≥70 years and 2,468 (23%) had stage IV CC at initial diagnosis. Older age was associated with greater comorbidity and less advanced disease ( p < 0.001, standardized mean difference > 0.1 for both). The vast majority (87%) of patients in the overall cohort received surgery while 34% received systemic therapy. In multivariable CPHM, older age was associated with lower DSS (HR 1.42, 95%CI 1.31-1.54, p < 0.001) while surgery and systemic therapy were each associated with higher DSS (HR 0.30, 95%CI 0.27-0.33, p < 0.001; HR 0.40, 95%CI 0.37-0.43, p < 0.001; respectively). However, the interaction between age and treatment status was not statistically significant ( p = 0.78 for surgery; p = 0.17 for systemic therapy). Compared to the younger age group, the odds of receiving surgery and systemic therapy were 3 and 5 times lower, respectively, among older patients (OR 0.27, 95%CI 0.18-0.40, p < 0.001; OR 0.18, 95%CI 0.16-0.20, p < 0.001; respectively). In addition to younger age, predictors of surgery receipt included less comorbidity and stage II/III vs I disease, whereas predictors of systemic therapy receipt included male sex, southern residence, higher neighbourhood income, less comorbidity, and stage III vs IV disease ( p < 0.05 for all). There were no statistically significant correlations between year of diagnosis and treatment receipt ( ptrend = 0.07 for surgery; ptrend = 0.26 for systemic therapy). Conclusions: Surgery and systemic therapy continue to improve CC outcomes regardless of age. However, rates of curative-intent treatment for CC were consistently lower in patients aged ≥70 years, with minimal changes over time. Better integration of CGAs into routine care may be needed to reduce persistent age-related treatment disparities.

Risk Factors for Early-Onset Colorectal Cancer: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Despite the widespread increase in the incidence of early-onset colorectal cancer (EoCRC), the reasons for this increase remain unclear. The objective of this study was to determine risk factors for the development of EoCRC.

METHODS

We conducted a systematic literature review and meta-analysis of studies examining non-genetic risk factors for EoCRC, including demographic factors, comorbidities, and lifestyle factors. Random effects meta-analyses were conducted for risk factors that were examined in at least three studies. Heterogeneity was investigated using the Q-test and I² statistic.

RESULTS

From 3304 initial citations, 20 studies were included in this review. Significant risk factors for EoCRC included CRC history in a first-degree relative (RR 4.21, 95% CI 2.61-6.79), hyperlipidemia (RR 1.62, 95% CI 1.22-2.13), obesity (RR 1.54, 95% CI 1.01-2.35), and alcohol consumption (high vs. non-drinkers) (RR 1.71, 95% CI 1.62-1.80). While smoking was suggestive as a risk factor, the association was not statistically significant (RR 1.35, 95% CI 0.81-2.25). With the exception of alcohol consumption, there was considerable heterogeneity among studies (I² > 60%). Other potential risk factors included hypertension, metabolic syndrome, ulcerative colitis, chronic kidney disease, dietary factors, sedentary behaviour, and occupational exposure to organic dusts, but these were only examined in one or two studies.

CONCLUSIONS

The results of this study advance the understanding of the etiology of EoCRC. High-quality studies conducted on generalizable populations and that comprehensively examine risk factors for EoCRC are required to inform primary and secondary prevention strategies.

Real-world treatment patterns and clinical outcomes in early stage non-small cell lung cancer (eNSCLC) in Canada

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Background: The prognosis of eNSCLC remains uniformly poor. An understanding of current therapies and outcomes can provide insights into how novel therapies can be integrated into our management paradigm. Methods: We conducted a large, retrospective, population-based cohort study of de novo eNSCLC patients (stages IB, IIA, IIB, and IIIA) diagnosed in Alberta, Canada between 2010-2019 using electronic medical records and administrative claims data. The primary objectives were to describe treatment patterns and survival outcomes among eNSCLC patients. In addition, we examined the association between systemic therapy (ST) and overall survival (OS) using multivariable Cox proportional hazards models. Results: A total of 5,126 eNSCLC patients were included. The stage distributions were: 31.0% IB, 13.4% IIA, 17.7% IIB, and 37.9% IIIA. The mean (SD) age was 71.3 (10.3) years and 52.5% were female. 45.3% of patients were referred to a medical oncologist, ranging from 23.7% in stage IB and 58.3% of IIIA. Among stage IB and II patients, 59.2% and 58.1% received surgery, respectively, while 25.7% of stage IIIA patients underwent surgery. 23.6% of patients initiated ST, ranging from 3.5% in stage IB to 38.5% in IIIA. ST use increased over the study period by 9.3% and 19.5% in stage IIB and IIIA disease, respectively. Median follow-up for the cohort was 21.86 months; median OS was 28.18 months (95% CI: 26.56-29.69). Median OS for stage IB, IIA, IIB, and IIIA were 49.01 (95% CI: 45.00-54.15), 36.56 (95% CI: 32.94-42.25), 29.23 (95% CI: 25.32-33.11), and 16.50 (95% CI: 15.39-17.59). Findings from the Cox analyses are tabulated (see Table). For stage IIB and IIIA individuals who received surgery, adjuvant ST was also associated with a decreased likelihood of death [hazard ratios (HR) of 0.77 (95% CI: 0.56-1.07) and 0.69 (95% CI: 0.54-0.89), respectively]. Conclusions: In a Canadian real-world setting, stage IIB and IIIA patients who received adjuvant ST tended to have better survival than patients who did not. However, a considerable proportion of patients are not referred to a medical oncologist to be considered for ST. Improving referral pathways appears to be an essential step to ensure that emerging novel therapies are implemented effectively in the real world so that potential survival gains from new drugs can be realized.[Table: see text]

The impact of population-based EGFR testing in metastatic non-small cell lung cancer in Alberta

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Background: While Epidermal Growth Factor Receptor (EGFR) Tyrosine Kinase Inhibitors have been shown to be effective in phase III randomized trials, the value of targeted therapies have been challenging to evaluate at the population level. We examined the impact of population-level EGFR testing and treatment on survival outcomes among metastatic Non-Small Cell Lung Cancer (NSCLC) patients. Methods: Real-world, population-level data were collected from all de novo metastatic non-squamous NSCLC patients in Alberta, Canada from 2004 to 2020. EGFR testing data were collected through Alberta Precision Laboratories using various text mining approaches. Differences in survival rates and overall survival (OS) pre (2004-2012) and post-initiation (post) (2013-2019) testing periods were evaluated using interrupted time series analyses. The impact of testing and subsequent treatment weas evaluated using multivariable Cox Proportional Hazards models. Results: In total, 4,578 metastatic NSCLC patients with a confirmed non-squamous cell carcinoma histology were diagnosed pre- EGFR testing and 4,457 patients were diagnosed post- EGFR testing (2013-2019). Among patients diagnosed in the pre- EGFR testing period, the 6-month, 1-year, and 2-year survival probabilities were 0.39 (95% CI: 0.38-0.41), 0.22 (95% CI: 0.21-0.23), and 0.09 (95% CI: 0.08-0.10), while the survival probabilities for patients diagnosed in the post- EGFR testing period were 0.45 (95% CI: 0.43-0.46), 0.29 (95% CI: 0.27-0.30), and 0.16 (95% CI: 0.15-0.1 7), respectively. After adjusting for baseline patient and clinical characteristics, OS in the post- EGFR period was significantly improved compared to the pre- EGFR period (HR: 0.81; 95% CI: 0.78-0.85). In the post-EGFR period, among patients who were treated with systemic therapy, those tested for an EGFR mutation had significantly greater survival than patients who were not tested HR of 0.81 (95% CI: 0.70-0.95). Conclusions: These results show the considerable impact of population-based molecular testing and subsequent targeted therapies on survival among advanced NSCLC patients. The estimates here can be used in future studies to evaluate the population-level cost-effectiveness of testing and treatment.

Implications of the United States recommendations for early-age-at-onset colorectal cancer screening in Canada

The United States Preventive Services Task Force (USPSTF) recently issued an updated recommendation for population-based colorectal cancer (CRC) screening starting at age 45, due to a sustained increase in the incidence of early-age-at-onset CRC (eoCRC). A similar increase in the incidence of eoCRC has been observed in Canada since the early 2000s. However, the inherent differences between the US and Canadian health care systems with many different reimbursement and capacity considerations limit the applicability of the recommendations to the Canadian context. In order to facilitate further discussion around Canadian guidelines and recommendations, several research gaps need to be addressed: 1) a detailed understanding of trends in histology, topography, initial stage at diagnosis, and mortality among eoCRC; 2) a detailed analysis of cost-effectiveness outlining the impacts to the current screening programs with potential harms and benefits; 3) a comprehensive understanding of risk factor profiles that may lead to meaningful recommendations for screening decisions within the 40-49 age group in the absence of wide-spread screening programs; and 4) an evaluation of the effectiveness of current and novel screening tests or biomarkers specifically in the 40-49 age group. In the meantime, we suggest that physicians and patients begin discussions about screening at age 45 by reviewing family history and alerting patients to symptoms of CRC, which may increase screening adherence at age 50. This issue will remain an active area of debate with Canada as a careful laggard in changing recommendations, while attempting to balance system considerations with eoCRC trends and patient outcomes.

Real-world treatment patterns, clinical outcomes, and health care resource utilization in advanced unresectable hepatocellular carcinoma

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Background: The incidence of advanced unresectable hepatocellular carcinoma (HCC) is increasing in several developed countries and the prognosis of advanced HCC remains poor. Real-world evidence of treatment patterns and patient outcomes can highlight the unmet clinical need within this population. Methods: We conducted a retrospective population-based cohort study of advanced unresectable HCC patients diagnosed in Alberta, Canada between 2008-2018 using electronic medical records and administrative claims data. A chart review was conducted among patients treated with systemic therapy to capture additional treatment information that is not available in the administrative data. The objectives of this study were to describe the treatment patterns, overall survival, and healthcare resource utilization of advanced HCC patients. Results: A total of 1,297 advanced HCC patients were included in this study, of which 555 (42.8%) were recurrent cases and the remainder were advanced unresectable cases at diagnosis. Median age at diagnosis was 64 (range: 21-94) and 82.1% were men. Only 274 patients (21.1%) received first-line systemic therapy and of those 32 patients (11.7%) initiated second-line therapy. Nearly all of the patients treated with systemic therapy received sorafenib (> 96.4%) in first-line and over half of these patients (55.8%) had a dose reduction during the course of treatment. Patients who received systemic therapy had considerably higher median overall survival (12.23 months; 95% CI: 10.72-14.10) compared to patients not treated with systemic therapy (2.66 months; 95% CI: 2.33-3.12; log-rank p-value < 0.001). Among patients who received first-line systemic therapy, the 2-year and 5-year survival rates were 17.9% (95% CI: 13.7-23.4) and 3.9% (95% CI: 1.8-8.6), respectively. Among patients treated with systemic therapy, overall survival was highest for recurrent cases, patients with Child-Pugh A, patients with hepatitis C virus or multiple known HCC risk factors, and for recurrent patients who received transarterial chemoembolization and ablation (separate procedures) in early stage (log-rank: p < 0.05). No significant differences in survival were observed for dose reduction in first-line therapy, age group, sex, the presence of cirrhosis, or the presence of metastatic disease (log-rank: p > 0.05). Among patients that received first-line systemic therapy, the average time spent in hospital was 9, 9, and 8 days per patient within years 1, 2, and 3, respectively. Conclusions: In a Canadian real-world setting, patients who received systemic therapy had considerably greater survival than those who did not, but the initiation rate was low and dose reductions were common. The low uptake of systemic therapy and the modest survival gains highlight the importance of earlier diagnosis and the need for novel and more effective first-line therapies.

Adverse events associated with endoscopic retrograde cholangiopancreatography: protocol for a systematic review and meta-analysis

INTRODUCTION

Endoscopic retrograde cholangiopancreatography (ERCP) is performed to diagnose and manage conditions of the biliary and pancreatic ducts. Though effective, it is associated with common adverse events (AEs). The purpose of this study is to systematically review ERCP AE rates and report up-to-date pooled estimates.

METHODS AND ANALYSIS

A comprehensive electronic search will be conducted of relevant medical databases through 10 November 2020. A study team of eight data abstracters will independently determine study eligibility, assess quality and abstract data in parallel, with any two concordant entries constituting agreement and with discrepancies resolved by consensus. The primary outcome will be the pooled incidence of post-ERCP pancreatitis, with secondary outcomes including post-ERCP bleeding, cholangitis, perforation, cholecystitis, death and unplanned healthcare encounters. Secondary outcomes will also include rates of specific and overall AEs within clinically relevant subgroups determined a priori. DerSimonian and Laird random effects models will be used to perform meta-analyses of these outcomes. Sources of heterogeneity will be explored via meta-regression. Subgroup analyses based on median dates of data collection across studies will be performed to determine whether AE rates have changed over time.

ETHICS AND DISSEMINATION

Ethics approval is not required for this study as it is a planned meta-analysis of previously published data. Participant consent is similarly not required. Dissemination is planned via presentation at relevant conferences in addition to publication in peer-reviewed journals.PROSPERO registration numberCRD42020220221.

Examining the etiology of early-onset breast cancer in the Canadian Partnership for Tomorrow's Health (CanPath)

PURPOSE

Breast cancer incidence among younger women (under age 50) has increased over the past 25 years, yet little is known about the etiology among this age group. The objective of this study was to investigate relationships between modifiable and non-modifiable risk factors and early-onset breast cancer among three prospective Canadian cohorts.

METHODS

A matched case-control study was conducted using data from Alberta's Tomorrow Project, BC Generations Project, and the Ontario Health Study. Participants diagnosed with breast cancer before age 50 were identified through provincial registries and matched to three control participants of similar age and follow-up. Conditional logistic regression was used to examine the association between factors and risk of early-onset breast cancer.

RESULTS

In total, 609 cases and 1,827 controls were included. A body mass index ≥ 30 kg/m² was associated with a lower risk of early-onset breast cancer (OR 0.65; 95% CI 0.47-0.90), while a waist circumference ≥ 88 cm was associated with an increased risk (OR 1.58; 95% CI 1.18-2.11). A reduced risk was found for women with ≥ 2 pregnancies (OR 0.76; 95% CI 0.59-0.99) and a first-degree family history of breast cancer was associated with an increased risk (OR 1.95; 95% CI 1.47-2.57).

CONCLUSIONS

In this study, measures of adiposity, pregnancy history, and familial history of breast cancer are important risk factors for early-onset breast cancer. Evidence was insufficient to conclude if smoking, alcohol intake, fruit and vegetable consumption, and physical activity are meaningful risk factors. The results of this study could inform targeted primary and secondary prevention for early-onset breast cancer.

Real-world treatment patterns, clinical outcomes, and health care resource utilization in extensive-stage small cell lung cancer in Canada

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Background: Extensive stage small cell lung cancer (ES-SCLC) patients face a high risk of recurrence and a uniformly poor prognosis. Real-world evidence related to treatment patterns, clinical outcomes, and healthcare resource utilization is needed to highlight the unmet clinical need and demand for novel therapies within this patient population. Methods: A population-based, retrospective, longitudinal study of adult ES-SCLC patients diagnosed in the province of Alberta, Canada between January 2010 and December 2018 was conducted using provincial electronic medical records and administrative claims data. Results: A total of 1,941 ES-SCLC patients were included of which 1,465 (75%) initially presented with ES-SCLC and 476 (25%) had recurrent disease. Among newly diagnosed ES-SCLC patients, front-line therapy was as follows: 523 (35.7%) chemotherapy and radiotherapy, 280 (19.1%) chemotherapy alone, 133 (9.1%) radiotherapy alone, and 529 (36.1%) best supportive care. The primary sites of radiation were the chest (67.1%) and the brain (45.7%). Median age at diagnosis was 70 years (range: 39-94) and 50.2% were men. In contrast to the de novo patients, the majority of recurrent cases (71.6%) received no front-line therapy. In the full cohort (de novo and recurrent cases), 46.5% of patients initiated first-line, 8.7% second-line, and 1.4% third-line chemotherapy. The majority of patients received either carboplatin plus etoposide (49.5%) or cisplatin plus etoposide (43.0%) in first-line. Median overall survival was higher for patients who were treated with chemotherapy and radiotherapy (10.59 months; 95% CI: 10.03-11.61) compared to patients who received chemotherapy alone (5.65 months; 95% CI: 5.06-6.12), radiotherapy alone (3.02 months; 95% CI: 2.47-4.01), or best supportive care (0.82 months; 95% CI: 0.72-0.92; log-rank p-value < 0.001). Among patients who received first-line systemic therapy, the 1-year, 2-year and 5-year survival was 29.1% (95% CI: 26.3-32.3), 7.3% (95% CI: 5.7-9.2) and 2.9% (95% CI: 1.8-4.5), respectively and the average time spent in hospital was 17, 11, and 10 days per patient within years 1, 2, and 3, respectively. Conclusions: In a Canadian real-world setting, the initiation of first-line treatment in ES-SCLC was low with significant attrition in subsequent lines. It was evident that patients who received treatment had greater survival compared to those who do not. Collectively, these results underscore the need for effective front-line therapeutic options and highlight the potential for novel therapies to improve patient outcomes.

Detailed incidence and mortality trends of early-onset colorectal cancer in Canada

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Background: There has been a consistent increase in the incidence of early-onset colorectal cancer (eoCRC), under the age of 50, in Canada since the late 1990s. Questions remain surrounding how these trends vary by topography, histology, and stage, and related trends with CRC-specific mortality. Methods: CRC incidence data were obtained from the Canadian Cancer Registry and CRC-specific mortality data from the Canadian Vital Statistics – Death Database for the years 2000 to 2017. Age-specific average annual percent changes (AAPC) in the incidence (by topography and histology) and mortality rates of CRC were estimated using the National Cancer Institute’s Joinpoint Regression Program. To determine age-specific differences (5-year age groups) in CRC diagnosis at late stage (III and IV) for years 2011 to 2017 combined, a logistic regression model adjusting for sex with the 50-54 age group as the referent was conducted. Results: AAPCs and 95% confidence intervals in the rates of incidence (topography and histology) and mortality of eoCRC from 2000 to 2017 in Canada are presented in Table. Different trends in topography were observed across sexes with the largest increases in the distal colon (splenic flexure, descending, and sigmoid) and rectum among males and rectum only among females. Significant increases were observed for non-mucinous adenocarcinomas, while significant decreases were observed for mucinous adenocarcinomas among the 40-49 age group. Compared to the 50-54 age group, only the 45-49 group had a significantly higher odds of developing late-stage colon cancer, while men and adults 25-49 had a higher odds of developing late stage rectal cancer. Despite increases in the incidence of eoCRC there has only been a significant increase in mortality for men aged 20-39. Trends in mortality vary by site, with significant decreases observed for colon cancer-specific mortality among the 40-49 age group and increases in rectal cancer-specific mortality for adults aged 20-49. Conclusions: These results indicate that the largest increases in incidence and mortality for eoCRC have occurred in the rectum and trends have varied by sex. Further research on the etiology and treatment outcomes of eoCRC patients are warranted for this patient population.[Table: see text]

The effect of acute outdoor air pollution on peak expiratory flow in individuals with asthma: A systematic review and meta-analysis

OBJECTIVES

Acute exposures to outdoor air pollution have been shown to reduce lung function in children with asthma, but the effect on adults with asthma has not been established in a meta-analysis. The objective of this study was to conduct a systematic literature review and meta-analysis of studies that assessed the relationship of outdoor air pollution and peak expiratory flow (PEF) in adults with asthma.

METHODS

Studies that contained data on outdoor air pollution levels (PM_10, PM_2.5, or NO₂) and PEF in adults with asthma were eligible for inclusion. Effect estimates were quantified for each air pollution measure using random effects models. Heterogeneity was investigated with the Q-test and I² statistics. Meta-regression and subgroup analyses were conducted to determine differences in effect by air pollution measures and the inclusion of smokers.

RESULTS

A total of 22 effect estimates from 15 studies were included in this review. A 10 μg/m³ increase in acute PM₁₀ exposure was associated with a -0.19 L/min (95% CI: 0.30, -0.09) change in PEF. For both PM₁₀ and PM_2.5, the inclusion of current smokers was a significant source of heterogeneity among studies (meta-regression: p = 0.04 and p = 0.03). Among studies that only included non-smokers, a 10 μg/m³ increase in acute exposure to PM₁₀ and PM_2.5 was associated with changes in PEF of -0.25 L/min (95% CI: 0.38, -0.13) and -1.02 L/min (95% CI: 1.79, -0.24), respectively.

CONCLUSIONS

This study provides evidence that acute increases in PM₁₀ and PM_2.5 levels are associated with decreases in PEF in adults with asthma, particularly among non-smokers.

Developing and validating multivariable prediction models for predicting the risk of 7-day neonatal readmission following vaginal and cesarean birth using administrative databases

BACKGROUND

Approximately 3.5% of deliveries in Canada result in potentially preventable neonatal readmission, often times due to preventable morbidities. With complexities in hospital discharge planning, health care providers may benefit in identifying infants at risk of readmission for additional monitoring.

OBJECTIVES

To develop and validate models for predicting 7-day neonatal readmission following vaginal or cesarean births.

METHODS

All liveborn term singleton infants without congenital anomalies in the province of Alberta who were not admitted to the NICU were identified using perinatal and hospitalization databases. A temporal split-sample was used for model development (2012-2014, vaginal n = 63,378; cesarean n = 21,225) and external validation (2014-2015, vaginal n = 21,583, cesarean n = 7,477). Multivariable logistic regression models using backward stepwise selection were used to identify predictors of 7-day readmission. We evaluated predictors of maternal age, Apgar score, length-of-stay, birthweight, gestational age, parity, residence, and sex. Hosmer-Lemeshow test and c-statistics were used to estimate calibration and discrimination.

RESULTS

The rate of readmission was 3.3% (95% CI 3.1%, 3.4%) and 2.1% (95% CI 1.9%, 2.3%) following vaginal and cesarean births in the development dataset. Prediction model following vaginal birth, excluding predictors of length-of-stay and birthweight, had sub-optimal performance in development (c-statistics 0.69) and validation data (c-statistics 0.68). Prediction model following cesarean birth, excluding predictors of maternal age, birthweight, and residence, had sub-optimal performance in development (c-statistics 0.62) and validation data (c-statistics 0.64). Readmission was observed in 7.9% (95% CI 7.1%, 8.8%) and 4.9% (95% CI 3.9%, 6.1%) of infants of vaginal and cesarean births, respectively, in the top quintile for the risk of 7-day readmission.

CONCLUSION

Using routinely collected administrative data, we developed and validated prediction models for neonatal readmission following vaginal and cesarean births. Presently the model is sub-optimal for use in risk assessment and planning at discharge, however, additional information may improve the predictive performance.

Combinations of modifiable lifestyle behaviours in relation to colorectal cancer risk in Alberta's Tomorrow Project

The objective of this study was to identify distinct clusters of individuals that exhibit unique patterns of modifiable lifestyle-related behaviours and to determine how these patterns are associated with the risk of developing colorectal cancer (CRC). The study consisted of 26,460 participants and 267 CRC cases from Alberta's Tomorrow Project. Exploratory latent class analysis of risk behaviours (obesity, physical inactivity, meat consumption, smoking, alcohol consumption, and fruit and vegetable consumption) and Cox proportional hazard models were utilized. Seven unique behavioural groups were identified, where the risk of CRC was 2.34 to 2.87 times greater for high risk groups compared to the low risk group. Sex-specific models identified higher risk groups among men (Hazard Ratios [HRs]: 3.15 to 3.89) than among women (HRs: 1.99 to 2.19). Targeting groups defined by clustering of behaviours could potentially lead to more effective prevention of CRC on a population level.

Mortality due to cancer treatment delay: systematic review and meta-analysis

OBJECTIVE

To quantify the association of cancer treatment delay and mortality for each four week increase in delay to inform cancer treatment pathways.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Published studies in Medline from 1 January 2000 to 10 April 2020.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Curative, neoadjuvant, and adjuvant indications for surgery, systemic treatment, or radiotherapy for cancers of the bladder, breast, colon, rectum, lung, cervix, and head and neck were included. The main outcome measure was the hazard ratio for overall survival for each four week delay for each indication. Delay was measured from diagnosis to first treatment, or from the completion of one treatment to the start of the next. The primary analysis only included high validity studies controlling for major prognostic factors. Hazard ratios were assumed to be log linear in relation to overall survival and were converted to an effect for each four week delay. Pooled effects were estimated using DerSimonian and Laird random effect models.

RESULTS

The review included 34 studies for 17 indications (n=1 272 681 patients). No high validity data were found for five of the radiotherapy indications or for cervical cancer surgery. The association between delay and increased mortality was significant (P<0.05) for 13 of 17 indications. Surgery findings were consistent, with a mortality risk for each four week delay of 1.06-1.08 (eg, colectomy 1.06, 95% confidence interval 1.01 to 1.12; breast surgery 1.08, 1.03 to 1.13). Estimates for systemic treatment varied (hazard ratio range 1.01-1.28). Radiotherapy estimates were for radical radiotherapy for head and neck cancer (hazard ratio 1.09, 95% confidence interval 1.05 to 1.14), adjuvant radiotherapy after breast conserving surgery (0.98, 0.88 to 1.09), and cervix cancer adjuvant radiotherapy (1.23, 1.00 to 1.50). A sensitivity analysis of studies that had been excluded because of lack of information on comorbidities or functional status did not change the findings.

CONCLUSIONS

Cancer treatment delay is a problem in health systems worldwide. The impact of delay on mortality can now be quantified for prioritisation and modelling. Even a four week delay of cancer treatment is associated with increased mortality across surgical, systemic treatment, and radiotherapy indications for seven cancers. Policies focused on minimising system level delays to cancer treatment initiation could improve population level survival outcomes.

The incidence of young-onset colorectal cancer in Canada continues to increase

BACKGROUND

Despite decreases in the overall incidence of colorectal cancer (CRC) in Canada, a concerning increase has been observed among younger adults in recent years. The aim of this study was to update age-specific incidence trends of CRC from 1971 to 2017 in Canada.

METHODS

Data was obtained from the National Cancer Incidence Reporting System and the Canadian Cancer Registry. Age-specific annual percent changes in the incidence of CRC was estimated using NCI's Joinpoint Regression Program.

RESULTS

The incidence of CRC among adults over age 50 has continued to decrease, while the incidence among adults under the age of 50 has continued to rise. The largest increases have occurred among 20-29 and 30-39 age groups for colon and rectal cancers, respectively.

CONCLUSION

The incidence of CRC among young adults, particularly those under 40, continues to increase among men and women in Canada. Studies examining potential risk factors for young-onset CRC are required.

Mutational landscape differences between young-onset and older-onset breast cancer patients

Background

The incidence of breast cancer among young women (aged ≤40 years) has increased in North America and Europe. Fewer than 10% of cases among young women are attributable to inherited BRCA1 or BRCA2 mutations, suggesting an important role for somatic mutations. This study investigated genomic differences between young- and older-onset breast tumours.

Methods

In this study we characterized the mutational landscape of 89 young-onset breast tumours (≤40 years) and examined differences with 949 older-onset tumours (> 40 years) using data from The Cancer Genome Atlas. We examined mutated genes, mutational load, and types of mutations. We used complementary R packages “deconstructSigs” and “SomaticSignatures” to extract mutational signatures. A recursively partitioned mixture model was used to identify whether combinations of mutational signatures were related to age of onset.

Results

Older patients had a higher proportion of mutations in PIK3CA, CDH1, and MAP3K1 genes, while young-onset patients had a higher proportion of mutations in GATA3 and CTNNB1. Mutational load was lower for young-onset tumours, and a higher proportion of these mutations were C > A mutations, but a lower proportion were C > T mutations compared to older-onset tumours. The most common mutational signatures identified in both age groups were signatures 1 and 3 from the COSMIC database. Signatures resembling COSMIC signatures 2 and 13 were observed among both age groups. We identified a class of tumours with a unique combination of signatures that may be associated with young age of onset.

Conclusions

The results of this exploratory study provide some evidence that the mutational landscape and mutational signatures among young-onset breast cancer are different from those of older-onset patients. The characterization of young-onset tumours could provide clues to their etiology which may inform future prevention. Further studies are required to confirm our findings.

Prognostic factors of adjuvant chemotherapy discontinuation among stage III colon cancer patients: A survey of medical oncologists and a systematic review and meta-analysis

Background

Factors that are prognostic of early discontinuation of adjuvant chemotherapy among stage III colon cancer patients have yet to be described. To address this gap, a survey of medical oncologists and a systematic review and meta‐analysis were conducted.

Methods

A survey was distributed in March 2019 to medical oncologists who treat colon cancer within Alberta, Canada. Clinicians were asked to rank the prognostic importance of a set of variables using a Likert scale and agreement was quantified using a weighted Cohen's kappa. In addition, we systematically searched four databases up to July 2019. Meta‐analyses were conducted using a random‐effects model.

Results

Of the 25 clinicians who were sent the survey, 14 responded. Overall, there was no agreement regarding which variables were prognostic of early discontinuation (weighted Cohen's kappa = 0.12; 95% CI = 0.05‐0.18). From an initial 3927 articles, 18 investigations were identified for inclusion in our review. Based upon evidence from both the survey and the systematic review, the following four variables were identified as being prognostic of early discontinuation: (a) comorbidity (OR_{2+ vs 0} = 1.53; 95% CI = 1.30‐1.79); (b) performance status (OR_{ECOG 2+ vs 0‐1} = 1.33; 95%CI = 1.07‐1.65); (c) T stage (OR_{T4 vs T1‐2} = 1.57; 95% CI = 0.99‐2.50); and (d) chemotherapy regimen (estimates not pooled due to heterogeneity). In addition to these factors, there was some suggestion that age, marital status/social support, muscle mass, N stage, and tumor grade had prognostic value.

Conclusions

Current evidence is heterogeneous and limited. Additional research is needed to confirm our findings and to explore additional prognostic factors.

Effect of outdoor particulate air pollution on FEV1 in healthy adults: a systematic review and meta-analysis

The effect of acute and long-term exposures to outdoor particulate air pollution on lung function in healthy adults is not well established. The objective of this study was to conduct a systematic literature review and meta-analysis of studies that assessed the relationship of outdoor particulate air pollution and lung function in healthy adults. Studies that contained data on outdoor air particulate matter levels (PM₁₀ or PM_2.5) and forced expiratory volume in 1 s (FEV₁) in healthy adults were eligible for inclusion. Effect estimates, in relation to long-term and acute exposures, were quantified separately using random effects models. A total of 27 effect estimates from 23 studies were included in this review. Acute exposures were typically assessed with PM_2.5, while long-term exposures were predominantly represented by PM₁₀ A 10 µg/m3 increase in short-term PM_2.5 exposure (days) was associated with a -7.02 mL (95% CI -11.75 to -2.29) change in FEV₁ A 10 µg/m³ difference in long-term PM₁₀ exposure was associated with a -8.72 mL (95% CI -15.39 to -2.07) annual change in FEV₁ and an absolute difference in FEV₁ of -71.36 mL (95% CI -134.47 to -8.24). This study provides evidence that acute and long-term exposure to outdoor particulate air pollution are associated with decreased FEV₁ in healthy adults. Residual confounding from other risk factors, such as smoking, may explain some of the effect for long-term exposures. More studies are required to determine the relationship of long-term exposure to PM_2.5 and short-term exposure to PM₁₀, which may have different biologic mechanisms.

Estimates of the current and future burden of melanoma attributable to ultraviolet radiation in Canada

Exposure to ultraviolet radiation (UVR) is an established cause of cutaneous melanoma. The purpose of this study was to estimate the current attributable and future avoidable burden of melanoma related to exposure to UVR and modifiable UVR risk behaviors (sunburn, sunbathing, and indoor tanning). The population attributable risk (PAR) associated with UVR in 2015 was estimated by comparing Canadian melanoma incidence rates in 2015 to estimated incidence rates of a 1920 birth cohort. Rates were adjusted for changes in reporting and ethnicity. We estimated PARs for modifiable UVR risk behaviors using Caucasian prevalence data from the Second National Sun Survey and relative risks that are generalizable to Canada from meta-analyses of relevant studies. Attributable cases apply to 98.9% of melanomas in Canada that occur in Caucasians. We also estimated the future burden of UVR risk behaviors using the potential impact fraction framework and potential reductions in prevalence of 10% to 50% from 2018 to 2042. Adult sunburn and sunbathing were associated with increased risks of melanoma of 1.28 (95% CI: 1.15, 1.43) and 1.44 (95% CI: 1.18, 1.76), respectively. In 2015, we estimate that 62.3% of melanomas in Canada were attributable to exposure to UVR and that 29.7% were attributable to the combination of sunburn (7.4%), sunbathing (17.8%), and indoor tanning (7.0%). A 50% reduction in modifiable UVR behaviors could avoid an estimated 11,980 melanoma cases by 2042. Prevention strategies aimed at modifiable UVR behaviors are crucial to reduce the growing burden of melanoma in Canada.

Estimates of the current and future burden of lung cancer attributable to PM2.5 in Canada

The International Agency for Research on Cancer has classified PM_2.5 (fine particulate matter, PM_2.5) as a lung cancer carcinogen in humans. We estimated the proportion of lung cancer cases attributable to PM_2.5 exposure in Canada in 2015, and future avoidable cancers over the period 2016-2042 under different future exposure scenarios. A meta-analysis was conducted to estimate the relative risk of lung cancer associated with PM_2.5 that was generalizable to Canada. A population-weighted Canadian distribution of residential PM_2.5 exposure was estimated annually using ecological-level, satellite-derived PM_2.5 data for the period 1990 to 2009. Population attributable risks (PAR) were estimated for PM_2.5 and applied to lung cancer incidence from the Canadian Cancer Registry. Potential impact fractions based on counterfactual scenarios for the year 2042 were estimated, along with cumulative preventable cases from 2016 to 2042. The relative risk of lung cancer associated with PM_2.5 was 1.09 (95% CI: 1.06-1.12) per an increase of 10 μg/m³. The average population-weighted exposure to PM_2.5 corresponding to a 20-year exposure window from 1990 to 2009 was 8.3 μg/m³. The PAR for PM_2.5 was estimated at 6.9%, accounting for 1739 attributable lung cancer cases in 2015. If patterns of decline in PM_2.5 continue, over 3000 lung cancer cases could be prevented between 2016 and 2042. Exposure to PM_2.5 contributes to a considerable burden of lung cancer in Canada and policies aimed at sustaining outdoor PM_2.5 declines are important for lung cancer prevention in Canada.

The burden of cancer attributable to modifiable risk factors in Canada: Methods overview

Up-to-date estimates of current and projected future cancer burden attributable to various exposures are essential for planning and implementing cancer prevention initiatives. The Canadian Population Attributable Risk of Cancer (ComPARe) study was conducted to: i) estimate the number and proportion of cancers diagnosed among adults in Canada in 2015 that are attributable to modifiable risk factors and ii) project the future avoidable cancers by 2042 under various intervention targets. We estimated the population attributable risk (with 95% confidence intervals) and the potential impact fraction of cancers associated with selected lifestyle, environmental, and infectious factors. Exposure-specific sensitivity analyses were also completed where appropriate. Several exposures of interest included active and passive smoking, obesity and abdominal adiposity, leisure-time physical inactivity, sedentary behaviour, alcohol consumption, insufficient fruit and vegetable intake, red and processed meat consumption, air pollution (PM2.5, NO₂), indoor radon gas, ultraviolet radiation (UVR), hepatitis B and C virus, Helicobacter pylori, Epstein-Barr virus, human papillomavirus, human herpesvirus type 8 and human T-cell lymphotropic virus type 1. We used the 2015 cancer incidence data for 35 cancer sites from the Canadian Cancer Registry and projected cancer incidence to 2042 using historical data from 1983 to 2012. Here, we provide an overview of the data sources and methods used in estimating the current and future cancer burden in Canada. Specific methodologic details for each exposure are included in the individual articles included as part of this special issue.

Estimates of the current and future burden of lung cancer attributable to residential radon exposure in Canada

Radon is widely recognized as a human carcinogen and findings from epidemiologic studies support a causal association between residential radon exposure and lung cancer risk. Our aim was to derive population attributable risks (PAR) to estimate the numbers of incident lung cancer due to residential radon exposure in Canada in 2015. Potential impact fractions for 2042 were estimated based on a series of counterfactuals. A meta-analysis was conducted to estimate the relative risk of lung cancer per 100 Becquerels (Bq)/m³ increase in residential radon exposure, with a pooled estimate of 1.16 (95% CI: 1.07-1.24). The population distribution of annual residential radon exposure was estimated based on a national survey with adjustment for changes in the population distribution over time, the proportion of Canadians living in high-rise buildings, and to reflect annual rather than winter levels. An estimated 6.9% of lung cancer cases in 2015 were attributable to exposure to residential radon, accounting for 1741 attributable cases. If mitigation efforts were to reduce all residential radon exposures that are above current Canadian policy guidelines of 200 Bq/m³ (3% of Canadians) to 50 Bq/m³, 293 cases could be prevented in 2042, and 2322 cumulative cases could be prevented between 2016 and 2042. Our results show that mitigation that exclusively targets Canadian homes with radon exposures above current Canadian guidelines may not greatly alleviate the future projected lung cancer burden. Mitigation of residential radon levels below current guidelines may be required to substantially reduce the overall lung cancer burden in the Canadian population.

Indoor tanning and skin cancer in Canada: A meta-analysis and attributable burden estimation

BACKGROUND

Consistent epidemiologic and experimental studies have demonstrated that UV-emitting tanning devices cause melanoma and non-melanoma skin cancer. The purpose of this study was to estimate the relative risk of skin cancer associated with the use of indoor tanning devices relevant to Canada, to estimate the proportion and number of skin cancers in Canada in 2015 that were attributable to indoor tanning, and to explore differences by age and sex.

METHODS

Skin cancer cases attributable to the use of an indoor tanning devices were estimated using Levin's population attributable risk (PAR) formula. Relative risks for skin cancer subtypes that were relevant to Canada were estimated through meta-analyses and prevalence of indoor tanning was estimated from the 2006 National Sun Survey. Age- and sex-specific melanoma data for 2015 were obtained from the Canadian Cancer Registry, while estimated NMSC incidence data were obtained from the 2015 Canadian Cancer Statistics report.

RESULTS

Ever use of indoor tanning devices was associated with relative risks of 1.38 (95% CI 1.22-1.58) for melanoma, 1.39 (1.10-1.76) for basal cell carcinoma (BCC), and 1.49 (1.23-1.80) for squamous cell carcinoma (SCC). Overall, 7.0% of melanomas, 5.2% of BCCs, and 7.5% of SCCs in 2015 were attributable to ever of indoor tanning devices. PARs were higher for women and decreased with age.

CONCLUSION

Indoor tanning contributes to a considerable burden of skin cancer in Canada. Strategies aimed at reducing use should be increased and a total ban or restrictions on use and UV-intensity should be considered by health regulators.

Physical Activity, Global DNA Methylation, and Breast Cancer Risk: A Systematic Literature Review and Meta-analysis

The extent to which physical activity reduces breast cancer risk through changes in global DNA methylation is unknown. We systematically identified studies that investigated the association between: (i) physical activity and global DNA methylation; or (ii) global DNA methylation and breast cancer risk. Associations were quantified using random-effects models. Heterogeneity was investigated through subgroup analyses and the Q-test and I ² statistics. Twenty-four studies were reviewed. We observed a trend between higher levels of physical activity and higher levels of global DNA methylation [pooled standardized mean difference = 0.19; 95% confidence interval (CI), -0.03-0.40; P = 0.09] which, in turn, had a suggestive association with a reduced breast cancer risk (pooled relative risk = 0.70; 95% CI, 0.49-1.02; P = 0.06). In subgroup analyses, a positive association between physical activity and global DNA methylation was observed among studies assessing physical activity over long periods of time (P = 0.02). Similarly, the association between global DNA methylation and breast cancer was statistically significant for prospective cohort studies (P = 0.007). Despite the heterogeneous evidence base, the literature suggests that physical activity reduces the risk of breast cancer through increased global DNA methylation. This study is the first to systematically overview the complete biologic pathway between physical activity, global DNA methylation, and breast cancer. Cancer Epidemiol Biomarkers Prev; 27(11); 1320-31. ©2018 AACR.

The effect of inflammation-related lifestyle exposures and interactions with gene variants on long interspersed nuclear element-1 DNA methylation

AIM

To examine the relationship between inflammation-related lifestyle factors and long interspersed nuclear element-1 (LINE-1) DNA methylation, and test for interaction by gene variants involved in one-carbon metabolism.

PATIENTS & METHODS

The study population consisted of 280 individuals undergoing colonoscopy screening. Multivariable linear regression was employed to examine associations of physical activity, BMI and NSAID use with LINE-1 DNA methylation and interactions with MTR and MTHFR gene variants.

RESULTS

The highest quartile of physical activity compared with the lowest was associated with higher LINE-1 DNA methylation (p = 0.005). Long-term NSAID use and a normal BMI were associated with increased LINE-1 DNA methylation among individuals with the variant MTR allele (p = 0.02; p = 0.03).

CONCLUSION

This study provides evidence that inflammation-related exposures may influence LINE-1 DNA methylation.

Integrative epigenetic and genetic pan-cancer somatic alteration portraits

Genetic and epigenetic alterations are required for carcinogenesis and the mutation burden across tumor types has been investigated. Here, we investigate epigenetic alterations with a novel measure of global DNA methylation dysregulation, the methylation dysregulation index (MDI), across 14 cancer types in The Cancer Genome Atlas (TCGA) database. DNA methylation data-obtained using Illumina HumanMethylation450 BeadChip-was accessed from TCGA. We calculated the MDI in 14 tumor types (n = 5,592 tumors), using adjacent normal tissues (n = 701) from each tumor site. Copy number alteration, and mutation burden were retrieved from cBioportal (n = 5,152). We tested the relation of subject MDI across tumors and with age, gender, tumor stage, estimated tumor purity, and copy number alterations for both overall MDI and genomic-context-specific MDI. We also investigated the top most dysregulated loci shared across tumor types. There was a broad range of extent in methylation dysregulation across tumor types (P < 2.2E-16). However, a consistent pattern of methylation dysregulation stratified by genomic context was observed across tumor types where the highest dysregulation occurred at non-CpG island regions. Considering other summary measures of somatic alteration, MDI was correlated with copy number alterations but not with mutation burden. Using the top dysregulated CpG sites in common across tumors, 4 classes of cancer types were observed, and the functional consequences of these alterations to gene expression were confirmed. This work identified the global DNA methylation dysregulation patterns across 14 cancer types showing a higher impact for the non-CpG island areas. The most dysregulated loci across cancer types identified common clusters across cancer types that may have implications for future treatment and prevention measures.

Deficiency of mitochondrial modulator MCJ promotes chemoresistance in breast cancer

Despite major advances in early detection and prognosis, chemotherapy resistance is a major hurdle in the battle against breast cancer. Identifying predictive markers and understanding the mechanisms are key steps to overcoming chemoresistance. Methylation-controlled J protein (MCJ, also known as DNAJC15) is a negative regulator of mitochondrial respiration and has been associated with chemotherapeutic drug sensitivity in cancer cell lines. Here we show, in a retrospective study of a large cohort of breast cancer patients, that low MCJ expression in breast tumors predicts high risk of relapse in patients treated with chemotherapy; however, MCJ expression does not correlate with response to endocrine therapy. In a prospective study in breast cancer patients undergoing neoadjuvant therapy, low MCJ expression also correlates with poor clinical response to chemotherapy and decreased disease-free survival. Using MCJ-deficient mice, we demonstrate that lack of MCJ is sufficient to induce mammary tumor chemoresistance in vivo. Thus, loss of expression of this endogenous mitochondrial modulator in breast cancer promotes the development of chemoresistance.

Epigenetic and genetic burden measures are associated with tumor characteristics in invasive breast carcinoma

The development and progression of invasive breast cancer is characterized by alterations to the genome and epigenome. However, the relationship between breast tumor characteristics, disease subtypes, and patient outcomes with the cumulative burden of these molecular alterations are not well characterized. We determined the average departure of tumor DNA methylation from adjacent normal breast DNA methylation using Illumina 450K methylation data from 700 invasive breast tumors and 90 adjacent normal breast tissues in The Cancer Genome Atlas. From this we generated a novel summary measure of altered DNA methylation, the DNA methylation dysregulation index (MDI), and examined the relation of MDI with tumor characteristics and summary measures that quantify cumulative burden of genetic mutation and copy number alterations. Our analysis revealed that MDI was significantly associated with tumor stage (P = 0.017). Across invasive breast tumor subtypes we observed significant differences in genome-wide DNA MDIs (P = 4.9E–09) and in a fraction of the genome with copy number alterations (FGA) (P = 4.6E–03). Results from a linear regression adjusted for subject age, tumor stage, and estimated tumor purity indicated a positive significant association of MDI with both MCB and FGA (P = 0.036 and P < 2.2E–16). A recursively partitioned mixture model of all 3 somatic alteration burden measures resulted in classes of tumors whose epigenetic and genetic burden profile were associated with the PAM50 subtype and mutations in TP53, PIK3CA, and CDH1. Together, our work presents a novel framework for characterizing the epigenetic burden and adds to the understanding of the aggregate impact of epigenetic and genetic alterations in breast cancer.