Breast and bowel cancers diagnosed in people 'too young to have cancer': A blueprint for research using family and twin studies.

Young breast and bowel cancers (e.g., those diagnosed before age 40 or 50 years) have far greater morbidity and mortality in terms of years of life lost, and are increasing in incidence, but have been less studied. For breast and bowel cancers, the familial relative risks, and therefore the familial variances in age-specific log(incidence), are much greater at younger ages, but little of these familial variances has been explained. Studies of families and twins can address questions not easily answered by studies of unrelated individuals alone. We describe existing and emerging family and twin data that can provide special opportunities for discovery. We present designs and statistical analyses, including novel ideas such as the VALID (Variance in Age-specific Log Incidence Decomposition) model for causes of variation in risk, the DEPTH (DEPendency of association on the number of Top Hits) and other approaches to analyse genome-wide association study data, and the within-pair, ICE FALCON (Inference about Causation from Examining FAmiliaL CONfounding) and ICE CRISTAL (Inference about Causation from Examining Changes in Regression coefficients and Innovative STatistical AnaLysis) approaches to causation and familial confounding. Example applications to breast and colorectal cancer are presented. Motivated by the availability of the resources of the Breast and Colon Cancer Family Registries, we also present some ideas for future studies that could be applied to, and compared with, cancers diagnosed at older ages and address the challenges posed by young breast and bowel cancers.

Canadian COVID-19 host genetics cohort replicates known severity associations.

The HostSeq initiative recruited 10,059 Canadians infected with SARS-CoV-2 between March 2020 and March 2023, obtained clinical information on their disease experience and whole genome sequenced (WGS) their DNA. We analyzed the WGS data for genetic contributors to severe COVID-19 (considering 3,499 hospitalized cases and 4,975 non-hospitalized after quality control). We investigated the evidence for replication of loci reported by the International Host Genetics Initiative (HGI); analyzed the X chromosome; conducted rare variant gene-based analysis and polygenic risk score testing. Population stratification was adjusted for using meta-analysis across ancestry groups. We replicated two loci identified by the HGI for COVID-19 severity: the LZTFL1/SLC6A20 locus on chromosome 3 and the FOXP4 locus on chromosome 6 (the latter with a variant significant at P < 5E-8). We found novel significant associations with MRAS and WDR89 in gene-based analyses, and constructed a polygenic risk score that explained 1.01% of the variance in severe COVID-19. This study provides independent evidence confirming the robustness of previously identified COVID-19 severity loci by the HGI and identifies novel genes for further investigation.

Sense of community belonging and influenza vaccine uptake in Canada.

OBJECTIVES: The objectives of this study are to determine the prevalence of influenza vaccine uptake across Canadians aged 18 to 64 years with different sense of community belonging (SoCB) and whether SoCB is associated with uptake of the seasonal influenza vaccine. METHODS: We combined the 2007 to 2014 cycles of the nationally representative Canadian Community Health Survey (N = 301,802). The main exposure, SoCB, was measured as "strong" vs "weak." The outcome of interest was receipt of the influenza vaccine within the preceding 12 months. We used robust Poisson regression to estimate prevalence ratios. Normalized weights were utilized to account for the unequal probability of sample selection. RESULTS: The adjusted prevalence of uptake of seasonal influenza vaccines was modestly greater for individuals with a strong SoCB compared to those with a weak SoCB (PR, 1.12; 95% CI, 1.11, 1.13). Older individuals, females, those with post-secondary education, non-immigrants, those who are married, those with at least one chronic condition, and those residing in a jurisdiction where pharmacists are authorized to administer influenza vaccine and/or where influenza vaccine is universally funded for all residents were more likely to have received an influenza vaccine within the past year. CONCLUSION: Canadians with a strong SoCB had modestly higher uptake of seasonal influenza vaccines. While the association is modest, findings suggest that SoCB may be an important component to investigate further and to consider in efforts aimed to increase the uptake of seasonal influenza vaccines.

RéSUMé: OBJECTIFS: Cette étude vise à déterminer la prévalence de la vaccination antigrippale chez les Canadiens âgés de 18 à 64 ans ayant un sentiment d'appartenance à la communauté différent et de déterminer si ce sentiment est associé à la vaccination contre la grippe saisonnière. MéTHODES: Nous avons combiné les cycles 2007 à 2014 de l'Enquête sur la santé dans les collectivités canadiennes représentative sur le plan national (N = 301 802). L'exposition principale, à savoir le sentiment d'appartenance à la communauté, a été mesurée comme « forte ¼ ou « faible ¼. Le résultat recherché était la réception du vaccin antigrippal au cours des douze derniers mois. Nous avons utilisé une régression de Poisson robuste pour estimer les rapports de prévalence (RP). Des poids normalisés ont été utilisés pour tenir compte de la probabilité inégale de l'échantillonnage. RéSULTATS: La prévalence ajustée de la vaccination contre la grippe saisonnière était légèrement plus élevée chez les personnes ayant un sentiment fort d'appartenance à la communauté par rapport à celles dont ce sentiment était faible (RP : 1,12; IC de 95 % : 1,11, 1,13). Les personnes plus âgées, les femmes, les personnes ayant fait des études supérieures, les non-immigrants, les personnes mariées, les personnes souffrant d'au moins une maladie chronique et les personnes résidant dans une juridiction où les pharmaciens sont autorisés à administrer le vaccin antigrippal et/ou où le vaccin antigrippal est financé de manière universelle pour tous les résidents, étaient plus susceptibles d'avoir reçu un vaccin antigrippal au cours de l'année écoulée. CONCLUSION: Les Canadiens ayant un sentiment fort d'appartenance à la communauté étaient légèrement plus nombreux à s'être fait vacciner contre la grippe saisonnière. Bien que l'association soit modeste, les résultats suggèrent que le sentiment d'appartenance à la communauté pourrait être un élément important à étudier davantage et à prendre en compte dans les efforts visant à augmenter la vaccination contre la grippe saisonnière.

Correlates of Circulating Osteoprotegerin in Women with a Pathogenic or Likely Pathogenic Variant in the BRCA1 Gene.

BACKGROUND: Lower levels of osteoprotegerin (OPG), the decoy receptor for receptor activator of NFκB (RANK)-ligand, have been reported among women with a BRCA1 mutation, suggesting OPG may be marker of cancer risk. Whether various reproductive, hormonal, or lifestyle factors impact OPG levels in these women is unknown. METHODS: BRCA1 mutation carriers enrolled in a longitudinal study, no history of cancer, and a serum sample for OPG quantification, were included. Exposure information was collected through self-reported questionnaire at study enrollment and every 2 years thereafter. Serum OPG levels (pg/mL) were measured using an ELISA, and generalized linear models were used to assess the associations between reproductive, hormonal, and lifestyle exposures at the time of blood collection with serum OPG. Adjusted means were estimated using the fully adjusted model. RESULTS: A total of 701 women with a median age at blood collection of 39.0 years (18.0-82.0) were included. Older age (Spearman r = 0.24; P < 0.001) and current versus never smoking (98.82 vs. 86.24 pg/mL; Pcat < 0.001) were associated with significantly higher OPG, whereas ever versus never coffee consumption was associated with significantly lower OPG (85.92 vs. 94.05 pg/mL; Pcat = 0.03). There were no other significant associations for other exposures (P ≥ 0.06). The evaluated factors accounted for 7.5% of the variability in OPG. CONCLUSIONS: OPG is minimally influenced by hormonal and lifestyle factors among BRCA1 mutation carriers. IMPACT: These findings suggest that circulating OPG levels are not impacted by non-genetic factors in high-risk women.

Trends in infection-related and infection-unrelated cancer incidence among people with and without HIV infection in Ontario, Canada, 1996-2020: a population-based matched cohort study using health administrative data.

BACKGROUND: People with HIV infection are at higher risk for certain cancers than the general population. We compared trends in infection-related and infection-unrelated cancers among people with and without HIV infection. METHODS: We conducted a retrospective population-based matched cohort study of adults with and without HIV infection using linked health administrative databases in Ontario, Canada. Participants were matched on birth year, sex, census division (rurality), neighbourhood income quintile and region of birth. We followed participants from cohort entry until the earliest of date of cancer diagnosis, date of death, Nov. 1, 2020, or date of loss to follow-up. Incident cancers identified from Jan. 1, 1996, to Nov. 1, 2020, were categorized as infection-related or-unrelated. We examined calendar periods 1996-2003, 2004-2011 and 2012-2020, corresponding to the early combination antiretroviral therapy (cART), established cART and contemporary cART eras, respectively. We used competing risk analyses to examine trends in cumulative incidence by calendar period, age and sex, and cause-specific hazard ratios (HRs). RESULTS: We matched 20 304 people with HIV infection to 20 304 people without HIV infection. A total of 2437 cancers were diagnosed, 1534 (62.9%) among infected people and 903 (37.0%) among uninfected people. The risk of infection-related cancer by age 65 years for people with HIV infection decreased from 19.0% (95% confidence interval [CI] 15.6%-22.3%) in 1996-2011 to 10.0% (95% CI 7.9%-12.1%) in 2012-2020. Compared to uninfected people, those with HIV infection had similar HRs of infection-unrelated cancer but increased rates of infection-related cancer, particularly among younger age groups (25.1 [95% CI 13.2-47.4] v. 1.9 [95% CI 1.0-3.7] for age 18-39 yr v. ≥ 70 yr); these trends were consistent when examined by sex.Interpretation: We observed significantly higher rates of infection-related, but not infection-unrelated, cancer among people with HIV infection than among uninfected people. The elevated rate of infection-related cancer in 2012-2020 highlights the importance of early and sustained antiretroviral therapy along with cancer screening and prevention measures.

Linkage of whole genome sequencing and administrative health data in autism: A proof of concept study.

Whether genetic testing in autism can help understand longitudinal health outcomes and health service needs is unclear. The objective of this study was to determine whether carrying an autism-associated rare genetic variant is associated with differences in health system utilization by autistic children and youth. This retrospective cohort study examined 415 autistic children/youth who underwent genome sequencing and data collection through a translational neuroscience program (Province of Ontario Neurodevelopmental Disorders Network). Participant data were linked to provincial health administrative databases to identify historical health service utilization, health care costs, and complex chronic medical conditions during a 3-year period. Health administrative data were compared between participants with and without a rare genetic variant in at least 1 of 74 genes associated with autism. Participants with a rare variant impacting an autism-associated gene (n = 83, 20%) were less likely to have received psychiatric care (at least one psychiatrist visit: 19.3% vs. 34.3%, p = 0.01; outpatient mental health visit: 66% vs. 77%, p = 0.04). Health care costs were similar between groups (median: $5589 vs. $4938, p = 0.4) and genetic status was not associated with odds of being a high-cost participant (top 20%) in this cohort. There were no differences in the proportion with complex chronic medical conditions between those with and without an autism-associated genetic variant. Our study highlights the feasibility and potential value of genomic and health system data linkage to understand health service needs, disparities, and health trajectories in individuals with neurodevelopmental conditions.

Canadian Healthcare Professionals' Views and Attitudes toward Risk-Stratified Breast Cancer Screening.

Given the controversy over the effectiveness of age-based breast cancer (BC) screening, offering risk-stratified screening to women may be a way to improve patient outcomes with detection of earlier-stage disease. While this approach seems promising, its integration requires the buy-in of many stakeholders. In this cross-sectional study, we surveyed Canadian healthcare professionals about their views and attitudes toward a risk-stratified BC screening approach. An anonymous online questionnaire was disseminated through Canadian healthcare professional associations between November 2020 and May 2021. Information collected included attitudes toward BC screening recommendations based on individual risk, comfort and perceived readiness related to the possible implementation of this approach. Close to 90% of the 593 respondents agreed with increased frequency and earlier initiation of BC screening for women at high risk. However, only 9% agreed with the idea of not offering BC screening to women at very low risk. Respondents indicated that primary care physicians and nurse practitioners should play a leading role in the risk-stratified BC screening approach. This survey identifies health services and policy enhancements that would be needed to support future implementation of a risk-stratified BC screening approach in healthcare systems in Canada and other countries.

Association between estimated cardiorespiratory fitness and breast cancer: a prospective cohort study.

OBJECTIVE: To examine the association between cardiorespiratory fitness (CRF) and the risk of breast cancer in postmenopausal women. METHODS: This study used data from 17 840 cancer-free postmenopausal women with a CRF assessment from the UK Biobank. High estimated CRF (eCRF) was categorised as being >80th percentile within 10-year age bands. Fine and Gray regression was used to examine the association between eCRF and breast cancer risk, accounting for both non-breast cancer diagnoses and all-cause mortality as competing risks. Age was used as the time scale. Several different models were produced, including those adjusting for known breast cancer risk factors, and stratified by measures of body fat (body mass index and per cent body fat). RESULTS: Over a median follow-up of 11.0 years there were 529 cases of invasive breast cancer, 1623 cases of non-breast cancer disease and 241 deaths. With adjustment for breast cancer risk factors, high eCRF was associated with a 24% (subdistribution HR (SDHR) 0.76, 95% CI 0.60 to 0.97) lower risk of breast cancer. When stratified by measures of body fat, we found evidence of effect measure modification. Mainly, having high eCRF was only associated with a lower risk of breast cancer among those classified as having overweight/obesity (SDHR 0.33, 95% CI 0.11 to 1.01) or percentage body fat above the 1st quintile (SDHR 0.65, 95% CI 0.45 to 0.94). CONCLUSION: Having higher CRF may be a protective factor against breast cancer in postmenopausal women but only for women with elevated body fat.

Validation of the International Breast Cancer Intervention Study (IBIS) model in the High Risk Ontario Breast Screening Program: A retrospective cohort study.

PURPOSE: Women with a remaining lifetime risk of breast cancer of ≥25%, estimated using the International Breast Cancer Intervention Study (IBIS) model, were eligible for the High Risk Ontario Breast Screening Program. This study examined the performance of IBIS 10-year risk estimates in the program. METHODS: This retrospective study included 7487 women aged 30 to 69 years referred to the High Risk Ontario Breast Screening Program between July 1, 2011, and December 31, 2016, with follow-up until December 31, 2018. Model calibration and discrimination were assessed. Analyses were conducted overall and stratified by age (< or ≥50 years). Different 10-year risk thresholds were compared with the current eligibility criteria. RESULTS: Overall, IBIS overestimated the risk of breast cancer with an expected vs observed case ratio of 1.17 (95% CI = 1.04-1.35). Overestimation was highest in women aged 50 to 69 years (expected vs observed case ratio = 1.29, 95% CI = 1.03-1.69) and for those in the top quartile of risk. Overall discrimination was fair with a concordance statistic of 0.66 (95% CI = 0.63-0.70). Furthermore, when using different 10-year risk eligibility thresholds, most cases would have been missed in the 30 to 49 age group using the 8% 10-year risk threshold, whereas relatively few women aged 50 to 69 would have been ineligible at any of the thresholds examined. CONCLUSION: We found that IBIS overestimated the risk of breast cancer in this screening cohort but had adequate discrimination. Age-specific risk thresholds should be considered to optimize the program eligibility criteria.

Screening behaviours, demographics, and stage at diagnosis in the publicly funded Ontario Breast Screening Program.

PURPOSE: The Ontario Breast Screening Program (OBSP) offers free screening mammograms every 2 years, to women aged 50-74. Study objectives were to determine demographic characteristics associated with the adherence to OBSP and if women screened in the OBSP have a lower stage at diagnosis than non-screened eligible women. METHODS: We used the Ontario cancer registry (OCR) to identify 48,927 women, aged 51-74 years, diagnosed with breast cancer between 2010 and 2017. These women were assigned as having undergone adherent screening (N = 26,108), non-adherent screening (N = 6546) or not-screened (N = 16,273) in the OBSP. We used multinomial logistic regression to investigate the demographic characteristics associated with screening behaviour, as well as the association between screening status and stage at diagnosis. RESULTS: Among women with breast cancer, those living in rural areas (versus the largest urban areas) had a lower odds of not being screened (odds ratio [OR] 0.73, 95% confidence interval [CI] 0.68, 0.78). Women in low-income (versus high-income) communities were more likely not to be screened (OR 1.42, 95% CI 1.33, 1.51). When stratified, the association between income and screening status only held in urban areas. Non-screened women were more likely to be diagnosed with stage II (OR 1.91, 95% CI 1.82, 2.01), III (OR 2.96, 95% CI 2.76, 3.17), or IV (OR 8.96, 95% CI 7.94, 10.12) disease compared to stage I and were less likely to be diagnosed with ductal carcinoma in situ (DCIS) (OR 0.91, 95% CI 0.84-0.98). CONCLUSIONS: This study suggests that targeting OBSP recruitment efforts to lower income urban communities could increase screening rates. OBSP adherent women were more likely to be diagnosed with earlier stage disease, supporting the value of this initiative and those like it.

Maternal acetaminophen use and cognitive development at 4 years: the Ontario Birth Study.

BACKGROUND: Studies have suggested a link between prenatal maternal acetaminophen use and adverse developmental outcomes in children. However, there exists a knowledge gap regarding overall cognitive development and use of acetaminophen, especially concerning the timing of use in pregnancy. This study aimed to characterize the relationship between maternal acetaminophen use and cognitive development at 4 years. METHODS: This analysis included data collected throughout pregnancy and delivery from women in the Ontario Birth Study prospective cohort from 2013 to 2019 and from the NIH Toolbox Early Childhood Cognition battery administered to 4-year-old children between 2018 and 2021 (n = 436). The exposure was maternal acetaminophen use and the primary outcome was a cognition composite score. The relationship between exposure and outcome was determined using Poisson regression with a robust error variance. RESULTS: We did not observe any association between maternal acetaminophen intake any time before or during pregnancy and low cognition composite score of offspring. The IRR of suboptimal overall cognition was 1.38 (0.78-2.45), 1.22 (0.67-2.22), 0.80 (0.44-1.47), and 1.56 (0.74-3.29) for maternal use of acetaminophen before, in early, late, or overall pregnancy, respectively. CONCLUSION: Current data do not provide evidence to support a relationship of maternal acetaminophen use during pregnancy with adverse cognitive effects at 4 years. IMPACT: Acetaminophen use during pregnancy may influence the risk of child neurocognitive disorders, but there is conflicting evidence of its relationship to sub-clinical measures of cognitive development such as executive function. The study design allowed us to examine the role of timing of acetaminophen use in its relationship with cognitive development, based on a validated and standardized tablet-administered instrument for children, instead of a teacher or parent report. We did not observe a clear relationship between maternal acetaminophen use at different timepoints during pregnancy and child cognitive development.

Considerations of biomarker application for cancer continuum in the era of precision medicine.

Purpose of the review: The goal of this review is to highlight emerging biomarker research by the key phases of the cancer continuum and outline the methodological considerations for biomarker application. Recent findings: While biomarkers have an established role in targeted therapy and to some extent, disease monitoring, their role in early detection and survivorship remains to be elucidated. With the advent of omics technology, the discovery of biomarkers has been accelerated exponentially, therefore careful consideration to ensure an unbiased study design and robust validity is crucial. Summary: The rigor of biomarker research holds the key to the success of precision health care. The potential clinical utility and the feasibility of implementation should be central to future biomarker research study design.

Polygenic risk scores and risk-stratified breast cancer screening: Familiarity and perspectives of health care professionals.

PURPOSE: Health care professionals are expected to take on an active role in the implementation of risk-based cancer prevention strategies. This study aimed to explore health care professionals' (1) self-reported familiarity with the concept of polygenic risk score (PRS), (2) perceived level of knowledge regarding risk-stratified breast cancer (BC) screening, and (3) preferences for continuing professional development. METHODS: A cross-sectional survey was conducted using a bilingual-English/French-online questionnaire disseminated by health care professional associations across Canada between November 2020 and May 2021. RESULTS: A total of 593 professionals completed more than 2 items and 453 responded to all questions. A total of 432 (94%) participants were female, 103 (22%) were physicians, and 323 (70%) were nurses. Participants reported to be unfamiliar with (20%), very unfamiliar (32%) with, or did not know (41%) the concept of PRS. Most participants reported not having enough knowledge about risk-stratified BC screening (61%) and that they would require more training (77%). Online courses and webinar conferences were the preferred continuing professional development modalities. CONCLUSION: The study indicates that health care professionals are currently not familiar with the concept of PRS or a risk-stratified approach for BC screening. Online information and training seem to be an essential knowledge transfer modality.

MRI background parenchymal enhancement, breast density and breast cancer risk factors: A cross-sectional study in pre- and post-menopausal women.

Breast tissue enhances on contrast MRI and is called background parenchymal enhancement (BPE). Having high BPE has been associated with an increased risk of breast cancer. We examined the relationship between BPE and the amount of fibroglandular tissue on MRI (MRI-FGT) and breast cancer risk factors. This was a cross-sectional study of 415 women without breast cancer undergoing contrast-enhanced breast MRI at Memorial Sloan Kettering Cancer Center. All women completed a questionnaire assessing exposures at the time of MRI. Prevalence ratios (PR) and 95% confidence intervals (CI) describing the relationship between breast cancer risk factors and BPE and MRI-FGT were generated using modified Poisson regression. In multivariable-adjusted models a positive association between body mass index (BMI) and BPE was observed, with a 5-unit increase in BMI associated with a 14% and 44% increase in prevalence of high BPE in pre- and post-menopausal women, respectively. Conversely, a strong inverse relationship between BMI and MRI-FGT was observed in both pre- (PR = 0.66, 95% CI 0.57, 0.76) and post-menopausal (PR = 0.66, 95% CI 0.56, 0.78) women. Use of preventive medication (e.g., tamoxifen) was associated with having low BPE, while no association was observed for MRI-FGT. BPE is an imaging marker available from standard contrast-enhanced MRI, that is influenced by endogenous and exogenous hormonal exposures in both pre- and post-menopausal women.

The burden of cancer among people living with HIV in Ontario, Canada, 1997-2020: a retrospective population-based cohort study using administrative health data.

BACKGROUND: With combination antiretroviral therapy (ART) and increased longevity, cancer is a leading cause of morbidity among people with HIV. We characterized trends in cancer burden among people with HIV in Ontario, Canada, between 1997 and 2020. METHODS: We conducted a population-based, retrospective cohort study of adults with HIV using linked administrative health databases from Jan. 1, 1997, to Nov. 1, 2020. We grouped cancers as infection-related AIDS-defining cancers (ADCs), infection-related non-ADCs (NADCs) and infection-unrelated cancers. We calculated age-standardized incidence rates per 100 000 person-years with 95% confidence intervals (CIs) using direct standardization, stratified by calendar period and sex. We also calculated limited-duration prevalence. RESULTS: Among 19 403 adults living with HIV (79% males), 1275 incident cancers were diagnosed. From 1997-2000 to 2016- 2020, we saw a decrease in the incidence of all cancers (1113.9 [95% CI 657.7-1765.6] to 683.5 [95% CI 613.4-759.4] per 100 000 person-years), ADCs (403.1 [95% CI 194.2-739.0] to 103.8 [95% CI 79.2-133.6] per 100 000 person-years) and infection-related NADCs (196.6 [95% CI 37.9-591.9] to 121.9 [95% CI 94.3-154.9] per 100 000 person-years). The incidence of infection-unrelated cancers was stable at 451.0 per 100 000 person-years (95% CI 410.3-494.7). The incidence of cancer among females increased over time but was similar to that of males in 2016-2020. INTERPRETATION: Over a 24-year period, the incidence of cancer decreased overall, largely driven by a considerable decrease in the incidence of ADC, whereas the incidence of infection-unrelated cancer remained unchanged and contributed to the greatest burden of cancer. These findings could reflect combination ART-mediated changes in infectious comorbidity and increased life expectancy; targeted cancer screening and prevention strategies are needed.

Association of contralateral breast cancer risk with mammographic density defined at higher-than-conventional intensity thresholds.

Mammographic dense area (MDA) is an established predictor of future breast cancer risk. Recent studies have found that risk prediction might be improved by redefining MDA in effect at higher-than-conventional intensity thresholds. We assessed whether such higher-intensity MDA measures gave stronger prediction of subsequent contralateral breast cancer (CBC) risk using the Women's Environment, Cancer, and Radiation Epidemiology (WECARE) Study, a population-based CBC case-control study of ≥1 year survivors of unilateral breast cancer diagnosed between 1990 and 2008. Three measures of MDA for the unaffected contralateral breast were made at the conventional intensity threshold ("Cumulus") and at two sequentially higher-intensity thresholds ("Altocumulus" and "Cirrocumulus") using the CUMULUS software and mammograms taken up to 3 years prior to the first breast cancer diagnosis. The measures were fitted separately and together in multivariable-adjusted logistic regression models of CBC (252 CBC cases and 271 unilateral breast cancer controls). The strongest association with CBC was MDA defined using the highest intensity threshold, Cirrocumulus (odds ratio per adjusted SD [OPERA] 1.40, 95% CI 1.13-1.73); and the weakest association was MDA defined at the conventional threshold, Cumulus (1.32, 95% CI 1.05-1.66). In a model fitting the three measures together, the association of CBC with Cirrocumulus was unchanged (1.40, 95% CI 0.97-2.05), and the lower brightness measures did not contribute to the CBC model fit. These results suggest that MDA defined at a high-intensity threshold is a better predictor of CBC risk and has the potential to improve CBC risk stratification beyond conventional MDA measures.

Platelet Count and Survival after Cancer.

Thrombocytosis is associated with cancer progression and death for many cancer types. It is unclear if platelet count is also associated with cancer survival. We conducted a cohort study of 112,231 adults in Ontario with a diagnosis of cancer between January 2007 and December 2016. We included patients who had a complete blood count (CBC) completed in the 30 days prior to their cancer diagnosis. Subjects were assigned to one of three categories according to platelet count: low (≤25th percentile), medium (>25 to <75th percentile), and high (≥75th percentile). Study subjects were followed from the date of their cancer diagnosis for cancer-specific death. Of the 112,231 eligible cancer patients in the cohort study, 40,329 (35.9%) died from their cancer in the follow-up period. Relative to those with a medium platelet count, the rate of cancer-specific death was higher among individuals with a high platelet count (HR 1.52; 95%CI 1.48-1.55) and was lower among individuals with a low platelet count (HR 0.91; 95%CI 0.88-0.93). A high platelet count was associated with poor survival for many cancer types. Platelet count could potentially be used as a risk stratification measure for cancer patients.

Analysis of Platelet Count and New Cancer Diagnosis Over a 10-Year Period.

Importance: Individuals with cancer often have an elevated platelet count at the time of diagnosis. The extent to which an elevated platelet count is an indicator of cancer is unclear. Objective: To evaluate the association of an elevated platelet count with a cancer diagnosis. Design, Setting, and Participants: This nested case-control study included Ontario residents enrolled in the provincial health insurance plan who had 1 or more routine complete blood count (CBC) tests performed between January 1, 2007, and December 31, 2017, with follow-up through December 31, 2018. Case patients were individuals with a new cancer diagnosis during the observation period. Eligible control individuals were cancer free before the date of diagnosis for a case patient to whom they were matched. One case patient was matched to 3 controls based on sex, age, and health care use patterns. Data were analyzed from September 24, 2020, to July 13, 2021. Exposures: Case patients and controls were assigned to 1 of 5 exposure groups based on age- and sex-specific platelet count distributions in the control population: very low (≤10th percentile), low (>10th to 25th percentile), medium (>25th to <75th percentile), high (75th to <90th percentile), and very high (≥90th percentile). Main Outcomes and Measures: Odds ratios (ORs) were estimated for specific cancer sites for each category of platelet count at intervals up to 10 years after a blood test. Results: Of the 8 917 187 eligible Ontario residents with a routine CBC record available, 4 971 578 (55.8%) were women; the median age at the first CBC was 46.4 years (IQR, 32.5-59.5 years). Among individuals with a routine CBC record available, 495 341 (5.6%) received a diagnosis of first primary cancer during the 10-year observation period. The OR for a solid tumor diagnosis associated with a very high platelet count vs a medium platelet count in the 6-month period before the diagnosis was 2.32 (95% CI, 2.28-2.35). A very high platelet count was associated with colon (OR, 4.38; 95% CI, 4.22-4.54), lung (OR, 4.37; 95% CI, 4.22-4.53), ovarian (OR, 4.62; 95% CI, 4.19-5.09), and stomach (OR, 4.27; 95% CI, 3.91-4.66) cancers. Odds ratios attenuated with increasing time from CBC test to cancer diagnosis. Conclusions and Relevance: In this nested case-control study, an elevated platelet count was associated with increased risk of cancer at several sites. Our findings suggest that an elevated platelet count could potentially serve as a marker for the presence of some cancer types.

Smoking, Radiation Therapy, and Contralateral Breast Cancer Risk in Young Women.

Evidence is mounting that cigarette smoking contributes to second primary contralateral breast cancer (CBC) risk. Whether radiation therapy (RT) interacts with smoking to modify this risk is unknown. In this multicenter, individually matched, case-control study, we examined the association between RT, smoking, and CBC risk. The study included 1521 CBC cases and 2212 controls with unilateral breast cancer, all diagnosed with first invasive breast cancer between 1985 and 2008 aged younger than 55 years. Absorbed radiation doses to contralateral breast regions were estimated with thermoluminescent dosimeters in tissue-equivalent anthropomorphic phantoms, and smoking history was collected by interview. Rate ratios (RRs) and 95% confidence intervals (CIs) for CBC risk were estimated by multivariable conditional logistic regression. There was no interaction between any measure of smoking with RT to increase CBC risk (eg, the interaction of continuous RT dose with smoking at first breast cancer diagnosis [ever/never]: RR = 1.00, 95% CI = 0.89 to 1.14; continuous RT dose with years smoked: RR = 1.00, 95% CI = 0.99 to 1.01; and continuous RT dose with lifetime pack-years: RR = 1.00, 95% CI = 0.99 to 1.01). There was no evidence that RT further increased CBC risk in young women with first primary breast cancer who were current smokers or had smoking history.

Mammographic texture features associated with contralateral breast cancer in the WECARE Study.

To evaluate whether mammographic texture features were associated with second primary contralateral breast cancer (CBC) risk, we created a "texture risk score" using pre-treatment mammograms in a case-control study of 212 women with CBC and 223 controls with unilateral breast cancer. The texture risk score was associated with CBC (odds per adjusted standard deviation = 1.25, 95% CI 1.01-1.56) after adjustment for mammographic percent density and confounders. These results support the potential of texture features for CBC risk assessment of breast cancer survivors.