Medical imaging utilization in migrants compared with nonmigrants in a universal healthcare system: A population-based matched cohort study.

BACKGROUND: Medical imaging is an integral part of healthcare. Globalization has resulted in increased mobilization of migrants to new host nations. The association between migration status and utilization of medical imaging is unknown. METHODS AND FINDINGS: A retrospective population-based matched cohort study was conducted in Ontario, Canada from April 1, 1995 to December 31, 2016. A total of 1,848,222 migrants were matched 1:1 to nonmigrants in the year of migration on age, sex, and geography. Utilization of computed tomography (CT), magnetic resonance imaging (MRI), radiography, and ultrasonography was determined. Rate differences per 1,000 person-years comparing migrants to nonmigrants were calculated. Relative rates were calculated using a recurrent event framework, adjusting for age, sex, and time-varying socioeconomic status, comorbidity score, and access to a primary care provider. Estimates were stratified by migration age: children and adolescents (≤19 years), young adults (20 to 39), adults (40 to 59), and older adults (≥60). Utilization rates of CT, MRI, and radiography were lower for migrants across all age groups compared with Ontario nonmigrants. Increasing age at migration was associated with larger differences in utilization rates. Older adult migrants had the largest gap in imaging utilization. The longer the time since migration, the larger the gap in medical imaging use. In multivariable analysis, the relative rate of imaging was approximately 20% to 30% lower for migrants: ranging from 0.77 to 0.88 for CT and 0.72 to 0.80 for MRI imaging across age groups. Radiography relative rates ranged from 0.84 to 0.90. All migrant age groups, except older adults, had higher rates of ultrasonography. The indication for imaging was not captured, thus it was not possible to determine if the imaging was necessary. CONCLUSIONS: Migrants utilized less CT, MRI, and radiography but more ultrasonography. Older adult migrants used the least amount of imaging compared with nonmigrants. Future research should evaluate whether lower utilization is due to barriers in healthcare access or health-seeking behaviors within a universal healthcare system.

A Prognostic Survival Model Incorporating Patient-Reported Outcomes for Transplant-Ineligible Patients With Multiple Myeloma.

Developing prognostic tools specifically for patients themselves represents an important step in empowering patients to engage in shared decision-making. Incorporating patient-reported outcomes may improve the accuracy of these prognostic tools. We conducted a retrospective population-based study of transplant-ineligible (TIE) patients with multiple myeloma (MM) diagnosed between January 2007 and December 2018. A multivariable Cox regression model was developed to predict the risk of death within 1-year period from the index date. We identified 2356 patients with TIE MM. The following factors were associated with an increased risk of death within 1 year: age > 80 (HR 1.11), history of heart failure (HR 1.52), "CRAB" at diagnosis (HR 1.61), distance to cancer center (HR 1.25), prior radiation (HR 1.48), no proteosome inhibitor/immunomodulatory therapy usage (HR 1.36), recent emergency department (HR 1.55) or hospitalization (HR 2.13), poor performance status (ECOG 3-4 HR 1.76), and increasing number of severe symptoms (HR 1.56). Model discrimination was high with C-statistic of 0.74, and calibration was very good. To our knowledge, this represents one of the first prognostic models developed in MM incorporating patient-reported outcomes. This survival prognostic tool may improve communication regarding prognosis and shared decision-making among older adults with MM and their health care providers.

Association between anaesthesia-surgery team sex diversity and major morbidity.

BACKGROUND: Team diversity is recognized not only as an equity issue but also a catalyst for improved performance through diversity in knowledge and practices. However, team diversity data in healthcare are limited and it is not known whether it may affect outcomes in surgery. This study examined the association between anaesthesia-surgery team sex diversity and postoperative outcomes. METHODS: This was a population-based retrospective cohort study of adults undergoing major inpatient procedures between 2009 and 2019. The exposure was the hospital percentage of female anaesthetists and surgeons in the year of surgery. The outcome was 90-day major morbidity. Restricted cubic splines were used to identify a clinically meaningful dichotomization of team sex diversity, with over 35% female anaesthetists and surgeons representing higher diversity. The association with outcomes was examined using multivariable logistic regression. RESULTS: Of 709 899 index operations performed at 88 hospitals, 90-day major morbidity occurred in 14.4%. The median proportion of female anaesthetists and surgeons was 28 (interquartile range 25-31)% per hospital per year. Care in hospitals with higher sex diversity (over 35% female) was associated with reduced odds of 90-day major morbidity (OR 0.97, 95% c.i. 0.95 to 0.99; P = 0.02) after adjustment. The magnitude of this association was greater for patients treated by female anaesthetists (OR 0.92, 0.88 to 0.97; P = 0.002) and female surgeons (OR 0.83, 0.76 to 0.90; P < 0.001). CONCLUSION: Care in hospitals with greater anaesthesia-surgery team sex diversity was associated with better postoperative outcomes. Care in a hospital reaching a critical mass with over 35% female anaesthetists and surgeons, representing higher team sex-diversity, was associated with a 3% lower odds of 90-day major morbidity.

Association of oxaliplatin-containing adjuvant duration with post-treatment fall-related injury and fracture in patients with stage III colon cancer: a population-based retrospective cohort study.

PURPOSE: Oxaliplatin-containing adjuvant chemotherapy yields a significant survival benefit in stage III colon cancer and is the standard of care. Simultaneously, it causes dose-dependent peripheral neuropathy that may increase the risk of fall-related injury (FRI) such as fracture and laceration. Because these events carry significant morbidity and the global burden of colon cancer is on the rise, we examined the association between treatment with a full versus shortened course of adjuvant chemotherapy and post-treatment FRI and fracture. METHODS: In this overlap propensity score weighted, retrospective cohort study, we included patients aged ≥ 18 years with resected stage III colon cancer diagnosed 2007-2019 and treated with oxaliplatin-containing adjuvant chemotherapy (oxaliplatin plus a fluoropyrimidine; capecitabine [CAPOX] or 5-fluorouracil and leucovorin [FOLFOX]). Propensity score methods facilitate the separation of design from analysis and comparison of baseline characteristics across the weighted groups. Treatment groups were defined as 50% (4 cycles CAPOX/6 cycles FOLFOX) and > 85% (7-8 cycles CAPOX/11-12 cycles FOLFOX) of a maximal course of adjuvant chemotherapy to approximate the treatment durations received in the IDEA collaboration. The main outcomes were time to any FRI and time to fracture. We determined the subdistribution hazard ratios (sHR) estimating the association between FRI/fracture and treatment group, accounting for the competing risk of death. RESULTS: We included 3,461 patients; 473 (13.7%) received 50% and 2,988 (86.3%) received > 85% of a maximal course of adjuvant therapy. For post-treatment FRI, median follow-up was 4.6 years and total follow-up was 17,968 person-years. There were 508 FRI, 301 fractures, and 692 deaths. Treatment with > 85% of a maximal course of therapy conferred a sHR of 0.84 (95% CI 0.62-1.13) for post-treatment FRI and a sHR of 0.72 (95% CI 0.49-1.06) for post-treatment fracture. CONCLUSION: For patients with stage III colon cancer undergoing treatment with oxaliplatin-containing adjuvant chemotherapy, any potential neuropathy associated with longer durations of treatment was not found to result in greater rates of FRI and fracture. Within the limits of this retrospective study, our findings suggest concern about FRI, while mechanistically plausible, ought not to determine treatment duration.

Longitudinal adherence to surveillance for late effects of cancer treatment: a population-based study of adult survivors of childhood cancer.

BACKGROUND: Adult survivors of childhood cancer are at elevated risk of morbidity and mortality compared to the general population, but their adherence to lifelong periodic surveillance is suboptimal. We aimed to examine adherence to surveillance guidelines for high-yield tests and identify risk factors for nonadherence in adult survivors of childhood cancer. METHODS: In this retrospective, population-based cohort study, we used health care administrative data from Ontario, Canada, to identify adult survivors of childhood cancer diagnosed between 1986 and 2014 who were at elevated risk of therapy-related colorectal cancer, breast cancer, or cardiomyopathy. Using a Poisson regression framework, we assessed longitudinal adherence and predictors of adherence to the Children's Oncology Group surveillance guideline. RESULTS: Among 3241 survivors, 327 (10%), 234 (7%), and 3205 (99%) were at elevated risk for colorectal cancer, breast cancer, and cardiomyopathy, respectively. Within these cohorts, only 13%, 6%, and 53% were adherent to recommended surveillance as of February 2020. During a median follow-up of 7.8 years, the proportion of time spent adherent was 14% among survivors at elevated risk for colorectal cancer, 10% for breast cancer, and 43% for cardiomyopathy. Significant predictors of adherence varied across the risk groups, but higher comorbidity was associated with adherence to recommended surveillance. INTERPRETATION: Survivors of childhood cancer in Ontario are rarely up to date for recommended surveillance tests. Tailored interventions beyond specialized clinics are needed to improve surveillance adherence.

A Population-Based Test-Negative Matched Case-Control Analysis of SARS-CoV-2 Vaccine Effectiveness Among Pregnant People in Ontario, Canada.

OBJECTIVE: Pregnancy is a risk factor for severe SARS-CoV-2 infection, which can result in adverse pregnancy outcomes, thus making understanding vaccine effectiveness (VE) in this population important. This study aimed to assess the VE of mRNA COVID-19 vaccines against symptomatic SARS-CoV-2 infection and COVID-19-related hospitalization in pregnant people. METHODS: Population-based matched test-negative case-control study of pregnant people aged 18-49 years, of 12 or more weeks gestation in Ontario, Canada, symptomatic with possible SARS-CoV-2 infection, and having at least 1 positive (n = 1842) or negative (n = 8524) real-time polymerase chain reaction (RT-PCR) SARS-CoV-2 test between December 14, 2020, and December 31, 2021. The exposure was receipt of ≥1 dose of mRNA COVID-19 vaccine versus no vaccination. Exposure was further stratified by number and recency of doses. The primary outcome was a positive SARS-CoV-2 RT-PCR test. As a secondary outcome, VE for COVID-19-related hospitalization was assessed. RESULTS: In the primary outcome analysis, there were 1821 positive cases, matched to 1821 negative controls. The mean (SD) maternal age was 31 (5) years. When compared to those unvaccinated, receipt of ≥1 dose was associated with an estimated VE of 39% (95% CI 29%-48%) for symptomatic infection, and 85% (95% CI 72%-92%) for COVID-19 hospitalization. VE estimates demonstrated waning with increased time since last vaccination. CONCLUSIONS: mRNA COVID-19 vaccines provide protection against symptomatic COVID-19 illness and are highly effective at preventing severe illness in pregnant people. The observed effect of vaccine waning highlights the importance of booster doses to provide optimal protection for pregnant people.

Risk of Cesarean Delivery Among People With Inflammatory Bowel Disease According to Disease Characteristics: A Population-Based Study.

OBJECTIVES: It is unclear if use of cesarean delivery in people with inflammatory bowel disease (IBD) is guideline-concordant. We compared the odds of cesarean delivery among primiparous individuals with IBD versus without, overall, and by disease characteristics, as well as time to subsequent delivery. METHODS: Retrospective matched population-based cohort study between 1 April 1994 and 31 March 2020. Primiparous individuals aged 15-55 years with IBD were matched to those without IBD on age, year, hospital, and number of newborns delivered. Primary outcome was cesarean delivery versus vaginal delivery. Multivariable conditional logistic regression analyses were performed to estimate the odds of cesarean delivery among individuals with and without IBD as a binary exposure, and a categorical exposure based on IBD-related indications for cesarean delivery. Time to subsequent delivery was evaluated using a Cox proportional hazard model. RESULTS: We matched 7472 individuals with IBD to 37 360 individuals without (99.02% match rate). Individuals with IBD were categorised as having perianal (PA) disease (IBD-PA, n = 764, 10.2%), prior ileal pouch-anal anastomosis (n = 212, 2.8%), or IBD-Other (n = 6496, 86.9%). Cesarean delivery rates were 35.4% in the IBD group versus 30.4% in their controls (adjusted odds ratio 1.27; 95% CI 1.20-1.34). IBD-ileal pouch-anal anastomosis had a cesarean delivery rate of 66.5%, compared to 49.9% in IBD-PA and 32.7% in IBD-Other. There was no significant difference in the rate of subsequent delivery in those with and without IBD (adjusted hazard ratio 1.03; 95% CI 1-1.07). CONCLUSIONS: The higher risk of cesarean delivery in people with IBD reflects guideline-concordant use. Individuals with and without IBD were equally likely to have a subsequent delivery with similar timing.

Vaccine Effectiveness Against 12-Month Incident and Persistent Anal Human Papillomavirus Infection Among Gay, Bisexual, and Other Men Who Have Sex With Men.

BACKGROUND: Real-world evidence of human papillomavirus (HPV) vaccine effectiveness (VE) against longitudinal outcomes is lacking among gay, bisexual, and other men who have sex with men (GBM). We compared 12-month incidence and persistence of anal HPV infection between vaccinated and unvaccinated GBM. METHODS: We recruited GBM aged 16-30 years in Montreal, Toronto, and Vancouver, Canada, from 2017 to 2019. Participants were followed over a median of 12 months (interquartile range, 12-13 months). Participants self-reported HPV vaccination and self-collected anal specimens for HPV DNA testing. We calculated prevalence ratios (PR) for 12-month cumulative incidence and persistence with ≥1 quadrivalent vaccine type (HPV 6/11/16/18) between vaccinated (≥1 dose at baseline) and unvaccinated participants using a propensity score-weighted, modified Poisson regression. RESULTS: Among 248 participants, 109 (44.0%) were vaccinated at baseline, of whom 62.6% received 3 doses. PRs for HPV 6/11/16/18 were 0.56 (95% confidence interval [CI], .24-1.31) for cumulative incidence and 0.53 (95% CI, .25-1.14) for persistence. PRs were 0.23 (95% CI, .05-1.03) and 0.08 (95% CI, .01-.59) for incidence and persistence, respectively, among participants who received their first dose at age ≤23 years and 0.15 (95% CI, .03-.68) and 0.12 (95% CI, .03-.54) among participants who were sexually active for ≤5 years before vaccination. CONCLUSIONS: Findings support national recommendations for HPV vaccination at younger ages or soon after sexual debut.

Previous Ischemic Stroke Significantly Alters Stroke Risk in Newly Diagnosed Cancer Patients.

BACKGROUND: Previous ischemic stroke (IS) is a risk factor for subsequent IS in the general population; it is unclear if this relationship remains true in patients with cancer. Our objective was to examine the association between previous IS and risk for future IS in individuals newly diagnosed with cancer. METHODS: We conducted a retrospective population-based matched cohort study of newly diagnosed adult cancer patients (excluding nonmelanoma skin cancers and primary central nervous system tumors) in Ontario, Canada from 2010 to 2020; those with prior IS were matched (1:4) by age, sex, year of cancer diagnosis, cancer stage, and cancer site to those without a history of stroke. Cumulative incidence function curves were created to estimate the incidence of IS. Subdistribution adjusted hazard ratios (aHRs) and 95% CIs were calculated, where death was treated as a competing event. Multivariable analysis was adjusted for imbalanced baseline characteristics. RESULTS: We examined 65 525 individuals with cancer, including 13 070 with a history of IS. The median follow-up duration was 743 days (interquartile range, 177-1729 days). The incidence of IS following cancer diagnosis was 261.3/10 000 person-years in the cohort with prior IS and 75.3/10 000 person-years in those without prior IS. Individuals with prior IS had an increased risk for IS after cancer diagnosis compared with those without a history (aHR, 2.68 [95% CI, 2.41-2.98]); they also had more prevalent cardiovascular risk factors. The highest risk for stroke compared with those without a history of IS was observed in the gynecologic cancer (aHR, 3.84 [95% CI, 2.15-6.85]) and lung cancer (aHR, 3.18 [95% CI, 2.52-4.02]) subgroups. The risk of IS was inversely correlated with lag time of previous stroke; those with IS 1 year before their cancer diagnosis had the highest risk (aHR, 3.68 [95% CI, 3.22-4.22]). CONCLUSIONS: Among individuals with newly diagnosed cancer, those with IS history were almost 3× more likely to experience a stroke after cancer diagnosis, especially if the prediagnosis stroke occurred within 1 year preceding cancer diagnosis.

Treatment patterns and outcomes in adolescents and young adults with nodular lymphocyte-predominant Hodgkin lymphoma: an IMPACT cohort study.

We leveraged population-based clinical and healthcare data to identify treatment patterns and long-term outcomes among adolescents and young adults (AYA) with nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). All Ontario, Canada, AYA aged 15-21 years at diagnosis with NLPHL between 1992 and 2012 were identified, and their detailed clinical data were collected. Linkage to healthcare databases identified additional events (subsequent malignant neoplasms [SMN], relapses and deaths). Event-free survival (EFS) and overall survival (OS) were compared by locus of care (adult vs. paediatric) and predictors of outcomes determined. Of 1014 AYA with Hodgkin lymphoma, 54 (5.3%) had NLPHL; 15 (27.8%) were treated at a paediatric centre. No paediatric centre patient received radiation only versus 16 (41.0%) of adult centre patients. Excision only was more common in paediatric centres (p < 0.001). The 20-year EFS and OS rates were 82.9% ± 5.2% and 100% respectively. Advanced stage (hazard ratio: 4.9, 95% CI: 1.3-18.4; p = 0.02) was associated with inferior EFS. Although the 25-year cumulative incidence of SMN was 19.3% ± 9.6% for the entire cohort, there were no SMN among the patients treated with excision only. AYA with NLPHL have outstanding long-term survival. Resection alone was rare outside of paediatric institutions but associated with excellent outcomes. Given substantial SMN risks, chemotherapy-sparing and radiation-sparing strategies for appropriate subsets of patients are warranted.

The Association Between Hospital High-volume Anesthesiology Care and Patient Outcomes for Complex Gastrointestinal Cancer Surgery: A Population-based Study.

OBJECTIVE: To examine the association of between hospital rates of high-volume anesthesiology care and of postoperative major morbidity. BACKGROUND: Individual anesthesiology volume has been associated with individual patient outcomes for complex gastrointestinal cancer surgery. However, whether hospital-level anesthesiology care, where changes can be made, influences the outcomes of patients cared at this hospital is unknown. METHODS: We conducted a population-based retrospective cohort study of adults undergoing esophagectomy, pancreatectomy, or hepatectomy for cancer from 2007 to 2018. The exposure was hospital-level adjusted rate of high-volume anesthesiology care. The outcome was hospital-level adjusted rate of 90-day major morbidity (Clavien-Dindo grade 3-5). Scatterplots visualized the relationship between each hospital's adjusted rates of high-volume anesthesiology and major morbidity. Analyses at the hospital-year level examined the association with multivariable Poisson regression. RESULTS: For 7893 patients at 17 hospitals, the rates of high-volume anesthesiology varied from 0% to 87.6%, and of major morbidity from 38.2% to 45.4%. The scatter plot revealed a weak inverse relationship between hospital rates of high-volume anesthesiology and of major morbidity (Pearson: -0.23). The adjusted hospital rate of high-volume anesthesiology was independently associated with the adjusted hospital rate of major morbidity (rate ratio: 0.96; 95% CI, 0.95-0.98; P <0.001 for each 10% increase in the high-volume rate). CONCLUSIONS: Hospitals that provided high-volume anesthesiology care to a higher proportion of patients were associated with lower rates of 90-day major morbidity. For each additional 10% patients receiving care by a high-volume anesthesiologist at a given hospital, there was an associated reduction of 4% in that hospital's rate of major morbidity.

Variation in Anesthesiology Provider-Volume for Complex Gastrointestinal Cancer Surgery: A Population-Based Study.

OBJECTIVE: Examine between-hospital and between-anesthesiologist variation in anesthesiology provider-volume (PV) and delivery of high-volume anesthesiology care. BACKGROUND: Better outcomes for anesthesiologists with higher PV of complex gastrointestinal cancer surgery have been reported. The factors linking anesthesiology practice and organization to volume are unknown. METHODS: We identified patients undergoing elective esophagectomy, hepatectomy, and pancreatectomy using linked administrative health data sets (2007-2018). Anesthesiology PV was the annual number of procedures done by the primary anesthesiologist in the 2 years before the index surgery. High-volume anesthesiology was PV>6 procedures/year. Funnel plots to described variation in anesthesiology PV and delivery of high-volume care. Hierarchical regression models examined between-anesthesiologist and between-hospital variation in delivery of high-volume care use with variance partition coefficients (VPCs) and median odds ratios (MORs). RESULTS: Among 7893 patients cared for at 17 hospitals, funnel plots showed variation in anesthesiology PV (median ranging from 1.5, interquartile range: 1-2 to 11.5, interquartile range: 8-16) and delivery of HV care (ranging from 0% to 87%) across hospitals. After adjustment, 32% (VPC 0.32) and 16% (VPC: 0.16) of the variation were attributable to between-anesthesiologist and between-hospital differences, respectively. This translated to an anesthesiologist MOR of 4.81 (95% CI, 3.27-10.3) and hospital MOR of 3.04 (95% CI, 2.14-7.77). CONCLUSIONS: Substantial variation in anesthesiology PV and delivery of high-volume anesthesiology care existed across hospitals. The anesthesiologist and the hospital were key determinants of the variation in high-volume anesthesiology care delivery. This suggests that targeting anesthesiology structures of care could reduce variation and improve delivery of high-volume anesthesiology care.

Impact of non-adherence to endocrine therapy on recurrence risk in older women with stage I breast cancer after breast-conserving surgery.

PURPOSE: We examined the impact of non-adherence to adjuvant endocrine therapy (ET) on the risk and site of recurrence among older women with early stage, hormone receptor positive (HR+) breast cancer (EBC). METHODS: A population-based cohort of women age ≥ 65 years with T1N0 HR + EBC who were diagnosed between 2010 and 2016 and treated with breast-conserving surgery (BCS) + ET was identified. Treatment and outcomes were ascertained through linkage with administrative databases. ET non-adherence was examined as a time-dependent covariate in multivariable cause-specific Cox regression models to evaluate its effect on the risks of ipsilateral local recurrence (LR), contralateral breast cancer, and distant metastases. RESULTS: The population cohort includes 2637 women; 73% (N = 1934) received radiation (RT) + ET and 27% (N = 703) received ET alone. At a median follow-up of 8.14 years, the first event was LR in 3.6% of women treated with ET alone and 1.4% for those treated with RT + ET (p < 0.001); the risk of distant metastases was < 1% in both groups. The proportion of time adherent to ET was 69.0% among those treated with RT + ET and 62.8% for those treated with ET alone. On multivariable analysis, increasing proportion of time non-adherent to ET was associated with increased risk of LR ((HR = 1.52 per 20% increase in time; 95%CI 1.25, 1.85; p < 0.001), contralateral BC (HR = 1.55; 95%CI 1.30, 1.84; p < 0.001), and distant metastases (HR = 1.44; 95%CI 1.08, 1.94; p = 0.01) but absolute risks were low. CONCLUSION: Non-adherence to adjuvant ET was associated with an increased risk of recurrence, but absolute recurrence rates were low.

Self-reported Human Papillomavirus Vaccination and Vaccine Effectiveness Among Men Who Have Sex with Men: A Quantitative Bias Analysis.

BACKGROUND: Self-report of human papillomavirus (HPV) vaccination has ~80-90% sensitivity and ~75-85% specificity. We measured the effect of nondifferential exposure misclassification associated with self-reported vaccination on vaccine effectiveness (VE) estimates. METHODS: Between 2017-2019, we recruited sexually active gay, bisexual, and other men who have sex with men aged 16-30 years in Canada. VE was derived as 1-prevalence ratio × 100% for prevalent anal HPV infection comparing vaccinated (≥1 dose) to unvaccinated men using a multivariable modified Poisson regression. We conducted a multidimensional and probabilistic quantitative bias analysis to correct VE estimates. RESULTS: Bias-corrected VE estimates were relatively stable across sensitivity values but differed from the uncorrected estimate at lower values of specificity. The median adjusted VE was 27% (2.5-97.5th simulation interval = -5-49%) in the uncorrected analysis, increasing to 39% (2.5-97.5th simulation interval = 2-65%) in the bias-corrected analysis. CONCLUSION: A large proportion of participants erroneously reporting HPV vaccination would be required to meaningfully change VE estimates.

The Association Between Pregnancy Timing and Cumulative Exposure on Survival in Melanoma.

BACKGROUND: As melanoma is common among young women, the impact of pregnancy on melanoma prognosis is of interest. OBJECTIVE: The purpose of this study was to examine the association between pregnancy and survival in female melanoma patients of childbearing age. METHODS: We performed a population-level, retrospective cohort study of women of childbearing age (18-45 years) diagnosed with melanoma from 2007 to 2017 using administrative data from Ontario, Canada. Patients were categorized according to pregnancy status (i.e. pregnancy before [conception from 60 to 13 months prior to melanoma], pregnancy-associated [conception 12 months prior to and after], and pregnancy after [conception 12 months after] melanoma). Cox models were used to examine melanoma-specific survival (MSS) and overall survival (OS) associated with pregnancy status. RESULTS: Of 1312 women with melanoma, most did not experience pregnancy (84.1%), with 7.6% experiencing a pregnancy-associated melanoma and 8.2% experiencing a pregnancy after melanoma. Pregnancy before melanoma occurred in 18.1% of patients. Pregnancy before (hazard ratio [HR] 0.67, 95% confidence interval [CI] 0.35-1.28), associated (HR 1.15, 95% CI 0.45-2.97), and after melanoma (HR 0.39, 95% CI 0.13-1.11) was not associated with a difference in MSS compared with those who did not experience a pregnancy during these time periods. Pregnancy status was also not associated with a difference in OS (p > 0.05). Cumulative weeks pregnant were not associated with a difference in MSS (4-week HR 0.99, 95% CI 0.92-1.07) or OS (4-week HR 1.00, 95% CI 0.94-1.06). CONCLUSIONS: In this population-level analysis of female melanoma patients of childbearing age, pregnancy was not associated with a difference in survival, suggesting that pregnancy is not associated with a worse melanoma prognosis.

The Association Between Surgical Axillary Staging, Adjuvant Treatment Use and Survival in Older Women with Early Stage Breast Cancer: A Population-Based Study.

BACKGROUND: Choosing Wisely guidelines recommend against surgical axillary staging (AS) in women ≥70 years with ER+/HER2- early stage breast cancer (BC). This study examined the impact of AS omission on survival in older patients with BC. METHODS: This was a population-based cohort study using health administrative data in Ontario, Canada. We identified women aged 65-95 years who underwent surgery for Stage I/II BC between 2010 and 2016. Patients were weighted by propensity scores for receipt of AS that included patient and disease characteristics using overlap weights. Association with overall survival (OS) was calculated using weighted Cox models, and breast cancer-specific survival (BCSS) was calculated using weighted Fine and Gray models, adjusting for biomarkers and adjuvant treatments. Adjuvant treatment receipt was modelled with weighted log-binomial models. RESULTS: Among 17,370 older women, the 1771 (10.2%) who did not undergo AS were older, more comorbid, and less likely to undergo mastectomy. Women who did not undergo AS were less likely to receive adjuvant chemotherapy (RR 0.68, 95% CI 0.57-0.82), endocrine therapy (RR 0.85, 95% CI 0.81-0.89) or radiotherapy (RR 0.69, 95% CI 0.65-0.74). After weighting and adjustment, there was no significant difference in BCSS (sdHR 0.98, 95% CI 0.77-1.25), but women who did not undergo AS had worse OS (HR 1.14, 95% CI 1.04-1.25). The results among 6215 ER+/HER2- women ≥70 years undergoing SLNB vs no AS were similar. CONCLUSIONS: The omission of AS in older women with early stage BC was not associated with adverse BCSS, although OS was worse.

Access to symptom screening and severe symptom risk among cancer patients with major mental illness.

INTRODUCTION: Cancer symptom screening has the potential to improve cancer outcomes, including reducing symptom burden among patients with major mental illness (MMI). We determined rates of symptom screening with the Edmonton Symptom Assessment System (ESAS-r) and risk of severe symptoms in cancer patients with MMI. METHODS: This retrospective cohort study used linked administrative health databases of adults diagnosed with cancer between 2007 and 2020. An MMI was measured in the 5 years prior to cancer diagnosis and categorized as inpatient, outpatient, or no MMI. Outcomes were defined as time to first ESAS-r screening and time to first moderate-to-severe symptom score. Cause-specific and Fine and Gray competing events models were used for both outcomes, controlling for age, sex, rural residence, year of diagnosis and cancer site. RESULTS: Of 389,870 cancer patients, 4049 (1.0%) had an inpatient MMI and 9775 (2.5%) had an outpatient MMI. Individuals with inpatient MMI were least likely to complete an ESAS-r (67.5%) compared to those with outpatient MMI (72.3%) and without MMI (74.8%). Compared to those without MMI, individuals with an inpatient or outpatient MMI had a lower incidence of symptom screening records after accounting for the competing risk of death (subdistribution Hazard Ratio 0.77 (95% CI 0.74-0.80) and 0.88 (95% CI 0.86-0.90) respectively). Individuals with inpatient and outpatient MMI status consistently had a significantly higher risk of reporting high symptom scores across all symptoms. CONCLUSIONS: Understanding the disparity in ESAS-r screening and management for cancer patients with MMI is a vital step toward providing equitable cancer care.

Morbidity and healthcare use among mothers of children with cancer: A population-based study.

BACKGROUND: The impact of a child's cancer diagnosis on subsequent maternal physical health is unclear. METHODS: We identified all Ontario children diagnosed less than 18 years with cancer between 1992 and 2017. Linkage to administrative databases identified mothers who were matched to population controls. We identified physical health conditions, acute healthcare use, and preventive healthcare use through validated algorithms using healthcare data, and compared them between exposed (child with cancer) and unexposed mothers. Predictors of health outcomes were assessed among exposed mothers. RESULTS: We identified 5311 exposed mothers and 19,516 matched unexposed mothers. For exposed mothers, median age at last follow-up was 48 years, (interquartile range: 42-53). Exposed mothers had an increased risk of cancer (hazard ratio [HR] 1.2, 95% confidence interval [95% CI]: 1.0-1.5, p = .03), but not of any other adverse physical outcomes or of increased acute healthcare use. Exposed mothers were more likely to receive influenza vaccinations (odds ratio 1.4, 95% CI: 1.3-1.5, p < .0001), and underwent cancer screening at the same rate as unexposed mothers. Among exposed mothers, bereavement was associated with a subsequent increased risk of cancer (HR 1.7, 95% CI: 1.2-2.5, p = .004) and death (HR 2.2, 95% CI: 1.2-4.1, p = .01). CONCLUSION: Mothers of children with cancer are at increased risk of developing cancer, but not of other adverse physical health outcomes, and were equally or more likely to be adherent to preventive healthcare practices. Bereaved mothers were at increased risk of subsequent cancer and death. Interventions targeting specific subpopulations of mothers of children with cancer or focused on screening for specific cancers may be warranted.

Rates and predictors of visits to primary care physicians during and after treatment of childhood acute lymphoblastic leukemia: A population-based cohort study.

INTRODUCTION: Patient re-engagement with primary care physicians (PCPs) after cancer treatment is essential to facilitate survivorship care and to meet non-oncology primary care needs. We identified rates and predictors of PCP visits both during and after treatment among a population-based cohort of children with acute lymphoblastic leukemia (ALL). METHODS: Children of age less than 18 years at ALL diagnosis in Ontario between 2002 and 2012 were linked to administrative data and matched to controls without cancer. PCPs at diagnosis were identified and PCP visit rates during treatment compared between patients and controls. Post-treatment PCP visit rates were also calculated. Predictors included demographic-, disease-, and PCP-related variables. RESULTS: A total of 743/793 (94%) patients and 3112/3947 (79%) controls had a PCP at diagnosis. Almost half of patients (361/743, 45%) did not visit their PCP during treatment. Visit rate during treatment was 0.64 per person per year (PPPY) versus 1.4 PPPY among controls (adjusted rate ratio [aRR] 0.47, 95th confidence interval [95CI]: 0.40-0.54; p < .0001). No disease- or PCP-related factors were associated with visit rates. Total 711 patients completed frontline therapy; 287 (40.4%) did not have a PCP visit after treatment. Nonetheless, survivors overall visited PCPs post treatment more often than controls (aRR 1.4, 95CI: 1.2-1.6; p < .0001). Survivors who saw their PCP during treatment had post-treatment visit rates twice that of other survivors (aRR 2.0, 95CI: 1.6-2.5; p < .0001). CONCLUSIONS: Only a portion of children with ALL see their PCPs during treatment and return to PCP care following treatment completion. Post-treatment engagement with PCPs may be improved by PCP involvement during ALL treatment.

Association Between Smoking Cessation Treatment and Healthcare Costs in a Single-Payer Public Healthcare System.

INTRODUCTION: There has been little investigation of whether the clinical effectiveness of smoking cessation treatments translates into differences in healthcare costs, using real-world cost data, to determine whether anticipated benefits of smoking cessation treatment are being realized. AIMS AND METHODS: We sought to determine the association between smoking cessation treatment and healthcare costs using linked administrative healthcare data. In total, 4752 patients who accessed a smoking cessation program in Ontario, Canada between July 2011 and December 2012 (treatment cohort) were each matched to a smoker who did not access these services (control cohort). The primary outcome was total healthcare costs in Canadian dollars, and secondary outcomes were sector-specific costs, from one year prior to the index date until December 31, 2017, or death. Costs were partitioned into four phases: pretreatment, treatment, posttreatment, and end-of-life for those who died. RESULTS: Among females, total healthcare costs were similar between cohorts in pretreatment and posttreatment phases, but higher for the treatment cohort during the treatment phase ($4,554 vs. $3,237, p < .001). Among males, total healthcare costs were higher in the treatment cohort during pretreatment ($3,911 vs. $2,784, p < .001), treatment ($4,533 vs. $3,105, p < .001) and posttreatment ($5,065 vs. $3,922, p = .001) phases. End-of-life costs did not differ. Healthcare sector-specific costs followed a similar pattern. CONCLUSIONS: Five-year healthcare costs were similar between females who participated in a treatment program versus those that did not, with a transient increase during the treatment phase only. Among males, treatment was associated with persistently higher healthcare costs. Further study is needed to address the implications with respect to long-term costs. IMPLICATIONS: The clinical effectiveness of pharmacological and behavioral smoking cessation treatments is well established, but whether such treatments are associated with healthcare costs, using real-world data, has received limited attention. Our findings suggest that the use of a smoking cessation treatment offered by their health system is associated with persistent higher healthcare costs among males but a transient increase among females. Given increasing access to evidence-based smoking cessation treatments is an important component in national tobacco control strategies, these data highlight the need for further exploration of the relations between smoking cessation treatment engagement and healthcare costs.