Differences in breast cancer diagnosis by patient presentation in Ontario: a retrospective cohort study

Abstract

Background: In Ontario, patients with breast cancer typically receive their diagnoses through the Ontario Breast Screening Program (OBSP) after an abnormal screen, through screening initiated by a primary care provider or other referring physician, or through follow-up of symptoms by patients’ primary care providers. We sought to explore the association of the route to diagnosis (screening within or outside the OBSP or via symptomatic presentation) with use of OBSP-affiliated breast assessment sites (O-BAS), wait times until diagnosis or treatment, health care use and overall survival for patients with breast cancer. Methods: In this retrospective cohort study, we used the Ontario Cancer Registry to identify adults (aged 18–105 yr) who received a diagnosis of breast cancer from 2013 to 2017. We excluded patients if they were not Ontario residents or had missing age or sex, or who died before diagnosis. We used logistic regression to evaluate factors associated with categorical variables (whether patients were or were not referred to an OBAS, whether patients were screened or symptomatic) and Cox proportional hazards regression to identify factors associated with all-cause mortality. Results: Of 51 460 patients with breast cancer, 42 598 (83%) received their diagnoses at an O-BAS. Patients whose cancer was first detected through the OBSP were more likely than symptomatic patients to be given a diagnosis at an O-BAS (adjusted odds ratio 1.68, 95% confidence interval [CI] 1.57 to 1.80). Patients screened by the OBSP were given their diagnoses 1 month earlier than symptomatic patients, but diagnosis at an O-BAS did not affect the time until either diagnosis or treatment. Patients referred to an O-BAS had significantly better overall survival than those who were not referred (adjusted hazard ratio 0.73, 95% CI 0.66 to 0.80). Interpretation: Patients screened through the OBSP were given their diagnoses earlier than symptomatic patients and were more likely to be referred to an O-BAS, which was associated with better survival. Our findings suggest that individuals with signs and symptoms of breast cancer would benefit from similar referral processes, oversight and standards to those used by the OBSP.

Improving Breast Cancer Diagnosis Pathways in Quebec

“…While triaging is an efficient way to distribute care among symptomatic patients outside the PQDCS, patients within organized programs consistently receive faster diagnosis (Habbous et al, 2022). Therefore, the PQDCS should aim to include those most likely to have breast cancer so that diagnosis and treatment happen as quickly as possible, ideally even prior to developing symptoms.…”

“…Combined with the fact that diagnosis is expectedly quicker for women within the screening program (Habbous et al, 2022), genetic susceptibility explains Ontario and Alberta's efforts to define higher-risk categories and to provide specific screening guidelines for high-risk individuals, which include eligibility for screening, screening frequency, and imaging methods. Ontario systematically includes high-risk individuals aged 30+ in a specific division of the screening program.…”

Améliorer les parcours de diagnostic du cancer du sein au Québec

“…Combinée au fait que l'établissement du diagnostic est vraisemblablement plus efficace dans le cadre du programme de dépistage (Habbous et al, 2022), la susceptibilité génétique justifie les efforts de l'Ontario et de l'Alberta pour définir des catégories de risque plus élevé et fournir des directives de dépistage propres aux personnes à risque élevé, qui portent notamment sur l'admissibilité au dépistage, la fréquence du dépistage et les méthodes d'imagerie. L'Ontario inclut systématiquement les personnes à risque élevé âgées de plus de 30 ans dans une division spéciale du programme de dépistage.…”

“…Bien que le triage soit un moyen efficace de soigner les personnes symptomatiques en dehors du PQDCS, les personnes participant aux programmes organisés reçoivent systématiquement un diagnostic plus rapide (Habbous et al, 2022). Par conséquent, le PQDCS devrait viser à inclure les personnes les plus susceptibles d'être atteintes d'un cancer du sein afin que l'établissement du diagnostic et le traitement aient lieu le plus rapidement possible, idéalement avant même l'apparition des symptômes.…”