Factors associated with the melanoma diagnostic interval in Ontario, Canada: a population-based study.

BACKGROUND: Protracted times to diagnosis of cancer can lead to increased patient anxiety, and in some cases, disease progression and worse outcomes. This study assessed the time to diagnosis for melanoma, and its variability, according to patient-, disease-, and system-level factors. METHODS: This is a descriptive, cross-sectional study in Ontario, Canada from 2007-2019. We used administrative health data to measure the diagnostic interval (DI)-and its two subintervals-the primary care subinterval (PCI) and specialist care subinterval (SCI). Multivariable quantile regression was used. RESULTS: There were 33,371 melanoma patients. The median DI was 36 days (interquartile range [IQR]: 8-85 days), median PCI 22 days (IQR: 6-54 days), and median SCI 6 days (IQR: 1-42 days). Increasing comorbidity was associated with increasing DI. Residents in the most deprived neighbourhoods and those in rural areas experienced shorter DIs and PCIs, but no differences in SCI. There was substantial variation in the DI and SCI across health regions, but limited differences in the PCI. Finally, patients with a history of non-melanoma skin cancer, and those previously established with a dermatologist experienced significantly longer DI, PCI, and SCI. DISCUSSION: This study found variability in the melanoma DI, notably by system-level factors.

A population-based validation study of the 8th edition UICC/AJCC TNM staging system for cutaneous melanoma.

BACKGROUND: The 8th edition UICC/AJCC TNM8 (Tumour, Nodes, Metastasis) melanoma staging system introduced several modifications from the 7th edition (TNM7), resulting in changes in survival and subgroup composition. We set out to address the limited validation of TNM8 (stages I-IV) in large population-based datasets. METHODS: This retrospective cohort-study included 6,414 patients from the population-based Ontario Cancer Registry diagnosed with cutaneous melanoma between January 1, 2007 and December 31, 2012. Kaplan-Meier curves estimated the melanoma-specific survival (MSS) and overall survival (OS). Cox proportional hazard models were used to estimate adjusted hazard ratios for MSS and OS across stage groups. The Schemper-Henderson measure was used to assess the variance explained in the Cox regression. RESULTS: In our sample, 21.3% of patients were reclassified with TNM8 from TNM7; reclassifications in stage II were uncommon, and 44.1% of patients in stage III were reclassified to a higher subgroup. Minimal changes in MSS curves were observed between editions, but the stage IIB curve decreased and the stage IIIC curve increased. For TNM8, Stage I (n = 4,556), II (n = 1,206), III (n = 598), and IV (n = 54) had an estimated 5-year MSS of 98.4%, 82.5%, 66.4%, and 14.4%, respectively. Within stage III, IIIA 5-year MSS was 91.7% while stage IIID was 23.5%. HRs indicated that TNM8 more evenly separates subgroups once adjusted for patient- and disease-characteristics. The variance in MSS explained by TNM7 and TNM8 is 18.9% and 19.7%, respectively. CONCLUSION: TNM8 performed well in our sample, with more even separation of stage subgroups and a modest improvement in predictive ability compared to TNM7.

Real-world colorectal cancer diagnostic pathways in Ontario, Canada: A population-based study.

OBJECTIVE: This study aimed to identify colorectal cancer (CRC) diagnostic pathways and describe patients in those pathway groups. METHODS: This was a cross-sectional study of CRC patients in Ontario, Canada, diagnosed 2009-2012 that used linked administrative data at ICES. We used cluster analysis on 11 pathway variables characterising patient presentation, symptoms, procedures and referrals. We assessed associations between patient- and disease-related characteristics and diagnostic pathway group. We further characterised the pathways by diagnostic interval and number of related physician visits. RESULTS: Six diagnostic pathways were identified, with three adhering to provincial diagnostic guidelines: screening (N = 4494), colonoscopy (N = 10,066) and imaging plus colonoscopy (N = 3427). Non-adherent pathways were imaging alone (N = 2238), imaging and emergency presentation (N = 2849) and no pre-diagnostic workup (N = 887). Patients in adherent pathways were younger, had fewer comorbidities, lived in less deprived areas and had earlier stage disease. The median diagnostic interval length varied across pathways from 12 to 126 days, correlating with the number of CRC-related visits. CONCLUSIONS: This study demonstrated substantial variations in real-world CRC diagnostic pathways and 25% were diagnosed through non-adherent pathways. Those patients were older, had more comorbid disease and had higher stage cancer. Further research needs to identify and describe the reasons for divergent diagnostic processes.

Disparities in diagnosis of advanced melanoma: a population-based cohort study.

BACKGROUND: International studies have observed inequities in stage at diagnosis of melanoma. As this has not been sufficiently studied in Canada, the purpose of this study was to investigate whether there are disparities in the diagnosis of advanced-thickness melanoma in the province of Ontario. METHODS: In this retrospective population-based cohort study, we obtained, abstracted and linked pathology reports for a 65% random sample of all cases of invasive cutaneous melanoma in Ontario from 2007 to 2012 in the Ontario Cancer Registry. Cases without pathology reports or with unreported thickness were excluded from the primary analysis. Associations between advanced melanoma (thickness > 2.0 mm) and patient, health-system and tumour factors were described and analyzed using multivariable modified Poisson regression. RESULTS: In total, 8042 patients had histologically confirmed melanoma and thickness information. Of these, 46.7% (n = 3755) were female, the median age at diagnosis was 62 years and 25.7% (n = 2069) had advanced melanoma. In multivariate analyses, advanced age (relative risk [RR] 1.53; 95% confidence interval [CI] 1.37-1.72), male sex (RR 1.12, 95% CI 1.05-1.20), lowest socioeconomic status quintile (RR 1.24; 95% CI 1.12-1.38) and health region (RR range 0.92-1.34, p = 0.005 for variable) were significantly associated with advanced melanoma. Presence of ulceration significantly modified many of these associations. INTERPRETATION: Disparate rates of advanced melanoma according to patient and health system factors suggest there may be inequitable access to timely diagnosis of melanoma in Ontario. This highlights a potential opportunity for system improvement to ensure timely and equitable access to melanoma care.