Do pre-diagnosis primary care consultation patterns explain deprivation-specific differences in net survival among women with breast cancer? An examination of individually-linked data from the UK West Midlands cancer registry, national screening programme and Clinical Practice Research Datalink

Abstract

Background: In England and Wales breast cancer survival is higher among more affluent women. Our aim was to investigate the potential of pre-diagnostic factors for explaining deprivation-related differences in survival.

Methods: Individually-linked data from women aged 50-70 in the West Midlands region of England, diagnosed with breast cancer 1989-2006 and continuously eligible for screening, was retrieved from the cancer registry, screening service and Clinical Practice Research Datalink. Follow-up was to the end of July 2012. Deprivation was measured at small area level, based on the quintiles of the income domain of the English indices of deprivation. Consultation rates per woman per week, time from last breast-related GP consultation to diagnosis, and from diagnosis to first surgery were calculated. We estimated net survival using the non-parametric Pohar-Perme estimator.

Results: The rate of primary care consultations was similar during the 18 months prior to diagnosis in each deprivation group for breast and non-breast symptoms. Survival was lower for more deprived women from 4 years after diagnosis. Lower net survival was associated with more advanced extent of disease and being non-screen-detected. There was a persistent trend of lower net survival for more deprived women, irrespective of the woman's obesity, alcohol, smoking or comorbidity status. There was no significant variation in time from last breast symptom to diagnosis by deprivation. However, women in more deprived categories experienced significantly longer periods between cancer diagnosis and first surgery (mean = 21.5 vs. 28.4 days, p = 0.03). Those whose surgery occurred more than 12 weeks following their cancer diagnosis had substantially lower net survival.

Conclusions: Our data suggest that although more deprived women with breast cancer display lifestyle factors associated with poorer outcomes, their consultation frequency, comorbidities and the breast cancer symptoms they present with are similar. We found weak evidence of extended times to surgical treatment among most deprived women who were not screen-detected but who presented with symptoms in primary care, which suggests that treatment delay may play a role. Further investigation of interrelationships between these variables within a larger dataset is warranted.

Keywords: Breast cancer; Consultation; Early Diagnosis; England; Pathways; Primary care; Socioeconomic inequalities; Survival.

Fig. 1

Conceptual framework for deprivation-specific differences in breast cancer survival. SD = screen-detected, non-SD = non-screen-detected

Fig. 2

Consultation rates in the 12 weeks prior to diagnosis by deprivation: women diagnosed in West Midlands with invasive breast cancer 1989–2006 found within the CPRD dataset (N = 786); a breast-related symptoms, b non-breast-related symptoms

Fig. 3

Net survival by deprivation: all women (N = 786). Footnotes: 95% CIs overlap, so are not displayed for clarity. Survival from date of cancer diagnosis to death, or the end of follow-up

Fig. 4

Net survival for all women in the sample (N = 786) by (a) the presence of comorbidities, (b) BMI, (c) smoking status and (d) alcohol consumption. Footnotes: Estimates smoothed. Survival from date of cancer diagnosis to death, or the end of follow-up

Fig. 5

Net survival by time from last symptom to (a) diagnosis (N = 331) and (b) surgery (N = 212) among those symptomatically detected and who reported breast symptoms prior to diagnosis. Footnotes: Estimates unsmoothed due to sparsity of some data. CIs not shown for clarity. Some survival curves rise over time because in certain intervals the survival of the cancer patients is better than the population from which they are drawn, thus the interval-specific estimate of net survival is greater than 100%. Survival from date of cancer diagnosis to death, or the end of follow-up