Impact of Age and Socio-Economic Inequalities in Cancer Survival of Patients with Hodgkin’s Lymphoma Diagnosed in England and Wales.

Abstract

Background: Survival from Hodgkin’s lymphoma (HL) increased during the last decades. However, similar to other cancers, survival from HL is influenced by factors related to tumor biology, treatment received and both biological and social patient characteristics. One obstacle in the analysis of the association between age, socio-economic factors and cancer deaths is the inclusion of unrelated death which might obscure the analysis. We therefore explored the survival chances of patients with HL compared to the life expectancy of the general population and adjusted for prognostic factors such as sex, histology and calendar period of diagnosis.

Objective: To examine trends in relative survival for patients with HL diagnosed in England and Wales and to explore the effects of socio-economic background and age on relative survival.

Methods: Anonymized data of 14,831 patients with HL diagnosed in England and Wales between 1986 and 1999 and followed up until the end of 2001 were analyzed. We estimated 5-year relative survival (5-ys-RS), using deprivation- and age specific life tables. Relative survival is the ratio of observed survival of cancer patients and survival that would have been expected if the patients had had the same age- and sex-specific mortality in each time period as the general population. We examined the calendar periods 1986–1990, 1991–1995 and 1996–2001. Patients were categorized to one of five deprivation categories, from ‘affluent’ to ‘deprived’ and into one of five age groups (15–24.9, 25–34.9, 25–44.9, 45–64.0, 65–99 years). We estimated differences trends over time using linear regression, weighted by the variance of the relative survival estimate. Generalized linear models were used to estimate relative excess risks of death, adjusted for patient and tumor characteristics, at 1 year and 2–5 years after diagnosis.

Results: Relative survival for patients with HL improved consistently and statistically significant throughout the 1980s and 1990s. Patients from deprived areas had a higher relative risk to die compared to patients from affluent areas (adjusted RR 1.33; CI95% 1.18–1.50), however, there was no evidence that the survival gap between patients from affluent and deprived areas increased over time. Compared to the general population young HL patients (aged 25–35) achieved high survival rates (5-ys-RS 90%; CI95% 88%–91%). In contrast, survival was poor for patients aged 45–65 (5 ys RS 69%; CI95% 68%–71%) and 65–99 (5-ys-RS 38%; CI95% 36–41%). Adjusting for histology, sex, socio-economic background and calendar period of diagnosis patients aged 45 to 65 had a 7-fold (RR 7.29, CI95% 5.63–9.42) and patients aged 65–99 had a 22-fold risk (RR 22.21, CI95% 17.30–28.53) to die during the first year after diagnosis compared to young patients aged 15–25.

Conclusion: The present analysis showed that treatment for HL patients improved over time. The existing deprivation gap in relative survival for both men and women confirms that cancer survival depends on socio-economic background and is inequitable. While improvements achieved in young patients are excellent, adult and elderly patients still have an unacceptable high risk to die, especially during first year after diagnosis. Further research is needed to clarify whether this excess risk is caused by more aggressive tumor biology, higher co morbidities and treatment related toxicities or socio-economic factors such as health care utilization.