Estimating the potential survival gains by eliminating socioeconomic and sex inequalities in stage at diagnosis of melanoma

Abstract

Background: Although inequalities in cancer survival are thought to reflect inequalities in stage at diagnosis, little evidence exists about the size of potential survival gains from eliminating inequalities in stage at diagnosis.

Methods: We used data on patients diagnosed with malignant melanoma in the East of England (2006-2010) to estimate the number of deaths that could be postponed by completely eliminating socioeconomic and sex differences in stage at diagnosis after fitting a flexible parametric excess mortality model.

Results: Stage was a strong predictor of survival. There were pronounced socioeconomic and sex inequalities in the proportion of patients diagnosed at stages III-IV (12 and 8% for least deprived men and women and 25 and 18% for most deprived men and women, respectively). For an annual cohort of 1025 incident cases in the East of England, eliminating sex and deprivation differences in stage at diagnosis would postpone approximately 24 deaths to beyond 5 years from diagnosis. Using appropriate weighting, the equivalent estimate for England would be around 215 deaths, representing 11% of all deaths observed within 5 years from diagnosis in this population.

Conclusions: Reducing socioeconomic and sex inequalities in stage at diagnosis would result in substantial reductions in deaths within 5 years of a melanoma diagnosis.

Figure 1

Stage-standardised survival for two example age groups (50–59 and 70–79 years) for men with melanoma. The left panel is stage standardised to the observed stage distribution, showing the observed survival estimates across deprivation groups. The three other panels relate to the three alternative stage standardisations. The alternative stage standardisations show the survival estimates across deprivation groups that would be achieved if the stage distribution could be improved to match that of females, the least deprived or the least deprived females, respectively.

Figure 2

Total number of deaths postponed beyond each time point separated by the deprivation group under the three different stage-standardisation scenarios. (A) Estimates for the East of England and (B) England. Note that these plots are stacked and thus partition the total into constituent deprivation group contributions. The most deprived patients contribute a smaller proportion to the total in the East of England because of differences in the proportion of deprived patients in this region compared with the whole of England.