Background This cross‐sectional study was carried out in a population‐based setting in Worcestershire to investigate the relationship between social deprivation and other potential prognostic factors.

Methods A total of 762 female patients diagnosed with primary breast cancer between 1 January 1998 and 31 December 1999 were selected. Breast cancer included all new cases of primary invasive breast cancer and ductal carcinoma in situ. A total of 753 patients were matched by their postcode of residence to enumeration district Townsend score and then divided into three groups based on Townsend quintiles (affluent n = 478; middle n = 157; deprived n = 118). Main outcome measures were relationships between social deprivation and tumour type, stage at presentation, oestrogen receptor status, tumour grade and treatment type.

Results Compared with the most deprived women, affluent women were less likely to present with invasive ductal tumours (70.8 per cent versus 85.9 per cent, χ2 linear trend = 6.757, p = 0.009), tumours of higher grade (36.0 per cent versus 44.7 per cent, χ2 linear trend = 4.201, p = 0.040), and oestrogen receptor negative tumours (22.4 per cent versus 33.3 per cent, χ2 linear trend = 3.501, p = 0.061). There was no significant difference in stage or tumour size at presentation between deprivation groups. More deprived women with invasive tumours of less than 20 mm maximum diameter were significantly more likely to have mastectomies than affluent women (47.8 per cent versus 32.1 per cent, χ2 linear trend = 4.091, p = 0.043).

Conclusions This study suggests that level of social deprivation is associated with tumour type, grade and oestrogen receptor status. There was also a suggestion that increased level of deprivation was associated with increased risk of potentially unnecessary mastectomies.