People who develop the most common forms of cancer are still more likely to be diagnosed at a late stage in their disease if they live in a deprived area, new research has found.
Researchers at University College London also found that social factors still influence access to services for the three most common forms of the disease - bowel, breast and lung cancer.
Scientists analysed statistics on hospitalisation for these forms of cancer between 1999 and 2006.
The researchers identified 564,821 patients aged 50 and over who were admitted to NHS hospitals in England because they had bowel, breast or lung cancer.
They then recorded the proportion of patients who were admitted as emergency cases - so at an advanced stage in their disease - and who received the recommended surgical treatment.
Analysis revealed that nearly a third of patients with bowel cancer and over half of lung cancer patients were admitted as emergencies.
But the proportion of breast cancer patients who were admitted as emergencies fell over the study period.
Patients from deprived areas were more likely to be admitted as emergencies and less likely to have received the recommended procedures, as were older people and women.
Writing in the British Medical Journal, the researchers said that timely diagnosis, early referral and the application of clinical guidelines will be necessary to improve survival rates among socially disadvantaged groups.
They also called for an audit of local surgical practice and monitoring of variations in procedure between different socio-economic groups "to raise standards and ensure best practice".
Sarah Woolnough, head of policy at Cancer Research UK, said that the study highlights a "continuing problem".
"We know that in this country, cancer is often diagnosed late when it is at an advanced stage, and this is a particular problem among deprived groups. This can have a knock-on effect on the type of treatment that can be given and, ultimately, on cancer survival.
"The updated Cancer Plan - the Cancer Reform Strategy - recognises these problems and is strongly prioritising early diagnosis and action to reduce inequalities in cancer treatment. But this is a critical issue and one that we believe must remain a priority for the future."