Age discrimination may be preventing older people from having access to vital surgery, a report suggests.
The Royal College of Surgeons and Age UK looked at surgery rates for six common procedures for English over-65s.
It found a wide variation in access to treatment depending on where people lived and a "worrying" difference between the over 65s and over 75s.
NHS England said it was committed to "ensuring older patients had equal access to treatment".
The report said there could be valid reasons for this - the patient opting not to have treatment for example - but said the NHS needed to investigate the findings.
Data was examined for the removal of breast and colorectal tissue (carried out in cancer care), removal of the gall bladder, hernia repairs, hip replacements and knee replacements in 2011-2012.
People with breast cancer who were aged over 65 faced the biggest variation depending on where they live - with a 37-fold difference in the rate of breast tissue removal.
In terms of the difference between age groups, there was a 34% drop in gall bladder operations and a 16.5% drop in breast tissue removal between the over 65s and over 75s. This came despite the fact the need for the treatment increases with age.
RCS president Prof Norman Williams said the analysis raised "important questions".
"Every patient must be treated as an individual."
Access to treatment
Caroline Abrahams, of Age UK, added: "The extent of variation suggests many places could be doing better."
Mia Rosenblatt, of Breast Cancer Campaign said patients with breast cancer faced the biggest variation in access to surgery depending on where they live.
"While many different factors might impact on breast surgery rates, with a third of all breast cancers occurring in women over 70, it is essential that older breast cancer patients have access to the treatments that will benefit them the most. "
Martin McShane, NHS England's director for people with long-term conditions, said: "NHS England is committed to ensuring older patients have equal access to treatment which should always be based on what is right for each individual patient, on their informed preferences, not their age."