There are 1.8m cancer patients with another long term health condition, research from Macmillan Cancer Support has revealed.
Those with cancer are 31% more likely to have a long term condition than those without it and 70% of those with cancer also have a long term condition.
Living with a long term condition is likely to reduce the chance of surviving cancer, the research also found about 700,000 cancer patients have three or more long term conditions.
Macmillan warned that the number of people with a long term condition and cancer could increase by a further 1m in the next 15 years.
A long term condition was defined for the study as being a condition which is chronic and needs active management or is acute leading to residual disability.
The study used data from the Health Survey England, Scottish Health Survey, primary care data from the Quality and Outcomes Framework records and Hospital Episode Statistics.
Juliet Bouverie, director of services & influencing at Macmillan Cancer Support, said: "Our research paints a grim picture where huge numbers of people living with cancer are also contending with at least one other long term condition.
"This means people have individual and complex needs and our health and social care system urgently needs to reflect this.
"We need to care for the whole person, not just treat single diseases and their individual symptoms separately.
"The face of cancer is changing; it is no longer just a case of being cured or dying from the disease.
"Instead, people are living with cancer and most of them are managing this alongside other conditions which may seriously affect their lives.
"A holistic needs assessment which identifies those living with complex needs has to be available to all people with cancer.
"A comprehensive recovery package will then support them to manage their health as they look to get their lives back to a new sense of normality after a cancer diagnosis."