There are 1.2 million people in Britain today living with cancer. This figure could rise to three million by 2020 as patients live longer. It's a disease that predominantly affects the over-fifties but nobody is exempt. We now understand its origins in the intricate molecular control machinery of the cell. This results in essentially a runaway cell with the accelerator full on and no brakes. Slowly, the abnormal cell multiplies and spreads to other parts of the body wreaking havoc as it goes. Lung, breast, prostate and colon are the most common starting places. There are more than 200 types of cancer.

For the moment symptoms develop, the patient has to live with uncertainty. Do I have cancer? What's the best treatment? Where's the best place to get care? What will I tell friends and family? Will I die from it? This creates profound difficulties for many who find it hard to cope with getting on with any semblance of normal life.

Britain has invested more than £2bn in trying to improve services for patients through the NHS Cancer Plan begun in 2000, but much of money has ended up in creating typical public-sector bureaucracies and not frontline care. So if your GP thinks you have cancer, you will be seen by a specialist within two weeks. But more than 60 per cent of patients don't have obvious symptoms, so they face greater delay. Fast-tracking one group inevitably lengthens the slow track for others.

Despite increasing the overall NHS budget threefold over the last 10 years, there are huge areas of under-capacity. Even if you are seen quickly, getting the scans and other tests to formulate the treatment plan can take months. Then you join another queue for treatment - several weeks for chemotherapy and up to four months for radiotherapy. The NHS target is 62 days from referral to treatment, but this can be massaged by administrators counting the removal of tissue for diagnosis as the first treatment.

Politicians unashamedly use our health-care system to win votes. Cancer is a favourite target. New money is often recycled for its PR value. New waiting-time initiatives, better access to diagnostics, the provision of new machines and drugs are all proclaimed with great eagerness. But the democratic process to win votes skews the importance of individual cancers.

When Nicole Kidman launched Breast Cancer Awareness Month at Madame Tussauds on Friday, she contributed to a process which will put breast cancer at a higher level than colon cancer in the political mind. When the media frenzy over the expensive drug Herceptin arose early this year, our health minister stepped in without waiting for our drug regulators' assessment and decided that it should be available for all suitable breast cancer patients. In a system of finite resources, this is surprising. We now have the bizarre situation that people are waiting longer for chemotherapy for other cancers as there simply isn't the capacity in the system. There are eight tenders now out to the private sector just to give Herceptin injections all over the country. This is crisis management driven by political imperative.

In Illness as a Metaphor, Susan Sontag, the American feminist writer, introduces the concept of romantic diseases. The Victorian poets had tuberculosis, the Eighties brought HIV and now we have cancer, all as metaphors of contemporary society. Not all cancers are equal - the old man dying in pain from spreading prostate cancer is not likely to be given the same attention as the young woman with breast cancer. We are living through a technological revolution, with 40 new drugs for cancer coming in in the next five years.

There are huge changes taking place in cancer medicine which will significantly impact on the costs of optimal care. The precedent of Herceptin is likely to be repeated for several other agents - Avastin, Erbitux, Nexavar, Suten, Tarceva and Tykerb over the next 12 months. Should the price we put on life be determined in part by the political importance of the disease, by romanticism or by robust analysis of the cost-effectiveness of newly available treatments? And how do we deal with pressure groups? When Avastin was turned down as too expensive for Israel's health service last month, patients went on a hunger strike outside its parliament. Within two weeks, the drug was made available.

Radiotherapy is also becoming increasingly sophisticated and costly with the availability of conformal therapy techniques to allow a higher dose of radiation to be delivered to the tumour while sparing surrounding tissue. Brachytherapy - the use of disposable radioactive seed implants - for prostate cancer may allow a more precise and quicker way to deliver radical therapy, but its costs are higher and is only available in certain centres. Direct-to-consumer advertorials for such techniques are moving across the Atlantic in men's magazines. How will we prioritise such developments alongside drugs for breast cancer?

Much is made of patient choice, but it has to be real. A recent survey by the information charity Cancerbackup found that 89 per cent of adults believe that if they had cancer, they should have access to the same standard of care regardless of where they live; 90 per cent believe that all groups in society should have equal access to cancer care, and the public is comfortable with a diversity of health-care providers with two-thirds being happy to go to a private centre provided their care was paid by the NHS. The public is clearly more sensible than its elected representatives.

We need to improve cancer care dramatically in Britain, but let's not attach a value to different cancers based on their romantic or political profile. Increasing capacity of our diagnostic and treatment services, providing clear information at all stages and rigorously assessing cost-effectiveness of new treatments will all help to reduce uncertainty and make life easier for all tomorrow's cancer patients.

· Karol Sikora is medical director of CancerPartnersUK, which is creating the largest UK cancer network as a series of joint ventures with the NHS. He was professor of cancer medicine at Hammersmith Hospital where he was director of cancer services for 12 years. He was chief of the WHO Cancer Programme and is editor of Treatment of Cancer, the standard British textbook for doctors.