Cancer prevalence is defined as the total number of people living with cancer at any point in time. It includes both people diagnosed with cancer in the past (who are still alive) as well as people recently diagnosed.

Cancer prevalence is not a measure of how common a cancer is. This number is reflected by cancer incidence, which is the number of people newly diagnosed with cancer in a given time period (usually one year). Prevalence is affected both by the incidence of a cancer and by how long people normally live with the disease.

For example, lung cancer is the second most common cancer in both men and women, but lung cancer prevalence is not as high as that of some less common cancers because people with lung cancer tend not to live as long once diagnosed.

The following numbers come from the US National Cancer Institute’s Surveillance Epidemiology and End Results (SEER) database for the year 2002, the most recent year for which reliable estimates are available. These are estimates based on a sampling of the US population. Numbers may not add up due to rounding to the nearest 1,000.

References

National Cancer Institute. SEER Cancer Statistics Review, 1975-2002. 2006.
Available at: http://seer.cancer.gov/csr/1975_2002/
Accessed January 31, 2006.
Revised: 02/22/2006

LONDON (Reuters Health) - At least 80 percent of women who have worrying evidence of cell abnormalities on a Pap smear will not go on to develop cervical cancer, a new analysis by British researchers suggests.
All of these women will be treated “just in case,” meaning that many will undergo further tests and small operations. But cervical cancer treatments are relatively minor, and not too invasive, meaning Pap screening is still worth doing despite these problems, say Dr. Angela E. Raffle and colleagues.
“You can’t escape the fact that to be effective in cancer screening you almost have to over-treat because the cell changes and tissue changes are so common,” said Raffle, from Avon Health Authority in Bristol.
Her group analyzed screening records from 348,419 women in the Bristol area. They report their findings in Friday’s British Medical Journal.
For every 10,000 women screened between 1976 and 1996, 1,564 had abnormal cervical cells detected in the Pap smear. Of those, 818 had further investigations, of whom 543 had evidence of abnormal cervical tissue. Within this group, 176 had abnormalities that persisted for 2 or more years.
Without screening, the researchers say, 80 of these women would be expected to develop cancer by 2011, of whom 25 would die. Screening would avoid 10 of these deaths.
“In the NHS cervical screening programme, around 1,000 women need to be screened for 35 years to prevent one death,” they write.
An important implication of their results is the need to help women understand what an abnormal Pap smear really means, the researchers say. While it is important for women to have tests and not to ignore the results, trauma caused by thinking it is something akin to a death sentence is not necessary.
“We really need to change people’s perception of what’s meant by an abnormal smear,” Raffle said.
“Most of these abnormalities are no problem at all, but the treatment’s simple and we really think that everyone with a high grade abnormality needs treatment because we know that for one in eighty it will make that big, life-saving difference.”
Cervical cancer is ideal for screening, because doctors can get to the cervix without surgery, it can be treated locally, Raffle said. But the same cannot be said of all other cancers.
“I think the real implications for our findings are for prostate cancer, bowel cancer, ovarian cancer — all these others that people say we must start screening for,” the Bristol researcher said.
It is possible that a large proportion of abnormalities detected in those organs will never develop into cancer, but the treatment can be much more damaging than that for cervical cancer — involving major surgery or radiation treatment.
“Our study points to the potential for harm. It’s only minimal harm with the cervix because you’re talking about worrying people, but if you’re talking about an operation that could leave you dead, or impotent or incontinent, then it’s a different equation really,” Raffle said.

A new Perth study has found alternative therapies like acupuncture and massage significantly improve the well- being of cancer patients.

More than 500 patients in the study began using complementary treatments in addition to traditional medicine like chemotherapy and morphine over a 17-month period.
The researchers at Sir Charles Gairdner Hospital found the therapies relieved physical symptoms such as nausea and pain, while improving the patient’s overall quality of life.

The director of the Cancer Support Centre, David Joske, says the treatments worked extremely well but more research needs to be done “to start to ask how can we get the best out of these two worlds which in the past really have been mutually exclusive in our society”.

He says he hopes the study gives greater credibility to the benefits of complementary medicine.