Study shows breast cancer can resolve itself without treatment

Oslo, November 25: A recent study has shown that breast cancer can resolve on its own even without any treatment. There are certain types of breast cancers, which would naturally regress, if left undiagnosed.

According to a study published in the Archives of Internal Medicine, breast cancer screening may not always lead to positive results. Screening programs can sometimes lead to over diagnosis of the cancer and to unnecessary treatments. The study has reported that there are about 22 percent of cases, which would resolve on their own if left unscreened.

Dr. Per-Henrik Zahl, the leader of the study and a senior statistician at the Norwegian Institute of Public Health, said, "If we are right, then this is a kind of paradigm shift."

Dr. Zahl together with his colleagues studied the national screening program for cancer in their country. They observed the breast cancer rates among 120,000 women between 50 to 60 years old who had three mammograms from 1996 to 2001. They also took note of the breast cancer rates of women between 50 to 64 years old during 1992, when the national screening program did not even exist.

The results obtained showed that the screened group had a 22 percent higher invasive cancer rate than those in the unscreened group. The researchers also found 32 documented cases of breast cancer regression. Though the number of women who experienced self-regression of their breast cancer is small, the researchers are confident that, "It may instead reflect the fact that these cancers are rarely allowed to follow their natural course."

The researchers also reported, "If all of these newly-detected cancers were destined to progress and become clinically evident as women age, a fall in incidence among older women should soon follow. The fact that this decrease is not evident raises the question: what is the natural history of these additional screen-detected cancers?"

Dr. Zahl remained firm in saying that over diagnosis of cancer poses real risks. Common treatments used for breast cancer are radiation, chemotherapy and surgery. All these treatments involve risks on the patient.

Dr. Patrick Remington, a professor of population health sciences at the University of Wisconsin, has been doing research on self-limiting breast cancers since the 1990s. He agrees with the recent research, which showed, there are some invasive cancers that resolve on its own. He said, "I would say a very good guess would be about one out of three women have cancers detected today that would not have progressed otherwise."