(RxWiki News) When the same tumor returns, this is known as a cancer recurrence. When a new tumor forms, this is called a second primary cancer. Researches looked at the risk factors for developing secondary cancers.
Cancer survivors have a more than doubled risk of developing the same type of primary cancer twice. The risk of developing a second primary cancer of a different type is only slightly increased.
"Don't self-medicate with vitamins or antioxidants during cancer treatment."
It's known that about 15 percent of cancer survivors around the world develop a second primary cancer.
To analyze secondary cancer risk factors, researchers in Denmark evaluated data for the country's entire population (7.5 million people) between 1980 and 2007. Here's what they learned:
- Roughly 10 percent of the population had one or more primary cancer diagnoses.
- Survivors had a 2.2-fold risk of a second primary cancer of the same type as their first diagnosis.
- Risk of developing a different primary cancer was 1.1-fold.
- Second cancers of the same type were reduced after prostate cancer and highest following sarcoma.
- Second cancers of a different type were reduced after prostate cancer and highest following larynx cancer.
According to lead author, Stig E. Bojesen, M.D., Ph.D., of Herlev Hospital, Copenhagen University Hospital and the University of Copenhagen, risks of second cancers vary by cancer type and seem to associated with a patient's genetics and lifestyle factors.
Dr. Bojesen told dailyRx, "During and after therapy (i.e. surgery, radiation and/or chemotherapy) the patient should adhere strictly to the doctors' advice and not initiate any self-medication without consulting the doctors.
As an example, it has been shown several times that supplements of vitamins and antioxidants - normally considered beneficial - are in fact harmful in cancer patients, because they increase the likelihood of relapse," Dr. Bojesen said.
The research team also looked at smoking as a risk factor for second primary cancers. The pattern held true. "The good news is that in the individual cancer survivor, the increased risk of a new cancer is mainly confined to the same cancer as the first — even in people with an unhealthy lifestyle such as smoking," Dr. Bojesen said.
This study was published November 28, 2011 in the Canadian Medical Association Journal.