Even so, experts say that the benefits of transplantation far outweigh the risks.
"People need to understand that transplantation is one of the biggest success stories in medicine. This is a very effective treatment for patients with severe organ disease," explains the study's lead author, Dr. Eric Engels, senior researcher of the infection and the epidemiology of the Division of Epidemiology Cancer and Genetics at the U.S. National Cancer Institute in Rockville.
Engels and his team examined data of almost 176,000 solid organ transplants performed in 1987 to 2008 in the U.S.. The researchers found that overall cancer incidence rate 2.1 times higher than expected in non-transplant population.
The risk of disease non-Hodgkin's lymphoma increased by more than seven times. Levels of lung cancer and liver also increased significantly, but Engels says this may be because the cancer has gone before.
For example, a treatment for some types of liver cancer is by way of a liver transplant, and it may be due to some cancer cells survive the transplantation process.
The risk of lung cancer is highest in lung transplant recipients and risk of liver cancer seems only to increase in liver transplant recipients.
According to this study, the incidence of kidney cancer increased almost five-fold in all transplant recipients. This is possible because the underlying disease patients need a new kidney and the possible immunosuppressive role in all transplant patients.
"Our research confirms that this population has a unique pattern of cancer risk. Transplant recipients need to be examined carefully and continuously monitored," Engels added, as quoted from HealthDay, Wednesday (11/02/2011).
In 2010, nearly 30,000 solid organ transplants performed in the United States. Kidney transplants account for more than half of that number, followed by liver, heart and lungs.
After transplantation, recipients must have an immune system suppressing drugs (immunosuppressants) are strong to prevent rejection of new organs.
"Suppressing the immune system increases the risk of cancer. And if a patient has cancer, it takes a strong immune system to fight cancer," says Dr. Darla Granger, director of the pancreas transplant program at St. John Hospital and Medical Center in Detroit.
Another issue related to the immunosuppressant drugs are cancer-related viruses. For example, Hodgkin's disease and non-Hodgkin's lymphoma associated with Epstein-Barr virus, while some types of cervical cancer are caused by human papillomavirus virus (HPV), and some liver cancers are caused by viral hepatitis B or C.
"We know that a particular tumor will develop after transplantation. Certain tumors are also associated with known viruses. So when we gave immunosuppressive drugs, we reduce the body's ability to fight viruses," explains Dr. Lewis Teperman, chief of transplant surgery at NYU Langone Medical Center in New York City.
Not all cancers are related to the immunosuppressant, but in cases such as liver cancer and lung cancer, there is little chance that the cancer had appeared in the body prior to transplantation.
"It's hard to sort out the causes of cancer with certainty, but some of them clearly related to the immunosuppressant," said Granger.
"This study raises some very good points. This suggests that screening for viruses to do, and that we should always try to reduce the use of immunosuppressants. It also creates a tendency to screen tumors in transplant recipients," Teperman said.
"This is an important finding. But I think it overestimated the actual risk of cancer may be lower than those seen in this paper," he added.
For someone who has been undergoing or awaiting transplantation, Granger suggested that lowering risk factors, ie do not smoke, follow good health practices, wear sunscreen, and if it is transplanted, live skrinin screenings recommended by doctors.
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