Thursday, November 3, 2011

Organ transplants double risk of developing cancer

A large comparison study has found that patients who received an organ transplant, being kidney, lung, heart or liver, have a much bigger chance to develop cancer. The researchers found that receiving an organ significantly increases the chance of developing a tumour in that particular organ. However, lung cancer was not only elevated in lung recipients, but also in kidney, liver and heart recipients. In addition, kidney cancer was found to be increased in kidney, heart and liver recipients. The overall increased risk on cancer after transplantation was found to be doubled compared to the general population, highlighting the need for proper screening after patients receive a new organ, and new therapies to accompany transplanted patients to decrease the risks.

The scientists looked at a total of 175,732 solid organ transplants and found the risk on 32 types of cancer to be elevated. The risk of developing non-hodgkin lymphoma showed the most profound increase in risk among organ recipients. Elevated numbers of certain cancers were also related to infections, which are common for patients that undergo organ transplantation.

It is already known that organ transplantation could pose a risk factor for the development of cancer. That is because patients receiving an organ need immunosuppresion, to prevent the destruction of the transplanted organ by the body's immune system. Because our drugs are not very specific, doctors have to disable the whole immune system, instead of just stopping the cells attacking the transplanted organ. Because it also functions as a guard against cells that become unstable and start growing uncontrollably, cancers have a bigger chance to develop in a body without proper functioning immune system.

Immunosuppresion generally also increases the risk on infection, because the body is less able to fight off infections. While these infections can cause cancer, they are also able to induce other diseases, rendering the life of a patient with a transplanted organ full of problems, and in constant need of a health assessment by the hospital.

To solve the increased risk of cancer that is associated with transplantation, scientists need to find new ways to protect organs against the immune system, without having to shut it off completely. A possible mechanism to explore includes localized protection against the immune system, for example to prevent the cells doing their job at the site of transplantation. 

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