Non-Hodgkin Lymphoma (NHL) is one of the fastest rising cancers in the developing countries. In many countries, including the US and Canada, the number of new cases diagnosed each year have almost doubled in the past 30 years.
When most cancers are on a downward trend both in terms of numbers and in deaths, NHL stands in stark contrast. With few known modifiable risk factors the situation has become a matter of alarm among the scientific community. What are the possible causes?
One of the only known risk factors for NHL is HIV infection. HIV is known to increase the chances of developing NHL, especially Primary CNS lymphoma, the lymphoma that attacks the brain first. One of the main varieties of NHL to increase steadily has been this one.
Another factor that increases the chances of NHL is organ transplantation. This may be related to the suppression of the immune system that is required for succesfully carrying out transplants. Lymphoma is a cancer of the immune system. With more and more transplants being carried out worldwide, the number of transplant patients with lymphoma are also rising.
Lymphomas are pretty complicated to deal with, and even diagnose. Diagnostic strategies have improved tremendously over the past few decades. Maybe the disease was always there. We just did not recognize it so efficiently before.
The above issues can only explain about a third of the number of new cases seen. What about the other two-thirds? The rise in lymphoma has been most marked among the elderly - those above 60 years of age. These individuals are neither likely to be HIV infected or get transplants. How did they get lymphoma? Research is on to get to the bottom of this alarming trend. We need to wait for the answers.
The last report from the Centers for Disease Control (CDC) on the trend of cancers in the US, published in October 2007, shows that even though the numbers are rising the rate of increase in NHL has slowed down in the last 10 years. The number of deaths due to NHL has actually started to fall. All is not lost yet.
