The short and longer term outlook for people diagnosed with non-Hodgkin lymphoma is better now than it was even 10 years ago, a new U.S. study finds.

Five- and 10-year survival rates for patients have increased from the 1990s, in part because treatment for the condition has evolved rapidly in recent years.

Non-Hodgkin lymphoma is not a single disease but rather a family of over 30 closely related cancers that attack the lymph nodes, spleen and other organs responsible for the body's immune system. It's the fifth most commonly diagnosed cancer and the sixth leading cause of cancer death in Canada.

German researchers reviewed data from a cancer surveillance program of the U.S. National Cancer Institute and found that overall:

• Five-year survival rates increased from 50.4 per cent between 1990 to 1992 to 66.8 per cent between 2002 to 2004
• Ten-year survival rates increased from 39.4 per cent to 56.3 per cent during the same period

Survival rate improvements were seen in all age groups and among both genders, but were most pronounced in patients younger than 45 years, the researchers note in their report, published in the Archives of Internal Medicine.

Two factors may explain these improvements, the authors led by Dr. Dianne Pulte and colleagues at the German Cancer Research Center in Heidelberg note.

"One is advances in therapy that have occurred between 1990 and 2004, particularly the introduction of antibody therapy for non-Hodgkin lymphoma," they write.

In particular, a key weapon against non-Hodgkin's lymphoma is the antibody therapy rituximab, sold under the brand name Rituxan in Canada and approved by Health Canada in 2000. The drug interferes with the growth and spread of cancer cells and was the first cancer drug to use antibodies to specifically target tumours.

But while the treatment has extended life expectancy in many cases, whether this extension represents a true cure is still unknown, the authors note.

In addition, improvements in the treatment of HIV have reduced the occurrence of HIV-related non-Hodgkin lymphomas and also made them easier to treat. People with HIV are at particular risk of developing non-Hodgkin lymphoma because the virus attacks their immune system.