Doctors in Italy are issuing a warning to heavy smokers diagnosed with hepatitis C that they face a significantly greater risk of developing a form of cancer known as non-Hodgkin's lymphoma (NHL).1
HCV Infection Complicates the Risk
While smoking by itself isn't necessarily thought to be a major risk factor for NHL,2 smokers with hepatitis C face about 4 times the risk, warn Renato Talamini, ScD, of the Istituto Nazionale Tumori (National Cancer Institute) in Aviano, Italy and his colleagues in the International Journal of Cancer.
"Tobacco smoking is a well-documented risk factor for several cancers, but the role of cigarette smoking in the [origins] of non-Hodgkin lymphoma is inadequately understood," the Italian study team wrote.
While HCV is linked with non-Hodgkin's lymphoma,3,4 the interactions between the virus and this form of cancer hasn't been studied much either, Talamini and his colleagues added. So, they set out to evaluate the link between the two diseases.
NHL: Many Forms Exist
Non-Hodgkin's lymphoma is a form of cancer that begins in your lymphatic system. This is part of the body's immune system, whose role is to fight infections and other diseases. In the lymphatic system, a network of lymph vessels carries clear fluid known as lymph. These vessels lead to small, round organs known as lymph nodes, which are filled with white blood cells that trap bacteria and other substances that may be in the lymph. Lymph nodes are found in the neck, underarms, chest, abdomen, and groin.
There are many forms of non-Hodgkin's lymphoma, which infects the cells of the lymphatic system. The cancer begins when a lymphocyte (a B-cell or T-cell) becomes abnormal. This abnormal cell divides to make copies of itself, and the process repeats over and over, making more abnormal cancer cells. These cells can then spread to other parts of the body.5
Common risk factors for NHL include a weak immune system; certain infections like HIV, Epstein-Barr virus and Helicobacter pylori, which are bacteria that cause stomach ulcers; and older age. Symptoms include swollen, painless lymph nodes; unexplained weight loss; fever; soaking night sweats; coughing, difficulty breathing, or chest pain; sustained weakness or fatigue; and pain, swelling, or a feeling of fullness in the abdomen.5
HCV and NHL: Investigating their Relationship
For the study, the researchers followed 225 consecutive patients who had been hospitalized with a diagnosis of NHL, and compared their prognoses with a group of 504 patients admitted to the same hospitals for conditions not related to cancer or tobacco use.
In this study, which ran from 1999 to 2002, it was found that patients who smoked at least 20 cigarettes per day faced twice the risk of NHL, on average, compared to those who had never smoked. This was true for all age groups and both sexes. However, some patients faced only a slightly higher risk.
The researchers then analyzed the risk of developing certain types of NHL—B-cell-low-grade, B-cell-intermediate and high-grade, and T-cell—related to smoking. The risk of developing B-cell NHL was inconclusive (some patients actually faced a lower risk while others faced more than a four-fold risk). However, heavy smokers faced more than 25 times the risk of developing T-cell NHL, on average, Talamini's team noted.
HCV's Impact on Cancer Risk
When the investigators evaluated the risk of developing the cancer in people with hepatitis C, they found it was four times higher.
"Our study confirms that tobacco is related to NHL, and reports on the combined effect of tobacco smoking and HCV," they wrote. "Infection acted together according to a multiplicative model, leading to a 4-fold elevated risk in current [smoking] HCV-positive subjects."
While the cause of this increased risk in those with HCV isn't yet known, it appears that cigarette smoking and hepatitis C infection act independently of one another in increasing the risk of non-Hodgkin's lymphoma, Talamini stated.
Physicians can play a key role in preventing NHL in smokers, he said, such as encouraging healthy lifestyles, engaging in anti-smoking campaigns, providing support for those giving up the smoking habit, and endorsing certain interventions against risky behaviors such as IV drug use and unprotected sexual intercourse, the researchers wrote.
1. Talamini R, Polesel J, Montella M et al. Smoking and non-Hodgkin lymphoma: case-control study in Italy. Int J Cancer 2005 Jul 1;115(4):606-10.
2. Zahm SH, Weisenburger DD, Holmes FF, Cantor KP, Blair A. Tobacco and non-Hodgkin's lymphoma: combined analysis of three case-control studies (United States). Cancer Causes Control 1997 Mar;8(2):159-66.
3. Libra M, Gasparotto D, Gloghini A, Navolanic PM, De Re V, Carbone A. Hepatitis C virus (HCV) I hepatitis C virus (HCV) infection and lymphoproliferative disorders. Front Biosci 2005 Sep 1;10:2460-71.
4. Bianco E, Marcucci F, Mele A et al. Prevalence of hepatitis C virus infection in lymphoproliferative diseases other than B-cell non-Hodgkin's lymphoma, and in myeloproliferative diseases: an Italian Multi-Center case-control study. Haematologica 2004 Jan;89(1):70-6.
5. National Cancer Institute. National Institutes of Health. What is non-Hodgkin's lymphoma? Available at: http://www.cancer.gov/cancertopics/wyntk/non-hodgkins-lymphoma/page3. Accessed July 7, 2005.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include overseeing health news coverage for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
