I have just returned from Kuching, Sarawak, Malaysia. My very first trip to East Malaysia was not for holiday but to give a lecture at a Liver Cancer Symposium. One of the speakers there, a palliative care physician, was recounting stories of how some retailers of mangosteen juice were targeting their sales at patients with advanced cancer and cancer patients in general. The promise of potential beneficial effects, from the potent anti-oxidant properties in mangosteen juice, was certainly a major selling point to patients who are desperate to try anything. Apparently the newest claim is that the durian skin contains powerful anti-oxidants which might be of use in treating cancer. (Durian is a local fruit with pungent soft flesh surrounded by a hard, thick thorny skin. You either love it or you are put off by the aroma!)

I am constantly being asked what to eat and what not to eat by my patients with cancer, whether there are any supplements or pills that will keep the cancer away or keep it under control. The patients and their loved ones look forlornly at me and wait with bated breath on my pronouncement.

A recent study from Harvard Medical School looked at the role of combined folic acid, vitamin B₆ and B₁₂ supplements in affecting cancer risk in women (JAMA 2008; 300: 2012 – 2021). Five thousand four hundred and forty two female health professionals aged 42 years or older participated in the Women’s Antioxidant and Folic Acid Cardiovascular Study (WAFACS). These women, with pre-existing cardiovascular disease or 3 or more coronary risk factors, were randomly assigned to receive 2.5 mg of folic acid, 50 mg of vitamin B₆ and 1 mg of vitamin B₁₂ daily or a placebo. They received the supplement from April 1998 to July 2005. None of the women taking the folic acid and vitamins were harmed. Neither did the supplements have an effect on lowering the risk for total invasive cancer or breast cancer among women. Taking the supplements also did not lower the risk of dying from any cause.

Cancer takes years to develop in our body. Its development is likely to be triggered by what we have been eating, drinking, breathing and coming into physical contact with. It takes years of exposure before the cancer emerges. Once you have developed cancer, it is logical to conclude that it would also take years for anything which has anti-cancer properties to have its beneficial effects on the cancer. At present I am not aware of any potent supplements that can retard or cure cancer in humans. Maintaining a healthy and balanced diet will certainly help your body cope with the cancer in your body. Having a healthy and balanced diet will also help you in fighting recurrence of cancer. I am certainly unaware of any large clinical studies proving the anti-cancer properties of mangosteen juice or durian skin. I do know that drinking large amount of mangosteen juice will knock a big hole in your bank account and possibly lead to severe lactic acidosis requiring hospital treatment (Am J Kidney Dis 2008; 51: 829 – 833)!

The Nobel Assembly in Stockholm has just announced the winners of the 2008 Nobel Prize in Medicine. The winners are Harald zur Hausen of Germany and the French researchers Francoise Barre-Sinoussi and Luc Montagnier. Zur Hausen was cited for finding human papilloma viruses that cause cervical cancer, the second most common cancer among women. Barre-Sinoussi of the Institut Pasteur in Paris and Montagnier, Director of the World Foundation for AIDS Research and Prevention, were cited for their discovery of human immunodeficiency virus (HIV) which causes AIDS. Kaposi sarcoma is common in AIDS patients.

There are many viruses which lead to the development of cancers in humans. At present, pancreatic cancer has not been linked to a specific virus. However, a recent publication from the University of Texas M. D. Anderson Cancer Center suggested a possible association between hepatitis B virus (HBV) and pancreatic cancer (J Clin Oncol 2008; 26: 4557 – 4562). The aim of their study was to determine whether HBV and hepatitis C virus (HCV) infections increase the risk for the development of pancreatic cancer. The researchers studied the blood samples from 476 pancreatic cancer patients and 879 age-, sex- and race-matched healthy controls. The samples were tested for the presence of HCV antibodies (anti-HCV), HBV surface antigen (HBsAg), antibodies to HBV core antigen (anti-HBc) and antibodies to HBsAg (anti-HBs). They found that the prevalence of past exposure to HBV, indicated by the presence of anti-HBc, was significantly higher in pancreatic cancer patients (7.6%) than controls (3.2%). Compared to controls, people who had had previous exposure to HBV but had developed immunity are 2.3 times more likely to develop pancreatic cancer. Diabetes also significantly increased the risk of pancreatic cancer in patients with past exposure to HBV. If you are an HBV carrier, you are 4 times more likely to develop pancreatic cancer. Interestingly the researchers did not find a significant association between HCV infection and pancreatic cancer.

The researchers have not proved that HBV causes pancreatic cancer. They have shown an association between HBV infection (past or present) and pancreatic cancer. They have suggested that perhaps because of their (the liver and pancreas) close proximity and sharing of blood supply and ducts, the pancreas may suffer collateral damage from the HBV infection and thus be predisposed to the development of cancer.

With many more years of research, it may be possible that a specific virus might be identified as the causal agent for pancreatic cancer. Until then we can only be vigilant and pay more attention to individuals with associated risk factors for pancreatic cancer. These are:- a history of diabetes mellitus, cigarette smoking, a

positive family history of cancer and possibly past / present history of HBV infection.