At the 7th Annual American Association for Cancer Research International Conference on Frontiers in Cancer Prevention Research (AACR FCPR 2008) held last week in Washington, D.C, several papers were presented on the role of vitamin supplementation in the prevention of cancers.

Researchers from Harvard University studied the potential benefits of vitamins E and C supplements on 14,461 male physicians, 50 years or older, who participated in the Physicians’ Health Study II. Participants were given 400 IU of vitamin E every other day or placebo and 500 mg of vitamin C daily or placebo. They were followed for a mean of 8 years. After 8 years, taking vitamin E supplements had no effect on the incidence of prostate cancer. Vitamin C supplementation had no effect on total cancers or on specific cancers such as colorectal, lung or prostate.   

In another study, the Calcium Polyp Prevention Study, from the Vanderbilt University, 930 men were randomized to receive placebo or calcium supplementation (1,000 mg daily for 4 years) to see if calcium supplementation could prevent colorectal adenoma recurrence. (Colorectal adenomas are precursors to colorectal cancers.) The researchers found that calcium supplementation only reduced polyp recurrence in people whose dietary ratio of calcium to magnesium intake was low before treatment and remained low during treatment. Among those with baseline calcium to magnesium ratio below the median, calcium supplementation reduced the risk of adenoma recurrence by 32%.  

In a separate published study from the Harbor-UCLA Medical Center, 36,282 postmenopausal women, who were enrolled in a Women’s Health Initiative clinical trial, were randomly assigned to 1000mg of elemental calcium with 400 IU of vitamin D3 daily or placebo for a mean of 7 years (J Natl Cancer Inst 2008; 100: 1581 – 1591). This study was carried out to look at the effects of supplement use on the incidence of hip fracture with incidence of invasive breast cancer as a secondary outcome. At the end of the study period, the incidence of invasive breast cancer in postmenopausal women was not affected by calcium and vitamin D supplementation.

An interesting study on the protective effects of consuming cruciferous vegetables in smokers was presented at the AACR FPCR 2008. Researchers from Roswell Park Cancer Institute in Buffalo, New York, studied 948 patients diagnosed with primary lung cancer and 1743 healthy controls between 1982 and 1998. The researchers found that there was a strong linear inverse association between intakes of fruit, total vegetables and cruciferous vegetables and the risk for lung cancer (odds ratio range 0.53 – 0.70). The study results suggest that the risk of developing lung cancer among smokers was reduced by 22 – 50 % if they consumed at least 4.5 servings of raw cruciferous vegetables per month compared to those who ate less than 2.5 servings per month. This inverse association of reduced lung cancer was only seen for squamous or small cell cancer, the 2 subtypes of lung cancer most commonly associated with heavy smoking. [The same group of researchers had demonstrated that the intake of raw cruciferous vegetables, including broccoli, broccoli sprouts, cabbage and cauliflower, was associated with a reduced risk for bladder cancer (Cancer Epidemiol Biomarkers Prev 2008; 17: 938 – 944). The protective action of cruciferous vegetables is derived from isothiocyanates, a group of phytochemicals which can be degraded by cooking.]

At present it is reasonable to conclude that supplementing with individual vitamins may not be sufficient to prevent cancer. Chemoprevention of cancer probably depends on a combination of vitamins and minerals. As yet we do not posses the knowledge to formulate the correct combination that works. Do multivitamin supplements work better? We do not have the answer yet. What we do know is that Mother Nature has perfected the combination in the form of fruits and vegetables. Seriously, why would you choose to take pills when you can enjoy the taste of fresh fruits and vegetables!

Over the last couple of years, the cost of everything has increased appreciably. Health care costs are no different. In an ideal society, the cost of providing health care would be borne in full by the State. Whenever a new drug or a new test was discovered, it would automatically be made available to the masses at no cost to the individual. Unfortunately, we do not live in a Utopian society. Managing ever increasing health care costs is a constant headache for all societies.

A recent study from the College of Pharmacy, Union University in Albany, New York, examined the variations in oncology treatment cost in patients with colorectal cancer (Am J Manag Care 2008; 14: 717- 725). From a nationwide registry they looked at the chemotherapy regimen used in 421 patients with colorectal cancer. The most common regimens were 5-fluorouracil-leucovorin calcium (5-FU/LV) in 147 patients (34.9%), fluorouracil-leucovorin-irinotecan hydrochloride (FOLFIRI) in 111 patients (26.4%) and fluorouracil-leucovorin-oxaliplatin (FOLFOX) in103 patients (24.5%). The total costs for 6-cycles of the commonly used regimens are shown in the following table. The largest cost differential was US$35,971 between FOLFIRI and 5-FU/LV.

Total Cost of 6 Cycles of Commonly Prescribed Treatment Regimens

The above study finished at the end of 2005 and thus did not assess the impact of using monoclonal antibodies such as cetuximab (Erbitux) and bavacizumab (Avastin) as part of the chemotherapy regimens. If these agents were included, the cost would be significantly higher than US$38,027!

The above study highlighted the fact that, even within USA, the chemotherapy regimen used for treating colorectal cancer varies. While 5 FU/LV is an effective regimen, some oncology centres would only use the FOLFIRI regime in order to improve the survival figure. The cost difference between the two is 38 times but is the survival difference between the two regime 38 times as well? The answer is no.

Given a limited budget to deliver health care to the community, the government has to decide which regimen gives the best bang for the buck. Thus, a government may decide that 5FU/LV is the only chemotherapy regimen available to all patients and the additional cost associated with the use of FOLFIRI / FOLFOX regimen is ‘not worth it’. For patients who are seeking private health care, cost may be an even bigger issue. When a patient is told that FOLFIRI is better than 5 FU/LV, he / she would naturally want to choose the FOLFIRI regimen despite a 38 times difference in cost. What patients are seldom aware of is that by paying 38 times more you are not assured a 5 years survival that is 38 times better.

The survival benefit of the FOLFOX and FOLFIRI regimens are very similar but yet the price difference is 100%. Whether you pay US$17,584 or US$38,027 for a 6-cycle treatment regimen is up to the personal preference of your oncologist and to some extent yours. (FOLFOX is the preferred regime in Europe because oxaliplatin (OX) is a ‘European drug’. FOLFIRI is the preferred regime in USA because irinotecan (IR) is an ‘American drug’.) If you are paying for your chemotherapy, you should be fiven full cost information on and survival benefit associated with the various chemotherapy regimen. Your oncologist can explain to you his preference and recommend to you what he thinks is the most suitable regimen. If the benefit is similar, the decision as to whether you spend US$38,027 or US$17,584 for 6-cycles of treatment rest solely with you. The question you need to answer is ‘Is it worth it’. In order to answer that properly you need to be fully informed.

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)!