US experts have found that taking high dose supplements of retinol, a form of vitamin A, may have a preventative role in melanoma among women. The researchers examined 69,635 men and women who were participants of the VITamins And Lifestyle (VITAL) cohort study to see whether dietary and supplemental vitamin A and carotenoid intake was associated with melanoma risk. The researchers found that high-dose (41,200 mg per day) supplemental retinol was associated with reduced melanoma risk, particularly amongst women. This protective effect seems to be specific to retinol, as higher dietary consumption of vitamin A and intake of carotenoids, related compounds, were not associated with a reduction in melanoma risk.

Feel free to use these quotes in your stories.  Any further comments will be posted on our website at www.aussmc.org once the embargo lifts. If you would like to speak to an expert, please don’t hesitate to contact us on (08) 7120 8666 or by email.

———–

Professor Graham Mann is a Professor  in Medicine at the University of Sydney. He is an expert in the genetic and environmental causes of skin cancer.

“The study is reasonably well done, and reasonably large, but is not conclusive. It has been designed to carefully address relationships of vitamin intake to health, with good information about vitamin use. It shows that women, but not men, who took retinol supplements (i.e. specific Vit A supplements) had a lower risk of melanoma, taking into account a mixture of melanoma risk factors.

The main limitation is that they did not assess sun exposure, which is the major risk factor for melanoma. Women who take vitamin supplements may well be better at sun protection, and this could account for the reduced number of melanomas, as the authors acknowledge. The authors don’t say whether or not vitamin use overall was associated with reduced risk of melanoma for these women.

Another contributing factor is that even though the study is large, the number of melanoma cases is small. Three or four more cases of melanoma in the 3,288 female retinol users would have wiped out the difference, so the result may well be entirely a chance finding. The lack of any apparent effect in men, where melanoma was more common and the numbers more robust, tends to suggest this.”

———–

Professor Rod Sinclair is Professor of Dermatology at the University of Melbourne

“Oral retinoids are medications that mimic the effects of mega-dose Vitamin A. They have been used ‘off-label’ by Australian dermatologists to prevent skin cancer for many years. The principle benefit is seen in prevention of SCC (squamous cell carcinoma) in people at very high risk. These agents are currently only available on prescription and while much safer than mega-dose vitamin A, they do have significant side-effects.

This paper from the USA suggests there may also be a reduction in risk of melanoma. Unfortunately the benefits were only seen in women who took very high doses of retinol. Retinol supplementation through diet did not reduce melanoma risk. Multivitamin formulations containing retinol did not reduce melanoma risk.

Australia has the highest rate of melanoma in the world. While the practical implications of this research to Australians is not clear, it does merit further investigation to see whether oral retinoids can be used to prevent melanoma. In the meantime ‘Slip, Slop, Slap’ is still the best advice going around.”

———–

Professor Ian Olver is CEO of the Cancer Council Australia

“Dietary vitamin supplements and cancer studies continue to yield mixed results, including a study of retinyl palmitate combined with beta carotene, which suggested a greater rate of lung cancer. In the current study supplements of retinol (but not dietary intake) were associated with a decreased risk of melanoma in women, but there was no significant association in men. In this study serum retinol levels were not measured and a clear dose response relationship with the supplement was not ascertained.

This result, while interesting, will not of itself change practice and further studies are required.”

———–

Dr Andrew Miller is a Clinical Senior Lecturer in Dermatology at ANU

“Whilst the study reported 566 melanomas; the benefits were reported to occur only in current supplement takers. This group in the study cohort only developed 28 melanomas. In these circumstances the small numbers render the study vulnerable to statistical aberrations. The use of a cancer registry for statistical ascertainment of melanoma diagnosis can yield misleading results; and since there was no attempt made to obtain an independent histologic confirmation of the diagnosis, any variation in diagnosis validity could significantly skew the results of the study. There was no internal stratification for the interaction of supplementation with other stronger risk factors for melanoma.

Vitamin A is a highly regulated essential nutrient involved in control of essential cellular functions including particularly control of cell growth and differentiation. As such it has a well-recognised toxicity profile where excessive ingestion occurs; whilst there are relatively few articles in peer reviewed journals demonstrating health benefits of supplementation in vitamin A replete subjects. The study indicates that a high daily intake of retinol is required to effect a reduction in melanoma risk for sun exposed sites in women only. Vitamin A foetal toxicity is a particular concern. Routine vitamin A supplementation of the female population without contraceptive advice cannot be recommended and may have unacceptable contingent risks of foetal injury. The dosage required exceeds the recommended daily intake; in the absence of confirmatory evidence I would have difficulty recommending such high doses without adequate monitoring for signs of toxicity.

The study is interesting. It falls far short of providing evidence for routine supplementation. Further studies need to be performed looking at high risk groups to see if they may benefit from such manipulations. When the potential for foetal damage and systemic toxicity from taking higher than recommended daily intakes is considered I would not recommend routine supplementation.

The best advice that I can give for mitigation of melanoma risk is careful sun protection and routine self-examination; particularly in high risk families.”

———–

Professor Bruce Armstrong is Professor of Public Health at the University of Sydney

“This is a valuable study because of its prospective design and large size. It provides moderately strong evidence for a lower rate of melanoma in people who took retinol supplements than people who didn’t. This observation, though, is not corroborated by evidence of an association of dietary vitamin A with melanoma risk; although problems in accurate recall of diet mean that the study would not necessarily be sensitive to effects of dietary micronutrients, and certainly not as sensitive as it would be to effects of supplemental micronutrients. I would put little store on the apparent difference between women and men in the association of retinol with melanoma – apparent protection from retinol greater in women than men. Results of observational studies like this should not be taken as encouragement for, or a guide to, taking dietary supplements to protect against cancer. Similar associations (e.g. apparent protection from lung cancer from taking beta carotene supplements) have not been found in appropriately designed randomised controlled trials.”

[* Association of Vitamin A and Carotenoid Intake with Melanoma Risk in a Large Prospective Cohort, Asgari et al., Journal of Investigative Dermatology advance online publication, 1 March 2012; doi:10.1038/jid.2012.21]

Danish researchers have investigated the risk of brain tumours in connection with mobile phones based on a study of 358,403 mobile phone subscribers over an 18 year period. It should be noted that the study is based on data from people with a mobile phone contract and does not include information on the actual time someone spends using a mobile phone.

The authors suggest that there was no increased risk of brain tumours in the large nationwide study of mobile phone subscribers. Editorial available.

This research was published online at bmj.com at 9.30am AEDT Friday 21 October.

Feel free to use these quotes in your stories.  Any further comments will be posted here. If you would like to speak to an expert, please don’t hesitate to contact us on (08) 7120 8666 or by email.

———–

Professor Bruce Armstrong is Professor of Public Health at the University of Sydney’s School of Public Health. Professor Armstrong is also the Australian lead author of the Interphone study, a large international epidemiological study into mobile phones and cancer published in 2010.

“This is an important study and the only credible cohort study currently that looks at the association between mobile phone subscription and risk of brain tumours. This particular analysis is much better than preceding ones because it takes in a longer period of time and because the authors have taken into account the different socio-economic status of mobile phone users and non-mobile phone users (allowing, for example, adjustment for education and income when estimating risks related to mobile phone use).

There are two things that must be borne in mind with this study. The first is that this is a study of mobile phone subscribers, not mobile phone use. Thus risk cannot be related to actual amount of use, only to length of subscription. The second thing is that it is not true to say that the study shows no association between mobile phone subscription and risk of brain tumours. There was weak evidence of an association between mobile phone use and risk of brain tumours, but any evidence of increased risk was not more evident in the temporal lobe (temporal glioma), which is the area that is most exposed to mobile phone radiation and where you would expect to find evidence of an association, nor in people who had held subscriptions for the longest time.

The bottom line is that the study does not change my overall view that there is still considerable uncertainty remaining about the risk of mobile phone use and brain tumours. While the evidence is weak, it is possible that mobile phone use does cause brain tumours and we need further research such as in the very large Cosmos cohort study being conducted in Europe.”

———–

Professor Rodney Croft is Executive Director of the Australian Centre for Radio Frequency Bioeffects Research and Professor of Health Psychology in the School of Psychology at the University of Wollongong

“This Danish study looked to see whether there was a relation between mobile phone use and brain tumours, across a very large number of people (358,403), and across a large time frame (up to 18 years). Consistent with previous research, it failed to find any relation between brain tumours and mobile phone use.

This is important because it has been argued that previous research was limited in that it had not looked at people who had used mobile phones for longer than 10 years, which this study was able to do. However, as acknowledged in the paper, this research design has limitations that make it difficult to be certain of the results (such as the reliance on mobile phone subscription data as a surrogate for mobile phone use), but its conclusions certainly support the view that mobile phone use does not cause cancer.”

———–

*Use of mobile phones and risk of brain tumours: update of Danish cohort study, Frei et al., BMJ, 343, 2011

Japanese scientists have found that dogs can distinguish people with colorectal cancer by the smell of their breath. It is thought that dogs can smell a chemical produced by the cancer cells which circulates in the blood and is present in the breath of people with colorectal cancer, even in early stages of the disease. The work was published today in the journal Gut. Australian experts comment below on the research and its implications.

This roundup was produced in collaboration with the Science Media Centre of Japan with support from the Australia-Japan Foundation. Translated comments from Japanese scientists will be posted on our website later today.

Feel free to use these quotes in your stories.  Any further comments will be posted here. If you would like to speak to an expert, please don’t hesitate to contact us on (08) 7120 8666 or by email.

———–

Professor Graeme Young is a gastroenterologist and specialist in colorectal cancer at Flinders University.

“There have been rumours floating around about dogs being able to “smell cancer’ on the breath of people with bowel cancer and it’s good to see some solid research to back it up. The scientific basis behind this finding is that cancer cells produce certain specific chemicals which circulate in the blood stream and are then expelled by the lungs. Dogs have an incredibly acute sense of smell and can be trained to detect these chemicals in the breath of cancer patients with a remarkable degree of accuracy. An important question is whether these molecules are specific to colorectal cancer or whether they are also given off by other cancers. It may be for example that different groups of cancer with different genetic makeups give off different chemicals. So a range of tests will need to be done on a variety of cancers to confirm the reliability of this type of screening technique.

Nonetheless, this research raises the possibility that we might eventually be able to develop something like a breath test to diagnose bowel cancer and potentially a range of other cancers as well.”

———–

Dr Trevor Lockett is theme leader on colorectal cancer and gut health in the CSIRO Preventative Health National Research Flagship

“For those of us seeking to improve bowel cancer diagnosis, this is a fascinating report. Most striking is the ability of the dogs to detect bowel cancer at its earliest stages. Most current non-invasive tests for bowel cancer detect later stage disease far more efficiently than early stage.  But detection of early stage cancers is the real holy grail in bowel cancer diagnosis because surgery can cure up to 90% of patients who present with early stage disease.  Cure rates decrease dramatically as the cancers become more advanced.

Operationally with diagnostics, it is generally easier to detect the presence of something new rather than the absence of a signal so the observation that the “cancer scent” appeared to relate to the presence of a new cancer-specific signal is encouraging. Importantly this study tells us that there is a bowel cancer scent, that at least dogs can detect, that is not associated with other more benign bowel diseases.  A slight complexity exists in that there may be some common features between scents from different cancers (e.g. bowel and breast) which may cloud diagnosis.

Smell is a remarkable sense and no animals do it better than dogs.  It may not just be a single chemical that the dogs are responding to but possibly a combination of chemicals present in specific proportions.  The real test will be whether our chemical detection systems are sophisticated enough to detect the key volatile components.

But one thing is for sure.  The dogs will continue to play an important part in the future research also as scientists seek to validate any diagnostic chemical signatures that they find.”
———–

Australian researchers contribute to an international study showing that for four major cancers (breast, ovarian, colorectal, and lung), survival rates at both 1 and 5 years are higher in Australia, Canada, and Sweden than in the UK and Denmark, while in Norway survival rates are intermediate. The results, for cancers diagnosed between 1995 and 2007, are consistent with late diagnosis or differences in treatment in Denmark and the UK, and in patients aged 65 and over across all jurisdictions.

Copies of the Lancet paper, press release and audio from a Lancet press conference is available on request.

Feel free to use these quotes in your stories.  Any further comments will be posted here. If you would like to speak to an expert, please don’t hesitate to contact us on (08) 7120 8666 or by email.

———–

Dr Andrew Penman is CEO of Cancer Council NSW

“This is an interesting study which reports once again that there is a league table in terms of cancer survival between different countries and that Australia, in this case NSW and Victoria, comparatively do very well in relation to survival rates of other countries.

It means we need to think about cancer care as a system and not just an isolated experience or a set of individual actions with doctors and patients. We need to think of cancer care as a system and designing that system to optimise performance. There are some strengths of the Australian system, one is a system for access to chemotherapy drugs which means that chemotherapy is very equitably provided in Australia. We have a very strong public system but with a private system that works closely with the public system, and that achieves quite equitable and effective treatment. We’ve worked very hard on things like cancer care guidelines and that accounts, for instance, for our good figures in breast cancer.

There is no question that if a country works on a cancer plan and thinks about improving their system, you can make a difference to outcomes.

However, it’s one thing to compare Australia’s survival rates with other countries and to congratulate ourselves on our good performance, but that doesn’t necessarily represent the optimum survival rate, and there’s good evidence that we could do even better in Australia. For instance, our rates of screening for colorectal cancer are very low and if we were to get a much higher proportion of the population over 50 years of age regularly screening for bowel cancer, then we would greatly increase the survival in that very common cancer. We know that while we compare well to overseas countries, there are discrepancies and differences in survival between different regions within Australia, and if we tackle those differences we could improve our survival. We also know that only somewhere between 35 and 40% of Australians receive radiotherapy during the course of their illness. If we achieve the 50% level of access to radiotherapy we could improve survival further.

It’s not time to rest on our laurels, it’s time to look at where we are in survival and what the optimal survival achievable is, and to work hard to bridge that gap.”

———–

Professor Mike Daube is Professor of Health Policy at Curtin University and Director of the Public Health Advocacy Institute

“It is very encouraging that Australia does well in this international comparison. The reality, as shown again by this study, is that Australia has one of the world’s best health systems. There is always progress to be made, but it is good that cancer survival here compares well with outcomes in other advanced countries.”

———–

Professor Ian Olver is CEO of Cancer Council Australia

“Australia’s high cancer survival rate is largely attributable to the success of population screening and the widespread adoption of effective treatments. Although Australia is doing well, we could achieve even better outcomes if the Australian Government completed the bowel screening program, providing free screening kits to Australians aged over 50 every two years. There is also a need to fund effective treatments and to address the disparity of outcomes, for example between people living in urban and rural areas, particularly Aboriginal communities, and people from culturally and linguistically diverse backgrounds.”

———–

Australians have a love affair with the sun, however this also means we have the highest rate of skin cancer of anywhere in the world. In fact, over two-thirds of Australians will have a skin cancer at some stage during their life. With another sun-drenched summer approaching, the AusSMC have organised a media briefing with three experts to discuss the science of sunscreens and skin protection.

The briefing discussed the following issues:

• What does the SPF actually tell us? How much better are the 50+ and 100+ sunscreens?
• Nanoparticles and sunscreen – what do the latest studies tell us?
• Are we using too much sunscreen? How is sun protection balanced with our need for Vitamin D?

Follow an audio visual presentation of the full event by clicking here

BRIEFING DETAILS:

DATE: Wed 3 November 2010
START TIME: 10.30am AEDT
DURATION: 45 min
VENUE:  Online

SPEAKERS:

• Professor Michael Kimlin – Program Head of the Australian Sun and Health Research Laboratory, Queensland University of Technology and head of the new NHMRC Centre for Research Excellence in Sun and Health | Listen (mp3)
• Mr Gavin Greenoak – Scientific Director of the Australian Photobiology Testing Facility, University of Sydney | Listen (mp3) | Gavin’s PowerPoint slides (pdf)
• Dr Brian Gulson – Professorial Fellow at the School of Environment, Macquarie University | Listen (mp3) | Brian’s PowerPoint slides (pdf)
• Listen to the Q and A session here (mp3) 

For further information, please contact the AusSMC on 08 7120 8666 or email info@aussmc.org.

Date issued: 2 November 2010