Does vitamin D help cancer patients?

John Frost almost paid a heavy price for a career that many would have envied. 

A former groundsman at Lord’s cricket ground in North London, he has spent many of his working hours bathed in hot sunshine.

‘I love being outside,’ he says. But in December 2016, he developed malignant melanoma, the deadliest form of skin cancer, which is linked to skin damage caused by high levels of sun exposure.

There are around 16,000 new cases of malignant melanoma every year, and incidence of the disease is rising. Chemotherapy often does not work and every year it claims about 2,300 lives.

‘I’d gone to the doctor about something else when he noticed a bad mole on my back,’ says John, 86, who lives in Wimbledon Chase, South-West London, with his wife Patricia, 84. 

‘He sent me straight to hospital, where they found another suspicious mole on my shoulder. They removed them a few days later and sent them for analysis, which confirmed malignant melanoma. I was worried but they said I didn’t need more treatment. I thought that was the end of it.’

Within a few weeks, however, the growth on John’s back returned.

‘By January 2017 it was the size of a 10p,’ he says. ‘This time they took out tissue all round it which has left a 6in scar.’

It seemed certain that John’s cancer would return with fatal consequences, but with the help of a radical new approach, he has been given hope.

Angus Dalgleish, a professor of oncology at St George’s Hospital in London, is one of a growing number of clinicians investigating the role of vitamin D in cancer treatment. ‘We know vitamin D is involved in regulating the immune system and seems to dampen the proliferation of cancer cells,’ he says. 

‘We also know some cancer patients with low vitamin D live longer if you give them a supplement.

‘We have more than 2,000 cancer patients where we have shown this and we have published several papers, but there is resistance to acknowledging it, possibly because there’s not much money to be made from it.’

NICE guidelines acknowledge studies showing melanoma patients with low vitamin D are more likely to die earlier, but say more research is needed to prove vitamin D has a protective effect. After John’s second operation, a blood test showed his vitamin D level was only 18g/ml (the normal is at least 25g/ml).

‘Professor Dalgleish prescribed me a very high vitamin D dose to take daily and now the level is 100,’ says John. ‘I’ve had five check-ups since and so far the cancer has not come back.’

Professor Dalgleish, who has no links with supplement manufacturers, argues the evidence for a link between low vitamin D and cancer is increasing.

‘New data is published every month,’ he says. ‘A five-year study of more than 21,000 Australians, led by QIMR Berghofer Medical Research Institute in Brisbane, comparing the number of deaths and cancer cases in those who take vitamin D supplements and placebo will give us more evidence later this year.’

Julia Newton-Bishop, a professor of dermatology at the University of Leeds, has researched the potential link. ‘It’s not unusual for melanoma patients to relapse after many years,’ she says.

‘Immunity is somehow reduced or something happens in the patient’s environment that causes the melanoma to start growing. We asked those who had relapsed about their lifestyles and found they were less likely to be taking vitamin D. We have also monitored around 1,000 melanoma patients since 2009, and found those with low vitamin D have done less well. We have tried to find out what’s happening in the cells to cause this and hope our work will be published later this year.’

Keith Harrison, 72, a taxi driver from Sanderstead, Surrey, believes vitamin D has transformed his health. He had a melanoma on the inside of his right leg in 2009 which was removed with nine lymph nodes from his groin.

‘They told me melanoma is linked to vitamin D and my blood level was very low,’ says Keith, who is married to Pamela, 72. He has been taking a daily dose since. ‘I play lawn bowls so I’m outdoors for about three hours every time, but I’ve had no recurrence of the cancer,’ he says.

Other experts stress more evidence is needed before vitamin D can be recommended to cancer patients. Martin Ledwick, information nurse at Cancer Research UK, said: ‘It looks as if something happens if you are vitamin D deficient and you have melanoma — you have a worse outcome. The NICE guidance says if you’re deficient in vitamin D then you should take a supplement, and that’s something we would support.’

Despite her research in the area, Professor Newton-Bishop adds that the role of vitamin D is not fully understood — and warns there is also some evidence that overdosing can damage the immune system, so it is important to stick to the recommended daily dose.

‘The main data is based on deficiency,’ she says. ‘I’m conscious of not saying the more you take, the better. It is more a case of not letting the level go below 25.’