When doctors at a hospital in Cornwall carried out a follow-up check last summer on a 61-year-old man recently diagnosed with cancer, they found something extraordinary.
The tumours, which scans just a few weeks earlier revealed were littering his torso, had almost gone.
The patient, who was unnamed but was featured in a paper in the British Journal of Haematology, had not yet started chemotherapy for the disease, called Hodgkin lymphoma — a type of blood cancer that affects about 2,100 people a year in the UK.
So the sudden disappearance of the cancerous cells that had riddled his body was a complete mystery.
Spontaneous remission of this type of cancer does occur but it’s incredibly rare; only a couple of dozen cases, from all over the world, have ever been recorded.
But there was one possible — albeit quite incredible — explanation for his cancer’s vanishing act. Just a few days after receiving his diagnosis, the patient was admitted to hospital with severe Covid-19.
After testing positive for the virus, he developed pneumonia, inflammation of the lungs caused by the viral infection.
He was put on oxygen to help him breathe while his lungs recuperated, and kept in hospital for 11 days, before being discharged home, fully recovered.
It was a few weeks later that a CT scan to check his cancer revealed it had all but gone.
The conclusion his doctors reached was extraordinary; Covid-19 had destroyed his cancer by firing up his immune system enough not just to see off the virus but to attack and destroy malignant cells, too.
Dr Sarah Challoner, one of the doctors treating the cancer at the Royal Cornwall Hospital in Truro, said in the published report: ‘We think Covid-19 triggered an anti-tumour immune response.’
She believes that infection-fighting cells, called T-cells, released on a large scale by the immune system to try to see off the coronavirus also attacked cancer cells which it recognised as ‘foreign’.
Hodgkin lymphoma is a type of blood cancer that develops when white blood cells, called lymphocytes, grow out of control, spilling out of the bone marrow (where white blood cells form) then spreading to the lymph nodes, a network of hundreds of tiny, bean-shaped structures round the body.
Lymph nodes allow a watery fluid, called lymph, to circulate around the body, draining waste products and delivering nutrients to cells. One of the first signs of the disease is painful swelling in lymph nodes in the neck, armpits or groin, as the cancerous white blood cells congregate.
It usually responds well to chemotherapy, the main treatment, and almost 90 per cent of patients are still alive five years after diagnosis. But this patient had yet to start treatment; the only change to his circumstances was to have Covid-19.
The idea that one of the most dangerous viruses the world has ever seen might save some lives — not claim them — seems nonsensical. But the Cornish example is not the only one — although experts have been quick to urge caution among cancer patients.
‘The message for anyone with cancer is that, deliberately exposing yourself to Covid-19 in the hope it will heal you is much more likely to lead to your untimely demise than to a cure,’ warns Paul Hunter, a professor of medicine at the University of East Anglia.
However the reports are remarkable. Last August, for example, in the journal Acta Biomedica, doctors at Cremona Hospital in Italy, reported the case of a 20-year-old man with non-Hodgkin lymphoma, a more common type of blood cancer that affects 13,000 people in Britain every year.
Despite treatments, the patient’s cancer had relapsed several times and appeared unresponsive to chemotherapy or radiotherapy. But after testing positive for Covid-19 early in the spring of 2020, when the outbreak in Italy was at its height, he suffered five days of exhaustion, fever and cough as his body tried to fight off the virus. A few weeks later, as with the man in Cornwall, scans showed the cancer had gone.
Doctors said: ‘Covid-19 infection might have played a crucial role in his remission.’
A third case, this time at the Humanitas Research Hospital in Milan, Italy, was reported in February in the European Journal of Nuclear Medicine and Molecular Imaging. All signs of lymphoma rapidly disappeared in a 61-year-old man who caught Covid-19. But can catching Covid really ‘cure’ cancer by bolstering the immune system and, if so, could vaccines against infection have the same effect?
Certainly, there are already isolated cases reported in the medical literature of vaccines making cancers disappear.
One involved a patient whose advanced skin cancer vanished after he was immunised against diphtheria, whooping cough and tetanus. In another case, a patient’s leukaemia went into remission after a smallpox jab.
However, British experts stress that such cases of spontaneous remission are probably more likely to occur in blood cancers such as lymphoma than solid tumours, such as breast, lung or prostate.
One reason may be that lymphomas can sometimes be caused by the Epstein-Barr virus. This is best known for causing glandular fever, but up to 90 per cent of us carry the virus in our bodies without signs of infection or illness.
In rare cases, the virus is thought to lead to blood cancer and according to Cancer Research UK, the virus is responsible for about half of all Hodgkin lymphoma cases, by interfering with immune system cells and causing them to grow and divide out of control.
When Covid infection fires up the immune system, it may be that it’s more likely to spot the presence of Epstein-Barr virus lurking inside cancer cells and launches an attack, which destroys the cancer cells and the virus.
Spontaneous remission in Hodgkin lymphoma is rare, occurring in possibly one case in every 100,000 cancers,’ says Professor Hunter. ‘I don’t think we fully understand the mechanisms, but some immune response is most likely to be the reason.
‘Tumours often evade the immune system and, in this case, Covid infection seems to have kick-started the immune system very effectively. Given how common cancer is, and how common Covid-19 is, it may not be surprising that we see more reports of spontaneous remission associated with a coronavirus.
‘But proving cause and effect will be very difficult unless we see quite a few such remissions.’
Professor Angus Dalgleish, a cancer specialist at St George’s Hospital in London, adds: ‘It looks like Covid-19 infection was the trigger in these cases. Spontaneous remission of cancer has been known to happen but it’s incredibly rare.’
However, it’s also not clear whether any Covid-induced remission is permanent.
In two of the three cases reported above, the lymphoma returned within weeks or months of the infection clearing up.
But the big question these cases throw up is, could Covid-19 vaccines have a similar effect to the virus itself and stop or prevent some cancers from growing?
‘It’s possible vaccines could trigger the same kind of immune response (as the virus) which could completely clear a tumour,’ says Professor Dalgleish.
Just a third of us eat our recommended five portions of fruit and veg a day. Here, nutritionist Angela Dowden shows you how to do it in just one delicious meal.
What to eat: A bowl of Soupologie Five-a-Day Garden Pea with Leafy Spinach soup (two-and-a-half servings), a Cheddar and tomato sandwich (half a serving) and a serving of melon and strawberries = five servings of fruit and veg.
How to do it: For one person, heat and serve half the pot (300 g) of soup. Make the cheese sandwich using 45 g Cheddar and half a full-sized sliced tomato. Toast if preferred. Cut up 80 g melon cubes, and hull and chop seven medium strawberries to eat as dessert.