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It’s a medical domino effect no one could have seen coming.
A 60-year-old man in Australia was suffering from Stage 4 melanoma, the deadliest form of skin cancer, and it had spread to several other places including his liver and thigh bone.
While he was in treatment, he had to undergo unrelated heart surgery — and was stunned to learn, months later, that his tumors had vanished.
“I was surprised, shocked, and relieved to hear the cancer had completely disappeared. I couldn’t control my emotions,” said the man, identified in the BMJ case study only as Mr. A.
But that wasn’t the only surprise in store.
Two years after the heart surgery, Mr. A had a life-threatening allergic reaction to a bee sting. That was noteworthy, because he’d never been allergic before — he was sure of it, since he’d been stung dozens of times.
While a sudden bee allergy may seem totally unrelated to heart surgery, the authors of the case study believe it could be a major clue in why his cancer had disappeared years prior.
Why Mr. A’s cancer was so dire
What makes his complete remission especially shocking is how far his cancer had developed.
Cancer is much harder to treat once is moves to distant parts of the body, as had happened in his case: Mr. A’s melanoma had spread to multiple lymph nodes, his liver and his left thigh bone. At this advanced stage, only 35% of patients survive for five years.
The liver, in particular, was a problem. The immune system is less effective at killing cancer there, while cancer in the organ could also cause toxins to accumulate in the blood.
Doctors put him on aggressive cancer medication, including chemotherapy. He had to stop because of severe side effects, but his tumors had not shrunk.
Mr. A’s heart surgery was to address a valve that had narrowed dangerously. While it’s not clear how the heart problems were related to his cancer, metastatic cancer patients often also have this heart issue, and radiation can play a role.
An immune reset? Solving the mystery
After the surgery, Mr. A developed a bacterial infection. Researchers believe the combination of the surgery and infection may have stimulated his immune system, spurring white blood cells that had previously failed to attack the cancer to spring into action.
“Significant bodily changes, such as viral infections, vaccines or surgeries, can alter abnormal immune responses and unexpectedly cause tumor regression by boosting anticancer immune responses,” the researchers said.
That would be surprising, given research showing that surgery can cause issues when it triggers major changes in the immune system.
After surgery, the immune system can become suppressed or overreactive. A mild response in either direction may allow for a smoother recovery, one review found. But if the immune system goes into extreme suppression or overactivity, it causes problems.
An overly suppressed immune system, for example, is often observed in patients after surgery and can make cancer spread faster.
But there is some other evidence that going under the knife like Mr. A did could turn cancer around. In one case, an 84-year-old with melanoma that had the tumor basically disappear after it was biopsied.
The theory that Mr. A’s immune system kicked into overdrive and defeated his cancer remains uncertain, but there is another clue that points to his immune system playing a role: the bee sting.
Two years after his heart surgery, Mr. A went into anaphylaxis after being stung by a bee — something that had never happened to him before. Anaphylaxis is a potentially life-threatening allergic reaction that can cause blood pressure to drop and make breathing difficult.
The researchers say this could indicate Mr. A’s immune system underwent major changes that contributed to his cancer remission.
It’s possible that the overactive immune response the researchers believe happened in Mr. A’s case remained, making him sensitive to allergens he wasn’t sensitive to before. There is some research to suggest surgery can create new allergies.
