HAE Patients Have High Rate of Cancer, Canadian Study Suggests
People with hereditary angioedema (HAE) commonly have histories of cancer, which raises the possibility that it might predispose a person to develop cancer.
These findings were reported in the study “Malignancy and immune disorders in patients with hereditary angioedema,” published in the journal Allergy, Asthma & Clinical Immunology.
HAE is a form of angioedema caused by genetic mutations. In most cases, these mutations lower the levels or lead to the production of a faulty version of a protein called C1 inhibitor, which ultimately leads to recurrent swelling attacks.
A pair of scientists now reviewed the medical charts of 49 HAE patients who were treated at a private allergy clinic in Vancouver, Canada. The diagnosis of HAE in all patients was confirmed with C1 inhibitor testing on at least two different occasions, along with genetic testing and/or a confirmed family history of the disease.
Of these 49 patients, six had a documented history of cancer, including two with breast cancer, one with melanoma, one with pancreatic cancer, one with kidney cancer, and one with cervical dysplasia (a precancerous condition in which there is an abnormal growth of cells in the cervix and is usually found on a Pap smear).
All six of these patients were diagnosed with cancer at age 50 or older, with the exception of the patient with cervical dysplasia, who was diagnosed in her early 40s. Three of the patients were diagnosed with cancer before being diagnosed with HAE.
“These observations raise the possibility of an increased incidence of malignant conditions [cancers] in older HAE patients,” particularly in those over the age of 50, the researchers wrote.
“There has not been any previous published data that has investigated if patients with HAE are at an increased risk of malignancy,” the team added, noting a need for further study into this possible connection.
Although there is no known connection between HAE and cancer, there is a well-established connection between acquired angioedema (AAE) and cancer. AAE and HAE manifest with similar symptoms, but while HAE is caused by genetic mutations, AAE is not.
Since these results suggest that HAE may also be connected to cancer, researchers stressed that doctors should consider looking for HAE-causing mutations in people with cancer experiencing angioedema symptoms.
“As HAE and AAE can present very similarly, we would advocate that older patients with malignancy who develop C1 inhibitor deficiency and angioedema, a high index of suspicion of HAE should be maintained as this could potentially identify relatives with undiagnosed HAE,” the researchers wrote.
In addition to the six patients with a history of cancer, six other patients had a history of autoimmune diseases, including two with ulcerative colitis, two with rheumatoid arthritis, one with Sjögren’s syndrome, and one with hypothyroidism and chronic spontaneous urticaria. For most of these patients, the age at which the autoimmune disorder was diagnosed was not known.
“Our data is consistent with other studies that have showed a higher incidence of autoimmune conditions in patients with HAE,” the researchers wrote.
“Although we are limited by our small sample size and lack of a control population, based on these findings we would recommend that physicians managing HAE patients should maintain a high index of suspicion of co-existing malignancy and immune disorders,” they concluded.