In the last five years, a new era was born in the fight against cancer. Immunotherapy is considered by many as the “fourth pillar” in cancer treatment, the first three being surgery, chemotherapy and radiotherapy.
A totally different mechanism is used in immunotherapy when compared to the last two options. Immunotherapy uses antibodies to activate out defences using our immune system to attack malignant cells. In a way, it follows a principle formulated by Hipocrates more than 2,000 years ago: “Our body contains the cure for everything.”
Unlike chemotherapy that requires cyclic administration and often becomes almost chronic, as is the case with metastatic disease, immunotherapy has cured various patients with advanced melanoma with only four administrations (i.e. ipilimumab). These cures result in a prolonged response due to the immunological memory which our organisms possess, remaining active over time.
In Portugal, the incidence of melanoma is nine new cases per year per 100,000 inhabitants. It is considered a rare skin tumour, representing 10% of all skin tumours, but with a high mortality rate. In the advanced stages of melanoma, the prognosis of life expectancy after five years was between 10% and 22%, but with these new drugs a very positive change (in these percentages) is expected.
There are two major categories of molecules and, consequently, of antibodies that can be used to maintain a high activity of the immune system. The first category to be developed were the antibodies against CTLA-4 (ipilimumab and tremelimumab) and after that the antibodies against PD-1 or its PD-L1 receptor. These molecules are permitting a substantial response to the treatment and survival rate in cases of melanoma and, more recently, in lung cancer.
When in May 2015 Jimmy Carter (ex President of the United States) was diagnosed with malignant melanoma with brain and liver metastasis, he was given an average of six to 12 months’ life expectancy. However, his oncologist put him on a new medication, pembrolizumab, which had recently been approved by the FDA (Food and Drug Administration – the government regulatory agency of food and medicine, among others).
Approximately six months after starting this new therapy, the former president declared that he was free of the disease, which was almost unthinkable until very recently in this type of cancer. During the clinical trials that led to the approval of this drug, the survival rate among patients with advanced melanoma was increasing every two weeks and 74% of patients were alive after one year.
Obviously, therapy should remain hand in hand with prevention, screening and early detection. We believe, however, that, in the next few years, the fight against cancer will change for some patients, as the course and outcome of these diseases will alter step by step.
The Hospital Particular do Algarve has a skilled team in the multidisciplinary approach of tumours and these new therapies. The team of specialists in medical oncology, dermatology, surgery and radiology work together in the treatment of these patients.
By Dr André Oliveira
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Dr André Oliveira, new resident Oncologist at Hospital Particular do Algarve in Gambelas (Faro) and Alvor (Portimão).