A totally different mechanism is used in Immunotherapy when compared to the last two options. Immunotherapy uses antibodies to activate our defences using our immune system to attack malignant cells. In a way, it follows a principle formulated by Hipocrates more than two thousand 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 4 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 9 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 5 years was between 10 to 22%, but with these new drugs there is a promise of a very positive change in these percentages.
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 DP-1 or its PDL-1 receptor. These molecules are permitting a substantial response in the treatment and survival of melanoma and more recently in cancer of the lung.
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 6 to 12 months life expectancy. However, his oncologist put him on a new medication: pembrolizumab, which had recently been approved by the FDA (Food & Drug Administration – the government regulatory agency of food and medicine, among others).
Approximately 6 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 disease. In the clinical trials that led to the approval of this drug, the survival rate among patients with advanced melanoma, every two weeks, were good: 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 game in the fight against cancer will change for some patients, where 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. These teams which include medical oncology, dermatology, surgery and radiology, work together in the treatment of these patients.