World Cancer Day: where we are and where we’re going?

Interview with Dr André Oliveira, Oncology Director at the HPA Alvor and Gambelas (Faro)

The diagnosis and treatment of cancer have evolved incredibly over the last decade. However, it is still a frightening word, especially due to the unknown such as survival rates and quality of life.

Despite oncology records for the southern region (Lisbon and The Tagus Valley, Alentejo, Algarve and Madeira) showing positive results for the survival of colon, rectum and breast cancers, the truth is that there are more than 24,000 new cases each year. This means three new cases are diagnosed every hour.

Which has evolved the most in the last few years – diagnosis or treatment?
These last few years have been revolutionary in the field of combatting cancer. The constant arrival of new therapies, such as immunotherapy and targeted therapies, together with the positive results they have brought, shows that we are on the right track towards treatment and cure.

The improvement of diagnostic techniques is also significant at the moment. Genetic study, which used to be difficult and slow to access, has now become accessible for any patient. Access to studies on circulating tumour cells and the use of liquid biopsies for research of oncogenic mutations has become a reality for certain types of pathologies such as cancer of the colon, lung or melanoma.

Does this mean that genetic techniques and liquid biopsies offer more precise diagnostic results when compared to image techniques such as magnetic resonance or positron tomography emission?
No, at the moment they offer additional help in the diagnosis. We are in the early stage, as these new diagnostic techniques have only recently been introduced for clinical use; they are in the process of improvement concerning the diagnostic specificity and sensitivity. They do not yet substitute the exams mentioned.

You spoke of targeted therapies and immunotherapy. What are these?
Targeted therapies are medications that have special characteristics that act in specific alterations that are found in the genesis of the growth of the tumour cells. This targeted attack of the tumour allows normal cells to be saved, thus significantly reducing the side effects common to many cytotoxins.

Immunotherapy treatments are more recent forms of cancer treatment. They are administered intravenously or subcutaneously, in order to act in a systemic way, in a day care hospital. These can be active or passive therapies. Active when they increase the patient’s immunological reactions against “foreign” cells. Passive when they allow certain antibodies (usually produced artificially) to attack specific locations of the cells that foster tumour growth.

Which type of cancer has the highest survival rate?
Surviving cancer very much depends on the stage in which it is diagnosed. That being said, testicular neoplasm still has the highest survival rate, even in the more advanced stages.

Which type of cancer has increased most in terms of prevalence?
We have to distinguish prevalence from incidence. Incidence is the number of new cases diagnosed and prevalence is the number of people living with the diagnosis. In terms of prevalence, breast cancer is the highest, partly because of treatment improvement and greater survival rate and, on the other hand, due to better screening methods.

As for incidence, in Portugal the highest are breast tumours, prostate, colon and lungs. In terms of an increased incidence, we can attest to a greater number of women developing neoplasm of the lungs. This factor is closely related to smoking habits.

Some cancers metastasise more than others. Why is that?
There are cancers which, when diagnosed, are detected in later stages and, therefore, have had more time to invade the blood and/or lymphatic vessels, thereby increasing the release of malignant cells into the circulation and subsequently causing metastasis. The tumours that have characteristics with the least adhesion to the primary tumour and a greater capacity for invasion are those that metastasise most frequently.

Are there any environmental factors that precipitate metastases?
At the moment, there is no clear scientific evidence that can directly associate an environmental factor to a greater risk of metastasis.