Some types of cancer

Cancer is the name which comprises a group of more than one hundred different diseases, which have in common an uncontrolled cell growth and the dissemination of abnormal cells.


In the normal body cells renew themselves in an orderly manner, enabling the harmonious repair and growth of the tissues of our body.


Cancer occurs when there is a lesion of the genetic material, in other words, of the cell DNA, causing the emergence of mutations. The next step is called «promotion», leading to an uncontrolled proliferation of abnormal cells.


In a healthy person, these cells are eliminated by the immune system. But if our body is unable to recognise and destroy them a malignant neoplasia or a cancer will occur.


Multiple factors can contribute for the emergence of a malignant disease:

  • Diet
  • Tobacco
  • Viral infections
  • Excessive exposure to solar radiation
  • Exposure to certain chemical agents, hormones and radiations
  • Genetic influence


These factors can act separately or in combination during several years until the disease is declared.


In many cases, if we avoid exposure to those factors, we can prevent some types of cancer. That is what happens, for instance, with lung cancer, which is directly related to smoking, and skin cancer related to chronic solar exposure.


Cancer can affect any organ. Nowadays, in Portugal, the most prevalent cancers are, in descending order of frequency, breast, prostate, lung, stomach and bladder cancers.


Most of these tumours have the capacity to infiltrate other organs or tissues and can invade the bloodstream, originating tumours away from original one – metastases -, putting the patients’ lives at risk. For instance, advanced breast cancer may affect the lungs, the liver, the bones, the brain.

Because of the great diversity of tumours, cancer should not be considered an isolated clinical entity.
It is fundamental to take into account the different growth and metastization patterns, which vary from case to case, according to the types of cancer and the patients’ characteristics.


Generally, cancer affects people over 40 years old, the risk being five times higher from this age on.
This disease may affect any age group, including children and youngsters, with specific type of cancers at these ages (Wilms tumour, neuroblastoma and severe lymphoblastic leukaemia, for instance).


Oncological diseases are the second cause of death in Portugal and the one that has increased most in the last years. The population ageing and lifestyles changes have contributed for the relative increase of the incidence of new cases.

On the other hand, the increase of the success of the treatments has contributed for a significant increase of the number of cancer survivors.

In spite of the fear and ignorance which still surrounds the cancer problematic, there have been great progresses in Oncology in the last years, both in diagnosis and treatment. About one third of the cancer cases in the adult and more than half in children can be cured, nowadays.


Early diagnosis, definitely, contributes for the larger number of cures and long-term remissions of the disease. To improve the primary and secondary prevention remain important challenges.


On the other hand, even in patients in advanced stages of the disease, for whom the cure of cancer is no longer possible, with the currently available palliative therapeutic means we can control, efficiently, most symptoms and, therefore, contribute for a better quality of life of these patients.