From a practical point of view, cancer is diagnosed under three different circumstances:
Chance finding. Cancer is diagnosed in patients that do not have any symptoms and who undergo an examination that is unrelated to a suspicion of cancer, such as a preoperative imaging test or routine analysis during an occupational medical check-up.
Screening. The suspicion of cancer is detected during a screening programme.
A search for the origin of nonspecific signs and symptoms.
Medical history. The first step when making a diagnosis is to analyse the symptoms and obtain all the relevant information about the risk factors, such as smoking, occupation and family history. After an interview (anamnesis) the doctor will assess whether the case needs to be studied further with additional tests. Once diagnosed, a specialist will evaluate the patient’s general state of health in order to select the best treatment strategy.
Laboratory tests. These determine the number of certain types of cells in the blood.
Imaging tests. Used to observe possible signs of the disease.
Analytical tests on samples and tissues. Once the presence of the tumour has been confirmed a biopsy is conducted, which is the extraction of a tissue sample for analysis to discover the shape of the cells. There are several methods of extracting these samples. The most appropriate procedure depends on the type of cancer and its location.