Classification

The results from the investigations may help to establish the type, position, size, grade and stage of the cancer. These will all be used to ensure an appropriate treatment is selected, along with a thorough assessment of the patient (this is discussed in Ch. 5). It is very important that the right words are used to describe all aspects of the cancer so that healthcare professionals are aware of the situation and the patient is not confused with too many different medical terms.

The word tumour is often used and, although it means ‘lump’, it is an ambiguous term and can mean either benign or malignant. This can confuse patients. If they are told they have a tumour, they may assume that they have a benign condition, when they actually have a malignant cancer. Although benign tumours can cause problems due to their size; be painful or unsightly; press on other body organs; take up space inside the skull (for example, like a brain tumour); and release hormones that affect how the body works, they are not cancers. Cancers are made up of malignant cells which are discussed in Chapter 2, so it is best to avoid the use of the word ‘tumour’, and use the word ‘cancer’ so that patients do not become confused. The main differences between benign and malignant tumours are given in Table 4.1.

Table 4.1 Difference between benign and malignant tumours

In the clinical setting, tumours are described according to their histogenesis (the names are specific to the cells/tissues from which they arise) and are often named from Greek and Latin terms. In general, benign tumours end in the suffix ‘-oma’ which means ‘lump’ in Latin. Malignant cancers usually have a prefix to the ‘-oma’ which is related to the tissue of origin. For example, malignant tumours that derive from epithelial tissues (lining tissues) are called carcinomas. Carcinomas account for 75% of all cancers and there are two types of carcinoma – adenocarcinoma (cancer in glandular tissue) and squamous cell carcinoma (cancer in squamous epithelium). Cancers arising in the connective tissues (bone, cartilage, muscle, fibrous tissue) are called sarcomas (accounting for 20% of cancers) and cancers in the neural tissue are called blastomas.

The specific names of tumours (both benign and malignant) are also made up of the specific tissue in the body (Table 4.2). So a benign, non-malignant tumour in the unstriated smooth muscle would be called a ‘leio-my-oma’ and a malignant cancerous tumour in the unstriated smooth muscle would be a ‘leio-myo-sarc-oma’. There are some exceptions to this rule. For instance, using the rules above, melanoma and lymphoma sound like they are benign tumours when in fact they are malignant.

Table 4.2 Naming of tumours

Other cancers are named after the researcher who first described them, for example Hodgkin’s lymphoma and Kaposi’s sarcoma.