[Quality of life in cancer patients]

Quality of life (QOL) is defined as "representation of people's day-to-day function". It has four components: physical and occupational functions, social interaction, psychological state, and somatic sensation. QOL can be mathematical presentation of these four component factors. QOL measurement tools (questionnaires) should have core modules as well as disease-specificity, simplicity, validity and reliability. At present, several patients' self-assessment questionnaires are widely used practical at the aims to assess what happens in the cancer patients and to improve the cancer treatment. A QOL study trials should be scientific. However, QOL is popular terms that there is a tendency to abuse it, and, therefore, to set up the study to get contradictory results. The author would introduce a practical overview of the tactics to perform a QOL research trial.