With ageing, function preservation and maintenance of quality of life represent a major goal in an increasing proportion of patients. Life expectancy is a function of age, comorbidity, disability and cancer type and stage. Decision-making involves a delicate balance among all these factors, evaluation of treatment related complications of the overall effects of cancer and cancer treatment on the patients' quality of life. Despite several instruments for the assessment of quality of life being validated, none have been calibrated to the special requirements of the older patients. The structured interview administered by a trained clinician represents a standard approach for geriatric research and even for clinical practice because of the frailty of the older population. The combination of this approach with the self-administered questionnaire appears the most effective way to minimise missing data in collecting information for patients unable to complete the form.