[Diagnostics in very old patients; when to apply it or not in cases of suspected malignancy?]

This paper focuses on considerations regarding diagnostics in case of a suspected malignancy in a very old or frail patient. The patient's preference and life-perspective lie at the core of shared decision-making. From a medical point of view, the estimated life-expectancy may be so short that further diagnostic testing for a malignancy may only be useful when there are treatable symptoms in play. In other cases, prior to diagnostics there may already be a suspicion that there will be no feasible oncologic treatment options. From the perspective of advance care planning and symptomatic treatment, it can nonetheless still be useful to confirm the presence of a malignancy through imaging diagnostics. Obtaining tissue for further specification in very old or frail patients is only useful when an easily tolerated, yet effective treatment is likely or possible, such as endocrine treatment in case of prostate cancer or breast cancer.