In cancer treatment, control of advanced stage disease and cure chances are increased after the introduction of new agents and combined treatments. Late side effects can be described as the effects that have not been recovering after treatment or developing after completion of treatment. Nowadays, patients who achieve long term cure are increasing therefore, thus many late side effects are more evident. These patients should be evaluated by a multidisciplinary team. Detection and early diagnosis programs should be performed to cancer survivors lifelong. In this rapidly growing population, we need guidelines that follow and describe late side effects objectively about cancer and cancer treatment. In this way, complications of cancer treatment can be detected earlier. By preventing sequelae formation with early treatment, quality of life and long term survival can be improved.