Chronic fatigue syndrome in cancer patients

Sindrom kroničnog umora u bolesnika sa zloćudnim bolestima je jedan od najčešćih i kompleksnih simptoma u onkoloških bolesnika. Približno 50% svih pacijenata pati od umora u trenutku dijagnoze. Taj broj raste i do 80-96% u bolesnika pod kemoterapijom i 60-93% u onih koji primaju radioterapiju. Umor je u bolesnika sa zloćudnim bolestima jedan od najviše uznemirujućih simptoma povezanih s tumorom i tumorskim liječenjem sa značajnim utjecajem na kvalitetu života i svakodnevno djelovanje. Umor u bolesnika sa zloćudnim bolestima se razlikuje od uobičajenog umora u zdravih ljudi po svojem intenzitetu, trajanju i uglavnom se ne otklanja odmorom. Etiologija umora u pacijenata sa zloćudnim bolestima je multifaktorijalna. Postoje brojni čimbenici povezani kako s terapijom tako i samim tumorom koji doprinose nastanku kroničnog umora, od kojih mnogi nisu u potpunosti razjašnjeni. Neki od dobro poznatih rizičnih čimbenika su anemija, gubitak tjelesne mase, vrućica, infekcija, kaheksija i depresija. U ovom radu biti će prikazani prevalencija, veličina problema i trenutno poznati patofiziološki mehanizmi u podlozi tumorski uvjetovanog umora. Nekoliko je hipoteza vezanih uz patofiziologiju tumorski uvjetovanog umora poput hipoteze proupalnih citokina, serotoninske hipoteze, hipoteze vagalne-aferentne aktivacije, anemije i adenozin trifosfat hipoteze. Razumijevanje specifičnih mehanizama u podlozi tumorski uvjetovanog umora moglo bi unaprijediti dijagnostiku i mehanizmom uvjetovanu intervenciju te otvoriti potencijalne putove prevencije i liječenja sindroma kroničnog umora u bolesnika sa zloćudnim bolestima.Cancer-related fatigue is one of the most prevalent and complex symptoms in patients with cancer. Nearly 50% of patients have cancer-related fatigue at the time of diagnosis. This number raises up to 80–96% in patients undergoing chemotherapy and 60–93% in patients receiving radiotherapy. Cancer-related fatigue is often reported as the most distressing symptom associated with cancer and its treatment, thereby having considerable impact on patients’ quality of life and daily functioning. Cancer-related fatigue differs from usual experience of fatigue in healthy individuals with its severity, persistence and it's usually not relieved by rest. Etiology of cancer-related fatigue is multifactorial. There are many treatment-related and disease-related factors that may contribute to the development of cancer related fatigue, many of which are not fully understood. Some of the well investigated contributing factors in cancer-related fatigue are anemia, weight loss, fever, infection, cachexia and depression. This paper will discuss prevalence, size of the problem and currently known pathophysiological mechanisms underlying cancer-related fatigue. There are several hypotheses regarding pathophysiology of cancer-related fatigue such as the pro-inflammatory hypothesis, the serotonin hypothesis, the vagal afferent-activation hypothesis, the anemia hypothesis, and the adenosine triphosphate hypothesis. Understanding specific mechanisms behind cancer-related fatigue could improve diagnosis of cancer-related fatigue and to administration of mechanism-driven interventions and could also provide potential routes for prevention and treatment of cancer-related fatigue