The Complexity of Aging: Cancer Risk Among Elderly People and Infectious Risk Among Those with Cancer

Aging is associated with a reduced capability of the immune system to adequately respond to pathogens and to prevent tumor formation. As a consequence ofimmunosenescence, older people have a higher risk to develop infections as wellas cancer. In addition, cancer itself may expose old patients to infections,including opportunistic infections, i.e. Pseudomonas aeruginosa, Aspergillusfumigatus and Cytomegalovirus infection. Patients with hematologic malignancieshave a higher risk than patients with solid tumors, because of more prolongeddisease-related and treatment-related neutropenia and intensive immunosuppressiveregimens. Co-existing medical conditions, e.g. chronic renal failure, diabetesmellitus, emphysema, which are quite common in the elderly, may also contributeto rising the infectious risk, as well as the use of long term vascularcatheters, which is required in a large number of cancer patients to administratechemotherapy. Neutropenic infections do not only represent a major cause ofmorbidity and mortality, but may be responsible for a reduction of theantineoplastic treatment dose and dose intensity, thus compromising the overalltreatment effectiveness. The use of antibiotic prophylaxis to reduceneutropenia-related infectious complications in patients with cancer is stillobject to debate. Quinolones represent the most attractive option, since thesedrugs have a broad antimicrobial spectrum, systemic bactericidal activity, goodtolerability and lack of myelosuppression. However, fluoroquinolone prophylaxishas already been associated with the emergence and spread of resistant bacteriaand strictly precludes the subsequent use of fluoroquinolones for initialempirical therapy; in addition, fluoroquinolones should be administered withcaution among elderly patients, especially those with more pronounced vascular ordegenerative impairment of the central nervous system, cardiac disease orelectrolyte disturbances.