[Pneumocystis jiroveci pneumonia in patients with cancer: is it unavoidable?]

Although the use of prophylactic medication has reduced the incidence of Pneumocystis jiroveci pneumonia (PCP), it still occurs in cancer patients and is associated with a high morbidity and mortality.

Patients with haematological malignancies are at high risk for PCP because of chemotherapy and steroid-induced immunosuppression. Despite highly active prophylactic regimens, most cases occur in patients who are not receiving any prophylactic treatment even though the risk factors are well described. PCR techniques have been used for PCP diagnosis but these highly sensitive methods may not be able to discriminate between airway colonisation and infection.

Prophylaxis should be widely recommended for patients receiving prolonged steroid therapy or other immunosuppressive drugs. A low CD4+-T cell count (less than 200/microl) may be a useful marker to identify high risk patients who should not discontinue prophylaxis.

Because PCP is very severe in cancer patients, higher risk patients must be identified and long-term prophylaxis should be maintained as long as immunosuppression persists.