Despite emerging risk of PJP in the era of new anti-cancer drugs, early diagnosis can be challenging. Rate of mortality in non-AIDS patients is 35-50%, with highest risk among cancer patients.
To determine the incidence, outcomes and predictors of mortality of PJP in cancer patients and to describe features that differentiate PJP from other inflammatory/infectious conditions or pulmonary toxicities related to anti-cancer treatments.
We conducted a single-centre retrospective chart review to identify all lung cancer patients with a clinical diagnosis of suspicious of PJP between January 2011 and December 2015. Proven PJP was defined as positive microbiological test of induced sputum. The associations between categorical variables were assessed using Pearson’s Chi squared, Fisher’s exact and independent sample t-tests.
Among 31 lung cancer patients with suspected PJP, 10 patients had confirmed diagnosis (Table 1). All were treated with trimethoprim-sulfamethoxazole and short course of corticosteroids. Clinical presentations commonly included new or worsening dyspnea, cough, and fever. Median time from commencing anti-cancer treatment to developing PJP was 2 months. Most patients received gemcitabine-based chemotherapy. Five patients fully recovered after treatment initiation while 5 patients died (50% mortality rate in confirmed cases). Length of stay (LOS) was shorter in non-survivors due to acute deterioration during hospitalization (Table 2). Factors associated with mortality were ECOG ≥2 and acute respiratory failure.
Clinical presentations, corticosteroid use, laboratory findings and LOS were similar between PJP and non-PJP cases. Radiological findings of diffused interstitial infiltrates were more common in PJP group. Other diagnoses include pneumonia, pulmonary embolism, lung cancer progression and pneumonitis.
PJP in lung cancer patients receiving treatment is associated with high mortality, particularly in patients with poor performance status and poor ECOG. Clinical presentations may resemble other pulmonary conditions therefore high clinical suspicion and confirmatory diagnosis is warranted.
Authors have no financial disclosure or conflict of interest.