Abstract
Dear Editor:
Malignant pleural effusions (MPEs) often cause debilitating symptoms that result in impaired quality of life. The limited clinical success of pleurodesis necessitates MPE management advancement. The clinical predictive value of objective markers, such as pH and adenosine deaminase, is still debated.1,2 The goal of the current study was to explore an objective indicator attesting to whether or not an MPE patient would benefit from talc pleurodesis. We hypothesized that C-reactive protein (CRP) levels in the intrapleural fluid would predict the clinical improvement in the patient's condition after talc installation objectively, as reflected by chest x-ray (CXR), and subjectively, via reports of respiratory symptoms, both evaluated one month posttreatment. The underlying rationale was that CRP levels represent an existing inflammation, and therefore the attempt to further induce a local inflammatory reaction via the installation of a chemical agent in the pleural space would be clinically constructive.
The current prospective study included 63 consecutive patients with symptomatic MPE, 35 of whom were included in the final analyses. Four grams of talc mixed in 150 ml of saline were administered after complete drainage of the pleural effusion.
Based on posttreatment CXR evaluations, pleurodesis was successful in 19 patients (54.29%). Based on subjective reports, pleurodesis was successful in 17 patients (48.58%). The subjective success criterion was in excellent agreement with the objective success criterion (κ=0.942). Of age, gender, CRP, pH, total protein, and lactate dehydrogenase, logistic regression analyses indicated that CRP was the sole predictor for the success of the pleurodesis procedure assessed objectively by CXR (P=0.018), while CRP and age were the sole predictors for pleurodesis success assessed subjectively (P=0.042). CRP levels in the patients who underwent a successful pleurodesis versus unsuccessful pleurodesis were different, based on posttreatment evaluations, both objective (CXR; P=0.021) and subjective (individual reports; P=0.039).
MPE patients with CRP levels ≥30 mg/L will most probably undergo a successful pleurodesis procedure, as assessed both objectively by CXR and subjectively by individual reports (P<0.0001). Due to the pleurodesis failure and high complication rates, it is reasonable to determine the patients in whom the pleurodesis procedure will succeed. Pleurodesis success rates among malignant pleural effusion patients may be as low as 47%. 2 However, of the 10 malignant pleural effusion patients of the current study, who demonstrated CRP levels greater than the critical threshold of 30 mg/L, 9 patients (90%) were successfully treated by pleurodesis. Bielsa and colleagues 3 reported that malignant effusions specifically due to lung cancer are particularly prone to a failed procedure. In the current study group, of the six lung cancer patients, five (83.3%) demonstrated a successful pleurodesis using the aforementioned CRP threshold value.
In conclusion, pleural effusion CRP levels may reliably predict pleurodesis success and symptomatic failure among MPE patients. Therefore, it may be advantageous when selecting patients for pleurodesis to incorporate in the clinic routine tests of pleural fluid CRP levels.