Daily tunneled catheter drainage might hasten autopleurodesis compared to every other day drainage in symptomatic patients with recurrent malignant pleural effusion
EBM Focus - Volume 12, Issue 19
- The optimal frequency of tunneled catheter drainage to manage malignant pleural effusion is unknown.
- In the ASAP trial, 162 adults with malignancy and symptomatic recurrent pleural effusion who were responsive to thoracentesis were randomized to daily vs. every other day drainage of a tunneled pleural catheter for 12 weeks. Patients with loculated pleural effusion or trapped lung were excluded.
- Daily catheter drainage increased the likelihood of partial or complete autopleurodesis (in 47% vs. 24% with every other day drainage, p = 0.003, NNT 5) and decreased the time to autopleurodesis (median 54 days vs. 90 days, p = 0.005). Baseline differences may have influenced the differences in outcomes.
Patients with malignant pleural effusion have a poor prognosis (Thorax 2014 Dec;69(12):1098) and management is focused on symptom relief. Palliative options include therapeutic pleural aspiration if life expectancy is < 1 month, intercostal tube drainage followed by chemical pleurodesis, thoracoscopy with drainage and chemical pleurodesis, and ambulatory tunneled catheter drainage in selected patients (British Thoracic Society Pleural Disease Guideline 2010). Tunneled catheters may remain in place for weeks to months, allowing outpatients to regularly drain pleural fluid, promoting pleural contact and adhesion and eventual pleurodesis (Trials 2015 Feb 12;16:48). A survey of thoracic surgeons indicates that guidance on the best frequency of pleural drainage is needed (Interact Cardiovasc Thorac Surg 2017 Mar 1;24(3):414). To address this question, the ASAP trial included 162 adults with malignancy and symptomatic recurrent pleural effusion who were responsive to thoracentesis. The patients were randomized to daily vs. every other day drainage via tunneled pleural catheter for 12 weeks. Patients with loculated pleural effusion or trapped lung were excluded. The primary outcome was autopleurodesis (complete and partial), defined as ≤ 50 mL pleural fluid on 3 consecutive drainages and lack of symptoms including shortness of breath, cough, or chest pain. When there was no radiographic evidence of effusion or blunting of the costophrenic angle only, the autopleurodesis was considered to be complete, and when the radiographic blunting extended beyond the costophrenic angle, the autopleurodesis was considered to be partial.
Despite randomization, baseline differences included higher rates of deep venous thrombosis or pulmonary embolism and bilateral pleural effusion in the daily drainage group and higher rates of lung cancer, chronic kidney disease, hypothyroidism, and hypertension in the every other day drainage group (statistical comparisons were not reported). Autopleurodesis occurred in 47% of patients in the daily drainage group vs. 24% of patients in the every other day group (p = 0.003, NNT 5) with a complete response observed in 30% vs. 16%, respectively (p = 0.037, NNT 7). The median time to autopleurodesis was 54 days with daily drainage vs. 90 days with every other day drainage (p = 0.005). No significant differences in adverse events were observed between the two groups, with pain upon drainage in 34% with daily drainage vs. 38% with every other day drainage, catheter occlusion in 11% vs. 5%, and any infection in 4% vs. 1%.
The ASAP trial showed that daily drainage of tunneled pleural catheters increased the likelihood of autopleurodesis and decreased the median time to autopleurodesis by 36 days compared to every other day drainage. The treatment arms were not balanced at baseline for some conditions potentially influencing the outcome, with higher rates of thromboembolic disease in the daily drainage group and higher rates of chronic kidney disease, hypertension, hypothyroidism, and lung cancer in the every other day drainage group. These differences may have been reflected in the mortality difference between the groups, with death occurring in 25% in the daily drainage group and in 34% of the every other day drainage group. This potential confounding despite randomization decreases the confidence in the estimated size of the effect. Moreover, the rate of autopleurodesis in the every other day group in the ASAP trial (24%) is lower than that reported in other trials (46%-51%) in patients with indwelling pleural catheters with recommended every other day or three times weekly drainage. This comparison, however, is complicated because these trials had longer periods of follow-up and did not strictly control drainage frequency (Cancer 1999 Nov 15;86(10):1992, JAMA 2012 Jun 13;307(22):2383). With these considerations in mind, daily drainage of tunneled pleural catheters may decrease time to autopleurodesis compared to every other day drainage in patients with malignant pleural effusion who may not want to undergo chemical pleurodesis.