Differential Survival Characteristics of Sarcomatoid Subtype in Biphasic Pleural Mesothelioma

Biphasic pleural mesothelioma (BPM) accounts for approximately 10% of all pleural mesothelioma. Our aim was to assess the clinical, radiologic, and pathologic factors impacting survival in BPM and to better identify patients most likely to benefit from active treatment.

A 10-year retrospective review was made of 214 biopsy-proven BPM cases with minimum 2-year follow-up. Patients with insufficient tissue for analysis were excluded (n = 96). Clinical and pathologic factors were evaluated along with radiologic assessment of pleural thickness. Survival was measured from time of diagnosis. Univariable and multivariable predictors of survival were evaluated.

In all, 118 patients were included; 28 underwent pleurectomy/decortication, with 27 receiving additional modalities. Ninety patients underwent chemotherapy (n = 18) or radiotherapy alone (n = 9), 63 received combination therapy, and 27 received best supportive care. Median overall survival was 11.2 months (range, 0.3 to 36.2). At univariable analysis, pleurectomy/decortication (p = 0.0061), radiotherapy (p < 0.0001), and chemotherapy (p < 0.0001) were associated with superior survival when compared with best supportive care alone. Pleurectomy/decortication demonstrated 40% survival improvement compared with no surgery (p = 0.122). In a multivariable model, necrosis was negatively prognostic (hazard ratio 2.1, SE 0.76). Furthermore, increased sarcomatoid component was associated with worse survival without radiotherapy.

BPM prognosis remains poor despite multimodality treatment. Anticancer treatment is associated with superior outcome in this nonrandomized retrospective series. Our findings suggest superior survival for patients with a lower proportion of sarcomatoid disease, with selective benefit of radiotherapy in higher proportions of sarcomatoid disease. When planning active treatment, the potential survival benefits require balancing against associated morbidity and recovery period.