There are two primary surgical methods used in the treatment of mesothelioma: pleurectomy/decortication (P/D) and extrapleural pneumonectomy (EPP). In a pleurectomy/decortication, the parietal pleura, visceral pleura, mediastinal pleura, pericardium and diaphragm are removed, leaving the lung as as intact as possible. An EPP involves a complete resection of the affected lung, along with the removal of the pleura, pericardium and diaphragm. As such, it is considered the more invasive of the two surgeries. In general, P/D has been used for patients in the earlier stages of the disease and EPP has been used in the later stages of the disease. However, surgeon bias has also had an important effect on the decision regarding which surgery to use and specific guidelines on when to use each procedure do not really exist. In an attempt to provide some guidance on this question, researchers in Japan have recently released the results of a study comparing the effectiveness of pleurectomy/decortication to extrapleural pneumonectomy.

Introduction to the Study

Mesothelioma remains a very difficult disease to treat properly. The disease is often undiagnosed until a fairly late stage and to date all available treatment modalities have had limited long-term success. However, there is active research in all areas of treatment, both in the development new treatments and in perfecting current treatments. As regards surgery, no guidelines have been definitely established as to when to use P/D or EPP or which has the better prognosis after the operation.

To analyze this question, the researchers looked at 87 patients with immunohistochemically-confirmed and histopathologically-confirmed malignant pleural mesothelioma. 65 patients were studied: 34 received a P/D, while 31 received an EPP. Of these patients, 58 were men and 7 were women. Histology showed 48 epithelial cases, 11 mixed cases and 6 sarcomatous ones. The latter two were grouped as a single variable so the comparison made was epithelial mesothelioma vs. non-epithelial mesothelioma. In terms of staging, 8 patients were Stage I, 13 were Stage II, 40 were Stage III and 4 were Stage IV.

Results

The authors did not find a significant difference in overall survival figures between P/D and EPP. For the 34 patients who underwent P/D, median survival was 17 months and three-year survival was 24%. For patients who underwent EPP, median survival was 13 months and three-year survival was 33%. Thus, patients who received a P/D had a longer median survival figure (17 months to 13 months), but a lower three year figure (24% to 33%).

When further comparing P/D to EPP, it was found that P/D was more often given to patients in the early stages (Stage I: 8, Stage II: 8) of the disease who presented with epithelial histology (29) than was EPP, which was not given to any stage I patients and only 5 stage II patients, and was given to 19 patients who presented with epithelial histology.

The study also included discussions not directly related to the P/D and EPP dichotomy. It once again confirmed that patients who present with an epithelial histological sub-type had a much better prognosis than those who present with mixed or sarcomatous histology. Median survival for the former was 18 months and three-year survival was 33%, which were clear improvements on the non-epithelial group where median survival was 8 months and three-year survival was 8%.

The study did not find a statistically significant difference in overall survivability between stage I and stage II patients, although it did note a marginal difference between stage II and stage III patients and a significant difference between stage III and stage IV patients.

When comparing all of the possible patients factors, the authors founds that older age, non-epithelial histology and late stage (III-IV) disease had a significant negative impact on survival.

The authors also noted that multimodal therapy with EPP provided excellent prognosis for the limited number of patients who underwent these procedures. Four patients underwent EPP with adjuvant hemi-thorax radiotherapy and five underwent an EPP with neo-adjuvant chemotherapy and adjuvant hemi-thorax radiotherapy. Eight of the nine patients survived and currently don’t show any signs of recurrence.

Conclusion

The study was designed to compare the effectiveness of P/D to EPP and to make recommendations on which procedure to perform. While it did not show any significant difference in survivability between the two procedures, the authors did note that P/D was more commonly used on those with early stage disease and epithelial histology, which has a better overall prognosis than does late stage and/or non-epithelial histology. The authors recommend that, given a patient who can tolerate both procedures, surgeons should attempt an EPP when possible, as complete resection of malignant tissue has the highest potential of achieving a complete cure. They also recommend, when possible, the use of trimodal therapy.

Labels: mesothelioma