September/October 2007

Thoracic Surgery News

By Mitchel L. Zoler
Elsevier Global Medical News

WASHINGTON--The two surgical options typically used for resecting malignant, pleural mesothelioma produced similar outcomes in a series of 663 consecutive patients from three centers.

But despite similar median survival rates following both extrapleural pneumonectomy (EPP) and pleurectomy/ decortication (P/D), “these two procedures are not interchangeable,” Dr. Raja M. Flores said at the annual meeting of the American Association for Thoracic Surgery.
That’s because the primary goal of surgery is to achieve at minimum an R1 resection of the tumor, defined as removal of all gross disease, which leaves behind only microscopic traces of the cancer, said Dr. Flores, a thoracic surgeon at Memorial Sloan-Kettering Cancer Center in New York. The ultimate goal is to produce an RO resection, which means that all microscopic and gross disease has been removed, but this is often not possible. The resection result to be avoided is that of leaving gross tumor behind, an R2 resection.

An EPP is an en-bloc resection of the lungs, pleura, pericardium, and diaphragm. The P/D spares the entire lung; it removes the parietal and visceral pleura, and removes the pericardium and diaphragm only when necessary. Thus, it is a more sparing procedure.

Most patients with stage 1 mesothelioma are treated with the more sparing P/D. These patients have less bulky tumors, and few need an EPP. But, in fact, even in some patients with a stage 3 tumor, an R1 resection can be achieved with a P/D.

Frequently, however, the more extensive EPP resection is needed to achieve an R1 result. “If a patient has a big, bulky tumor, you need to use EPP, period,” according to Dr. Flores.

“There is confusion about which is the better surgery EPP or P/D. I’d say the goal is a macroscopic, complete resection [R1], regardless of which procedure is used,” commented Dr. David J. Sugarbaker, chief of thoracic surgery at the Dana-Farber Cancer Institute in Boston. The review by Dr. Flores and his associates included all patients who underwent surgery for a malignant, pleural mesothelioma at any of three U.S. centers during 1990-2006: Memorial Sloan-Kettering; the National Cancer Institute in Bethesda, Md.; or the Karmanos Cancer Institute in Detroit. The average patient age was 63 years. Among the 385 patients who had EPP, the median survival was 12 months, and among the 278 patients treated with P/D, the median survival was 16 months. This suggests that P/D produces better outcomes, but use of the two alternatives was skewed based on tumor stage, according to Dr. Flores. Those patients who had a P/D tended to more commonly have lower-stage tumors, with EPP used for higher-stage tumors.

In a Cox proportional hazard regression analysis that controlled for tumor stage and histology type, patients treated with EPP had a 20% higher risk of death, compared with patients treated with P/D, a difference that reached statistical significance but wasn’t highly significant (P = 0.04).

Mesothelioma histology and tumor stage were both more powerful, independent predictors of survival in the same analysis. A nonepithelioid histology was linked with a 50% increased risk of death, and having stage 3 or 4 cancer was associated with a 90% increased risk of death.

Both of these links were highly significant, with P values of less than .00 1. The data also confirmed that patients treated with EPP who develop recurrent disease were more likely to have a distant recurrence (66% of all recurrences in this subgroup), whereas patients treated with P/D were more likely to have a local recurrence (65% of all recurrences in the P/D subgroup). “The results emphasized the similar survival with both EPP and P/D,” Dr. Flores said. “If an R1 resection is not possible with P/D, then EPP is the procedure of choice.”