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Pleural Mesothelioma and Surgery

Tuesday, January 27, 2009

Article: Surgery for Malignant Pleural Mesothelioma

Malignant mesothelioma is one of the most difficult diseases in all of medicine to manage effectively. Median survival time typically averages only 12-14 months. For patients lucky enough to receive a diagnosis in the disease’s earliest stages, median survival can sometimes be extended two or three years, but a complete cure remains impossible and the vast majority of people who are diagnosed with pleural mesothelioma or peritoneal mesothelioma will eventually die from the disease. Because of this disappointing situation, physicians and scientists all over the world are searching for more effective treatments. In some cases, this research may focus on the investigation of a novel therapeutic strategy; in other cases, it may focus on improving a current treatment modality or on comparing the effectiveness of competing modalities when a standard-of-care has not yet been established.

One of the most controversial questions in contemporary mesothelioma treatment research concerns the choice of pleurectomy/decortication (P/D) vs. extrapleural pneumonectomy (EPP) for the surgical management of pleural mesothelioma. Both of these treatments are highly invasive procedures and both are properly considered radical surgery, but there is not yet clear guidance on which surgery should be performed for what patient. EPP is considered the more invasive of the two procedures, so some physicians will perform P/D on early-stage patients and EPP on late-stage patients, but a standard does not exist which actually specifies this. In many cases, the question of procedure will be based on a physician’s personal history in treating the disease. A number of retrospective studies have been performed, but direct comparison of their results is impossible due to differences in study design, staging guidelines, reporting and a host of other factors. However, these studies are still helpful for the working physician and many doctors will look at these studies in an attempt to draw some conclusions from their findings.

In an article recently published in the Annals of Diagnostic Pathology, David Rice, MB, BCh, FRCSI, of the MD Anderson Cancer Center, summarized much of the available literature on the treatment of pleural mesothelioma and addressed the controversy of P/D vs. EPP as well. He stated that the goal of any curative surgery should be the removal of all macroscopic evidence of disease, but that the available evidence does not indicate which procedure should be the one deployed for this purpose, because neither shows any greater long-term survival when compared to the other. EPP has demonstrated better rates of local disease control than P/D has and it more readily allows the use of radiation than does pleurectomy/decortication, which are important factors in its favor. However, EPP is also associated with a greater risk of serious side effects and of treatment-related death than is pleurectomy/decortication. It is also associated with a greater likelihood of metastatic spread of the disease. Because of this situation, the choice regarding which procedure is more effective is still an open question. Dr. Rice does say, however, that should physicians be able to stop the metastasic spread of the disease, then EPP would likely lead to longer survival in patients who are able to tolerate it.

Labels: epp, mesothelioma, pd, pleuralmesothelioma, treatments

posted by Belluck & Fox at 5:39 PM
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Histologic Assessment and Prognostic Factors of Malignant Pleural Mesothelioma Treated With Extrapleural Pneumonectomy

Wednesday, December 3, 2008

Source: American Journal of Clinical Pathology

Preoperative histologic assessment of mesothelioma tissue is one of the primary means by which mesothelioma specialists develop individualized treatment plans. It is commonly known that patients who present with epithelioid mesothelioma typically demonstrate better treatment response and longer survival times than do patients who present with sarcomatoid mesothelioma, so histological analysis is used to determine which patients will be treated with aggressive therapies and which patients will be treated more palliatively. However, a number of recent studies have noted that post-operative assessment of resected tissue is increasingly reclassifying the pre-op histological diagnosis so the value of determining mesothelioma treatment plans based on this preoperative prognosis is increasingly being called into question.

A group of researchers from the MD Anderson Cancer Center at the University of Texas have recently published the results of a small-scale study that looked at the value of preoperative histological assessment and its relationship to a final histological determination made after surgery. While their findings reinforced the notion that sarcomatoid mesothelioma is associated with a worse treatment response, they also showed a very high number of histological reclassifications and called for more study into this question.

Overview of the Study

The researches analyzed the results of 56 patients with confirmed pleural mesothelioma who underwent extrapleural pneumonectomy. The median age of this cohort was 61 years old. There were 50 males and 6 females. Preoperative staging identified 1 case of Stage I disease, 6 cases of Stage II disease, 33 cases of Stage III disease and 14 Stage IV cases. Preoperative histological analysis identified 37 cases of epithelioid mesothelioma, 9 sarcomatoid cases, 6 cases of biphasic mesothelioma and 4 cases where the type was not specified.

When the researchers compared the results of the preoperative histological diagnoses with those of the post-operative analyses they found significant differences between the two. Post-op analysis showed 21 cases of epithelioid mesothelioma, down from 37; 6 cases of sarcomatoid mesothelioma, down from 9; and the biggest change: 28 cases of biphasic mesothelioma, up from just 6 in the preoperative classification. These results showed that preoperative determinations of histological subtype cannot be used in a categorical manner to determine a treatment plan.

The researchers analyzed these results in a number of other ways as well. They showed that patients with sarcomatoid mesothelioma were associated with a 3.1x greater risk of dying from disease-specific symptoms than were patients with epithelioid mesothelioma. They also showed that patients who received some form of post-operative therapy, such as radiation therapy, demonstrated a greater than 70% decreased risk of disease-specific death or recurrence than patients who did not receive post-operative therapy.

Conclusion

Due to the high number of reclassifications, the authors conclude their article by questioning the prognostic value of preoperative histological analysis. They feel that the limited scope of the tissues made available during biopsy do not provide enough sample area to determine treatment strategies, especially because so little is known about the behavior of biphasic tumors. Because of this, they call for more research into the biphasic subtype of malignant pleural mesothelioma.

Labels: diagnosis, epp, mesothelioma, pleuralmesothelioma

posted by Joseph DiCastro at 5:39 PM
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Incidence of Atrial Fibrillation after Extrapleural Pneumonectomy versus Pleurectomy in patients with Malignant Pleural Mesothelioma

Friday, August 29, 2008

Source: Interactive Cardiovascular and Thoracic Surgery

The two most common surgeries for the treatment of pleural mesothelioma are extrapleural pneumonectomy (EPP) and pleurectomy-decortication (PD). Both are considered radical surgery and both have been associated with significant postoperative complications, with EPP being the more radical procedure and the one more likely to have serious side effects. One of the side effects seen in both procedures is atrial fibrillation (AF), a type of irregular heartbeat where the upper chambers of the heart (the atria) quiver and beat in a chaotic fashion instead of properly contracting in a controlled and efficient manner. AF can increase a person’s chance of developing a blood clot that can travel to the brain and cause a stroke, or even death, so it’s clearly a serious condition to watch out for. Even as contemporary surgical techniques have reduced the gross number of surgical complications, side effects are always possible, so research is being conducted to investigate the conditions under which they can occur.

An article was recently published in the journal Interactive Interactive Cardiovascular and Thoracic Surgery that compared the incidence of atrial fibrillation in mesothelioma patients after EPP and P/D. The study was designed to discover which procedure was more likely to cause AF and what co-factors were most likely to affect this causation.

Overview of the Study

To investigate the incidence of atrial fibrillation following extrapleural pneumonectomy and pleurectomy, the authors of the article conducted a retrospective analysis of patients who were treated for pleural mesothelioma between November 2001 and October 2003. 130 patients were initially identified, but the study only looked at 127 of them because three patients had experienced atrial fibrillation at some point prior to the surgeries under consideration. The study specifically looked at the number of patients that experienced atrial fibrillation within three days of surgery and it used the patients who did not experience AF as the control group. The authors conducted a statistical analysis that utilized and reported on single variable causation factors, as well as a multivariate analysis that reported on the likelihood of AF when a number of interacting variables were considered as co-factors.

Results

127 patients were specifically included in the study results. 70 patients underwent an EPP and 57 underwent pleurectomy-decortication. Within the total patient population, the study sample included 45 patients who experienced atrial fibrillation within three days of surgery, leaving a control sample of 82 patients. 36 patients in the study sample underwent EPP, while only 9 underwent P/D.

The authors compared the two groups along a number of standard classification variables, but the only statistically significant, single variable differences between the two groups were incidence of AF and cell histology. Along with the higher incidence of postop AF, the EPP group also had a larger number of epithelial mesothelioma cases as compared to the P/D group. There is no indication that cell histology has any relationship to likelihood of atrial fibrillation, but EPP was found to be a definite risk factor for AF.

Other factors that appeared to contribute to the likelihood of AF were EPP + patient age and pre-existing structural abnormalities in the heart. The authors found that patients older than 65 had a significantly higher risk of AF after undergoing EPP than did patients who were younger than 65 that also underwent EPP. When studying echocardiogram results from a subgroup of the patient population, they found that those patients whose results suggested structural abnormalities were also at increased risk of atrial fibrillation. However, EPP was still the primary risk factor.

Deploying both univariate and multivariate analyses of the following variables and patient characteristics did not reveal any significant increase in risk: gender, affected side, preoperative heart rate, heart disease or preoperative use of beta-blockers.

Conclusion

Extrapleural pneumonectomy is the one of the most important techniques in the treatment of pleural mesothelioma because it allows the most extensive resection of malignant tissue, so limiting post-op complications is clearly an important factor for patient health. Contemporary surgical methods have definitely reduced the incidences of associated side effects, but this study has clearly shown that the nature of the procedure itself be a risk factor for atrial fibrillation. The authors suggest that the “increased pulmonary pressure and right atrial stress after complete removal of one lung causes right heart distention in the early postoperative phase” and that this could “increase the risk of arrhythmias” in patients who undergo the procedure. Because of this, they recommend that steps be taken to prepare for AF or that measures be enacted to limit the heart stress associated with EPP.

Labels: epp, mesothelioma, pd, treatments

posted by Belluck & Fox at 3:51 PM
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