Of the three cellular variations for mesothelioma, sarcomatoid is the rarest and the most difficult to treat. The most common form of the disease is characterized by epithelioid cells; the third variation is "biphasic," a combination of sarcomatoid and epithelioid cells. Sarcomatoid cells are resistant to certain types of chemotherapy found to be effective with other forms of carcinoma. They are also aggressive cells that are fast-moving in their reproduction and spreading across the afflicted area. The three treatment options for mesothelioma or any other form of cancer are surgery, chemotherapy, and radiation treatment. The options for these three treatment modalities are different for the two different types of mesothelioma cells.
Sarcomatoid Mesothelioma Surgery
Relatively early diagnosis for mesothelioma often makes surgical resection of some or all of the diseased tissue possible. Sarcomatoid mesothelioma tumors are generally a single large mass, which makes them different from the diffuse, small malignant nodes that characterize epithelioid mesothelioma. Accordingly, surgical intervention for sarcomatoid mesothelioma may involve removal of a larger mass but one that is more compact in nature. The surgeon may remove the surrounding mesothelium tissue as a precautionary measure.
Chemotherapy for Sarcomatoid Mesothelioma
The most common chemotherapy drugs used for mesothelioma treatment are pemetrexed and cisplatin, both of which have proven to be somewhat effective with epithelioid cells but less so with the spindle-shaped sarcomatoid variety. There have been dozens of clinical trials that have combined pemetrexed with other chemotherapy agents to see what might have a better impact on sarcomatoid mesothelioma. Some cases have had success with a combination of other drugs, but no definitive protocol for chemotherapy has been established for sarcomatoid mesothelioma.
In recent years oncologists have developed a method of hyperthermal chemotherapy that utilized during and after surgery. Heated chemotherapy drugs are applied directly to the affected area during surgery, or by a shunt that has been installed after surgery. This method of high-level exposure to the chemotherapy drugs seems to be an effective option by comparison with the standard arterial drip method used for generalized chemotherapy.
Radiation Treatment of Sarcomatoid Mesothelioma
Standard external radiation treatment for post-surgical or non-operative mesothelioma patients is a standard option that is employed in most cases in combination with chemotherapy. It has not proven to be particularly effective with sarcomatoid mesothelioma cells; however recent innovations in the delivery of radiation treatment have improved its impact on all types of the disease. The use of direct radiation during the course of surgery has been one option employed by surgeons; there has also been a treatment protocol that involves implanting radiation "seeds" that impact an immediate area.
Intensity modulated radiation therapy (IMRT) is a technology allowing changes in radiation intensity during treatment, which allows for greater concentration of radiation on the targeted area.
1. A case of sarcomatoid malignant peritoneal mesothelioma responding to combination chemotherapy of cyclophosphamide, vincristine, adriamycin and dacarbazine. Kusama et al, Kobe University School of Medicine, March 2009
2. Outcomes After Extrapleural Pneumonectomy and Intensity-Modulated Radiation Therapy for Malignant Pleural Mesothelioma, Rice et al, The Annals of Thoracic Surgery, November 2006
3. Resection Margins, Extrapleural Nodal Status, and Cell Type Determine Postoperative Long Term Survival in Trimodality Therapy of Malignant Pleural Mesothelioma. Sugarbaker, et al, American Association for Thoracic Surgery, May 1998
