John Han-Chih Chang, MD and Kenneth Blank, MD
Last Modified: November 1, 2001
Dear OncoLink "Ask the Experts,"
I saw the article on Gene Therapy for Thoracic Cancer: A Trial for Malignant Mesothelioma. My dad was just diagnosed with mesothelioma. He has no asbestos exposure history and no other risk factor that we can discern. It only in one lung without spread.
My question is:
Has any progress been made in the treatment of mesotheliomas, including the above trial.
Thanks for the articles and the program it has given me, a layman, a better handle on what is really happening, for better or worse, in words I can understand.
John Han-Chih Chang, MD and Kenneth Blank, MD, Editorial Assistants for Oncolink, respond:
Thank you for your interest and question.
Mesothelioma is an uncommon entity. Though asbestos exposure places one at higher risk to develop mesothelioma, there are 30% to 50% of patients without any history of exposure, such as your father. The usual age of diagnosis is at age 60.
Because mesotheliomas are usually diffuse at diagnosis, treatment of this disease may need to be multifaceted: surgery, chemotherapy and radiation therapy.
Surgery for this disease includes pleurectomy/decortication and extrapleural pneumonectomy. Results of using surgery alone in these patients have been disappointing ? median survivals of approximately 10 months and perioperative mortality of 2% - 10%.
Radiation therapy has been utilized in the setting of mesothelioma with equivocal results. The median survival is nearly the same as surgery alone. Survival in these treated patients is not significantly different than those treated with supportive care alone, but the quality of life can be affected. Radiation can effectively palliate pain, shortness of breath and other symptoms. Mesotheliomas are moderately responsive to radiation, but the limiting factor remains the morbidity of treating such a large volume of tumor.
The most readily used agents in chemotherapy consists of doxorubicin (adriamycin), cyclophosphamide (cytoxan), 5-fluorouracil and methotrexate. The response rates have been approximately 20% with doxorubicin alone, doxorubicin-based chemotherapy and other combination chemotherapy agents. Intrapleural infusion of cisplatinum has some promise but remains in the early stages experimentation.
The areas of furthering treatment options are numerous. Combined modality treatment or the use of more than one treatment may be beneficial. The use of surgery combined with either radiation or chemotherapy has been shown to increase the median survival by nearly double. The studies revealing these data are utilized by a small number of patients, thus, conclusive statements about these treatments cannot be made.
Gene therapy for any type of cancer remains very experimental. The goal of gene therapy is to incorporate from an outside source the damaged genetic material in the cancer cell that makes it aberrant. It is an enormous undertaking.
Finally, photodynamic therapy has been proposed for this type of cancer. This utilizes an intravenous photosensitizing drug that is taken up by the cancer cells. The photosensitizer is then activated by a specific wavelength of laser light to fatally damage the cancer cell. This again is in the preliminary stages of testing.
Again, please consult your oncologist or cancer physician for the options available.