Patients facing late-stage mesothelioma often only have the option of palliative treatment. The aggressive disease has progressed too much for surgery or other curative options to be effective or safe for them. But a recent study has found some hope in a combination therapy that could even be viable for some facing advanced mesothelioma.
The study tested 90 pleural mesothelioma patients who had the epithelial cell type, observing them from 2005 – 2013. Each of the participants underwent a lung-sparing surgery followed by photodynamic therapy. In some cases, the patients also underwent chemotherapy. While further research is needed to better understand the effectiveness of this multimodal treatment, these initial results show a lot of promise and provide hope for late-stage patients in the future.
Exploring Surgery and Photodynamic Therapy
Surgery is a current standard treatment for all types of mesothelioma, and very often is used in combination with chemotherapy or radiation or both. For pleural mesothelioma patients, there are several surgical options that will depend on the extent of the disease. In the case of curative surgery, patients face two options: extrapleural pneumonectomy or pleurectomy.
Extrapleural pneumonectomy is considered far more aggressive, as the surgery removes the entire lung, part of the diaphragm, the lung lining and the covering of the heart. Pleurectomy/decortication (P/D) surgery is also aggressive, but less intensive on the body as it spares the affected lung. Instead, P/D surgery focuses on removing the diseased parts of the membrane on the lungs and chest wall, and then removes any visible tumors in the chest (decortication). In some cases, the membrane around the heart may also be removed if it appears thickened and diseased as well.
Participants in this clinical trial underwent P/D surgery, though the researchers noted it’s still unclear if this would be a preferred method over extrapleural pneumonectomy. After surgery, patients then underwent photodynamic therapy (PDT), which is also referred to as photoradiation therapy or phototherapy.
PDT is a treatment combining specialized drugs, known as photosensitizing agents, with light to kill cancer cells. The photosensitizing agent is injected into the body through a vein or put on the skin depending on where a patient is being treated. After some time, the cancer cells will absorb the agent and light will then be applied to the treated area. The light will cause the drugs to react with oxygen, and in turn form a chemical that kills the cancer cells.
Photodynamic therapy has also been found to help alert the immune system to present cancer cells and help trigger a reaction. This treatment may also help destroy any blood vessels that feed the cancer cells.
Researchers have found PDT to be as successful as surgery or radiation for some types of cancers. It’s a beneficial treatment because it isn’t invasive, can be extremely targeted, and hasn’t been found to cause any troubling side effects if applied appropriately. PDT can also be done quickly and repeatedly if needed, but it also has some disadvantages.
Typically, PDT can only treat areas light can reach, meaning it’s often only a treatment for problems just under the skin’s surface or on the linings of organs, like the lining of the lungs in the case of pleural mesothelioma. If a cancer has spread too much, PDT is generally not a viable option. For the patients in this study, even though the mesothelioma was advanced, PDT in combination with surgery provided promising results.
A Promising Treatment
The clinical trial included 90 patients, and 73 of them achieved a complete resection of the disease. All 73 patients had either stage 3 or stage 4 pleural mesothelioma, which has an average life expectancy of just 12 – 16 months. But after this treatment, the median overall survival was 3 years and 1.2 years disease-free.
For some patients, the results were even better. Out of the 90 patients, 19 had late stage mesothelioma that had not spread to their lymph nodes. For those patients, they experienced a median survival of 7 years and a little over 2 years disease-free. These results are very encouraging, especially when considering even patients who have stage 1 mesothelioma only have a life expectancy of about 21 months.
While the researchers don’t want to make any definitive conclusions from such a small group, they were especially intrigued by the difference in overall survival and survival after recurrence. Mesothelioma recurrence is fairly common, but the researchers noted most only have months to live when the disease comes back.
The team of researchers wants to further explore this difference in survival to and continue to investigate the potential of this combination treatment. Though there is still a lot of work ahead, these results are encouraging that more patients, even those diagnosed at a later stage, can potentially beat the odds. Hopefully with continued research and participation in clinical trials like this one, we’ll continue to improve the survival of current patients and get closer to finding a cure.