PDT Beats Mainstream Treatments for Advanced Lung Cancer, Part 2
When it comes to lung cancer, the long-term outcome of treatment depends heavily on the stage at which the disease is initially detected. If you happen to catch it at its earliest stage, known as Stage 1A lung cancer, your chances of living five years are nearly 50%. But the picture changes dramatically if you’re diagnosed with Stage IV lung cancer, which is typically treated with high-dose chemotherapy. At that point, the probability of surviving for five years—the oncology establishment’s definition of “cure”—drops to a mere 1%.
Against this backdrop, innovative options are urgently needed for the treatment of this aggressive and often lethal disease. Photodynamic therapy (PDT), clinically improved for the treatment of lung cancer in the United States and several other countries, offers some striking advantages over traditional treatment methods.
In Part 1 of this article, we highlighted a large population study of PDT for lung cancer. The study provided some intriguing results that had to be placed in context and counterbalanced by poor study design. In this second part, we share some important findings from two recent clinical studies indicating that PDT can confer a survival advantage for patients with metastatic lung cancer.
The most recently published study of PDT for advanced lung cancer took place at the National Taiwan University Hospital in Taipei. The study focused on 18 patients with metastases that had spread to the pleura, the thin membrane surrounding the lungs. This so-called pleural spread is difficult to treat. Both surgery and chemotherapy are viewed only as “palliative” options aimed at reducing the chest pain, shortness of breath, and other disturbing symptoms associated with this metastatic lung disease.
The Taipei researchers analyzed the treatment outcomes for patients with pleural spread who received pleural PDT and surgery over an eight-year period. Their study can be found online in the 20 July 2015 issue of Plos One.
The study’s hypothesis was that surgery would remove the visible bulk of the cancer, while PDT would eliminate any microscopic or “invisible” disease in the lung area. Their findings seemed to confirm this hypothesis. Lung cancer patients treated with PDT showed a greater than doubling in survival when compared to patients receiving chemotherapy or molecular targeted therapy—39 months for PDT patients versus 17.6 months for chemo and targeted therapy patients, a statistically significant finding. (Other research has found similar response rates for chemo-treated patients with this pleural disease.)
In the Taipei study, the five- survival rates for PDT-treated cancer patients with pleural spread was 57%. In the mainstream treatment setting, only about 8% of patients with advanced lung cancer and pleural spread are expected to survive five years.
The researchers also note that their findings seem to confirm those of a previous phase II clinical trial at the University of Pennsylvania. In that study, a greater than doubling in overall survival was again shown for lung cancer patients with pleural spread who were treated with PDT and compared to those receiving chemotherapy, as reported in the June 2004 Journal of Clinical Oncology.
Of course, medical scientists will find ways to criticize such uncontrolled clinical studies, arguing that definitive proof can only come from large controlled clinical trials. But the difficulties of conducting such costly gold standard studies are immense. Along with their hefty price tag is the challenge of finding enough patients with advanced disease who are willing to be randomly assigned to the different treatment groups.
After seeing the results from the Taipei and University of Pennsylvania studies, many more lung cancer patients will be clamoring for PDT, and many more will refuse to be randomized to far less humane treatments. PDT is already an approved treatment for lung cancer in a number of countries. It’s just a matter of time before more oncologists begin to see this non-toxic light-based therapy as the best choice, and as the best way to honor the first tenet of the Hippocratic oath: “Do no harm.”
Sources
Chen KC1, Hsieh YS2, Tseng YF3, Shieh MJ4, Chen JS3, Lai HS3, Lee JM3. Pleural Photodynamic Therapy and Surgery in Lung Cancer and Thymoma Patients with Pleural Spread. PLoS One. 2015 Jul 20;10(7):e0133230. eCollection 2015.
Wang BY, Wu YC, Hung JJ, Hsu PK, Hsieh CC, Huang CS, et al. Prognosis of non-small-cell lung cancer with unexpected pleural spread at thoracotomy. J Surg Res. 2011; 169(1): e1–e5.
Mordant P, Arame A, Foucault C, Dujon A, Le Pimpec Barthes F, Riquet M. Surgery for metastatic pleural extension of non-small-cell lung cancer. Eur J of Cardiothorac Surg. 2011; 40(6): 1444–1449
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