Photodynamic Therapy for the Treatment of Vertebral Metastases
Condition: Vertebral Metastases
MeSH terms: Neoplasm Metastasis
Study type: Interventional
Phase: Phase 1

Summary: 
      An estimated 10 percent of primary breast, prostate, lung, thyroid and renal cell tumors
      metastasize to the spine. The majority of these tumors are detected before surgical
      intervention is required and most patients receive radiation therapy for symptomatic relief.
      Complete pain control, duration of pain control, high recurrence rates and soft tissue
      complications make radiation a less than ideal treatment. Also, pre-operative radiation
      therapy is a significant negative predictor for surgical outcomes. To improve the treatment
      options for patients with advanced cancer with spinal lesions the research team investigated
      a new minimally invasive therapy known as photodynamic therapy (PDT) that targets metastatic
      spine lesions with limited side effects. PDT involves the use of a photo-activated
      chemotherapeutic agent, given intravenously that when stimulated by non-thermal
      wavelength-specific light allows for selective ablation of tumor tissue. The light is
      delivered to the spine through small fiber optic cables using a diode laser. By combining
      canine and porcine studies the investigators have strong evidence to support that PDT is both
      safe and effective for the treatment of metastatic tumors in the spine. PDT is targeted,
      repeatable, minimally invasive and has limited local and systemic side effects. Its use would
      enhance the treatment options for patients with advanced stage cancer. The goal of the
      present study is to demonstrate that PDT can be safely and effectively given to treat spinal
      metastases in patients with advanced stage cancer who have multiple lesions or who have
      failed radiation or surgical intervention. The effectiveness of this treatment will be
      determined through clinical and radiographic endpoints along with recurrence and survival.
      The investigators intend to demonstrate that PDT is a minimally invasive method with low
      morbidity and mortality by which spinal tumors can be ablated and later stabilized through
      vertebroplasty, optimizing quality of life and providing effective treatment.
    

Detailed description: 
      There are over 1.5 million cases of cancer reported each year in North America and a
      significant number of patients eventually suffer from metastases to the spine which present
      as an extremely challenging problem for both the clinician and patient. Primary tumors that
      most commonly affect the spine include breast, prostate, lung, thyroid and renal cell cancer.
      Estimates from large clinical series report at least a 10 percent rate of metastases to the
      spine from these most common tumors. These lesions are extremely painful and significantly
      affect the quality of life of advanced stage cancer patients. The majority of these tumors
      are detected before surgical intervention is required and most patients receive radiation
      therapy for their spine lesions for symptomatic relief. However, complete pain control,
      duration of pain control along with a high recurrence rate of lesions and soft tissue
      complications makes radiation a less than an ideal treatment. In addition, pre-operative
      radiation therapy is a significant negative prognosticator for surgical outcomes.

      To improve the treatment options for patients with advanced cancer with spinal lesions the
      research team has investigated a new minimally invasive therapy, known as photodynamic
      therapy (PDT) that targets metastatic spine lesions directly and has limited side effects.
      PDT involves the use of a photo-activated chemotherapeutic agent, benzoporphyrin derivative
      (verteporfin/Visudyne) given intravenously that when stimulated by non-thermal
      wavelength-specific light allows for selective ablation of tumor tissue. The light is
      delivered to the spine through small fiber optic cables (outer diameter 0.98mm, inner core of
      0.5mm mm) using a diode laser. Visudyne is an FDA and Health Canada approved photosensitizer
      that has been used in over one million patients for the treatment of age related macular
      degeneration, a leading cause of blindness in the elderly. To investigate the use of PDT for
      spinal metastases the investigators initially developed a bioluminescent metastatic rodent
      model using human breast cancer that metastasized to the spine. Using this model it was
      determined that PDT was effective at treating metastatic breast cancer lesions in the spine.
      The research team next utilized non-tumor bearing canine and porcine models to determine that
      the treatment could be safely delivered to the spine and conduct light dosimetry analysis.
      The safety of PDT intra-operatively was assessed using somatosensory evoked potentials and
      through post-treatment clinical examination and magnetic resonance imaging (MRI). The effects
      PDT had on the spine were analyzed by comparing pre-operative and post-operative MR imaging
      and correlating those in turn with histological analysis. None of these animals suffered
      weakness or complication from the use of PDT around the spinal cord. During these studies the
      investigators developed the planning, delivery and instrumentation methodologies to deliver
      PDT to spinal tumors and the methodology to combine this therapy with vertebroplasty, a
      percutaneous method of stabilizing the spine. In addition, in a separate set of studies,
      highgrade osteosarcomas in canines were treated to determine the effect PDT had on large bone
      tumors. The results of this study again provided comparison of pre and post-treatment effects
      seen on MRI and histological analysis. The volume of effect seen in the osteosarcomas was up
      to 25cm (cubed) and was comparable to the volume of effect required for complete treatment of
      spinal lesions. By combining the canine and porcine studies there is strong evidence that PDT
      is both safe and effective for the treatment of metastatic tumors in the spine.

      PDT has many advantages over current therapies; it is targeted, repeatable, minimally
      invasive and has limited local and systemic side effects. Its use would enhance the treatment
      options for patients with advanced stage cancer. The goal of the present study is to
      demonstrate that PDT can be safely and effectively given to treat spinal metastases in
      patients with advanced stage cancer. The study is a pilot study and will determine the safe
      and accurate treatment of 30 patients with spinal metastases who have multiple lesions or who
      have failed radiation or surgical intervention. The effectiveness of this treatment will be
      determined through clinical and radiographic endpoints with recurrence and survival also
      determined. The investigators intend to demonstrate that PDT provides a minimally invasive
      method with low morbidity and mortality by which spinal tumors can be ablated and later
      stabilized through vertebroplasty, optimizing quality of life and providing effective
      treatment for this devastating manifestation of advanced stage cancer.
    

Intervention name(s): Visudyne
Intervention type(s): Drug
Other intervention name(s): Verteporfin
Intervention MeSH terms: Verteporfin
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment