Evaluating clinical outcomes of PDT

Efficacy studies are required for regulatory approval of new medical treatments in the United States and elsewhere. Although efficacy studies may demonstrate safety and efficacy, they are not always sufficient for characterizing the effects of a treatment in actual clinical practice. Ongoing outcomes research is necessary to identify outcomes of treatment and treatment patterns in actual clinical practice. Criteria for evaluating palliative treatments in outcomes research must reflect the treatment's capacity to relieve symptoms while entailing minimal risks and adverse effects. However, the measurement of symptom relief as a result of treatment is prone to error because symptoms are inherently subjective and may be influenced by a variety of non-treatment factors, such as individual perception, physical exertion, and concurrent symptom management strategies. PDT patients treated with Photofrin® and 630-nm light at our center have had reduced dysphagia grade and stable performance status for approximately one month after PDT (N= 7-26), but these effects did not necessarily persist at the three-month followup interval. Preliminary data on five patients collected in a pilot study of a new symptom burden measurement tool suggest that the perceived burden of photosensitivity may increase with time. Fatigue, poor appetite and decreased overall quality of life appear to be the most troubling symptoms for our late-stage esophageal cancer PDT patients. The least burdensome symptoms were anxiety, pain and depression.