Photodynamic therapy (PDT) may be used to ablate high-grade dysplasia/early stage cancer (HGD/T1) in patients with Barrett's esophagus.
Photodynamic therapy may result in esophageal stricture.
Dr Panjehpour and colleagues from Tennessee, America designed a nonrandomized, unblinded, dose de-escalation study in order to determine the lowest light dose effective for ablation of HGD/T1 while reducing the incidence of stricture.
The researchers enrolled a total of 113 consecutive patients to receive an injection of porfimer sodium (2 mg/kg).
Three days later, the researchers delivered 630 nm light by using a 20-mm-diameter photodynamic therapy balloon at doses of 115 J/cm (n=59), 105 J/cm (n=18), 95 J/cm (n=17), or 85 J/cm (n=19).
|At 115 J/cm, 15% of patients developed severe strictures vs 5% of those treated with lower doses|
The research team determined treatment efficacy by obtaining biopsy specimens of the treated area 3 months later.
The team then also determined the incidence of stricture by the need for esophageal dilation to treat dysphagia.
A stricture was considered severe if 6 or more dilations were required.
The researchers found that the incidence of severe stricture was related to the light dose.
The team noted that at 115 J/cm, 15% of patients developed severe strictures compared with 5.3% to 5.6% of those treated with the lower doses.
In addition, the researchers found that at a light dose of 115 J/cm, 17% of patients had residual HGD/T1.
Light doses of 105 J/cm, 95 J/cm, and 85 J/cm resulted in residual HGD/T1 in 33%, 29%, and 32% of patients, respectively.
None of the observations were statistically significant.
Dr Panjehpour concluded, "Decreasing the light dose below 115 J/cm appeared to result in a reduced incidence rate of severe stricture but higher relative frequencies of residual HGD/T1 in Barrett's esophagus."