Page 28 - ITPS-8-2

INNOSC Theranostics and
Pharmacological Sciences The biochemical and biophysical guide for photodynamic therapy

rate that was equal to or better than Nd: YAG. The main esophageal cancer. The only significant side effect was skin
limitation of PDT is temporary photosensitivity, but PDT hypersensitivity. The study showed that PDT is effective in
is easier to perform and involves fewer invasive procedures treating superficial tumors.
than Nd: YAG laser therapy, which was a key conclusion The greatest risk factor for esophageal cancer is Barrett’s
of the study. esophagus. Kelly et al.’s conducted a study to compare
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In another study on esophageal cancer, patients argon plasma coagulation and PDT for the ablation of
were orally administered 60 mg/kg of 5-aminolevulinic Barrett’s esophagus. A total of 65 patients were included,
acid (ALA). Twenty-four hours after administration, with 34 assigned to argon plasma coagulation and 34 to
gastroscopy was performed. Initially, tumor localization PDT using ALA. Multiple sessions were conducted over
was done using white light, after which the light source 24 months. After completion of treatment, a macroscopic
was switched to red light with an intensity of 100 J/cm for reduction in the area of Barrett’s esophagus was observed in
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600 s. Gastroscopy was repeated 48 h later and again seven all patients. In the argon plasma coagulation group, better
days after the first procedure. The degree of dysphagia was results were noted in terms of esophageal obstruction
recorded both before treatment and 14 days after treatment. (97%) and a lower incidence of occult glands (24%)
The study included patients with advanced, unresectable compared to PDT (50%). Both methods were effective in
tumors – two of whom had squamous cell carcinoma of the ablation of Barrett’s esophagus.
the middle esophagus and three had terminal esophageal In a separate study, patients with esophageal cancer
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adenocarcinoma – mild, self-limited reactions were were monitored for 5 years and underwent PDT using the
observed in all patients. Treatment had no significant effect same PSs as in the previous study. A biopsy of the primary
on liver and kidney function, hemoglobin concentration, segment of Barrett’s esophagus was taken according to the
or leukocyte count, which helped ensure the accuracy of Seattle protocol, followed by endoscopy. Patients who did
the test results. Most patients showed improvement in not respond to PDT or had recurrent neoplasia underwent
dysphagia. The final conclusion of the study was that PDT, additional EMR therapy. Initially, better results were
using ALA as a PS and non-laser therapy, may provide an observed in patients treated with ALA, and most patients
effective approach for treating dysphagia in such patients. 14 responded well. Compared to Photofrin, ALA showed
Given the promising results of new PSs, such as greater effectiveness and caused fewer relapses. However,
ALA, in reducing skin phototoxicity during PDT, Maier after longer follow-up, there was no significant difference
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et al. conducted a study to evaluate the effectiveness in the long-term complete reversal of intestinal metaplasia
of poly hematoporphyrin (Photosan) as a PS in PDT and dysplasia. Four patients in each group developed
for advanced esophageal cancer. This study aimed to invasive esophageal adenocarcinoma. The likelihood of
compare the effectiveness of ALA with Photosan in the long-term remission was significantly increased in patients
treatment of advanced esophageal cancer, with a focus on who initially responded to ALA-PDT therapy. As a result,
skin phototoxicity and dysphagia reduction. Following radiofrequency ablation combined with EMR has become
diagnosis, 22 patients received therapy using ALA, the preferred minimally invasive ablative therapy due to its
whereas 27 patients received Photosan. PDT was delivered lower therapeutic efficacy compared to PDT.
using a dye laser with a wavelength of 630 nm, and In Ackroyd et al.’s study, 36 patients with dysplastic
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hyperbaric oxygen therapy was used as an adjunct. Both Barrett’s esophagus, who received omeprazole for acid
groups demonstrated therapeutic effects, including visible suppression, were assigned to receive oral ALA at a dose
narrowing of the tumor’s diameter and length, with slightly of 30 mg/kg or a placebo. Four hours later, laser endoscopy
greater effectiveness noted for the Photosan treatment. was performed. Follow-up endoscopic examinations were
Neither group experienced severe treatment-related performed at 1, 6, 12, and 24 months. In the ALA group,
complications, and no cases of sunburn were reported. No 16 of 18 patients showed a reduction in the affected area.
mortality occurred during the treatment period. The study In the placebo group, a 10% reduction in surface area was
concluded that Photosan is more effective than ALA in observed in two patients, whereas no changes were noted in
PDT for esophageal cancer. 16 patients. None of the patients treated with PDT showed

Another study involved 64 patients with various columnar epithelial dysplasia in the treated area, whereas
types of cancer, including five with esophageal cancer. 12 patients in the placebo group still exhibited dysplasia.
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The PS was administered intravenously, and light with No serious side effects, either short- or long-term, were
a wavelength of 630 nm was delivered through quartz observed. The therapeutic effects lasted up to 24 months.
fibers. After treatment, complete remission was achieved The question of whether PDT has long-term effectiveness
in 48 of the 58 treated patients, including those with in patients with high-grade dysplasia in Barrett’s esophagus

Volume 8 Issue 2 (2025) 22 doi: 10.36922/itps.4559