The restoration of squamous epithelium after
photodynamic therapy (
PDT) for
Barrett esophagus (BE) and its related
neoplasms has been noted. It may result in the development of buried
neoplasms and/or BE underneath restored squamous epithelium which maintain their potential for malignant transformation. The purpose of this study was to evaluate the prevalence, endoscopic, and histologic characteristics and also response to further treatment of buried neoplastic epithelium developing after
PDT. Fifty-two BE patients with high-grade dysplasia (n=19), intramucosal
adenocarcinoma (n=28), and invasive
adenocarcinoma (n=5) were treated with
porfimer PDT. Buried
neoplasms completely covered by squamous epithelium were seen in 1 patient before and in 13 patients after
PDT. Their prevalence was 0.6% and 7.4% of pre and post-
PDT biopsy levels positive for
neoplasia (P=0.001). Buried
neoplasms, representing the highest grade of
residual neoplasm, were noted in a series of 11 post-
PDT endoscopies (7.1% of 155 post-
PDT endoscopies with neoplastic diagnoses) of 8 patients. Their occurrence after
PDT was neither associated with the length of BE, the diffuseness of
neoplasms nor the presence of buried lesions before treatment. There was no prevalent location for these lesions in relation to the original segment of BE, although the majority of both surface and buried
neoplasms were found in the prior neoplastic sites. Patients with buried
neoplasms responded to further treatment similarly to those with only surface
neoplasms (8 of 13 vs. 17 of 24) (P=0.33). In conclusion, buried
neoplasms are not uncommon after
PDT. Thorough endoscopic surveillance with extensive biopsies, especially of the sites previously positive for
neoplasia is important to avoid overlooking buried
neoplasms that may progress.