Endoscopic thermal
laser therapy of colorectal
villous adenomas is associated with a high recurrence rate due to incomplete
tumor ablation, as treatment over carries a risk of perforation.
Photodynamic therapy has been shown to be a promising in the treatment of small malignant
tumors, and may be useful for benign
adenomas. Eight patients with nine colosigmoid
villous adenomas measuring 1-5 cm in length were treated with
photodynamic therapy using either haematoporphyrin derivative or
Photofrin as
photosensitizer and multiple (4-16) applications of interstitial photoirradiation with red light (630 nm, 100 mW x 500 s per application). All but one
adenoma had previously been incompletely treated with
Nd-YAG laser therapy. Some skin sensitivity to light was seen in one patient. Seven
adenomas were eradicated (follow-up 9-56 months, median = 12) as judged by follow-up endoscopy and biopsy. No local complications were seen. Substantial
necrosis was produced in the other two
adenomas, but they were not completely destroyed, probably due to inadequate light.
PDT holds promise in the non-surgical management of
villous adenomas, particularly after initial tumour debulking with the
Nd-YAG laser.