The effect of Tookad-mediated photodynamic ablation of the prostate gland on adjacent tissues--in vivo study in a canine model.
Photodynamic therapy (PDT) mediated with vascular acting photosensitizer Tookad (Pd-bacteriopheophorbide) was investigated as an alternative modality for treating prostate cancer. Photodynamic effects on the prostate gland and its adjacent tissues were evaluated in a canine model. Interstitial prostate PDT was performed by irradiating individual lobes with a cylindrical diffuser fiber at various drug/light doses. The sensitivity of the adjacent tissues to Tookad PDT was determined by directly irradiating the surface of the bladder, colon, abdominal muscle and pelvic plexus with a microlens fiber at various drug/light doses. The prostate and adjacent tissues were harvested one-week after the treatment and subjected to histopathological examination. PDT-induced prostate lesions were characterized by marked hemorrhagic necrosis. The bladder, colon, abdominal muscle and pelvic plexus appeared to be sensitive to PDT although the Tookad PDT-induced responses in these tissues were minimal compared to that of the prostate gland at the same dose levels. Nevertheless, the protection of the adjacent tissues should be taken into consideration during the total prostate ablation process due to their sensitivity to PDT. The sensitivity of the prostatic urethra is worth further investigation. Direct intraurethral irradiation might provide an ideal means to determine the sensitivity of the prostatic urethra and might lead to transurethral PDT protocols for the management of benign prostatic hyperplasia (BHP).
Huang
Zheng
Z
AMC Cancer Research Center and Department of Radiation Oncology, Aurora, Colorado, USA. zheng_huang@msn.com
Chen
Qun
Q
Dole
Kenneth C
KC
Barqawi
Al B
AB
Chen
Yang K
YK
Blanc
Dominique
D
Wilson
Brian C
BC
Hetzel
Fred W
FW
D000005:Abdomen / Q000528:radiation effects; D000818:Animals; D001429:Bacteriochlorophylls / Q000494:pharmacology*; D003106:Colon / Q000187:drug effects / Q000528:radiation effects; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000528:radiation effects; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D011467:Prostate / Q000187:drug effects* / Q000528:radiation effects*; D001743:Urinary Bladder / Q000187:drug effects / Q000528:radiation effects
D001429:Bacteriochlorophylls; D017319:Photosensitizing Agents; C456120:palladium-bacteriopheophorbide