Photodynamic therapy for obstructing esophageal cancer: light dosimetry and randomized comparison with Nd:YAG laser therapy.
OBJECTIVE
Light dosimetry analysis to achieve predictable tumor necrosis has not been performed for photodynamic therapy (PDT) in the gastrointestinal tract. We evaluated dihematoporphyrin ethers for sensitizing esophageal carcinomas to 630 nm light and compared PDT with neodymium:yttrium-aluminum-garnet (Nd:YAG) laser therapy in a randomized trial.


METHODS
Of 52 patients with dysphagia, 32 received palliative PDT. Ten patients treated with PDT participated in a preliminary trial using various doses of 630-nm light, and 22 patients treated with PDT participated in a randomized trial using a derived standardized light dose for comparison with 20 patients treated with the Nd:YAG laser.


RESULTS
Light dosimetry correlated with depth of tumor necrosis (r = 0.664; P < 0.001). PDT activity was similar for squamous cell and adenocarcinoma. Among randomized patients, both PDT and Nd:YAG therapy relieved dysphagia, but PDT resulted in improved Karnofsky performance status at 1 month (+7 vs. -7; P < 0.001) and longer duration of response (84 vs. 57 days; P = 0.008). Skin photoreactions were unique to PDT.


CONCLUSIONS
The extent of PDT tumor ablation correlates with light dosimetry, enabling selection of a standardized light dose. PDT can relieve esophageal obstruction from squamous cell and adenocarcinoma and is an alternative to Nd:YAG thermal necrosis with a longer duration of response. However, PDT requires patient precautions to minimize skin photoreactions.
Heier
S K
SK
Division of Gastroenterology, New York Medical College, Valhalla, USA.
Rothman
K A
KA
Heier
L M
LM
Rosenthal
W S
WS
D000230:Adenocarcinoma / Q000188:drug therapy* / Q000532:radiotherapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000532:radiotherapy; D003680:Deglutition Disorders / Q000209:etiology; D017323:Dihematoporphyrin Ether / Q000627:therapeutic use; D004938:Esophageal Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy; D004940:Esophageal Stenosis / Q000188:drug therapy*; D005260:Female; D006801:Humans; D053685:Laser Therapy; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010166:Palliative Care; D010778:Photochemotherapy; D016016:Proportional Hazards Models; D011874:Radiometry; D012074:Remission Induction
D017323:Dihematoporphyrin Ether