Vascular-targeted photodynamic therapy (padoporfin, WST09) for recurrent prostate cancer after failure of external beam radiotherapy: a study of escalating light doses.
OBJECTIVE
To report on the efficacy of TOOKAD (WST 09; NegmaLerads, Magny-Les-Hameaux, France) vascular-targeted photodynamic therapy (VTP) as a method of whole-prostate ablation in patients with recurrent localized prostate cancer after the failure of external beam radiotherapy (EBRT).


METHODS
Patients received a fixed photosensitizer dose of 2 mg/kg and patient-specific light doses as determined by computer-aided treatment planning. Up to six cylindrical light-diffusing delivery fibres were placed transperineally in the prostate under ultrasonographic guidance. The treatment response was assessed by measuring serum prostate-specific antigen (PSA) levels, lesion formation (avascular areas of tissue) measured on 7-day gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI) and a 6-month biopsy.


RESULTS
Treatment of the whole prostate was possible with minimal effects on surrounding organs. An increased light dose improved the tissue response, with MRI-detectable avascular lesions, encompassing up to 80% of the prostate in some patients. A complete response, as determined by the 6-month biopsy, required that patients received light doses of at least 23 J/cm(2) in 90% of the prostate volume (D(90) > 23 J/cm(2)). Of the 13 patients who received at least this light dose, eight were biopsy-negative at 6 months. In this group of eight patients, PSA levels decreased and did so to negligible levels for those patients with a baseline PSA level of <5 ng/mL. Side-effects were modest and self-limited in most patients; there were recto-urethral fistulae in two patients, one of which closed spontaneously.


CONCLUSIONS
TOOKAD-VTP can produce large avascular regions in the irradiated prostate, and result in a complete negative-biopsy response at high light doses. A response rate of more than half for those patients receiving the highest light doses shows the clinical potential of TOOKAD-VTP to manage recurrence of prostatic carcinoma after EBRT.
Trachtenberg
John
J
Surgical Oncology, Ontario Cancer Institute/Princess Margaret Hospital, Toronto, Canada. john.trachtenberg@utoronto.ca
Weersink
Robert A
RA
Davidson
Sean R H
SR
Haider
Masoom A
MA
Bogaards
Arjen
A
Gertner
Mark R
MR
Evans
Andrew
A
Scherz
Avigdor
A
Savard
Joanne
J
Chin
Joseph L
JL
Wilson
Brian C
BC
Elhilali
Mostafa
M
D001429:Bacteriochlorophylls / Q000627:therapeutic use*; D001706:Biopsy / Q000379:methods; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy* / Q000473:pathology; D010778:Photochemotherapy / Q000379:methods*; D011467:Prostate / Q000098:blood supply / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy; D016896:Treatment Outcome
D001429:Bacteriochlorophylls; C456120:palladium-bacteriopheophorbide; D017430:Prostate-Specific Antigen