Vascular-targeted photodynamic therapy (padoporfin, WST09) for recurrent prostate cancer after failure of external beam radiotherapy: a study of escalating light doses.

Abstract

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).

PATIENTS AND 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.

• Authors: John Trachtenberg, Robert A Weersink, Sean R H Davidson, Masoom A Haider, Arjen Bogaards, Mark R Gertner, Andrew Evans, Avigdor Scherz, Joanne Savard, Joseph L Chin, Brian C Wilson, Mostafa Elhilali
• Journal: BJU international (BJU Int) Vol. 102 Issue 5 Pg. 556-62 (Aug 05 2008) ISSN: 1464-410X [Electronic] England
• PMID: 18494829 (Publication Type: Clinical Trial, Phase II, Journal Article, Multicenter Study, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Bacteriochlorophylls
• palladium-bacteriopheophorbide
• Prostate-Specific Antigen

Topics

• Bacteriochlorophylls (therapeutic use)
• Biopsy (methods)
• Dose-Response Relationship, Drug
• Humans
• Magnetic Resonance Imaging
• Male
• Neoplasm Recurrence, Local (drug therapy, pathology)
• Photochemotherapy (methods)
• Prostate (blood supply, pathology)
• Prostate-Specific Antigen (blood)
• Prostatic Neoplasms (drug therapy, pathology, radiotherapy)
• Treatment Outcome