Location of Recurrence by Gallium-68 PSMA-11 PET Scan in Prostate Cancer Patients Eligible for Salvage Radiotherapy - 28/07/19

Doi : 10.1016/j.urology.2018.12.055

Lauren Boreta ^a,^{^{1
These authors contributed equally to this manuscript.}}, Adam J. Gadzinski ^b,^{^{1
These authors contributed equally to this manuscript.}}, Susan Y. Wu ^a, Melody Xu ^a, Kirsten Greene ^b, Kathryn Quanstrom ^b, Hao G. Nguyen ^b, Peter R. Carroll ^b,^c, Thomas A. Hope ^c,^d,^e, Felix Y. Feng ^a,^c,^⁎
^a Department of Radiation Oncology, University of California, San Francisco, CA
^b Department of Urology, University of California, San Francisco, CA
^c University of California San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, CA
^d Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA
^e Department of Radiology, San Francisco VA Medical Center, San Francisco, CA

^⁎Address correspondence to: Felix Feng, M.D., UCSF Radiation Oncology/Helen Diller Comprehensive Cancer Center, 1600 Divisadero Street, H1031, San Francisco, CA 94115.UCSF Radiation Oncology/Helen Diller Comprehensive Cancer Center1600 Divisadero Street, H1031San FranciscoCA94115

Abstract

Objective

To identify locations of recurrence after radical prostatectomy (RP) with prostate-specific antigen (PSA) <2 by Gallium-68 prostate-specific membrane antigen (PSMA)-11 Positron Emission Tomography (PET) imaging, and to determine whether standard nodal radiation fields would cover the location of prostate cancer recurrence.

Materials and Methods

We performed a retrospective review of patients with PSMA-PET imaging for biochemical recurrence following RP with PSA ≤2.0 ng/mL and assessed if the recurrent disease was within standard radiation target volumes. We compared patient and clinical variables between men with recurrences covered by standard salvage radiation fields and those with recurrences outside of standard fields.

Results

We identified 125 patients for study inclusion. The median PSA at imaging was 0.40 ng/mL (interquartile range 0.28-0.63). PSMA-avid disease was found in 66 patients (53%). Of these, 25 patients (38%) had PSMA-avid lesions found outside of the pelvis, 33 (50%) had lesions confined to the pelvic lymph nodes and prostate bed, and 8 (12%) men had PSMA-avid recurrence only in the prostate bed. Salvage radiation including standard Intensity Modulated Radiation Therapy (IMRT) pelvic nodal volumes would not cover PSMA-avid nodal disease in 38 men (30%). PSA at the time of imaging was statistically associated with having PSMA-avid disease outside of standard nodal fields (P <.01).

Conclusion

The 68Ga-PSMA-11 PET detects disease in a majority of patients with PSA ≤2.0 following RP. Nearly one-third of men had PSMA-avid disease that would be missed by standard radiation fields. This imaging modality may dramatically impact the design and use of post-RP salvage radiotherapy.

Le texte complet de cet article est disponible en PDF.

Plan

MATERIALS AND METHODS

Financial Disclosure: There are no financial disclosures or funding to support this project. Authors responsible for statistical analyses: Lauren Boreta, Adam Gadzinski, and Susan Wu.