Identification of Site-specific Recurrence Following Primary Radiation Therapy for Prostate Cancer Using C-11 Choline Positron Emission Tomography/Computed Tomography: A Nomogram for Predicting Extrapelvic Disease.
Management of recurrent prostate cancer (CaP) after radiotherapy (RT) is dependent on accurate localization of the site of recurrent disease.



To describe the anatomic patterns and clinical features associated with CaP recurrence following RT identified on advanced imaging.



Retrospective review of 184 patients with a rising prostate-specific antigen (PSA) after RT for CaP.



C-11 choline positron emission tomography/computed tomography (CholPET).



Recurrence patterns were classified as pelvic soft tissue only (as a surrogate for potentially salvageable disease) versus any extrapelvic disease, and clinical features were compared between patterns. Multivariable logistic regression was used to generate a predictive nomogram for extrapelvic recurrence. Discrimination was assessed with a c-index.



Recurrence site was identified in 161 (87%) patients, with 95 (59%) sites histologically confirmed. Factors associated with the detection of recurrence included the difference between PSA nadir and PSA at CholPET (odds ratio: 1.30, p<0.01) and National Comprehensive Cancer Network high-risk classification (odds ratio: 10.83, p=0.03). One hundred (54.3%) patients recurred in the pelvic soft tissue only, while 61 (33%) had extrapelvic recurrence. Of 21 patients who underwent CholPET prior to meeting the Phoenix criteria of biochemical failure, 15 (71%) had recurrence identified on CholPET with 11 localized to the pelvis. On multivariable analysis, the difference between PSA nadir and PSA at CholPET, time from RT, and National Comprehensive Cancer Network risk group were predictive of recurrence outside of the pelvis, and a nomogram was generated with a c-index of 0.79.



CholPET identified the site of recurrence in 87% of patients with a rising PSA after RT; most commonly within the pelvis in potentially salvageable locations. A predictive nomogram was generated, and pending external validation, this may aid in assessing the risk of disease beyond the pelvis. These findings underscore the importance of advanced imaging when considering management strategies for patients with a rising PSA following primary RT.



We identified anatomic patterns of recurrence in patients with a rising prostate-specific antigen after radiotherapy using C-11 choline positron emission tomography/computed tomography. Most recurrences were localized to the pelvis and we were able to generate a tool to aid in disease localization prior to evaluation with advanced imaging.
Department of Urology, Mayo Clinic, Rochester, MN, USA.
William P
WP
Parker
Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA. Electronic address: davis.brian@mayo.edu.
Brian J
BJ
Davis
Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA.
Sean S
SS
Park
Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA.
Kenneth R
KR
Olivier
Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA.
Richard
R
Choo
Department of Radiology, Mayo Clinic, Rochester, MN, USA.
Mark A
MA
Nathan
Department of Radiology, Mayo Clinic, Rochester, MN, USA.
Val J
VJ
Lowe
Department of Radiology, Mayo Clinic, Rochester, MN, USA.
Timothy J
TJ
Welch
Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA.
Jaden D
JD
Evans
Department of Health Services Research, Mayo Clinic, Rochester, MN, USA.
William S
WS
Harmsen
Department of Urology, Mayo Clinic, Rochester, MN, USA.
Harras B
HB
Zaid
Department of Urology, Mayo Clinic, Rochester, MN, USA.
Ilya
I
Sobol
Department of Urology, Mayo Clinic, Rochester, MN, USA.
Daniel M
DM
Moreira
Department of Urology, Mayo Clinic, Rochester, MN, USA.
Rimki
R
Haloi
Department of Urology, Mayo Clinic, Rochester, MN, USA.
Matthew K
MK
Tollefson
Department of Urology, Mayo Clinic, Rochester, MN, USA.
Matthew T
MT
Gettman
Department of Urology, Mayo Clinic, Rochester, MN, USA.
Stephen A
SA
Boorjian
Department of Urology, Mayo Clinic, Rochester, MN, USA.
Lance A
LA
Mynderse
Department of Urology, Mayo Clinic, Rochester, MN, USA.
R Jeffrey
RJ
Karnes
Department of Urology, Mayo Clinic, Rochester, MN, USA.
Eugene D
ED
Kwon
D000368:Aged; D002250:Carbon Radioisotopes; D002794:Choline; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D049451:Nomograms; D016017:Odds Ratio; D010388:Pelvis / Q000000981:diagnostic imaging; D000072078:Positron Emission Tomography Computed Tomography; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D011878:Radiotherapy; D012189:Retrospective Studies
D002250:Carbon Radioisotopes; C000615233:Carbon-11; D002794:Choline
Nomogram; PET/CT; Prostate Cancer; Radiation Therapy; Recurrence