The relevance of prostatectomy findings for brachytherapy selection in patients with localized prostate carcinoma.
BACKGROUND
The efficacy of brachytherapy for patients with localized prostate carcinoma depends on adequate radiotherapeutic coverage of the primary tumor and its subclinical extraprostatic extensions. Predictive models based on pretherapy factors may be useful to estimate the likelihood for clinically relevant extraprostatic disease and may be incorporated into selection criteria for this procedure.


METHODS
Multivariate logistic regression model building was performed using pretherapy factors in 2905 surgically staged patients with localized prostate carcinoma to estimate the probability of seminal vesicle and/or lymph node involvement. Bootstrap methods were employed to assess the stability of the final model parameters and to determine the sensitivity and specificity of the final model.


RESULTS
Clinical tumor classification, biopsy Gleason score groupings, and serum prostate specific antigen (PSA) levels were associated with seminal vesicle and/or pelvic lymph node involvement. These factors were incorporated into a multivariate model that predicted for these adverse histopathologic features. Allowing for up to a 10% likelihood for seminal vesicle and/or pelvic lymph node involvement, patients with tumors classified as T1c-T2a, Gleason scores of 2-6, and PSA < or = 16 ng/mL; or with tumors classified as T1c-T2a, Gleason scores of 7-10, and PSA < or = 4 ng/mL; or with tumors classified as T2b-T2c, Gleason scores of 2-6, and PSA < or = 6 ng/mL would be potential candidates for brachytherapy alone.


CONCLUSIONS
The predictive model presented may provide criteria whereby an adequately performed prostate brachytherapy procedure is expected to encompass the intraprostatic and adjacent extraprostatic disease. Prostate brachytherapy alone may be considered in these circumstances, whereas the addition of external beam radiotherapy may be reserved for patients with disease that is apt to extend beyond the brachytherapy target volume.
Pisansky
Thomas M
TM
Division of Radiation Oncology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. pisansky.thomas@mayo.edu
Blute
Michael L
ML
Hillman
David W
DW
Davis
Brian J
BJ
Haddock
Michael G
MG
Suman
Vera J
VJ
Wilson
Torrence M
TM
Zincke
Horst
H
D001918:Brachytherapy / Q000592:standards; D003131:Combined Modality Therapy; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy / Q000592:standards; D011471:Prostatic Neoplasms / Q000097:blood / Q000532:radiotherapy* / Q000601:surgery*; D015203:Reproducibility of Results; D012669:Seminal Vesicles / Q000473:pathology; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
D017430:Prostate-Specific Antigen