AIMS: Residual cancer morphology in radical prostatectomies (RP) after neoadjuvant hormonal therapy includes inconspicuous cytology, and treated tumor cells can be difficult to identify in lymph nodes.
This study evaluated the role of immunohistochemistry (IHC) in identifying occult lymph node metastases following neoadjuvant hormonal treatment of prostate cancer.
METHODS AND RESULTS: 128 lymph nodes from 24 patients treated with neoadjuvant hormone therapy, including abiraterone acetate alone or combined with leuprolide, were stained with antibodies to keratin AE1/AE3, prostate specific antigen (PrSA), prostate specific acid phosphatase (PrAP), androgen receptor (AR), and NKX3.1. IHC slides were scored 'blind' and then retrospectively compared to H&E slides and pathology reports. IHC identified carcinoma in 6 lymph nodes from 3 patients. All metastases were positive for NKX3.1 and AR, 5 of 6 were positive for AE1/AE3, 3 of 6 were positive for PrSA, and PrAP was negative in all metastatic foci. All 6 lymph node metastases had been identified by H&E at the time of RP.
CONCLUSIONS: These findings suggest that routine use of IHC on lymph nodes from neoadjuvant treated prostate carcinomas is not necessary. Nevertheless, for suspicious small foci of atypical cells in neoadjuvant treated lymph nodes, NKX3.1 and AR appear to have the greatest sensitivity.
Kehr E, Masry P, Lis R, Loda M, Taplin ME, Hirsch MS. Are you the author?
Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States; Harvard Medical School, Boston, MA; Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, United States.
Reference: Histopathology. 2015 May 27. Epub ahead of print.