Detecting metastatic prostate carcinoma in pelvic lymph nodes following neoadjuvant hormone therapy: the eyes have it!

Residual cancer morphology in radical prostatectomies (RPs) after neoadjuvant hormone therapy includes inconspicuous cytology, and treated tumour cells can be difficult to identify in lymph nodes. The aim of this study was to evaluate the role of immunohistochemistry (IHC) in identifying occult lymph node metastases following neoadjuvant hormone treatment of prostate cancer.

One hundred and twenty-eight lymph nodes from 24 patients treated with neoadjuvant hormone therapy, including abiraterone acetate alone or combined with leuprolide, were stained with antibodies against keratin AE1/AE3, prostate-specific antigen (PSA), prostate-specific acid phosphatase (PrAP), androgen receptor (AR), and NKX3.1. IHC slides were scored 'blind', and then retrospectively compared with haematoxylin and eosin (H&E)-stained slides and pathology reports. IHC identified carcinoma in six lymph nodes from three patients. All metastases were positive for NKX3.1 and AR, five of six were positive for AE1/AE3, and three of six were positive for PSA; PrAP was negative in all metastatic foci. All six lymph node metastases had been identified by H&E staining at the time of RP.

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.

Histopathology. 2015 May 27. doi: 10.1111/his.12739. [Epub ahead of print]

Kehr E1,2, Masry P1,2, Lis R3, Loda M1,2,3, Taplin ME2,3, Hirsch MS1,2.

1 Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
2 Harvard Medical School, Boston, MA, USA.
3 Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA.