Prostatic Needle Biopsies Following HIFU Therapy
Prostatic Needle Biopsies Following HIFU Therapy
Aims High intensity focused ultrasound (HIFU) is currently offered as primary treatment for patients with clinically localised prostate cancer. Data on histopathological features of post-treatment biopsies are limited.
Methods Pretreatment biopsies were identified in 45 men (age range 41–85) who received primary HIFU therapy. Post-HIFU biopsies were performed in 30 of these patients (67%) at mean 14.1 months (95% CI 11.7 to 16.5) follow-up, 22 due to rising PSA and eight as part of routine follow-up. Biopsies were examined for presence, distribution and extent of adenocarcinoma, Gleason scores, use of standard immunohistochemistry and ablative tissue changes were attributable to HIFU.
Results In post-HIFU biopsies performed for biochemical failure, 17/22 (77%) contained adenocarcinoma; 4/22 (18%) had higher post-HIFU Gleason score; 3/22 (14%) had newly recognised bilateral involvement; and 4/22 (18%) had higher percentage tissue involvement compared with pre-HIFU biopsies. Of cases without rising post-HIFU PSA, 2/8 (25%) routine follow-up biopsies contained adenocarcinoma. Stromal fibrosis was the commonest finding in non-tumour post-HIFU biopsy tissue (17/30, 57%) with coagulative necrosis occurring in fewer cases (4/30, 13%) and over a shorter follow-up interval than cases showing fibrosis (8.5 (0.2–16.8) vs 15.3 (11.5–19.1) months). Treatment effects in tumour cells precluding the assignment of Gleason scores or use of immunohistochemistry in post-HIFU biopsies were not identified.
Conclusion Post-HIFU biopsies are positive in more than 75% of patients with elevated or rising PSA. Stromal fibrosis is common but the tissue effects of this modality do not appear to impair pathologists' ability to detect and grade adenocarcinoma in follow-up biopsies.
Prostate cancer (CaP) is most commonly diagnosed as localised, low to intermediate risk disease, with established treatments including radical prostatectomy and various forms of radiation therapy. To address concerns of possible overtreatment, recently developed minimally invasive therapies such as high intensity focused ultrasound (HIFU) aim to ablate the entire prostate or only a portion of the gland (focal therapy) while sparing surrounding organs in order to preserve urinary and sexual function. HIFU, first used in the treatment of benign prostatic hyperplasia in 1994 and for CaP in 1995, rapidly heats targeted tissue causing coagulative necrosis. More recently, it has been used in the salvage setting for radiation therapy failures in addition to the aforementioned primary therapy for clinically localised CaP.
When biochemical failure (using any of several competing definitions) occurs post-HIFU treatment, many patients undergo biopsy to confirm the presence of residual disease. Also, patients who fail HIFU may have poorer pathological and functional outcomes following salvage radical prostatectomy, which may provide another reason to monitor such patients with biopsy after their initial HIFU treatment. Despite the existence of clinical and biopsy follow-up data, information on the histological changes seen in tumour and non-tumour prostate tissue following primary HIFU therapy is limited to studies of whole canine prostates and human prostatectomy specimens examined soon after exposure to HIFU. With respect to post-HIFU biopsies, the details are limited to one recently published series of 25 patients who underwent biopsy 180 days after primary HIFU therapy as part of an investigational protocol.
In this study, post-HIFU biopsies were reviewed and morphologic features compared with pre-HIFU biopsies, with a focus on assessing tumour morphology for treatment effects that might impact on the applicability of Gleason scoring.
Abstract and Introduction
Abstract
Aims High intensity focused ultrasound (HIFU) is currently offered as primary treatment for patients with clinically localised prostate cancer. Data on histopathological features of post-treatment biopsies are limited.
Methods Pretreatment biopsies were identified in 45 men (age range 41–85) who received primary HIFU therapy. Post-HIFU biopsies were performed in 30 of these patients (67%) at mean 14.1 months (95% CI 11.7 to 16.5) follow-up, 22 due to rising PSA and eight as part of routine follow-up. Biopsies were examined for presence, distribution and extent of adenocarcinoma, Gleason scores, use of standard immunohistochemistry and ablative tissue changes were attributable to HIFU.
Results In post-HIFU biopsies performed for biochemical failure, 17/22 (77%) contained adenocarcinoma; 4/22 (18%) had higher post-HIFU Gleason score; 3/22 (14%) had newly recognised bilateral involvement; and 4/22 (18%) had higher percentage tissue involvement compared with pre-HIFU biopsies. Of cases without rising post-HIFU PSA, 2/8 (25%) routine follow-up biopsies contained adenocarcinoma. Stromal fibrosis was the commonest finding in non-tumour post-HIFU biopsy tissue (17/30, 57%) with coagulative necrosis occurring in fewer cases (4/30, 13%) and over a shorter follow-up interval than cases showing fibrosis (8.5 (0.2–16.8) vs 15.3 (11.5–19.1) months). Treatment effects in tumour cells precluding the assignment of Gleason scores or use of immunohistochemistry in post-HIFU biopsies were not identified.
Conclusion Post-HIFU biopsies are positive in more than 75% of patients with elevated or rising PSA. Stromal fibrosis is common but the tissue effects of this modality do not appear to impair pathologists' ability to detect and grade adenocarcinoma in follow-up biopsies.
Introduction
Prostate cancer (CaP) is most commonly diagnosed as localised, low to intermediate risk disease, with established treatments including radical prostatectomy and various forms of radiation therapy. To address concerns of possible overtreatment, recently developed minimally invasive therapies such as high intensity focused ultrasound (HIFU) aim to ablate the entire prostate or only a portion of the gland (focal therapy) while sparing surrounding organs in order to preserve urinary and sexual function. HIFU, first used in the treatment of benign prostatic hyperplasia in 1994 and for CaP in 1995, rapidly heats targeted tissue causing coagulative necrosis. More recently, it has been used in the salvage setting for radiation therapy failures in addition to the aforementioned primary therapy for clinically localised CaP.
When biochemical failure (using any of several competing definitions) occurs post-HIFU treatment, many patients undergo biopsy to confirm the presence of residual disease. Also, patients who fail HIFU may have poorer pathological and functional outcomes following salvage radical prostatectomy, which may provide another reason to monitor such patients with biopsy after their initial HIFU treatment. Despite the existence of clinical and biopsy follow-up data, information on the histological changes seen in tumour and non-tumour prostate tissue following primary HIFU therapy is limited to studies of whole canine prostates and human prostatectomy specimens examined soon after exposure to HIFU. With respect to post-HIFU biopsies, the details are limited to one recently published series of 25 patients who underwent biopsy 180 days after primary HIFU therapy as part of an investigational protocol.
In this study, post-HIFU biopsies were reviewed and morphologic features compared with pre-HIFU biopsies, with a focus on assessing tumour morphology for treatment effects that might impact on the applicability of Gleason scoring.
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