Advances in prostatic surgery: Total prostatectomy for prostate carcinoma in dogs

Description

Prostate carcinoma (PCA) in dogs has a poor prognosis due to location, high metastasis rate, and high complication rates from local treatments. Palliative treatment with NSAIDs or a combination of NSAIDs + chemo and local palliation in cases of urinary obstruction using urethral stenting result in median survival times (MST) of around 4 months (ranging from 20 days to 7 months).1–3
Surgery +/- adjuvant treatments for PCA in dogs has been met with high complication rates and poor prognosis.4–6 Total prostatectomy (TP) for PCA has been associated with up to 100% occurrence of urinary incontinence and reported MST after TP was 17 days, with only 4/10 animals surviving to discharge from the hospital.5 In contrast, palliative intracapsular subtotal prostatectomy (ISP), in which prostatic tumor tissue is debulked using electrosurgery or laser7 while sparing a dorsolateral rim of tissue and overlying capsule of the prostate, improved outcome with improvement or resolution of clinical signs and no or minor (18%) urinary incontinence. Reported MST after ISP was 103 – 130 days. However, complications resulted in perioperative death or euthanasia in 18-38% of the cases.5,8
Introduction of nerve-sparing TP procedures in humans significantly reduced complications of incontinence and erectile dysfunction.9 However, TP in men is still associated with urinary incontinence in 4-31%.10 Factors associated with post-operative incontinence include surgical (nerve sparing) technique, tumor size, and preservation of the bladder neck. Characterization of the complex (peri)prostatic nerve anatomy is subject of ongoing research.11 Because of size and anatomical resemblance, the dog is an ideal model for human prostate treatments.12 Hence, feasibility and complications of novel therapies are often evaluated in normal dogs, which may aid to improve treatment in dogs with PCA.13
Recent retrospective analysis of TP for prostate carcinoma in dogs showed 35% long-term post-operative incontinence of varying degree and a median survival time of 231 days.14 Similarly, total prostatectomy for PCA in primarily small breed dogs in Japan resulted in mild urinary incontinence in 78% and severe in 11% of the cases, and a median survival of 525 days.15 Possible reasons for these improved results of TP compared to historical data may be improved clinical staging and selection of cases considered suitable for surgical intervention based on advanced imaging results. Furthermore, improved knowledge of anatomy and efficacy of nerve sparing surgery in humans (and laboratory dogs) may also contribute to refinement of the surgical procedure in dogs with PCA. Limited clinical data of nerve sparing TP at the presenting authors institution is in agreement with recent literature that nerve sparing TP may be a viable option for treatment for PCA in dogs in an early disease stage, with rapid recovery after surgery and mostly minor urinary incontinence if present.
In this lecture, surgical technique and comparative anatomical aspects will be discussed (Figure 1). Considering that the reported cause of death was tumor-related in 86% of cases,14 development of adjuvant therapies is warranted for further improvement of outcome. Other treatment modalities that may further improve outcome or provide a treatment option for more advanced local disease include radiation therapy,16,17 transurethral resection,18 minimally invasive local ablative techniques,19 and experimental procedures such as arterial embolization of the prostate.20

Period	6 Jul 2019
Event title	European College of Veterinary Surgeons: Annual Scientific Meeting 2019
Event type	Conference
Conference number	28
Location	Budapest, HungaryShow on map
Degree of Recognition	International