Diego Aguilar Palacios

Focal cryosurgical ablation of the prostate: a single institute’s perspective

BackgroundWith the stage migration of prostate cancer witnessed in the late 1990’s and early 2000’s along with the persistent morbidities associated with prostatectomy and radiation therapy, the concept of focal prostate cancer treatment remains quite attractive. Herein we evaluate the tolerability and non-oncologic outcomes of a highly select cohort of men that underwent focal cryoablation of the prostate for the treatment of localized prostate cancer.MethodsPre-operatively, erectile function was assessed by SHIM questionnaire while voiding symptoms were assessed by AUA symptom score. Twenty-six highly select patients (23 low-risk prostate cancer and 3 intermediate-risk prostate cancer) with documented minimal disease on saturation prostate biopsy underwent focal cryoablation of the prostate (24 hemi-ablation and 2 subtotal ablation). Subsequently, serum PSAs were obtained every 3 months for 2 years and then every 6 months thereafter. PSA failure was defined as an increase of 0.50 ng/ml over nadir. Mean follow-up was 19.1 months. Subjective assessment of erectile function and voiding was assessed post-operatively at each visit.ResultsBased on our PSA failure definition, 11.5% (3 patients) of the cohort experienced biochemical failure. In two of the three patients, localized disease was detected on subsequent transrectal ultrasound guided biopsy. These two patients went on to have favorable PSA nadirs after undergoing conventional definitive therapy (one patient had external beam radiation and one patient had whole gland cryoablation). Within the study cohort, 27% (7 patients) reported new post-operative erectile dysfunction requiring therapy while no patients reported new post-operative urinary incontinence or worsening of voiding symptoms.ConclusionThese preliminary results add to the expanding body of literature that the minimally invasive focal cryosurgical ablation of the prostate is a safe procedure with few side effects. The true extent of cancer control remains in question, but in highly select patients, favorable PSA kinetics have been demonstrated. If confirmed by further studies with long-term follow-up, this treatment approach could have a profound effect on prostate cancer management.

Radiosensitization in prostate cancer: mechanisms and targets.

Prostate cancer is the second most commonly diagnosed cancer in American men over the age of 45 years and is the third most common cause of cancer related deaths in American men. In 2012 it is estimated that 241,740 men will be diagnosed with prostate cancer and 28,170 men will succumb to prostate cancer. Currently, radiation therapy is one of the most common definitive treatment options for localized prostate cancer. However, significant number of patients undergoing radiation therapy will develop locally persistent/recurrent tumours. The varying response rates to radiation may be due to 1) tumor microenvironment, 2) tumor stage/grade, 3) modality used to deliver radiation, and 4) dose of radiation. Higher doses of radiation has not always proved to be effective and have been associated with increased morbidity. Compounds designed to enhance the killing effects of radiation, radiosensitizers, have been extensively investigated over the past decade. The development of radiosensitizing agents could improve survival, improve quality of life and reduce costs, thus benefiting both patients and healthcare systems. Herin, we shall review the role and mechanisms of various agents that can sensitize tumours, specifically prostate cancer.

MP49-04 EXCISED PARENCHYMAL MASS AND DEVASCULARIZED PARENCHYMAL MASS ASSOCIATED WITH PARTIAL NEPHRECTOMY: IMPACT ON FUNCTIONAL RECOVERY

INTRODUCTION AND OBJECTIVES: Robot-assisted partial nephrectomy (RAPN) is reportedly superior to laparoscopic partial nephrectomy (LPN) in renal function preservation. This is partly due to the shortened warm ischemia time (WIT), but related evidence remains unclear. This study aimed to examine the cause of renal functional loss after minimally invasive partial nephrectomy. METHODS: A total of 273 patients underwent LPN (n 1⁄4 141) or RAPN (n 1⁄4 132) at a single institution between 2010 and 2015. The factors influencing the >10% decrease in the estimated glomerular filtration rate (eGFR) 6 months postoperatively were evaluated, and the percentage of decrease in eGFR and parenchymal volume were compared in LPN and RAPN matched cohorts. RESULTS: The mean WIT was significantly longer (24 vs. 18 minutes, p < 0.001) and the postoperative decrease in eGFR 6 months after surgery was significantly higher (-9.9% and -3.4%, p < 0.001) in LPN than in RAPN. Multivariate analysis showed that the >10% postoperative decrease in eGFR was significantly influenced by the surgical procedure (p 1⁄4 0.0004), but not by WIT (p 1⁄4 0.07). Patient variables, including age, sex, body mass index, tumor size, RENAL nephrometry score (RENAL-NS), preoperative eGFR, and WIT, were adjusted, and each group included 42 patients (mean tumor size 23 mm, RENAL-NS 6.4, preoperative eGFR 69 mL/min/1.73 m2, WIT 21 minutes). Six months after surgery, the percentage of decrease in eGFR (-9.4% vs. -1.9%, p 1⁄4 0.0008) and parenchymal volume (-23% vs. -9%, p < 0.0001) was significantly higher in LPN than in RAPN. CONCLUSIONS: The better preservation of renal function in RAPN, compared with LPN, is not caused by shortened WIT but by better preservation of parenchymal volume.