Philip J Dorsey

Weill Cornell Medical College, New York City, New York, United States

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Publications (10)14.77 Total impact

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    ABSTRACT: Next-generation DNA and RNA sequencing requires intact nucleic acids from high-quality human tissue samples to better elucidate the molecular basis of cancer. We have developed a prostate biobanking protocol to acquire suitable samples for sequencing without compromising the accuracy of clinical diagnosis. To assess the clinical implications of implementing this protocol, we evaluated 105 consecutive radical prostatectomy specimens from November 2008 to February 2009. Alternating levels of prostate samples were submitted to Surgical Pathology as formalin-fixed, paraffin-embedded blocks and to the institutional biobank as frozen blocks. Differences in reported pathologic characteristics between clinical and procured specimens were compared. Clinical staging and grading were not affected by the biobank protocol. Tumor foci on frozen hematoxylin and eosin slides were identified and high-density tumor foci were scored and processed for DNA and RNA extractions for sequencing. Both DNA and RNA were extracted from 22 cases of 44 with high-density tumor foci. Eighty-two percent (18/22) of the samples passed rigorous quality control steps for DNA and RNA sequencing. To date, DNA extracted from 7 cases has undergone whole-genome sequencing, and RNA from 18 cases has been RNA sequenced. This protocol provides prostate tissue for high-throughput biomedical research and confirms the feasibility of actively integrating prostate cancer into The Cancer Genome Atlas Program, a member of the International Cancer Genome Consortium.
    Diagnostic molecular pathology: the American journal of surgical pathology, part B 05/2012; 21(2):61-8. · 1.58 Impact Factor
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    ABSTRACT: It is postulated that intraoperative injury to the cavernosal nerves results in hemodynamic and histologic changes within the penis, which manifest clinically as ED. We hypothesize that non-neuronal cause, such as vascular insults due to intraoperative tissue handling, may also have a minor but definite role in penile ischemia and consequent postoperative sexual dysfunction. Between May 2008 and July 2008, 64 patients were enrolled in the study (group 1). Following sterilization, the Odissey Tissue Oximeter probe was placed on the shaft of the penis, 2 cm from its base. The patient underwent continuous penile tissue saturation monitoring. Surgical dissection was altered whenever the oxygen saturation alarm went off until it was restored to 85%. In addition, 192 patients, matched for age, preoperative prostate-specific antigen, clinical stage, baseline sexual function, Charlson comorbidity index and nerve-sparing status operated between October 2007 and July 2008, formed the control group (group 2). These patients did not have any intraoperative tissue oxygenation monitoring. Opening of the endopelvic fascia and steps of nerve sparing were associated with significant drops in oxygen levels, especially if done using torque. Drop in oxygen levels were also noted whenever excessive traction was applied on the Foley catheter, seminal vesicles or prostate during apical dissection. We deliberately modified our surgical steps to make surgery more traction free. A significantly higher percentage of group 1 patients with bilateral nerve sparing had no ED compared with group 2 patients at 6 weeks (24.5% vs 10.4%; P=0.014) and 52 weeks (83.7% vs 68%; P=0.029). Overall, 93.9% of patients in study group had Sexual Health Inventory for Men (SHIM) score of 17 (mild to no ED) at 1 year compared with 78.4% of patients in the control group. We demonstrated that avoidance of ischemic stress, aided by intraoperative penile oxygenation monitoring, may help surgeons improve their technique and thus functional outcomes in patients.
    International journal of impotence research 08/2011; 24(1):11-9. · 2.73 Impact Factor
  • Gerald Y. Tan, Philip J. Dorsey, Ashutosh K. Tewari
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    ABSTRACT: Serum prostate-specific antigen (PSA) screening, coupled with a rising incidence of needle biopsies in asymptomatic men, have all contributed to prostate cancer becoming the most common cancer in men in the United States1,2 and other parts of the world.3 With increasing evidence of improved long-term survival and progression-free outcomes,4–7 radical prostatectomy has become increasingly popular as the treatment of first choice for organ-confined disease.
    02/2011: pages 229-247;
  • British Journal of Medical and Surgical Urology 11/2010; 3(6):259.
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    ABSTRACT: Creation of an optimally apposed, tension-free, well-supported vesicourethral anastomosis remains the cornerstone for anastomotic healing after radical prostatectomy. We report the effect of three techniques of bladder neck reconstruction during robot-assisted radical prostatectomy on anastomotic leak, stricture formation, and continence recovery. Between January 2005 to September 2009, 1900 consecutive patients underwent robotic-assisted laparoscopic prostatectomy (RALP) by a single surgeon. Of these, the first 214 underwent vesicourethral conventional anastomosis (CA); the next 303 men underwent anterior reconstruction (AR) only; and last 1383 men underwent total anatomic restoration (TR). Data elements included patient age, body mass index, preoperative biopsy Gleason score and prostate-specific antigen level, prostate volume, total operative time, console time, time for performing vesicourethral anastomosis, estimated blood loss, tumor stage, and margin status on final pathologic findings. Primary end points were rates of clinically significant anastomotic leaks, bladder neck contractures, and time to return of continence. Chi-square and Fisher exact tests were used for analysis of categoric variables. The Cox proportional hazard model was used for both univariate and multivariate analysis. Clinically significant anastomotic leakage and bladder neck strictures were significantly fewer in the reconstructed groups (2.3% vs 1.0% vs 0.3% and 3.7% vs 1.3% vs 0.5% in the CA, AR, and TR groups, P < 0.01). Continence rates at 1, 6, 12, 26, and 52 weeks after RALP were also significantly better at all time points with AR and TR compared with CA alone (P < 0.001). TR of the continence mechanism optimizes vesicourethral anastomosis healing and hastens early continence return after RALP.
    Journal of endourology / Endourological Society 10/2010; 24(12):1975-83. · 1.75 Impact Factor
  • Gerald Y. Tan, Philip J. Dorsey, Ashutosh K. Tewari
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    ABSTRACT: Prostate cancer remains a pressing public health concern worldwide. In 2009, more than 192,000 men were diagnosed with the disease, and more than 27,000 men died from it in the United States alone [1]. The advent of serum prostate-specific antigen (PSA) screening, coupled with a rising incidence of needle biopsies in asymptomatic men, has contributed to prostate cancer becoming the most common cancer in men in the United States [1, 2] and other parts of the world [3]. With increasing evidence of improved long-term survival and progression-free outcomes [4–10], radical prostatectomy has become increasingly popular as the treatment of first choice for organ-confined disease. KeywordsRobotic-Prostatectomy-Prostate-Cancer-Potency-Continence-Margins-Anatomy
    12/2009: pages 211-231;
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    ABSTRACT: Patients with large median prostate lobes undergoing robot-assisted radical prostatectomy are at potential risk of ureteric orifice injury, during posterior bladder neck transection and vesicourethral anastomosis reconstruction. We describe our technique of in situ robot-assisted ureteral stenting with double-pigtail stents for accurate observation and preservation of the ureteral orifices. We have performed this maneuver in over 30 patients in our cohort of over 1500 patients undergoing robot-assisted radical prostatectomy to date--none of these patients developed urinary leak or bladder neck contracture, and had uneventful cystoscopic removal of stents at 6 weeks after surgery.
    Journal of endourology / Endourological Society 11/2009; 23(12):1975-7. · 1.75 Impact Factor
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    ABSTRACT: The use of prostate-specific antigen (PSA) as a screening test remains controversial. There have been several attempts to refine PSA measurements to improve its predictive value. These modifications, including PSA density, PSA kinetics, and the measurement of PSA isoforms, have met with limited success. Therefore, complex statistical and computational models have been created to assess an individual's risk of prostate cancer more accurately. In this review, the authors examined the methods used to modify PSA as well as various predictive models used in prostate cancer detection. They described the mathematical underpinnings of these techniques along with their intrinsic strengths and weaknesses, and they assessed the accuracy of these methods, which have been shown to be better than physicians' judgment at predicting a man's risk of cancer. Without understanding the design and limitations of these methods, they can be applied inappropriately, leading to incorrect conclusions. These models are important components in counseling patients on their risk of prostate cancer and also help in the design of clinical trials by stratifying patients into different risk categories. Thus, it is incumbent on both clinicians and researchers to become familiar with these tools. Cancer 2009;115(13 suppl):3085-99. (c) 2009 American Cancer Society.
    Cancer 07/2009; 115(13 Suppl):3085-99. · 5.20 Impact Factor
  • Journal of Urology - J UROL. 01/2009; 181(4):670-671.
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    ABSTRACT: A rise in temperature of more than 55 degrees C in tissues, even for short a duration has been implicated in irreversible tissue damage. This study was aimed at recording real time temperature changes at the neurovascular bundle (NVB) during the use of cautery in robotic radical prostatectomy. The temperature was monitored with a needle electrode in 15 cases of athermal nerve sparing and 10 cases of non-nerve sparing robotic radical prostatectomy (RRP). The needle was placed in the peritoneal cavity through the camera port and inserted around the NVB. Body temperature was recorded by nasal cannula and compared with the baseline temperature at the neurovascular bundle. The distance of the needle probe from the area of cautery use, changes in temperature at the neurovascular bundle and the duration of cautery use was recorded during the use of monopolar and bipolar current in tissue dissections. The mean baseline temperature at the neurovascular bundle was 0.8 degrees C lower than the body temperature. Average duration for cautery use at the anterior bladder neck and NVB with monopolar and bipolar current was 53.6 (45-65) and 79.8 (70-92) and 56.8 (45-60) and 65.7 seconds (59-76) respectively. The mean temperature rise during bladder neck dissection (distance more than 1 cm) was 43.6 degrees C [36.4-47.3 degrees C] with the monopolar and 38.8 degrees C [36.8 degrees-42.6 degrees C] with bipolar. During NVB dissection, the mean temperature rise was 53.6 degrees C (45.1 to 68.1 degrees C) with monopolar and 60.91 degrees C (47.2 to 109.8 degrees C) with bipolar. Though this difference was not significant, the mean time to return to baseline temperature was 3 seconds more with bipolar than monopolar. Bipolar cautery may not be safer than monopolar because of a greater rise in temperature of surrounding tissues within 1 cm of its use. Further investigation is needed to fully establish the pathologic consequences associated with increased temperature due to cautery.
    Journal of endourology / Endourological Society 11/2008; 22(10):2313-7. · 1.75 Impact Factor