David D. Buethe
University of Oklahoma
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Featured researches published by David D. Buethe.
The Journal of Urology | 2012
David D. Buethe; Sammy Moussly; Hui-Yi Lin; Binglin Yue; Alejandro R. Rodriguez; Philippe E. Spiess; Wade J. Sexton
PURPOSE We evaluated the ability of renal tumor complexity, as assessed by the R.E.N.A.L. (radius, exophytic, nearness to collecting system, anterior/posterior and location) nephrometry scoring system, to predict the functional efficacy of nephron sparing surgery. MATERIALS AND METHODS We evaluated 42 patients who presented with an anatomically (32) or a functionally (10) solitary kidney and underwent partial nephrectomy. Each renal unit was assigned a R.E.N.A.L. nephrometry score using preoperative imaging. The CKD-EPI equation was applied to calculate the estimated glomerular filtration rate. The difference between the estimated glomerular filtration rate at baseline and at postoperative time points served as a measurement of the renal functional loss attributable to partial nephrectomy. RESULTS In the 42 patients who underwent partial nephrectomy the mean preoperative estimated glomerular filtration rate was 61.5 ml/minute/1.73 m(2). The median total nephrometry score was 8 (range 4 to 10). In the immediate postoperative period the cohort mean estimated glomerular filtration rate of 48.6 ml/minute/1.73 m(2) was significantly less than the preoperative value (p <0.0001). At 6-month followup the mean estimated glomerular filtration rate had recovered at 54.1 ml/minute/1.73 m(2) but it remained significantly less than the preoperative value (p = 0.0002). We noted no relationship between the postoperative decrease in the estimated glomerular filtration rate and the assigned total nephrometry score or in any individual component of the R.E.N.A.L. scoring system related to the targeted lesion. CONCLUSIONS Neither the individual components of the R.E.N.A.L. nephrometry scoring system nor the total nephrometry score predicted the realized functional loss, as assessed by the estimated glomerular filtration rate in patients with a solitary kidney treated with nephron sparing surgery. However, nephron sparing surgery was quite efficacious for preserving renal function since only a durable 11.6% decrease was noted in the estimated glomerular filtration rate.
International Scholarly Research Notices | 2011
Jonathan E. Heinlen; David D. Buethe; Daniel J. Culkin; Gennady Slobodov
Multiple Endocrine Neoplasia type 2A (MEN-2a) is a rare disease associated with tumors of endocrine organs. Presentation most commonly is with medullary thyroid cancer and infrequently with other complaints. Pituitary adenoma has been seen coincidentally with this disease very rarely. Presented is a case of coincident MEN-2a with a symptomatic pituitary adenoma and an asymptomatic pheochromocytoma. A brief review is also provided.
International Urology and Nephrology | 2012
C. Dirk Engles; Gennady Slobodov; David D. Buethe; Stanley Lightfoot; Daniel J. Culkin
Primary large cell neuroendocrine carcinomas (NECs) of the bladder are rarely encountered, and only a few reports have been documented. Frequently, they are found to be admixed with other histologies. In this report, we describe such a tumor found in a 65-year-old man who underwent radical cystectomy, after initial transurethral resection discovered a small cell NEC pathology. We also reviewed the limited number of neuroendocrine tumors reported containing a large cell component. Given the paucity of these tumors and the resultant difficulty in developing generalized treatment protocols, we promote the use of gene expression models to tailor chemotherapeutic regimens for individual tumors.
International Urology and Nephrology | 2012
Jonathan E. Heinlen; David D. Buethe; Daniel J. Culkin
Penile cancer is an uncommon disease in the industrialized world that most frequently presents at low stage and is cured with treatment of local and regional surgery. In cases of advanced cancer, the use of more aggressive surgical techniques and the addition of adjuvant therapy may be warranted. So far, few agents have been found that improve survival with metastatic disease and thus aggressive primary treatment is required. This review discusses diagnosis, staging, and therapy for high risk penile cancer.
Cancer Control | 2013
David D. Buethe; Philippe E. Spiess
BACKGROUND Nephron-sparing treatments remain underutilized for the management of small renal masses despite a rise in incidentally detected renal cell carcinoma and a downward stage migration. METHODS Historical publications representative of currently accepted paradigms were reviewed, and the results of a contemporary scientific literature search conducted in PubMed focusing on studies involving humans, published in English, and inclusive of clinical trials, meta-analyses, randomized controlled trials, and practice guidelines are included. Results from contemporary retrospective trials augment the data when level I or II evidence is absent. RESULTS Phase III clinical trial results substantiate the long-held tenet that partial nephrectomy is equivalent to radical nephrectomy with respect to safety and oncologic efficacy. Further, minimally invasive techniques using laparoscopy and robotic assistance to achieve partial nephrectomy appear equally effective to traditional open techniques. Although no prospective randomized studies are available, large retrospective studies support the notion that active surveillance and thermal ablative techniques are viable options for carefully selected patients. CONCLUSIONS The management of small renal masses encompasses a host of therapeutic options, all of which must be considered and discussed with the individual patient.
Journal of Clinical Oncology | 2013
David D. Buethe; Christopher M. Russell; Binglin Yue; Hui-Yi Lin; Julio M. Pow-Sang
238 Background: Limited derived benefit from definitive treatment has been observed with respect to prostate cancer-specific mortality (PCSM) in those low-risk disease and only small absolute risk reductions in both overall PCSM and incidence of metastasis have been demonstrated. Thus, active surveillance (AS) strategies have been adopted to monitor for disease progression with intent for intervention at time of disease reclassification. Yet, the timing and frequency of surveillance remain without evidence-based standardization. We assessed the relationship between the frequency of surveillance prostate biopsies and the oncologic outcomes in those patients with low-risk prostate cancer (CaP) managed by AS. METHODS An IRB approved retrospective chart review identified 114 patients placed on AS for their CaP between November of 1997 and November of 2000. Of those, 96 patients meet study inclusion criteria mandating a Gleason sum of < 7, tumor presence in < 4 sextets, involvement of <50% of any single biopsy core. Eligible patients were surveyed by serum PSA, DRE, and surveillance TRUS-guided biopsies at physician determined intervals. RESULTS At diagnosis, the mean age was 70.3 (SD±5.3) years with a mean PSA value of 8.2 (SD±8.2) ng/dL. While on AS, patients underwent a median of 3.5 (SD±2.02) TRUS-guided biopsies; at a frequency approaching 1 biopsy every 18 months. At a median follow-up of 134.8 months (95%CI: 114.5, 148.7), multivariate analysis found more frequent prostatic biopsy acquisition to be inversely associated a worse prognosis with respect to both progression-free (p<0.0001) and overall survival (p=0.0002). Both progression-free (p<0.0001) and overall survival (p=0.0207) were progressively shorter as the interval between biopsies declined from greater than 2 years, to 1-2 years, and then less than 1 year. CONCLUSIONS No survival advantage was achieved by frequent re-biopsy of the prostate. Patients biopsied more frequently were paradoxically found have poorer survival outcomes.
Journal of Clinical Oncology | 2013
David D. Buethe; Christopher M. Russell; Binglin Yue; Hui-Yi Lin; Julio M. Pow-Sang
170 Background: Prostate cancer (CaP) has exhibited a downward stage migration during the PSA era. Approximately 70% of those newly diagnosed with CaP, harbor tumors of low-risk. Such tumors often prove to be of low-volume and of clinical insignificance at time of radical prostatectomy (RP), suggesting over treatment and excessive exposure to the morbidity associated with definitive management. Over the last decade, active surveillance (AS) strategies have become a more accepted practice when addressing low-risk tumors. We present the long-term oncologic outcomes of patients placed on AS. METHODS An IRB approved retrospective chart review identified 114 patients placed on AS for their CaP between November of 1997 and November of 2000. Of those, 96 patients meet study inclusion criteria mandating a Gleason sum of < 7, tumor presence in < 4 sextets, and involvement of <50% of any single biopsy core. Eligible patients were surveyed by serum PSA , digital rectal exam, and surveillance transrectal ultrasound (TRUS)-guided biopsies at physician determined intervals. RESULTS At diagnosis, the mean age was 70.3 (SD±5.3) years with a mean PSA value of 8.2 (SD±8.2) ng/dL. Surveillance patterns approached acquisition of a PSA at a mean of 9 months and a TRUS-guided biopsy of the prostate every 1.5 years. The median total number of PSAs and biopsies obtained while on surveillance were 6.0 (SD±5.72) and 3.5(SD±2.02), respectively. At a median follow-up of 134.8 months (95%CI: 114.5, 148.7), 52 (54%) of patients had been reclassified or demonstrated disease progression. The median progression-free and overall survival for the cohort were 68.7 (95%CI: 53.2, 97.3) months and 156.9 (95%CI: 139.9, 161.5) months, respectively. Only one prostate cancer specific mortality was identified. CONCLUSIONS AS presents a reasonable management strategy option for low-risk prostate cancer in appropriately selected patients. However, treatment at time of disease progression did not improve survival. A significant percentage of men on AS are exposed to progression of their disease if alive beyond 10 years from their diagnosis.
Journal of Clinical Oncology | 2012
David D. Buethe; Sammy Moussly; Hui-Yi Lin; Xiuhua Zhao; Philippe E. Spiess; Wade J. Sexton
399 Background: Recently, the R.E.N.A.L. nephrometry scoring system was introduced to objectively describe renal masses with respect to size, the degree to which they are exo/endophytic, the nearness to the collecting system, whether they are anterior or posterior and the location relative to polar lines. It is our aim to evaluate the R.E.N.A.L. nephrometry scoring systems ability to predict functional renal loss attributed to nephron-sparing surgery (NSS). METHODS We evaluated 42 patients presenting with either an anatomic (32) or functionally solitary (10) kidneys undergoing partial nephrectomy (PN). Each renal unit was assigned a R.E.N.A.L. nephrometry score utilizing pre-operative cross-sectional imaging. The CKD-EPI equation was applied to serum creatinine levels to generate corresponding estimated glomerular filtration rates (eGFR). The difference between the eGFR at baseline and at post-operative time points served as a measurement of renal function loss attributed to PN. RESULTS Forty-two patients underwent PN with mean pre-operative eGFR of 61.5 mL/min/1.73m2. The median total nephrometry score was 8, ranging from 4-10. Twenty-eight (66.7%) of the renal lesions were ≤ 4 cm, 13 (31%) were between 4 and 7 cm, and 1 (2.4%) was >7 cm in diameter. The majority (54.8%) of the patients had tumors with more than 50% of tumor burden lying outside the expected renal border whereas 3 patients (7.1%) had tumors considered to be completely endophytic. Twenty-seven (64.3%) were within 4 mm of the collecting system. Tumor locations defined as: completely polar, interpolar, and completely central were assigned to 11, 15, and 16 lesions respectively. By post-operative month 6, the overall average eGFR of 53.9 mL/min/1.73m2 was significantly less (p = 0.0293) than the pre-operative value. However, we were unable to correlate change in post-operative eGFR with pre-operative total or individual R.E.N.A.L. scoring parameters. CONCLUSIONS Neither the individual components of the R.E.N.A.L. nephrometry scoring system nor the total nephrometry score correlated with realized functional loss as assessed by eGFR in patients with a solitary kidney undergoing NSS.
Case reports in urology | 2011
Adamantios M. Mellis; Daniel C. Parker; David D. Buethe; Gennady Slobodov
We report on the evaluation and management of a 47-year-old white male found to have primary carcinoid tumor of the ileal segment of his diverting ileovesicostomy thirty-five months after initial creation. Subsequent to presentation with intermittent gross hematuria, CT urogram highlights an 8 mm enhancing lesion near the enterovesical junction of urinary diversion. Office cystoscopy confirms presence of a lesion that was later endoscopically resected and found to be a well-differentiated carcinoid tumor. Evaluation with serum markers, direct visualization utilizing endoscopy, and imaging was without finding of alternate primary or metastatic lesions. The patient ultimately had the proximal ileal portion of his ileovesicostomy excised and the distal portion converted into an ileal conduit. After briefly discussing the carcinoid tumor and the carcinoid syndrome it may cause, we review the literature on the incidence of carcinoid tumors in a population requiring the use of intestine in the urinary tract.
BMC Bioinformatics | 2008
Mikhail G. Dozmorov; Kimberly D. Kyker; Paul J. Hauser; Ricardo Saban; David D. Buethe; Igor Dozmorov; Michael Centola; Daniel J. Culkin; Robert E. Hurst