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Dive into the research topics where Allan Siperstein is active.

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Featured researches published by Allan Siperstein.


Cancer | 2000

Medullary thyroid carcinoma: clinical characteristics, treatment, prognostic factors, and a comparison of staging systems.

Electron Kebebew; Philip H. G. Ituarte; Allan Siperstein; Quan-Yang Duh; Orlo H. Clark

The clinical courses of patients with medullary thyroid carcinoma (MTC) vary, and a number of prognostic factors have been studied, but the significance of some of these factors remains controversial.


Journal of Clinical Oncology | 2005

Predictors of Survival After Radiofrequency Thermal Ablation of Colorectal Cancer Metastases to the Liver: A Prospective Study

Eren Berber; Robert Pelley; Allan Siperstein

PURPOSE The aim of this study was to determine the predictors of survival at the time of radiofrequency thermal ablation (RFA) in patients with colorectal liver metastasis. PATIENTS AND METHODS One hundred thirty-five patients with colorectal liver metastases who were not candidates for resection underwent laparoscopic RFA. RESULTS The median Kaplan-Meier survival for all patients was 28.9 months after RFA treatment. Patients with a carcinoembryonic antigen (CEA) less than 200 ng/mL had improved survival compared with those with a CEA more than 200 (34 v 16 months; P = .01). Patients with the dominant lesion less than 3 cm in diameter had a median survival of 38 v 34 months for lesions 3 to 5 cm, and 21 months for lesions greater than 5 cm (P = .03). Survival approached significance for patients with one to three tumors versus more than three tumors (29 v 22 months; P = .09). The presence of extrahepatic disease did not affect survival. Only the largest liver tumor size more than 5 cm was found to be a significant predictor of mortality by Cox proportional hazards model, with a 2.5-fold increased risk of death versus the largest liver tumor size less than 3 cm (P = .05). CONCLUSION This study determines which patients do best after RFA. Historical survival with chemotherapy alone is 11 to 14 months, suggesting RFA has a positive impact on overall survival. Limited amounts of extrahepatic disease do not appear to affect survival adversely. RFA is a useful adjunct to chemotherapy in those patients with liver-predominant disease.


Surgery | 1997

Laparoscopic thermal ablation of hepatic neuroendocrine tumor metastases

Allan Siperstein; Stanley J. Rogers; Paul Hansen; Alexis Gitomirsky

BACKGROUND Neuroendocrine tumor metastases to the liver are generally slow growing, but patients suffer from hormone hypersecretion despite aggressive multimodality therapy. A minimally invasive method of tumor ablation affords symptomatic improvement with minimal morbidity. METHODS Radiofrequency electrical energy is delivered to tissues via a 4-prong catheter resulting in tissue heating to 60 to 70 degrees C and cell death. Porcine studies were conducted to define appropriate parameters for energy delivery and then applied to patients using laparoscopic techniques. RESULTS In the porcine model 3.5 to 4 cm lesions were reproducibly created in 15 minutes using 30 to 50 W of power. The ablation process was monitored via temperature feedback from thermocouples in the catheter tips and by a hyperechoic blush noted on ultrasonography. Laparoscopic thermal ablation of 13 tumors in six patients with carcinoid (two patients), gastrinoma, insulinoma, nonsecreting islet cell cancer, or medullary thyroid cancer was performed. There were no intraoperative complications, and all patients were discharged the next day. Successful ablation was confirmed by spiral-computed tomography and by symptomatic improvement in patients with secreting tumors. CONCLUSIONS Laparoscopic thermal ablation of hepatic tumors is a novel, minimally invasive method of providing effective cytoreduction of neuroendocrine tumors metastatic to the liver.


Annals of Surgical Oncology | 2000

Local Recurrence After Laparoscopic Radiofrequency Thermal Ablation of Hepatic Tumors

Allan Siperstein; Adella M. Garland; Kristen L. Engle; Stanley J. Rogers; Eren Berber; Arash Foroutani; Andreas String; Tamara Ryan; Philip H. G. Ituarte

AbstractBackground: Since we first described laparoscopic radiofrequency ablation (LRFA) of liver tumors, several reports have documented technical and safety aspects of this procedure. Little is known, however, about the long-term follow-up of such patients. Methods: From January 1996 to February 1999, we performed LRFA on 250 liver tumors in 66 patients. Triphasic spiral computed tomographic scanning was obtained preoperatively and at 1 week, and every 3 months postoperatively. Lesion diameter was measured in the x- and y-axes and the volume estimated; 181 lesions in 43 patients for whom computed tomographic scans available were included in the study. The tumor types were as follows: 64 metastatic adenocarcinomas, 79 neuroendocrine metastases, 27 other metastases, and 11 primary liver tumors. Results: One week postoperatively, the ablated zone was larger than the original tumor in 178 of 181 lesions, which suggests ablation of the tumor and a margin of normal liver tissue. A progressive decline in lesion size was seen in 156 (88%) of 178 lesions, followed for at least 3 months (mean, 13.9 months; range, 4.9–37.8 months), which suggests resorption of the ablated tissue. Fourteen definite local treatment failures were apparent by increase in size and change in computed tomographic scan appearance, and eight lesions were scored as failures because of multifocal recurrence that encroached on ablated foci (22 total recurrences). Predictors of failure include lack of increased lesion size at 1 week (2 of 3 such lesions failed), adenocarcinoma or sarcoma (18 of 22 failures; P < .05), larger tumors (failures, M < 18cm3 vs. successes, M < 7cm3; P < .005) and vascular invasion on laparoscopic ultrasonography. By size criteria, 17 of 22 failures were apparent by 6 months. Energy delivered per gram of tissue was not significantly different (P < .45). Conclusions: LRFA has a 12% local failure rate, with larger adenocarcinomas and sarcomas at greatest risk. Failures occur early in follow-up, with most occurring by 6 months. LRFA seems to be a safe and effective treatment technique for patients with primary and metastatic liver malignancies.


World Journal of Surgery | 2002

Laparoscopic radiofrequency ablation of neuroendocrine liver metastases.

Eren Berber; Nora Flesher; Allan Siperstein

We previously reported on the safety and efficacy of laparoscopic radiofrequency thermal ablation (RFA) for treating hepatic neuroendocrine metastases. The aim of this study is to report our 5-year RFA experience in the treatment of these challenging group of patients. Of the 222 patients with 803 liver primary and secondary tumors undergoing laparoscopic RFA between January 1996 and August 2001, a total of 34 patients with 234 tumors had neuroendocrine liver metastases. There were 25 men and 9 women with a mean ± SEM age of 52 ± 2 years who underwent 42 ablations. Primary tumor types included carcinoid tumor in 18 patients, medullary thyroid cancer in 7, secreting islet cell tumor in 5, and nonsecreting islet cell tumor in 4. There was no mortality, and the morbidity was 5%. The mean hospital stay was 1.1 days. Symptoms were ameliorated in 95%, with significant or complete symptom control in 80% of the patients for a mean of 10+ months (range 6–24 months). All patients were followed for a mean ± SEM of 1.6 ± 0.2 years (range 1.0–5.4 years). During this period new liver lesions developed in 28% of patients, new extrahepatic disease in 25%, and local liver recurrence in 13%; existing liver lesions progressed in 13%. Overall 41% of patients showed no progression of their cancer. Nine patients (27%) died. Mean ± SEM survivals after diagnosis of primary disease, detection of liver metastases, and performance of RFA were 5.5 ± 0.8 years, 3.0 ± 0.3 years, and 1.6 ± 0.2 years, respectively. Sixty-five percent of the patients demonstrated a partial or significant decrease in their tumor markers during follow-up. In conclusion, RFA provides excellent local tumor control with overnight hospitalization and low morbidity in the treatment of liver metastases from neuroendocrine tumors. It is a useful modality in the management of these challenging group of patients.


Annals of Surgery | 2007

Survival after radiofrequency ablation of colorectal liver metastases: 10-year experience.

Allan Siperstein; Eren Berber; Naveen Ballem; Rikesh T. Parikh

Objective:To assess factors affecting long-term survival of patients undergoing radiofrequency ablation (RFA) of colorectal hepatic metastases, with attention to evolving chemotherapy regimens. Methods:Prospective evaluation of 235 patients with colorectal metastases who were not candidates for resection and/or failed chemotherapy underwent laparoscopic RFA. Preoperative risk factors for survival and pre- and postoperative chemotherapy exposure were analyzed. Results:Two hundred and thirty-four patients underwent 292 RFA sessions from 1997 to 2006, an average of 8 months after initiation of chemotherapy. Twenty-three percent had extrahepatic disease preoperatively. Patients averaged 2.8 lesions, with a dominant diameter of 3.9 cm. Kaplan-Meier actuarial survival was 24 months, with actual 3 and 5 years survival of 20.2% and 18.4%, respectively. Median survival was improved for patients with ≤3 versus >3 lesions (27 vs. 17 months, P = 0.0018); dominant size <3 versus >3 cm (28 vs. 20 months, P = 0.07); chorioembryonic antigen <200 versus >200 ng/mL (26 vs. 16 months, P = 0.003). Presence of extrahepatic disease (P = 0.34) or type of pre/postoperative chemotherapy (5-FU-leucovorin vs. FOLFOX/FOLFIRI vs. bevacizumab) (P = 0.11) did not alter median survival. Conclusions:To our knowledge, this is both the largest and longest follow-up of RFA for colorectal metastases. The number and dominant size of metastases, and preoperative chorioembryonic antigen value are strong predictors of survival. Despite classic teaching, extrahepatic disease did not adversely affect survival. In this group of patients who failed chemotherapy, newer treatment regimens (pre- or postoperatively) had no survival benefit. The actual 5-year survival of 18.4% in these patients versus near zero survival for chemotherapy alone argues for a survival benefit of RFA.


Annals of Surgery | 1995

Clinical manifestations of primary hyperparathyroidism before and after parathyroidectomy. A case-control study.

Allen K. Chan; Quan-Yang Duh; M. H. Katz; Allan Siperstein; Orlo H. Clark

BackgroundThere has been an National Institutes of Health consensus meeting concerning the management of patients with “asymptomatic” primary hyperparathyroidism, yet there is no clear definition of this condition. The authors, therefore, documented the clinical manifestations and frequencies of these manifestations in unselected patients with primary hyperparathyroidism and determined whether these clinical manifestations resolved after parathyroidectomy. BackgroundThe authors studied 152 unselected consecutive patients with primary hyperparathyroidism and 132 control patients with nontoxic thyroid disorders who were treated by parathyroidectomy or thyroidectomy, respectively, between January 1986 and June 1991. All patients received a questionnaire during their initial office visits and the same questionnaire again after their operations. Patients were also questioned about their perception of the success of the operation. Eighty percent of the parathyroid patients and 70.5% of the thyroid patients completed the questionnaires, and the mean follow-up time was 20 months. ResultsOnly 7 (4.6%) patients with primary hyperparathyroidism had no symptoms, and 26 (17.1%) had no associated conditions despite 74.3% of these patients having serum calcium levels less than 12 mg/dL. Symptoms including fatigue, exhaustion, weakness, polydipsia, polyuria, nocturia, joint pain, bone pain, constipation, depression, anorexia, nausea, heartburn, and associated conditions, including nephrolithiasis, and hematuria occurred more often in patients with primary hyperparathyroidism than in the thyroid control patients (p < 0.05). After parathyroidectomy, only eight (5.3%) patients failed to have any improvement in symptoms or associated conditions. Fifty-seven percent of the parathyroid patients verses 30% of the thyroid patients felt better overall after the operation; strength subjectively improved in 29% of parathyroid patients versus 13% in thyroid patients; thirty-seven percent of the parathyroid patients versus 13% of the thyroid patients claimed they were less depressed.


World Journal of Surgery | 2002

Complications of neck dissection for thyroid cancer.

W. Keat Cheah; Cumhur Arici; Philip H. G. Ituarte; Allan Siperstein; Quan-Yang Duh; Orlo H. Clark

rophylactic and therapeutic neck dissections are used to control or eliminate local nodal disease in patients with thyroid cancer. The purpose of this study was to evaluate the results and complications of neck dissection. From 1992 to 1999 a series of 115 consecutive neck dissections were performed in 74 patients (32 men, 42 women; mean age 48 years) with thyroid cancer and nodal metastases. Operations included central compartment, lateral modified, and suprahyoid dissection with and without total or completion thyroidectomy. Sixty-four percent of the patients had papillary, 4% follicular, and 32% medullary thyroid cancer. Complications included transient hypocalcemia (23%) defined by a postoperative serum calcium level of <2.0 mmol/L (8.0 mg/dl), one neck hematoma (0.9%), and one cardiac death (0.9%). There were no permanent recurrent nerve palsies. Hypocalcemia occurred more frequently when neck dissection was combined with total thyroidectomy than without it (p <0.005). In this group, the incidence of hypocalcemia was higher after central, than lateral, neck dissection. When neck dissection was performed without thyroidectomy, there was no difference in the rates of hypocalcemia between central, lateral, or central with lateral neck dissection (p = NS). Hypocalcemia did not increase with repeated neck dissectionsp = NS). Permanent hypoparathyroidism occurred in 0.9%. There were no complications after suprahyoid dissection. The median duration of hospitalization was 1 day. Therapeutic neck dissection or repeated neck dissection can be performed relatively safely in patients with thyroid cancer. Hypocalcemia occurs most frequently when neck dissection is combined with total thyroidectomy.


Journal of The American College of Surgeons | 2008

Surgical Site Infection Prevention: The Importance of Operative Duration and Blood Transfusion—Results of the First American College of Surgeons–National Surgical Quality Improvement Program Best Practices Initiative

Darrell A. Campbell; William G. Henderson; Michael J. Englesbe; Bruce L. Hall; Michael O'Reilly; Dale W. Bratzler; E. Patchen Dellinger; Leigh Neumayer; Barbara L. Bass; Matthew M. Hutter; James Schwartz; Clifford Y. Ko; Kamal M.F. Itani; Steven M. Steinberg; Allan Siperstein; Robert G. Sawyer; Douglas J. Turner; Shukri F. Khuri

BACKGROUND Surgical site infections (SSI) continue to be a significant problem in surgery. The American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) Best Practices Initiative compared process and structural characteristics among 117 private sector hospitals in an effort to define best practices aimed at preventing SSI. STUDY DESIGN Using standard NSQIP methodologies, we identified 20 low outlier and 13 high outlier hospitals for SSI using data from the ACS-NSQIP in 2006. Each hospital was administered a process of care survey, and site visits were conducted to five hospitals. Comparisons between the low and high outlier hospitals were made with regard to patient characteristics, operative variables, structural variables, and processes of care. RESULT Hospitals that were high outliers for SSI had higher trainee-to-bed ratios (0.61 versus 0.25, p < 0.0001), and the operations took significantly longer (128.3+/-104.3 minutes versus 102.7+/-83.9 minutes, p < 0.001). Patients operated on at low outlier hospitals were less likely to present to the operating room anemic (4.9% versus 9.7%, p=0.007) or to receive a transfusion (5.1% versus 8.0%, p=0.03). In general, perioperative policies and practices were very similar between the low and high outlier hospitals, although low outlier hospitals were readily identified by site visitors. Overall, low outlier hospitals were smaller, efficient in the delivery of care, and experienced little operative staff turnover. CONCLUSIONS Our findings suggest that evidence-based SSI prevention practices do not easily distinguish well from poorly performing hospitals. But structural and process of care characteristics of hospitals were found to have a significant association with good results.


Annals of Surgery | 2008

Predicting the success of limited exploration for primary hyperparathyroidism using ultrasound, sestamibi, and intraoperative parathyroid hormone: analysis of 1158 cases.

Allan Siperstein; Eren Berber; German F. Barbosa; Michael Tsinberg; Andrew B. Greene; Jamie Mitchell; Mira Milas

Objective:The aim of this study was to determine the success of limited neck exploration (LE) for primary hyperparathyroidism (1° HPT). Methods:Between 1999 and 2007, 1407 patients with hyperparathyroidism underwent bilateral neck exploration (BE). Of these, 1158 patients with first-time sporadic 1° HPT were analyzed prospectively. Based on surgeon-performed ultrasound (US) and sestamibi scan (MIBI), LE was initially performed. Regardless of results, BE followed to identify the presence of additional parathyroid pathology. Results:Of 1158 patients, 242 (21%) were found to require concomitant thyroid surgery thus excluding LE. Of the remaining 916 patients, a single abnormal gland was identified on MIBI in 682 (74%), US in 731 (80%), and concordance of both in 588 (64%). Unsuspected multiglandular disease (MGD) was identified at BE in 22%, 22%, and 20% of patients, respectively. Adding intraoperative parathyroid hormone sampling (IOPTH) further reduced the rate of unsuspected MGD to 16%, 17%, and 16%. Overall, IOPTH correctly predicted MGD in only 22%. Neither concomitant nonsurgical thyroid disease nor more stringent selection criteria (preop Ca>11 mg/dL and PTH>120 pg/dL) altered success rates. In patients with MGD, a subsequent gland identified was larger than the index gland in 23%. Ninety-eight percent of BE patients were cured of 1° HPT. Conclusions:This is the largest study to evaluate the prevalence of additional parathyroid pathology in patients who are candidates for LE. Limitations in localizing studies and IOPTH fail to identify MGD in at least 16% of patients, risking future recurrence.

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Orlo H. Clark

University of California

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Quan-Yang Duh

University of California

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