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Dive into the research topics where Nicholas G. Berger is active.

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Featured researches published by Nicholas G. Berger.


Surgery | 2017

Overall survival after resection of retroperitoneal sarcoma at academic cancer centers versus community cancer centers: An analysis of the National Cancer Data Base

Nicholas G. Berger; Jack P. Silva; Harveshp Mogal; Callisia N. Clarke; M. Bedi; John A. Charlson; Kathleen K. Christians; Susan Tsai; T. Clark Gamblin

Background Operative resection remains the definitive curative therapy for retroperitoneal sarcoma. Data published recently show a correlation between improved outcomes for complex oncologic operations and treatment at academic centers. For large retroperitoneal sarcomas, operative resection can be complex and require multidisciplinary care. We hypothesized that survival rates vary between type of treating center for patients undergoing resection for retroperitoneal sarcoma. Methods Patients with stage I to III nonmetastatic retroperitoneal sarcomas who underwent operative resection were identified from the National Cancer Database during the years 2004–2013. Treating centers were categorized as academic cancer centers or community cancer centers. Overall survival was analyzed by log‐rank test and graphed using Kaplan‐Meier method. Results A total of 2,762 patients were identified. A majority of patients (59.4%, n = 1,642) underwent resection at an academic cancer centers. Median age at diagnosis was 63 years old. Neoadjuvant radiotherapy was more common at academic cancer centers, while adjuvant radiotherapy was more common at community cancer centers. Improved overall survival was seen at academic cancer centers across all stages compared with community cancer centers (P = .014) but, after multivariable Cox regression analysis, was not a significant independent predictor of survival (hazard ratio = 0.91, 95% confidence interval, 0.79–1.04, P = .171). Academic cancer centers exhibited a greater rate of R0 resection (55.9% vs 47.0%, P < .001) and a lesser odds of positive margins (odds ratio 0.83, 95% confidence interval, 0.69–0.99, P = .044) after multivariable logistic regression. Conclusion Resection for retroperitoneal sarcoma performed at academic cancer centers was an independent predictor of margin‐negative resection but was not a statistically significant factor for survival. This observation suggests that site of care may contribute to some aspect of improved oncologic resection for retroperitoneal sarcoma.


Clinics in Colon and Rectal Surgery | 2016

Low Anterior Resection Syndrome: Current Management and Future Directions

Timothy J. Ridolfi; Nicholas G. Berger; Kirk A. Ludwig

Outcomes for rectal cancer surgery have improved significantly over the past 20 years with increasing rates of survival and recurrence, specifically local recurrence. These gains have been realized during a period of time in which there has been an increasing emphasis on sphincter preservation. As we have become increasingly aggressive in avoiding resection of the anus, we have begun accepting bowel dysfunction as a normal outcome. Low anterior resection syndrome, defined as a constellation of symptoms including incontinence, frequency, urgency, or feelings of incomplete emptying, has a significant impact on quality of life and results in many patients opting for a permanent colostomy to avoid these symptoms. In this article, we will highlight the most recent clinical and basic science research on this topic and discuss areas of future investigation.


Clinical and Experimental Gastroenterology | 2015

Delayed gastrointestinal recovery after abdominal operation – role of alvimopan

Nicholas G. Berger; Timothy J. Ridolfi; Kirk A. Ludwig

Postoperative Ileus (POI), which occurs after surgical manipulation of the bowel during abdominal operations, is associated with prolonged hospital stay, increasing medical costs, and delayed advancement of enteral diet, which contributes to a significant economic burden on the healthcare system. The use of accelerated care pathways has shown to positively impact gut function, but inevitable postoperative opioid use contributes to POI. Alvimopan is a peripherally acting μ-opioid receptor antagonist designed to mitigate antimotility effects of opioids. In our review, we examined ten trials on alvimopan’s use after abdominal operations. Several of the earlier studies on patients undergoing bowel resection showed correlations between the study group and GI recovery as defined by passage of flatus, first bowel movement, and time to readiness for discharge. Data in patients undergoing total abdominal hysterectomy showed similarly decreased GI recovery time. Additionally, data within the past few years shows alvimopan is associated with more rapid GI recovery time in patients undergoing radical cystectomy. Based on our review, use of alvimopan remains a safe and potentially cost-effective means of reducing POI in patients following open GI surgery, radical cystectomy, and total abdominal hysterectomy, and should be employed following these abdominal operations.


Journal of Surgical Oncology | 2017

The prognostic utility of baseline alpha‐fetoprotein for hepatocellular carcinoma patients

Jack P. Silva; Richard A. Gorman; Nicholas G. Berger; Susan Tsai; Kathleen K. Christians; Callisia N. Clarke; Harveshp Mogal; T. Clark Gamblin

Alpha‐fetoprotein (AFP) has a valuable role in postoperative surveillance for hepatocellular carcinoma (HCC) recurrence. The utility of pretreatment or baseline AFP remains controversial. The present study hypothesized that elevated baseline AFP levels are associated with worse overall survival in HCC patients.


Diseases of The Colon & Rectum | 2017

Loop Ileostomy Closure as an Overnight Procedure: Institutional Comparison With the National Surgical Quality Improvement Project Data Set

Nicholas G. Berger; Raymond Chou; Elliot S. Toy; Kirk A. Ludwig; Timothy J. Ridolfi; Carrie Y. Peterson

BACKGROUND: Enhanced recovery pathways have decreased length of stay after colorectal surgery. Loop ileostomy closure remains a challenge, because patients experience high readmission rates, and validation of enhanced recovery pathways has not been demonstrated. This study examined a protocol whereby patients were discharged on the first postoperative day and instructed to advance their diet at home with close telephone follow-up. OBJECTIVE: The hypothesis was that patients can be safely discharged the day after loop closure, leading to shorter length of stay without increased rates of readmission or complications. DESIGN: Patients undergoing loop ileostomy closure were queried from the American College of Surgeons National Surgical Quality Improvement Project and compared with a single institution (2012–2015). Length of stay, 30-day readmission, and 30-day morbidity data were analyzed. SETTINGS: The study was conducted at a tertiary university department. PATIENTS: The study includes 1602 patients: 1517 from the National Surgical Quality Improvement Project database and 85 from a single institution. MAIN OUTCOME MEASURES: Length of stay and readmission rates were measured. RESULTS: Median length of stay was less at the single institution compared with control (2 vs 4 d; p < 0.001). Thirty-day readmission (15.3% vs 10.4%; p = 0.15) and overall 30-day complications (15.3% vs 16.7%; p = 0.73) were similar between cohorts. Estimated adjusted length of stay was less in the single institution (2.93 vs 5.58 d; p < 0.0001). There was no difference in the odds of readmission (p = 0.22). LIMITATIONS: The main limitations of this study include its retrospective nature and limitations of the National Surgical Quality Improvement Program database. CONCLUSIONS: Next-day discharge with protocoled diet advancement and telephone follow-up is acceptable after loop ileostomy closure. Patients can benefit from decreased length of stay without an increase in readmission or complications. This has the potential to change the practice of postoperative management of loop ileostomy closure, as well as to decrease cost. See Video Abstract at http://links.lww.com/DCR/A310.


Urologic Oncology-seminars and Original Investigations | 2018

Improved surgical outcomes following radical cystectomy at high-volume centers influence overall survival

Kyle Scarberry; Nicholas G. Berger; Kelly Scarberry; Shree Agrawal; John J. Francis; Jessica M. Yih; Christopher M. Gonzalez; Robert Abouassaly

OBJECTIVES Positive surgical margins (PSM) and lymph node yield (LNY) following radical cystectomy (RC) for urothelial carcinoma of the bladder affect survival. Variations in PSM or LNY at different care facilities are poorly described. We evaluated the relationship between hospital surgical volume and academic hospital status with these surgical outcomes and overall survival (OS). METHODS AND MATERIALS Patients with nonmetastatic urothelial carcinoma of the bladder who underwent RC were identified from the National Cancer Database (2004-2013). Treatment centers were categorized as academic (ACC) and community cancer centers (CCC). Logistic regression was used to identify factors associated with PSM status and LNY, and a multivariate Cox proportional hazards model was used to determine factors associated with OS. RESULTS In our cohort, 39,274 patients underwent RC. A lower proportion of PSMs (10% vs.12%; P<0.001) and higher median LNY (14 vs. 8, P<0.001) was observed at ACCs compared to CCCs. On logistic regression, there were lower odds of PSM (OR = 0.89, 95% CI: 0.81-0.97) and higher odds of LNY ≥ 10 nodes (OR = 1.84, 95% CI: 1.74-1.96) among patients at ACCs compared to CCCs. Cox proportional hazards analysis demonstrated benefit to OS at high-volume centers (HR = 0.91, 95% CI: 0.87-0.95) but not based on ACC designation. The OS advantage at high-volume centers is attenuated (HR = 0.95, 95% CI: 0.91-0.99) by PSM status and LNY. CONCLUSIONS ACCs demonstrate improved surgical outcomes following RC, and a survival advantage attributable to high surgical volume is identified. Centralization of care may lead to improved outcomes in this lethal malignancy.


Journal of Surgical Oncology | 2017

External radiation or ablation for solitary hepatocellular carcinoma: A survival analysis of the SEER database

Nicholas G. Berger; Michael N. Tanious; Abdulrahman Y. Hammad; John T. Miura; Harveshp Mogal; Callisia N. Clarke; Kathleen K. Christians; Susan Tsai; T. Clark Gamblin

Hepatocellular carcinoma (HCC) patients are often not candidates for resection. This study hypothesized that external beam radiation (XRT) could be equally effective compared to ablation therapy (AT) for selected HCC patients.


Surgery | 2018

The effect of prior upper abdominal surgery on outcomes after liver transplantation for hepatocellular carcinoma: An analysis of the database of the organ procurement transplant network

Jack P. Silva; Nicholas G. Berger; Ziyan Yin; Ying Liu; Susan Tsai; Kathleen K. Christians; Callisia N. Clarke; Harveshp Mogal; T. Clark Gamblin

Objectives: Orthotopic liver transplantation (OLT) is the preferred treatment for hepatocellular carcinoma (HCC) in select patients. Many patients listed for OLT have a history of prior upper abdominal surgery (UAS). Repeat abdominal surgery increases operative complexity and may cause a greater incidence of complication. This study sought to compare outcomes after liver transplantation for patients with and without prior UAS. Methods: Adult HCC patients undergoing OLT were identified using the database from the Organ Procurement and Transplantation Network (1987–2015). Patients were separated by presence of prior UAS into 2 propensity‐matched cohorts. Overall survival (OS) and graft survival (GS) were analyzed by log‐rank test and graphed using Kaplan‐Meier method. Recipient and donor demographic and clinical characteristics were also studied using Cox regression models. Results: A total of 15,043 patients were identified, of whom 6,205 had prior UAS (41.2%). After 1:1 propensity score matching, cohorts (UAS versus no UAS) contained 4,669 patients. UAS patients experienced shorter GS (122 months vs 129 months; P < .001) and shorter OS (130 months vs 141 months; P < .001). Median duration of stay for both cohorts was 8 days. Multivariate Cox regression models revealed that prior UAS was associated with an increased hazard ratio (HR) for GS (HR 1.14; 95% confidence interval (CI) 1.06–1.22; P < .001) and OS (HR 1.14; 95% CI 1.06–1.23; P < .001). Conclusion: Prior UAS is an independent negative predictor of GS and OS after OLT for HCC. OLT performed in patients with UAS remains a well‐tolerated and effective treatment for select HCC patients but may alter expected outcomes and influence follow‐up protocols.


Archive | 2018

Is There Still a Role for Hand-Assisted Laparoscopic Surgery (HALS)?

Nicholas G. Berger; Timothy J. Ridolfi; Kirk A. Ludwig

Laparoscopy has been widely adopted for a variety of abdominal operations, and laparoscopic colorectal surgery has been shown to be oncologically equivalent and superior in terms of perioperative pain, length of stay, and decreased complications compared to traditional open surgery. However, laparoscopic colon surgery is fraught with a steep learning curve, longer operative times, and high conversion rates compared to traditional open surgery. Hand-assisted laparoscopic surgery (HALS) is an alternative to laparoscopic colon surgery which has been shown in several randomized controlled trials to have similar perioperative outcomes with decreased operative times and lower conversion rates. While some consider HALS an intermediate option for those developing the skills or volume in laparoscopic colorectal surgery, this chapter discusses how HALS colorectal surgery can be utilized as an effective first option with advantages over open surgery and similar short-term benefits seen with straight laparoscopic colorectal surgery. This is especially the case in the context of complicated operations, extended resections, and operations conducted in overweight or obese patients. The authors firmly believe that the HALS approach is a valuable technique for the minimally invasive colorectal surgeon.


Journal of Surgical Oncology | 2018

Gallbladder carcinoma: An analysis of the national cancer data base to examine hispanic influence

Chrissy Liu; Nicholas G. Berger; Lisa Rein; Sergey Tarima; Callisia N. Clarke; Harveshp Mogal; Kathleen K. Christians; Susan Tsai; T. Clark Gamblin

Gallbladder cancer (GBC) is a lethal disease with high incidence among Hispanics. Overall survival (OS) among races/ethnicities has not been described using the most recent National Cancer Database. This study hypothesized that prognosis is worse for Hispanics compared to similar non‐Hispanic populations.

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T. Clark Gamblin

Medical College of Wisconsin

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Susan Tsai

Medical College of Wisconsin

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Callisia N. Clarke

Medical College of Wisconsin

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Harveshp Mogal

Medical College of Wisconsin

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Jack P. Silva

Medical College of Wisconsin

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Kirk A. Ludwig

Medical College of Wisconsin

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Timothy J. Ridolfi

Medical College of Wisconsin

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Fabian M. Johnston

Medical College of Wisconsin

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