The Impact of Regionalization of Pancreaticoduodenectomy for Pancreatic Cancer in North Carolina since 2004

Pancreaticoduodenectomy (PD) carries a significant risk. High-volume centers (HVCs) provide improved outcomes and regionalization is advocated. Rapid regionalization could, however, have detrimental effects. North Carolina has multiple HVCs, including an additional HVC added in late 2006. We investigated regionalization of PD and its effects before, and after, the establishment of this fourth HVC. The North Carolina Hospital Discharge Database was queried for all PDs performed during 2004 to 2006 and 2007 to 2009. Hospitals were categorized by PD volume as: low (one to nine/year), medium (10 to 19/year), and high (20/year or more). Mortality and major morbidity was assessed by comparing volume groups across time periods. Number of PDs for cancer increased 91 per cent (129 to 246 cases) at HVCs, whereas decreasing at low-volume (62 to 58 cases) and medium-volume (80 to 46 cases) centers. Percentage of PD for cancer performed at HVCs increased significantly (47.6 to 70.3%) while decreasing for low- and medium-volume centers ( P < 0.001). Mortality was significantly less at HVCs (2.8%) compared with low-volume centers (10.3%) for 2007 to 2009. Odds ratio for mortality was significantly lower at HVCs during 2004 to 2006 (0.31) and 2007 to 2009 (0.34). Mortality for PD performed for cancer decreased from 6.6 to 4.6 per cent ( P = 0.31). Major morbidity was not significantly different between groups within either time period; however, there was a significant increase in major morbidity at low-volume centers ( P = 0.018). Regionalization of PD for cancer is occurring in North Carolina. Mortality was significantly lower at HVCs, and rapid regionalization has not detracted from the superior outcomes at HVCs.

Training and practice of the next generation HPB surgeon: analysis of the 2014 AHPBA residents' and fellows' symposium survey

BACKGROUND

Hepato-pancreato-biliary (HPB) surgery is a complex subspecialty drawing from varied training pools, and the need for competency is rapidly growing. However, no board certification process or standardized training metrics in HPB surgery exist in the Americas. This study aims to assess the attitudes of current trainees and HPB surgeons regarding the state of training, surgical practice and the HPB surgical job market in the Americas.

STUDY DESIGN

A 20-question survey was distributed to members of Americas Hepato-Pancreato-Biliary Association (AHPBA) with a valid e-mail address who attended the 2014 AHPBA. Descriptive statistics were generated for both the aggregate survey responses and by training category.

RESULTS

There were 176 responses with evenly distributed training tracks; surgical oncology (44, 28%), transplant (39, 24.8%) and HPB (38, 24.2%). The remaining tracks were HPB/Complex gastrointestinal (GI) and HPB/minimally invasive surgery (MIS) (29, 16% and 7, 4%). 51.2% of respondents thought a dedicated HPB surgery fellowship would be the best way to train HPB surgeons, and 68.1% felt the optimal training period would be a 2-year clinical fellowship with research opportunities. This corresponded to the 67.5% of the practicing HPB surgeons who said they would prefer to attend an HPB fellowship for 2 years as well. Overall, most respondents indicated their ideal job description was clinical practice with the ability to engage in clinical and/or outcomes research (52.3%).

CONCLUSIONS

This survey has demonstrated that HPB surgery has many training routes and practice patterns in the Americas. It highlights the need for specialized HPB surgical training and career education. This survey shows that there are many ways to train in HPB. A 2-year HPB fellowship was felt to be the best way to train to prepare for a clinically active HPB practice with clinical and outcomes research focus.

Outcomes of surgical resection and loco-regional therapy in patients with stage 3A hepatocellular carcinoma: a retrospective review from the national cancer database

OBJECTIVES

In advanced stages, hepatocellular carcinoma (HCC) is often associated with major vascular involvement (cava, portal vein). The aim of the present study was to analyse the role of surgical resection (SR) and loco-regional therapy (LRT) in these advanced stage patients to determine if there was a survival benefit.

METHODS

The study is a retrospective analysis from the Commission on Cancer's National Cancer Data Base (NCDB) from 1998 to 2011. In total, 148,882 patients with liver cancer were identified, of which 126,984 had HCC. Of these, 64,264 patients (1998-2006) had 5-year survival data available and 8825 patients had Stage 3A disease based on AJCC classification. Of these patients, 884 had SR, 771 had LRT and 7170 patients had neither intervention. Kaplan-Meier curves and log-rank tests were used for statistical analysis.

RESULTS

Eight thousand eight hundred and twenty-five patients met analysis criteria. The mean age (years) in the SR, LRT and no intervention group were 62.5, 64.3 and 64.2, respectively. Most patients were males in all three groups (77.5%, 74.5% and 68.1%). The mean tumour size (cm) in the three groups was 9.8, 6.4 and 8.4, respectively. SR and LRT were primarily performed in major academic and comprehensive cancer programmes compared with community cancer programmes and other centres (SR: 93% versus 7%; LRT: 94.6% versus 5.4%). The median 5-year survival (months) was 26.6 in SR, 16.5 in LRT and 4.8 in the no intervention group (P < 0.0001).

CONCLUSION

A SR and LRT offer a survival benefit in select patients diagnosed with Stage 3A HCC.

Optimal Ablation Volumes Are Achieved at Submaximal Power Settings in a 2.45-GHz Microwave Ablation System

Introduction. Local ablative therapies, including microwave ablation (MWA), are common treatment modalities for in situ tumor destruction. Currently, 2.45-GHz ablation systems are gaining prominence because of the shorter application times required. The aims of this study were to determine optimal power and time to ablation volume (AbV) ratios for a new 1.8-mm–2.45-GHz antenna using ex vivo tissue models. Methods. The 1.8-mm–2.45-GHz Accu2i MWA system was employed to perform ablations in bovine liver, porcine muscle, and porcine kidney ex vivo. Whole tissues were prewarmed (35°C) and multiple ablations performed at power settings of 60 to 180 W for 2- to 6-minute time intervals. Postablation, tissues were dissected, AbVs calculated, and correlations to power and time settings made. Results. Significant increases in AbV were measured between each of the time points for a constant power setting in all 3 tissues. Increasing power settings led to significant increases in AbV at power settings ≤140 W. However, no significant increase in AbV was obtained at power settings >140 W. Conclusions. Optimal efficiency for MWA using a new 1.8-mm–2.45-GHz system is achieved at settings of ≤140 W for 6 minutes in a range of ex vivo tissue and no additional benefit occurs by increasing the power setting to 180 W in these tissues.

Laparoscopic microwave ablation of human liver tumours using a novel three-dimensional magnetic guidance system

BACKGROUND

Accurate antenna placement is essential for effective microwave ablation (MWA) of lesions. Laparoscopic targeting is made particularly challenging in liver tumours by the needle's trajectory as it passes through the abdominal wall into the liver. Previous optical three-dimensional guidance systems employing infrared technology have been limited by interference with the line of sight during procedures.

OBJECTIVE

The aim of this study was to evaluate a newly developed magnetic guidance system for laparoscopic MWA of liver tumours in a pilot study.

METHODS

Thirteen patients undergoing laparoscopic MWA of liver tumours gave consent to their participation in the study and were enrolled. Lesion targeting was performed using the InnerOptic AIM™ 3-D guidance system to track the real-time position and orientation of the antenna and ultrasound probe.

RESULTS

A total of 45 ablations were performed on 34 lesions. The median number of lesions per patient was two. The mean ± standard deviation lesion diameter was 18.0 ± 9.2 mm and the mean time to target acquisition was 3.5 min. The first-attempt success rate was 93%. There were no intraoperative or immediate postoperative complications. Over an average follow-up of 7.8 months, one patient was noted to have had an incomplete ablation, seven suffered regional recurrences, and five patients remained disease-free.

CONCLUSIONS

The AIM™ guidance system is an effective adjunct for laparoscopic ablation. It facilitates a high degree of accuracy and a good first-attempt success rate, and avoids the line of site interference associated with infrared systems.

Survival analysis of patients with stage I and II hepatocellular carcinoma after a liver transplantation or liver resection

INTRODUCTION

Liver transplantation (LT) is a treatment option in select patients with hepatocellular carcinoma (HCC). The aim of the present study was to compare survival in Stage I or II HCC patients undergoing either liver transplant (LT) or a liver resection (LR).

METHOD

The study is a retrospective analysis of the National Cancer Data Base (1998-2011). In total, 148,882 patients with liver cancer were identified, of which 5-year survival data (1998-2006) were available for 64,227 patients. Patients were stratified by the American Joint Committee on Cancer (AJCC) clinical stage I and II. Kaplan-Meier curves and log-rank tests were used for statistical analysis.

RESULTS

3340 HCC patients met analysis criteria. Among stage I HCC, 860 had LT and 871 had LR. Among stage II HCC, 833 had LT and 776 LR. In stage I patients the median survival for LT and LR were 127.9 and 56.7 months, respectively, (P < 0.0001) and in stage II patients the median survival was 110.8 and 42.8 months (P < 0.0001). Unlike LT patients, LR patients with Stage I HCC had a longer median survival compared with Stage II patients (P = 0.0002).

CONCLUSION

Liver transplantation offers a survival advantage compared with a liver resection among patients with Stage I and II HCC. LT is the best surgical treatment for early stage (I/II) HCC in patients with advanced fibrosis or cirrhosis, whereas LR provides equivalent outcomes to LT in patients without advanced fibrosis and should be considered as the first surgical option.

The impact of regionalization of pancreaticoduodenectomy for pancreatic Cancer in North Carolina since 2004

Pancreaticoduodenectomy (PD) carries a significant risk. High-volume centers (HVCs) provide improved outcomes and regionalization is advocated. Rapid regionalization could, however, have detrimental effects. North Carolina has multiple HVCs, including an additional HVC added in late 2006. We investigated regionalization of PD and its effects before, and after, the establishment of this fourth HVC. The North Carolina Hospital Discharge Database was queried for all PDs performed during 2004 to 2006 and 2007 to 2009. Hospitals were categorized by PD volume as: low (one to nine/year), medium (10 to 19/year), and high (20/year or more). Mortality and major morbidity was assessed by comparing volume groups across time periods. Number of PDs for cancer increased 91 per cent (129 to 246 cases) at HVCs, whereas decreasing at low-volume (62 to 58 cases) and medium-volume (80 to 46 cases) centers. Percentage of PD for cancer performed at HVCs increased significantly (47.6 to 70.3%) while decreasing for low- and medium-volume centers (P < 0.001). Mortality was significantly less at HVCs (2.8%) compared with low-volume centers (10.3%) for 2007 to 2009. Odds ratio for mortality was significantly lower at HVCs during 2004 to 2006 (0.31) and 2007 to 2009 (0.34). Mortality for PD performed for cancer decreased from 6.6 to 4.6 per cent (P = 0.31). Major morbidity was not significantly different between groups within either time period; however, there was a significant increase in major morbidity at low-volume centers (P = 0.018). Regionalization of PD for cancer is occurring in North Carolina. Mortality was significantly lower at HVCs, and rapid regionalization has not detracted from the superior outcomes at HVCs.

Changes in subcellular distribution of the ammonia transporter, Rhcg, in response to chronic metabolic acidosis

The primary mechanism by which the kidneys mediate net acid excretion is through ammonia metabolism. In the current study, we examined whether chronic metabolic acidosis, which increases ammonia metabolism, alters the cell-specific and/or the subcellular expression of the ammonia transporter family member, Rhcg, in the outer medullary collecting duct in the inner stripe (OMCDi). Chronic metabolic acidosis was induced in normal SD rats by HCl ingestion for 7 days; controls were pair-fed. The subcellular distribution of Rhcg was determined using immunogold electron microscopy and morphometric analyses. In intercalated cells, acidosis increased total Rhcg, apical plasma membrane Rhcg, and the proportion of total cellular Rhcg in the apical plasma membrane. Intracellular Rhcg decreased significantly, and basolateral Rhcg was unchanged. Because apical plasma membrane length increased in parallel with apical Rhcg immunolabel, apical plasma membrane Rhcg density was unchanged. In principal cells, acidosis increased total Rhcg, apical plasma membrane Rhcg, and the proportion of total cellular Rhcg in the apical plasma membrane while decreasing the intracellular proportion. In contrast to the intercalated cell, chronic metabolic acidosis did not significantly alter apical boundary length; accordingly, apical plasma membrane Rhcg density increased. In addition, basolateral Rhcg immunolabel increased in response to chronic metabolic acidosis. These results indicate that in the rat OMCDi 1) chronic metabolic acidosis increases apical plasma membrane Rhcg in both the intercalated cell and principal cell where it may contribute to enhanced apical ammonia secretion; 2) increased apical plasma membrane Rhcg results from both increased total protein and changes in the subcellular distribution of Rhcg; 3) the mechanism of Rhcg subcellular redistribution differs in intercalated and principal cells; and 4) Rhcg may contribute to regulated basolateral ammonia transport in the principal cell.

Renal expression of the ammonia transporters, Rhbg and Rhcg, in response to chronic metabolic acidosis

Chronic metabolic acidosis induces dramatic increases in net acid excretion that are predominantly due to increases in urinary ammonia excretion. The current study examines whether this increase is associated with changes in the expression of the renal ammonia transporter family members, Rh B glycoprotein (Rhbg) and Rh C glycoprotein (Rhcg). Chronic metabolic acidosis was induced in Sprague-Dawley rats by HCl ingestion for 1 wk; control animals were pair-fed. After 1 wk, metabolic acidosis had developed, and urinary ammonia excretion increased significantly. Rhcg protein expression was increased in both the outer medulla and the base of the inner medulla. Intercalated cells in the outer medullary collecting duct (OMCD) and in the inner medullary collecting duct (IMCD) in acid-loaded animals protruded into the tubule lumen and had a sharp, discrete band of apical Rhcg immunoreactivity, compared with a flatter cell profile and a broad band of apical immunolabel in control kidneys. In addition, basolateral Rhcg immunoreactivity was observed in both control and acidotic kidneys. Cortical Rhcg protein expression and immunoreactivity were not detectably altered. Rhcg mRNA expression was not significantly altered in the cortex, outer medulla, or inner medulla by chronic metabolic acidosis. Rhbg protein and mRNA expression were unchanged in the cortex, outer and inner medulla, and no changes in Rhbg immunolabel were evident in these regions. We conclude that chronic metabolic acidosis increases Rhcg protein expression in intercalated cells in the OMCD and in the IMCD, where it is likely to mediate an important role in the increased urinary ammonia excretion.