One hundred thirty resections for pancreatic neuroendocrine tumor: evaluating the impact of minimally invasive and parenchyma-sparing techniques

Surgical treatment of sporadic pancreatic neuroendocrine tumors: a state of the art review

Pancreatic neuroendocrine tumors (PNETs) are rare neoplasms. They are clinically diverse and divided into functioning and nonfunctioning disease, depending on their ability to produce symptoms due to hormone production. Surgical resection is the only curative treatment and remains the cornerstone therapy for this patient group, even in patients with advanced disease. Over the last decade there has been a noticeable trend towards more aggressive surgery as well as more minimally invasive surgery in patients with PNETs. This has resulted in improved long-term survival in patients with locally advanced and metastatic disease treated aggressively, as well as shorter hospital stays and comparable long-term outcomes in patients with limited disease treated minimally invasively. There are still controversies related to issues of surgical treatment of PNETs, such as to what extent enucleation, lymph node sampling, and vascular reconstruction are beneficial for the oncologic outcome. Histopathologic tumor classification is of high clinical importance for treatment planning and prognostic evaluation of patients with PNETs. A constant challenge, which relates to the treatment of PNETs, is the lack of an internationally accepted histopathological classification system. This paper reviews current issues on the surgical treatment of sporadic PNETs with specific focus on surgical approaches and tumor classification.

Parenchyma-sparing resections for pancreatic neuroendocrine tumors

BACKGROUND

Parenchyma-sparing pancreatectomy (PSP), including enucleation and central pancreatectomy, has been investigated as an alternative to standard resection for pancreatic endocrine neoplasm, but the benefit/risk of these procedures remains little known.

METHODS

From 1998 to 2010, among 197 patients operated for well-differentiated pancreatic neuroendocrine tumors, 67 underwent PSP (45 enucleations and 22 central pancreatectomies) and 66 standard resections (35 pancreaticoduodenectomies and 31 distal pancreatectomies) for a tumor below 4 cm, without synchronous distant metastasis. Groups were compared regarding postoperative morbidity, mortality, long-term pancreatic function, and survival calculated using the Kaplan-Meier method.

RESULTS

Tumors operated by PSP had a median size of 15 mm, were mainly incidentally diagnosed (n = 46, 69 %), and nonfunctioning (n = 55, 82 %). Overall morbidity rate was higher after PSP than standard resection (SR) (76 vs 58 %, p = 0.0028), including more frequent pancreatic fistulas (69 vs 42 %, p = 0.003). Postoperative diabetes was less frequent following PSP than pancreaticoduodenectomy (5 vs 21 %; p = 0.022) but equivalent to the one observed after distal pancreatectomy (4 %, p = 1). Exocrine insufficiency was significantly less frequent after PSP than SR (3 vs 32 %; p < 0.0001). The overall and recurrence-free 5-year survival after PSP for nonfunctioning tumors was 96 and 98 %, respectively.

CONCLUSION

In selected patients, with small and low-grade tumors, PSP are associated with excellent overall and recurrence-free survivals. These procedures are associated with an increased postoperative morbidity but an excellent postoperative pancreatic function. Therefore, they should be considered as a valid therapeutic option in selected well-differentiated pancreatic neuroendocrine tumors.

Laparoscopic pancreatectomy for malignancy

Utilization of laparoscopic techniques for resection of the pancreas has slowly gained acceptance in specific situations and is now being applied to more challenging endeavors, such as pancreaticoduodenectomy for cancer. This review provides a summary of laparoscopic applications for pancreatic malignancy, with specific attention to the most common methods of pancreatic resection and their respective oncologic outcomes, including margin status, lymph node retrieval, and survival.

Lymph nodes and survival in pancreatic neuroendocrine tumors

HYPOTHESIS

Lymph node metastases decrease survival in patients with pancreatic neuroendocrine tumors (pNETs).

DESIGN

Prospective database searches.

SETTING

National Institutes of Health (NIH) and Stanford University Hospital (SUH).

PATIENTS

A total of 326 patients underwent surgical exploration for pNETs at the NIH (n = 216) and SUH (n = 110).

MAIN OUTCOME MEASURES

Overall survival, disease-related survival, and time to development of liver metastases.

RESULTS

Forty patients (12.3%) underwent enucleation and 305 (93.6%) underwent resection. Of the patients who underwent resection, 117 (35.9%) had partial pancreatectomy and 30 (9.2%) had a Whipple procedure. Forty-one patients also had liver resections, 21 had wedge resections, and 20 had lobectomies. Mean follow-up was 8.1 years (range, 0.3-28.6 years). The 10-year overall survival for patients with no metastases or lymph node metastases only was similar at 80%. As expected, patients with liver metastases had a significantly decreased 10-year survival of 30% (P < .001). The time to development of liver metastases was significantly reduced for patients with lymph node metastases alone compared with those with none (P < .001). For the NIH cohort with longer follow-up, disease-related survival was significantly different for those patients with no metastases, lymph node metastases alone, and liver metastases (P < .001). Extent of lymph node involvement in this subgroup showed that disease-related survival decreased as a function of the number of lymph nodes involved (P = .004).

CONCLUSIONS

As expected, liver metastases decrease survival of patients with pNETs. Patients with lymph node metastases alone have a shorter time to the development of liver metastases that is dependent on the number of lymph nodes involved. With sufficient long-term follow-up, lymph node metastases decrease disease-related survival. Careful evaluation of number and extent of lymph node involvement is warranted in all surgical procedures for pNETs.

Rate of clinically significant postoperative pancreatic fistula in pancreatic neuroendocrine tumors

BACKGROUND

In 2005, the International Study Group of Pancreatic Fistula (ISGPF) developed a definition and grading system for postoperative pancreatic fistula (POPF). The authors sought to determine the rate of POPF after enucleation and/or resection of pancreatic neuroendocrine tumors (PNET) and to identify clinical, surgical, or pathologic factors associated with POPF.

METHODS

A retrospective analysis of pancreatic enucleations and resections performed from March 1998 to April 2010. We defined a clinically significant POPF as a grade B that required nonoperative intervention and grade C.

RESULTS

One hundred twenty-two patients were identified; 62 patients had enucleations and 60 patients had resections of PNET. The rate of clinically significant POPF was 23.7 % (29/122). For pancreatic enucleation, the POPF rate was 27.4 % (17/62, 14 grade B, 3 grade C). The pancreatic resection group had a POPF rate of 20 % (12/60, 10 grade B, 2 grade C). This difference was not significant (p = 0.4). In univariate analyses, patients in the enucleation group with hereditary syndromes (p = 0.02) and non-insulinoma tumors (p = 0.02) had a higher POPF rate. Patients in the resection group with body mass index (BMI) > 25 (p < 0.01), multiple endocrine neoplasia type 1 (MEN-1; p < 0.01) and those who underwent simultaneous multiple procedures (p = 0.02) had a higher POPF rate. Multivariate analyses revealed that hereditary syndromes were able to predict POPF in the enucleation group, while having BMI > 25 and increasing lesion size were also associated with POPF in the group undergoing resection.

CONCLUSIONS

We found a clinically significant POPF rate after surgery in PNET to be 23.7 % with no difference by the type of operation. Our POPF rate is comparable to that reported in the literature for pancreatic resection for other types of tumors. Certain inherited genetic diseases-von Hippel-Lindau disease (VHL) and MEN-1-were associated with higher POPF rates.

Neuroendocrine tumors of the pancreas

PURPOSE OF REVIEW

Pancreatic neuroendocrine tumors (PNETs) are rare tumors, with an incidence of one per 100, 000 individuals per year, and they account for 1-2% of all pancreatic neoplasms. PNETs are a heterogeneous group with varying clinical presentation, tumor biology and prognosis. This article reviews the current diagnostic strategy and treatment armamentarium for PNETs. Special attention is paid to recent and ongoing developments in treatment, particularly with regards to multimodality treatment and newer systemic therapies for unresectable disease.

RECENT FINDINGS

There has been significant progress in the genetic understanding of hereditary syndromes in regards to PNETs, as well as in the diagnosis and treatment of resectable and nonresectable PNETs. Whereas surgical therapy remains the most advisable therapy for resectable neuroendocrine tumors of the pancreas, there have been significant recent advances in systemic therapy for those with unresectable disease. Results from recent clinical trials examining mammalian target of rapamycin inhibitors and tyrosine kinase inhibitors for unresectable disease are promising in expanding treatment options for metastatic PNETs.

SUMMARY

Neuroendocrine tumors of the pancreas are a heterogeneous group of tumors with varying clinical presentation, tumor biology and prognosis. Clinicians must be aware of the variety of manifestations of this disease, as well as the role of systemic chemotherapy in treatment of unresectable disease.