The landscape of treatment options in neuroendocrine tumors (NET) has changed in the last 5 years. Novel targeted drugs have been introduced and approved for distinct types of NET. Furthermore, with the first randomized trial on 177Lu-DOTATATE peptide receptor radionuclide therapy (PRRT) in midgut NET, not only is approval of this treatment awaited but also its more widespread use. Techniques and choices of radionuclides have changed over time as well as imaging tools. Recognition of well-differentiated NET G3 within the group of neuroendocrine neoplasms G3 has widened the spectrum of chemotherapeutic drugs used in this field. Even more so, it has become important to provide recommendations for daily clinical practice on how to safely use novel drugs, chemotherapeutic agents, and PRRT. The updated ENETS consensus guidelines for the standards of care in NET provide a tool to accurately assess the diagnosis of NET as well as practical recommendations for the use of surgery, and the different systemic therapeutic options that are available for the management of NET.

In 2009, the first consensus guidelines for the standards of care in neuroendocrine tumors (NET) have been published by the European Neuroendocrine Tumor Society (ENETS) based on a consensus conference held in Palma de Mallorca, Spain in November 2007, with leading experts in the field [1]. Since then, the landscape of treatment options has changed. Novel targeted drugs, such as the mTOR inhibitor everolimus and the multiple tyrosine kinase inhibitor sunitinib, have been introduced in the treatment of NET and approved for distinct types of NET. Furthermore, with the first randomized trial on 177Lu-DOTATATE peptide receptor radionuclide therapy (PRRT) in midgut NET, not only is approval of this treatment awaited but also its more widespread use. Techniques and choices of radionuclides have changed over time as well as imaging tools. In the same period, the recognition of well-differentiated NET G3 within the group of neuroendocrine neoplasms G3 has widened the spectrum of chemotherapeutic drugs used in this field. Even more so, it has become important to provide recommendations for daily clinical practice on how to safely use novel drugs, chemotherapeutic agents, and PRRT.

While recently updated and published consensus guidelines for the management of digestive NET [2] provide guidance for appropriate therapy selection, standards of care needed to be addressed for recently introduced novel therapies and updated for established standard therapies. The same group of experts who developed the recent ENETS consensus guidelines update for the management of patients with digestive NET convened at a consensus meeting held in Antibes on November 5-6 in 2015 to update technical and practical details necessary for implementing consensus guidelines.

The consensus sessions covered the following topics:

• pathology - diagnosis and prognostic stratification

• biochemical markers

• radiological, nuclear medicine and hybrid imaging

• surgery for small intestinal and pancreatic NET

• pre- and perioperative therapy

• systemic therapy: biotherapy, novel targeted agents, chemotherapy

• PRRT with radiolabeled somatostatin analogues

• follow-up and documentation in patients with NET

Fifty-five experts active in the field of NET from 22 countries attended the Antibes consensus conference. Attendees were members of the ENETS advisory board including adjunct members and recognized US physicians with high-level expertise in the field. The attendees represented all medical specialtiesinvolved in managing patients with gastroenteropancreatic NET. They were assigned to different working groups according to the topics outlined above. The complete list of participants is provided at the end of each of the following papers.

Eight working groups and their group leaders were determined before the conference. The group leaders prepared a first draft on standards of care in their field reviewing and integrating all relevant literature published beyond 2009. The draft manuscript was sent to all group members before the consensus conference and served as a structure for the discussion. On the first day of the meeting after a short introduction and presentation of the topic in a plenary session, each working group gathered separately to discuss group-specific questions. The group leaders presented the management to their breakout group members and the management was discussed in detail. On-site comments were collected continuously throughout the conference. Each working group gathered separately to discuss group-specific questions. The results of each working group were presented on the second day of the meeting to the general assembly where all participants attended. Consensus statements were discussed and approved or rejected by all participants gathered in the general assembly. This procedure was followed for all 8 sessions.

After the conference, the group leaders revised their manuscripts including all consensus statements and adding additional information where requested before sending the revised manuscripts to all participants of their breakout sessions for review. The Organizing Committee defined the rules to establish the design of each paper, the tasks for authors, and the general authorship policy. The papers were designed to update and amend the previously published ENETS standards of care guidelines, incorporating all novel information and approved consensus statements.

The following 9 papers [3,4,5,6,7,8,9,10,11] are the result of an Advisory Board Consensus Conference meeting. These ENETS guidelines for the standards of care in NET provide a tool to accurately assess the diagnosis of NET and provide practical recommendations for the use of surgery, and the different systemic therapeutic options that are available for the management of NET. A great effort was made by all participants devoting their time, experience and enthusiasm to building the standards of care consensus guidelines. We expect that this practical information will provide useful and important information for health care providers and will support the endeavor to provide high-quality care for NET patients. We thank all participants for their efforts, contributions, and great dedication to construct these guidelines.

The consensus conference held in Antibes, France in 2015 was supported by the European Neuroendocrine Tumor Society (ENETS).

1.
Plöckinger U, Wiedenmann B, de Herder W: ENETS consensus guidelines for the standard of care in neuroendocrine tumors. Neuroendocrinology 2009;90:159-161.
2.
O'Toole D, Kianmanesh R, Caplin M: ENETS 2016 consensus guidelines for the management of patients with digestive neuroendocrine tumors: an update. Neuroendocrinology 2016;103:117-118.
3.
Perren A, Couvelard A, Scoazec J-Y, Costa F, Borbath I, Delle Fave G, Gorbounova V, Gross D, Grossman A, Jensen RT, Kulke M, Oberg K, Rindi G, Sorbye H, Welin S, all other Antibes Consensus Conference participants: ENETS consensus guidelines for the standards of care in neuroendocrine tumors: pathology - diagnosis and prognostic stratification. Neuroendocrinology 2017;105:196-200.
4.
Sundin A, Arnold R, Baudin E, Cwikla JB, Eriksson B, Fanti S, Fazio N, Giammarile F, Hicks RJ, Kjaer A, Krenning E, Kwekkeboom D, Lombard-Bohas C, O'Connor JM, O'Toole D, Rockall A, Wiedenmann B, Valle JW, Vullierme M-P, all other Antibes Consensus Conference participants: ENETS consensus guidelines for the standards of care in neuroendocrine tumors: radiological, nuclear medicine and hybrid imaging. Neuroendocrinology 2017;105:212-244.
5.
Oberg K, Couvelard A, Delle Fave G, Gross D, Grossman A, Jensen RT, Pape U-F, Perren A, Rindi G, Ruszniewski P, Scoazec J-Y, Welin S, Wiedenmann B, Ferone D, all other Antibes Consensus Conference participants: ENETS consensus guidelines for the standards of care in neuroendocrine tumors: biochemical markers. Neuroendocrinology 2017;105:201-211.
6.
Partelli S, Bartsch DK, Capdevila J, Chen J, Knigge U, Niederle B, Nieveen van Dijkum EJM, Pape U-F, Pascher A, Ramage J, Reed N, Ruszniewski P, Scoazec J-Y, Toumpanakis C, Kianmanesh R, Falconi M, all other Antibes Consensus Conference participants: ENETS consensus guidelines for the standards of care in neuroendocrine tumors: surgery for small intestinal and pancreatic neuroendocrine tumours. Neuroendocrinology 2017;105:255-265.
7.
Kaltsas G, Caplin M, Davies P, Ferone D, Garcia-Carbonero R, Grozinsky-Glasberg S, Hörsch D, Tiensuu Janson E, Kianmanesh R, Kos-Kudla B, Pavel M, Rinke A, Falconi M, de Herder WW, all other Antibes Consensus Conference participants: ENETS consensus guidelines for the standards of care in neuroendocrine tumors: pre- and perioperative therapy in patients with neuroendocrine tumors. Neuroendocrinology 2017;105:245-254.
8.
Pavel M, Valle JW, Eriksson B, Rinke A, Caplin M, Chen J, Costa F, Falkerby J, Fazio N, Gorbounova V, de Herder W, Kulke M, Lombard-Bohas C, O'Connor J, Sorbye H, Garcia-Carbonero R, all other Antibes Consensus Conference Participants: ENETS consensus guidelines for the standards of care in neuroendocrine neoplasms: systemic therapy - biotherapy and novel targeted agents. Neuroendocrinology 2017;105:266-280.
9.
Garcia-Carbonero R, Rinke A, Valle JW, Fazio N, Caplin M, Gorbounova V, O'Connor J, Eriksson B, Sorbye H, Kulke M, Chen J, Falkerby J, Costa F, de Herder W, Lombard-Bohas C, Pavel M, all other Antibes Consensus Conference participants: ENETS consensus guidelines for the standards of care in neuroendocrine neoplasms: systemic therapy - chemotherapy. Neuroendocrinology 2017;105:281- 294.
10.
Hicks RJ, Kwekkeboom DJ, Krenning E, Bodei L, Grozinsky-Glasberg S, Arnold R, Borbath I, Cwikla J, Toumpanakis C, Kaltsas G, Davies P, Hörsch D, Tiensuu Janson E, Ramage J, all other Antibes Consensus Conference participants: ENETS consensus guidelines for the standards of care in neuroendocrine neoplasia: peptide receptor radionuclide therapy with radiolabelled somatostatin analogues. Neuroendocrinology 2017;105:295-309.
11.
Knigge U, Capdevila J, Bartsch DK, Baudin E, Falkerby J, Kianmanesh R, Kos-Kudla B, Niederle B, Nieveen van Dijkum E, O'Toole D, Pascher A, Reed N, Sundin A, Vullierme M-P, all other Antibes Consensus Conference participants: ENETS consensus recommendations for the standards of care in neuroendocrine neoplasms: follow-up and documentation. Neuroendocrinology 2017;105:310-319.
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