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Current tumor classification, grading, and staging systems are limited for most neuroendocrine neoplasm (NEN) subtypes. There are presently a number of treatment options, but none that are sufficiently effective. A clear-cut guide to choosing the best strategy is essential. In this special issue, NEN experts identify the most relevant unmet needs in an effort to keep research and understanding moving forward toward the development of new approaches. They address the lack of predictive and prognostic markers which would help determine which tumors should undergo resection and which should only be monitored. The debate over determining tumor (metastases) responses and how to best measure them is addressed. The absence of registered or approved adjuvant treatment options is also discussed, along with the need for a systematic approach to the follow-up on patients with NENs.

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