From the Guidelines
A growth rate cannot be definitively determined as consistent or inconsistent with a grade 2 Neuroendocrine Tumor (NET) without specific growth measurements. Grade 2 NETs typically have a Ki-67 proliferation index of 3-20% and/or 2-20 mitoses per 10 high-power fields, indicating intermediate growth characteristics, as reported in a study published in the Journal of the National Comprehensive Cancer Network 1. These tumors generally grow more slowly than high-grade (grade 3) NETs but faster than low-grade (grade 1) NETs. The actual growth rate of a specific NET depends on multiple factors including the primary site, differentiation status, and individual tumor biology. Some key points to consider when evaluating the growth rate of a NET include:
- The importance of serial imaging studies to assess tumor growth over time 1
- The role of histopathological grading from a biopsy or surgical specimen in determining tumor grade and guiding treatment decisions 1
- The individualized approach to treatment, taking into account tumor location, extent, symptoms, and growth characteristics, with options ranging from observation to surgical resection, somatostatin analogs (octreotide or lanreotide), targeted therapies, or in some cases, chemotherapy 1 To accurately assess if a particular growth rate is consistent with a grade 2 NET, it is essential to consider these factors and consult the most recent and highest-quality studies, such as those published in 2024 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Growth Rate Consistency with Grade 2 NET
The question of whether a specific growth rate is consistent with a grade 2 Neuroendocrine Tumor (NET) requires an understanding of the characteristics of NETs and their behavior.
- Grade 2 NETs are defined by a Ki-67 index between 3% and 20% 2.
- The growth rate of NETs can vary, but grade 2 NETs are generally considered to have a moderate growth rate compared to grade 1 (low) and grade 3 (high) NETs.
- Studies have shown that liver metastases from NETs can have heterogeneous Ki-67 indices, even within the same patient 2.
- Tumor growth kinetics, including the reciprocal of doubling time (RDT), can be used as an imaging biomarker to assess response to treatment in liver metastases, including those from NETs 3.
Relevance of Study Findings
While the provided studies do not directly address the growth rate of grade 2 NETs, they do offer insights into the behavior of NETs and their liver metastases.
- A study on liver metastases from small intestine NETs found that Ki-67 heterogeneity was common and correlated with tumor size 2.
- Another study demonstrated the effectiveness of hepatic intraarterial injection of yttrium 90 ((90)Y) tetraazacyclododecane tetraacetic acid (DOTA) lanreotide as a palliative treatment for patients with progressive large-volume somatostatin receptor-positive liver metastases from NETs 4.
- Liver transplantation has been proposed as a treatment option for patients with liver metastases from NETs, particularly when the primary tumor is located in the head of the pancreas 5.
Implications for Grade 2 NET Growth Rate
Based on the available evidence, it is difficult to determine a specific growth rate that is consistent with a grade 2 NET without more information about the individual tumor's characteristics, such as its Ki-67 index and tumor size.
- However, it is clear that grade 2 NETs can exhibit moderate growth rates and that tumor growth kinetics can be an important factor in assessing response to treatment 2, 3.
- Further studies are needed to fully understand the growth patterns of grade 2 NETs and to develop effective treatment strategies for these tumors 6, 4, 5, 2, 3.