Influence of Tumour and Patient's Related Factors on the Response to Medical Treatments in Well Differentiated GEP-NENs

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) represent the most common NeuroEndocrin Neoplasms (NEN) site, comprising 55-70% of all NENs, and they are extremely heterogeneous diseases in terms of clinical presentation and aggressiveness. In recent years there has been a significant increase in the incidence of such neoplasms, partially due to incidental findings of small indolent lesions. However, the behavior of GEP- NEN is variable and mainly dictated by some factors as age, sex, histologic grade, primary site, and stage at diagnosis1. As for grade which is defined by the proliferative activity as measured by mitotic count or ki67 staining, some 75% of neoplasms fall into the G1 grading category, 15% into the G2 category, and 10% into the G3 category. The probability of developing metastases is directly correlated with grading. In addition, the grading of GEP-NENs is also correlated with the type of differentiation of the neoplasm (well differentiated or poorly differentiated). Managing the complexity of this type of neoplasm has made it necessary to stratify patients into progression risk classes. The therapeutic approach is accordingly defined, and may include different treatments (surgery, loco-regional, targeted therapies, chemotherapies,...). Among treatments, the most widely used for patients with well-differentiated NENs are somatostatin analogs (SSAs), targeted therapies, and the combination of oral capecitabine and temozolomide. Systemic intravenous chemotherapy is instead employed in a subset of G3 neoplasms, especially if poorly differentiated.

Sex

All

Minimum age

18 Years

Inclusion Criteria:

* Age \>= 18
* Well-differentiated, localized (but not suitable for surgical treatment) or advanced (locally or with distant metastasis) GEP-NENs
* availability of data on site of primary tumor, stage of the, date of diagnosis
* treated with one (or more) of the following therapies:

  * Somatostatin analogs

    * G1 or G2 (Ki67 \<10%) GEP-NENs
    * Treated for at least 6 months
    * first-line therapy (or as second-line after surgery in patients with residual disease or recurrence after surgical resection)
  * Sunitinib/Everolimus

    * G1/G2 GEP-NENs
    * Treated for at least 6 months
    * first- or second-line therapy
  * Capecitabine-Temozolomide (CAP-TEM)

    * G2 or G3 (Ki67 \< 55%) GEP-NENs
    * first-, second-, or third-line therapy
    * Treated for at least 6 months

Exclusion Criteria:

* Age \< 18aa
* Patients concomitantly treated with loco-regional treatments
* Patients previously treated with radioligand therapy
* Patients with need of CAP-TEM dose reduction of more than 33% for at least 3 administrations
* NENs of unknown primitivity (including patients with biopsy on secondary lesion compatible with metastasis from GEP-NEN, but with occult primary neoplasm)
* Patients with Mixed NENs (MiNENs)
* Patients with poorly differentiated neuroendocrine carcinoma
* Pregnancy and breastfeeding