Do patients with NETs develop drug resistance?
Resistance to octreotide in terms of symptom control and/or tumor growth can be defined in several ways: (i) primary absolute failure to achieve symptomatic and/or tumor growth control in spite of dose escalations; (ii) secondary failure of response to dose escalations after initial control of symptoms and/or tumor growth; and (iii) in spite of excellent symptom control of functional symptoms, an increase in tumor size or tumor markers. In the latter case, additional treatment options such as hepatic arterial chemoembolization or local thermal ablation of hepatic metastases may be considered. During these procedures octreotide therapy should be continued for symptom control. Also, the addition of interferon or even chemotherapy could be considered. Most importantly, consideration should be given to referring the patient for participation in experimental protocols.
