Peptide receptor radionuclide therapy for aggressive atypical pituitary adenoma/carcinoma: variable clinical response in preliminary evaluation

Purpose There are limited treatment options for progressive atypical pituitary adenomas and carcinomas. Peptide receptor radionuclide therapy that targets somatostatin receptors has recently been proposed as a potential treatment option. The theoretical rationale for efficacy is elegant but evaluation of outcomes in the first patients treated for this indication is required to assess whether further study is warranted. Methods We performed a case review of the three pituitary patients we have treated with 177 Lutetium DOTATATE in our institution (two atypical adenomas, one carcinoma) and dosimetric analysis of the radiation uptake in one patient. Results Treatment was well tolerated. One patient with slowly progressive pituitary carcinoma has stable disease 40 months after completing the planned 4 cycles of treatment. Two patients with rapidly progressive atypical adenomas terminated treatment early due to continued disease progression. Dosimetric evaluation revealed inhomogenous uptake across the tumour (1.3-11.9 Gy with one cycle). Conclusion We have found mixed results in our first 3 patients with stable disease achieved only in the patient with the more slowly progressive tumour. As only a limited number of centres offer Peptide receptor radionuclide therapy, a formal study with prospective data collection may be feasible and if carried out should include dosimetric evaluation of absorbed dose.