Mild erythrocytopenia is the most frequent long-term sequel after peptide receptor radionuclide Therapy: Results of long-term follow-up in more than 500 Patients from a single centre

Full text of publication follows. Aim: Peptide receptor radionuclide therapy (PRRT) is highly effective in well differentiated neuroendocrine neoplasms (NENs) and lends a benefit in overall survival of several years. Renal toxicity is a well-known adverse effect of PRRNT. Hematological toxicity as possible long-term sequel has been hardly examined. Therefore we investigated the effect of PRRT on the hematological status (erythrocytes, leukocytes, thrombocytes) of patients who received individualized therapy at our centre. Materials and Methods: Out of over 500 patients, 59 chemotherapy naive patients with well-differentiated NENs who were treated with at least 3 cycles of PRRT with ¹⁷⁷Lu- and/or ⁹⁰Y- labeled DOTATATE/DOTATOC and long-term follow-up were selected for this analysis. Blood counts were documented before the first cycle and repeated at monthly intervals between further cycles and during re-staging examinations after PRRT for many years. Comparisons were done between the hematological status before the first cycle and the one 3 years after the last cycle of PRRT. Results: All 3 cell lines were significantly decreased 3 years after the last radionuclide therapy (erythrocytes, leukocytes: p=0,000; thrombocytes: p=0,002; confidence interval 95%). But only erythrocytes showed a significant decrement, i.e., below the reference level of our in-house laboratory (mean value ± standard deviation: (4.07 ± 0.69)/l; reference level: 4.1-5.4/l). Conclusions: Mild erythrocytopenia is the most frequent long-term sequel after PRRT. Although it has to be considered that repeated cycles probably cause impoverishment in bone marrow reserve (or red cell precursors), PRRT achieves both significant improvement in clinical symptoms and excellent palliation. Thus it remains a safe procedure if performed at specialized centres with interdisciplinary and long-term care. (authors)