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Updated: Apr 25, 2026
A Whole Body Dosimetry Protocol for Peptide-Receptor Radionuclide Therapy PRRT: 2D Planar Image and Hybrid 2D+3D SPECT/CT Image Methods
Published on: April 24, 2020
Peptide receptor chemoradionuclide therapy in small cell carcinoma: from bench to bedside
Jeremy Lewin1, Carleen Cullinane, Tim Akhurst
1Division of Hematology and Medical Oncology, East Melbourne, VIC, Australia.
Purpose:
Small cell cancers (SmCC), whether pulmonary (SCLC) or extrapulmonary, have a poor prognosis unless localised at diagnosis. Given a proportion of these cancers express somatostatin receptor subtype 2 (SSTR2), we aimed to investigate the efficacy of targeted peptide receptor chemoradionuclide therapy (PRCRT).
Methods:
In this preclinical study, we used a SCLC xenograft mouse model with high expression of SSTR2 to investigate the effect of peptide receptor radionuclide therapy (PRRT) with chemotherapy compared to either alone. We subsequently explored the clinical utility in a patient with SmCC with high SSTR expression treated with PRCRT.
Results:
Robust expression of SSTR2 in NCI-H69 SCLC xenografts was documented by (68)Ga-DOTA-octreotate (GaTate) (tumour to background uptake ratio = 35). The combination of PRRT using (177)Lu-DOTA-octreotate (LuTate) with carboplatin/etoposide (C/E) chemotherapy was more effective than either LuTate or C/E alone for regression of the NCI-H69 model (p value < 0.05). PRCRT was associated with significantly prolonged survival versus PRRT (p value = 0.0001) or chemotherapy alone (p value = 0.0058). In the subsequent case study, a patient with relapsed SmCC with high SSTR2 expression on GaTate PET underwent PRCRT with radiosensitising etoposide with evidence of a complete metabolic response for 4 months.
Conclusion:
Given the limited treatment options in this setting, PRCRT is a promising therapeutic option for SSTR2-expressing SmCC.
Insights
Peptide receptor chemoradionuclide therapy (PRCRT) combined with chemotherapy shows promise for treating somatostatin receptor subtype 2 (SSTR2)-expressing small cell cancers. This combination significantly improved tumor regression and survival in preclinical models and a patient case study.
Area of Science:
- Oncology
- Nuclear Medicine
- Radiopharmaceutical Therapy
Background:
- Small cell cancers (SmCC), including small cell lung cancer (SCLC), generally have a poor prognosis.
- A subset of SmCC expresses somatostatin receptor subtype 2 (SSTR2), presenting a potential therapeutic target.
Observation:
- Preclinical studies utilized a SCLC xenograft mouse model with high SSTR2 expression.
- The study documented robust SSTR2 expression in xenografts using (68)Ga-DOTA-octreotate (GaTate) PET imaging.
- A clinical case involved a patient with relapsed SmCC and high SSTR2 expression.
Findings:
- Combination peptide receptor radionuclide therapy (PRRT) with (177)Lu-DOTA-octreotate (LuTate) and carboplatin/etoposide (C/E) chemotherapy demonstrated superior tumor regression compared to either modality alone in the SCLC model.
- PRCRT significantly prolonged survival in preclinical models compared to PRRT or chemotherapy alone.
- The patient treated with PRCRT and radiosensitizing etoposide achieved a complete metabolic response lasting 4 months.
Implications:
- PRCRT represents a promising therapeutic strategy for SSTR2-expressing small cell cancers, addressing a significant unmet need.
- The findings support further clinical investigation of PRCRT in patients with SSTR2-positive SmCC.
- Targeted radionuclide therapy offers a novel approach for managing aggressive small cell malignancies.
