Targeted radiotherapy for small cell lung cancer using 90Yttrium-DOTATOC, an Yttrium-labelled somatostatin analogue: a pilot trial.

Background: Some small cell lung carcinomas (SCLC) express neuro-endocrine markers, such as somatostatin receptors. Therefore, somatostatin analogues can be radio-labelled with 111Indium (Octreoscan) for diagnostic scintigraphy, or with 90Y-DOTATOC for therapeutic use. This is the first trial to assess the toxicity and efficacy of treatment with 90Y-DOTATOC in patients with Octreoscan positive SCLC.

Methods: Patients with SCLC after > or =first line chemotherapy received an Octreoscan scintigraphy and results were compared to CT scans. Patients with strong somatostatin-receptor expression were treated with 60 mCi/m2 90Y-DOTATOC i.v. every 3 weeks, for a total of three cycles. Major inclusion criteria were measurable tumour lesions, disease progression, normal creatinine clearance, PS < or = 2.

Results: Octreoscan scintigraphy identified 70% of all primary tumours, 87% of all mediastinal lesions, but only 26% of all extrathoracic tumour manifestations. Six patients were treated. Median number of 90Y-DOTATOC cycles was 2 (1-3). The only grade 3 toxicity was fatigue (n = 2) and dyspnea (n = 1). There were no severe renal or haematological toxicities. All six patients had tumour progression, median progression free survival (PFS) was 37.5 days (28-52) and median overall (OS) was 103.5 days (28-269).

Conclusion: This is the first report of somatostatin-receptor targeted radiotherapy for SCLC in the literature. In contrast to well differentiated neuro-endocrine tumours, 90Y-DOTATOC seems to be inactive in SCLC.