title: Somatostatin receptor expression in small cell lung cancer as a prognostic marker and a target for peptide receptor radionuclide therapy.
abstract: Despite initial responsiveness to both chemotherapy and radiotherapy, small cell lung cancer (SCLC) commonly relapses within months. Although neuroendocrine characteristics may be difficult to demonstrate in individual cases, a relevant expression of somatostatin receptors (SSTR) on the cell surface has been described. We aimed to evaluate the prognostic value of SSTR-expression in advanced SCLC. We further examined pre-requisites for successful peptide receptor radionuclide therapy (PRRT). 21 patients with extensive stage SCLC were enrolled. All patients underwent positron emission tomography/computed tomography (PET/CT) with 68Ga-DOTATATE to select patients for SSTR-directed therapy. PET scans were visually and semi-quantitatively assessed and compared to SSTR2a and SSTR5 expression in biopsy samples. Peak standardized uptake values (SUVpeak) of tumors as well as tumor-to-liver ratios were correlated to progression-free (PFS) and overall survival (OS). In 4/21 patients all SCLC lesions were PET-positive. 6/21 subjects were rated "intermediate" with the majority of lesions positive, the remaining 11/21 patients were PET-negative. PET-positivity correlated well with histologic SSTR2a, but not with SSTR5 expression. Neither PET-positivity nor SUVpeak were predictors of PFS or OS. In 4 patients with intensive SSTR2a-receptor expression, PRRT was performed with one partial response and one stable disease, respectively. SSTR-expression as detected by 68Ga-DOTATATE-PET and/or histology is not predictive of PFS or OS in patients with advanced SCLC. However, in patients exhibiting sufficient tracer uptake, PRRT might be a treatment option given its low toxicity and the absence of effective alternatives.
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany.
authors.forename: Constantin
authors.initials: C
authors.lastname: Lapa
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany.
authors.forename: Heribert
authors.initials: H
authors.lastname: Hänscheid
authors.affiliation: Institute for Pathology, University of Würzburg, 97080 Würzburg, Germany.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Wild
authors.affiliation: Department of Internal Medicine, University Hospital Würzburg, 97080 Würzburg, Germany.
authors.forename: Theo
authors.initials: T
authors.lastname: Pelzer
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schirbel
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany.
authors.forename: Rudolf A
authors.initials: RA
authors.lastname: Werner
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Droll
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany.
authors.forename: Ken
authors.initials: K
authors.lastname: Herrmann
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany.
authors.forename: Andreas K
authors.initials: AK
authors.lastname: Buck
authors.affiliation: Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Lückerath
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D009942:Organometallic Compounds / Q000378:metabolism*; D000072078:Positron Emission Tomography Computed Tomography; D011379:Prognosis; D019275:Radiopharmaceuticals / Q000378:metabolism*; D017481:Receptors, Somatostatin / Q000378:metabolism*; D055752:Small Cell Lung Carcinoma / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000532:radiotherapy / Q000556:secondary
chemical_list: D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; D017481:Receptors, Somatostatin; C574734:SSTR2 protein, human; C094573:somatostatin receptor 5; C513399:gallium Ga 68 dotatate
keywords: PET; molecular imaging; positron emission tomography; small cell lung cancer; somatostatin receptor