{"title":"Somatostatin receptor-targeted theranostics in patients with estrogen receptor-positive metastatic breast cancer-a prospective exploratory study.","authors":"Kunal Ramesh Chandekar, Swayamjeet Satapathy, Yamini Dharmashaktu, Sanjana Ballal, Piyush Ranjan, Atul Batra, Ajay Gogia, Sandeep Mathur, Chandrasekhar Bal","doi":"10.1007/s10549-025-07651-4","DOIUrl":null,"url":null,"abstract":"<p><strong>Purpose: </strong>Somatostatin receptor (SSTR) expression has been reported in estrogen receptor-positive (ER +) metastatic breast cancer (mBC) by pathology and immunohistochemistry studies. We aimed to investigate whether SSTR could be a viable target for PET imaging and potential theranostics in ER + mBC.</p><p><strong>Methods: </strong>Thirty prospectively recruited patients with ER + mBC underwent PET/CT imaging with [<sup>18</sup>F]FDG and [<sup>68</sup>Ga]Ga-DOTATATE (within three weeks). Detection rates (per-patient, per-region), number of lesions detected, SUVmax values, Krenning scores, SSTR-FDG visual scores, and PET-based staging with both radiotracers were compared.</p><p><strong>Results: </strong>[<sup>18</sup>F]FDG and [<sup>68</sup>Ga]Ga-DOTATATE PET/CT had similar per-patient detection rates (100% vs 96.7%, P = 1.0). Per-region and per-lesion analyses revealed comparable detection of local/breast lesions, nodal, and skeletal metastases. However, [<sup>18</sup>F]FDG outperformed [<sup>68</sup>Ga]Ga-DOTATATE in detecting visceral/other metastases (235 vs 128 lesions, P = 0.003). [<sup>68</sup>Ga]Ga-DOTATATE resulted in a lower PET-based M-stage compared to [<sup>18</sup>F]FDG in 10% of patients, although T-/N-stages were concordant in all patients. HER2- patients showed a trend of higher [<sup>68</sup>Ga]Ga-DOTATATE lesional SUVmax values compared to the HER2 + sub-group (median 9.0 vs 3.8, P = 0.078). 3/30 (10%) participants had a patient-level Krenning score ≥ 3 ([<sup>68</sup>Ga]Ga-DOTATATE uptake higher than liver background in majority of the lesions), potentially making them suitable for SSTR-targeted radionuclide therapy.</p><p><strong>Conclusions: </strong>SSTR-targeted theranostics may represent a novel potential alternative in a subset of patients with ER + mBC. Its generalized applicability is limited by poor sensitivity for visceral metastases and significant inter-lesion heterogeneity. Future studies must identify how tumor subtype, proliferation, and prior systemic therapies impact SSTR expression levels in these patients to ensure meaningful clinical translation.</p><p><strong>Clinical trial registration: </strong>Clinical Trials Registry-India: CTRI/2023/03/051025 (prospectively registered on 23.03.2023).</p>","PeriodicalId":9133,"journal":{"name":"Breast Cancer Research and Treatment","volume":" ","pages":"363-373"},"PeriodicalIF":3.0000,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Breast Cancer Research and Treatment","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1007/s10549-025-07651-4","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2025/2/26 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"ONCOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Purpose: Somatostatin receptor (SSTR) expression has been reported in estrogen receptor-positive (ER +) metastatic breast cancer (mBC) by pathology and immunohistochemistry studies. We aimed to investigate whether SSTR could be a viable target for PET imaging and potential theranostics in ER + mBC.
Methods: Thirty prospectively recruited patients with ER + mBC underwent PET/CT imaging with [18F]FDG and [68Ga]Ga-DOTATATE (within three weeks). Detection rates (per-patient, per-region), number of lesions detected, SUVmax values, Krenning scores, SSTR-FDG visual scores, and PET-based staging with both radiotracers were compared.
Results: [18F]FDG and [68Ga]Ga-DOTATATE PET/CT had similar per-patient detection rates (100% vs 96.7%, P = 1.0). Per-region and per-lesion analyses revealed comparable detection of local/breast lesions, nodal, and skeletal metastases. However, [18F]FDG outperformed [68Ga]Ga-DOTATATE in detecting visceral/other metastases (235 vs 128 lesions, P = 0.003). [68Ga]Ga-DOTATATE resulted in a lower PET-based M-stage compared to [18F]FDG in 10% of patients, although T-/N-stages were concordant in all patients. HER2- patients showed a trend of higher [68Ga]Ga-DOTATATE lesional SUVmax values compared to the HER2 + sub-group (median 9.0 vs 3.8, P = 0.078). 3/30 (10%) participants had a patient-level Krenning score ≥ 3 ([68Ga]Ga-DOTATATE uptake higher than liver background in majority of the lesions), potentially making them suitable for SSTR-targeted radionuclide therapy.
Conclusions: SSTR-targeted theranostics may represent a novel potential alternative in a subset of patients with ER + mBC. Its generalized applicability is limited by poor sensitivity for visceral metastases and significant inter-lesion heterogeneity. Future studies must identify how tumor subtype, proliferation, and prior systemic therapies impact SSTR expression levels in these patients to ensure meaningful clinical translation.
期刊介绍：
Breast Cancer Research and Treatment provides the surgeon, radiotherapist, medical oncologist, endocrinologist, epidemiologist, immunologist or cell biologist investigating problems in breast cancer a single forum for communication. The journal creates a "market place" for breast cancer topics which cuts across all the usual lines of disciplines, providing a site for presenting pertinent investigations, and for discussing critical questions relevant to the entire field. It seeks to develop a new focus and new perspectives for all those concerned with breast cancer.
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