The quest for an accurate functional tumor volume with (68)Ga-DOTATATE PET/CT Journal Article


Authors: Reddy, R. P.; Schmidtlein, C. R.; Giancipoli, R. G.; Mauguen, A.; LaFontaine, D.; Schoder, H.; Bodei, L.
Article Title: The quest for an accurate functional tumor volume with (68)Ga-DOTATATE PET/CT
Abstract: Ga-68-labeled somatostatin analog (SSA) PET/CT is now a standard-of-care component in the management of neuroendocrine tumors (NETs). However, treatment response for NETs is still assessed with morphologic size measurements from other modalities, which can result in inaccuracy about the disease burden. Functional tumor volume (FTV) acquired from SSA PET/CT has been suggested as a possible metric, but no validated measurement tool to measure FTV exists. We tested the precision of multiple FTV computational approaches compared with morphologic volume measurements to identify a candidate for incorporation into future FTV studies to assess tumor burden more completely and accurately. Methods: The clinical and imaging data of 327 NET patients were collected at Memorial Sloan Kettering Cancer Center between December 2016 and April 2018. Patients were required to have SSA PET/CT and dedicated CT scans within 6 wk and were excluded if they had any intervention between scans. When paired studies were evaluated, 150 correlating lesions demonstrated SSA. Lesions were excluded if they contained necrotic components or were lobulated. This exclusion resulted in 94 lesions in 20 patients. The FTV for each lesion was evaluated with a hand-drawn assessment and 3 automated techniques: 50% threshold from SUVmax, 42% threshold from SUVmax, and background-subtracted lesion activity. These measurements were compared with volume calculated from morphologic volume measurements. Results: The FTV calculation methods showed varying correlations with morphologic volume measurements. FTV using a 42% threshold had a 0.706 correlation, hand-drawn volume from PET imaging had a 0.657 correlation, FTV using a 50% threshold had a 0.645 correlation, and background-subtracted lesion activity had a 0.596 correlation. The Bland-Altman plots indicated that all FTV methods had a positive mean difference from morphologic volume, with a 50% threshold showing the smallest mean difference. Conclusion: FTV determined with thresholding of SUVmax demonstrated the strongest correlation with traditional morphologic lesion volume assessment and the least bias. This method was more accurate than FTV calculated fromhand-drawn volume assessments. Threshold-based automated FTV assessment promises to better determine disease extent and prognosis in patients with NETs.
Keywords: everolimus; therapy; pet/ct; neuroendocrine tumors; neuroendocrine; quantification; f-18-fdg pet/ct; somatostatin analogs; functional tumor volume
Journal Title: Journal of Nuclear Medicine
Volume: 63
Issue: 7
ISSN: 0161-5505
Publisher: Society of Nuclear Medicine  
Date Published: 2022-07-01
Start Page: 1027
End Page: 1032
Language: English
ACCESSION: WOS:000823739000023
DOI: 10.2967/jnumed.121.262782
PROVIDER: wos
PMCID: PMC9258575
PUBMED: 34772795
Notes: Article -- Source: Wos
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MSK Authors
  1. Heiko Schoder
    546 Schoder
  2. Audrey   Mauguen
    157 Mauguen
  3. Lisa   Bodei
    205 Bodei
  4. Ryan Padira Reddy
    13 Reddy