Observational Study
Copyright ©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Radiol. Jul 28, 2024; 16(7): 265-273
Published online Jul 28, 2024. doi: 10.4329/wjr.v16.i7.265
Incidence of exclusive extrapelvic skeletal metastasis in prostate carcinoma on bone scintigraphy
Parneet Singh, Kanhaiyalal Agrawal, Ashique Rahman, Tejasvini Singhal, Girish Kumar Parida, Gopinath Gnanasegaran
Parneet Singh, Kanhaiyalal Agrawal, Ashique Rahman, Tejasvini Singhal, Girish Kumar Parida, Department of Nuclear Medicine, All India Institute of Medical Sciences, Bhubaneshwar 751019, Odisha, India
Gopinath Gnanasegaran, Department of Nuclear Medicine, Royal Free Hospital, London NW3 2QG, United Kingdom
Co-first authors: Parneet Singh and Kanhaiyalal Agrawal.
Author contributions: Singh P and Agrawal K contributed to conception and design; Singh P and Singhal T contributed to drafting the manuscript; Agrawal K, Parida GK and Gnanasegaran G contributed to analysis and interpretation of data; Rahman A contributed to data collection, interpretation of data; All authors have confirmed the final approval.
Institutional review board statement: The study was approved by the institutional review board under IEC No. T/IM-NF/Nucl.Med/23/187.
Informed consent statement: Patients were not required to give informed consent to the study as the current study is a retrospective analysis of data and study was performed maintaining anonymity of the patients. The scintigraphy data were obtained after each patient agreed to the imaging by written consent.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: The data used to support the findings of this study are available from the corresponding author upon request at nucmed_kanhaiyalal@aiimsbhubaneswar.edu.in.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Kanhaiyalal Agrawal, MBBS, MD, Additional Professor, Department of Nuclear Medicine, All India Institute of Medical Sciences, Sijua, Dumuduma, Bhubaneshwar 751019, Odisha, India. nucmed_kanhaiyalal@aiimsbhubaneswar.edu.in
Received: May 8, 2024
Revised: June 8, 2024
Accepted: July 2, 2024
Published online: July 28, 2024
Processing time: 76 Days and 16.9 Hours
Abstract
BACKGROUND

Bone is one of the common sites of metastasis from prostate carcinoma. Bone scintigraphy (BS) is one of the most sensitive imaging modalities currently used for bone metastatic work-up. Skeletal metastasis in prostate carcinoma commonly involves pelvic bones but rarely involves extrapelvic-extraspinal sites.

AIM

To retrospectively analyze the BS data to determine the pattern of skeletal metastases in the prostate carcinoma.

METHODS

This retrospective observational study involves patients with biopsy-proven prostate carcinoma referred for BS for staging assessment. Patients with abnormal BS were evaluated for the pattern of skeletal involvement and data were presented in descriptive format in the form of percentages.

RESULTS

A total of 150 patients with biopsy-proven prostate cancer who were referred for staging were included in the study. Thirteen of 150 patients (8.67%) had no abnormal uptake on planar images, ruling out metastatic disease. Twenty-four patients (16%) had heterogeneous uptake in the spine with distribution characteristic of degenerative disease and no scan pattern of metastatic disease. Thirty patients (20%) had multifocal uptake involving both pelvic and extra pelvic bones on planar images typical for skeletal metastasis and were considered metastatic. Eighty-three out of 150 patients (55.3%) had increased tracer uptake, which was indeterminate, thus, single photon emission computed tomography-computed tomography (SPECT-CT) was acquired, which showed 51 with metastatic disease, 31 benign lesions, and one indeterminate finding. Seven of 150 patients had exclusive pelvic bone uptake, which was found to be metastatic in 4/7 patients in SPECT-CT. Fifty six out of 150 patients showed exclusive extrapelvic tracer uptake, of which only 3 had vertebral metastatic disease. None of the patients with increased uptake exclusively in the extrapelvic-extraspinal location was metastatic.

CONCLUSION

The incidence of exclusive extrapelvic skeletal metastatic disease in prostate carcinoma is 2% (excluding one patient with indeterminate findings). Further, none of the patients in the current study had exclusive extrapelvic-extraspinal metastasis. Thus, exclusive extrapelvic-extraspinal focal abnormality on planar BS carries a very low probability of metastatic disease and hence, further imaging or SPECT-CT can be safely avoided in such cases.

Keywords: Pelvic; Prostate cancer; Bone scan; Single photon emission computed tomography-computed tomography; Skeletal metastasis

Core Tip: The current study analyzed bone scintigraphy (BS) data from 150 patients with biopsy-proven prostate carcinoma to determine skeletal metastasis patterns. The most common site of skeletal metastasis was pelvis. The incidence of exclusive extrapelvic skeletal metastatic disease was 2%, excluding one indeterminate case. Additionally, no patients in the study had exclusive extrapelvic-extraspinal metastasis. Therefore, exclusive extrapelvic-extraspinal focal abnormalities on planar BS have a very low likelihood of being metastatic, making further imaging or single photon emission computed tomography-computed tomography often unnecessary.