Study explores value of whole-body low-dose CT in prostate cancer management

Even in the era of PSMA-PET imaging, whole-body low-dose computed tomography (CT) still offers value in the management of patients with prostate cancer, according to a study published in Insights into Imaging.¹

“In the initial staging of prostate cancer patients based on the above-mentioned criteria, whole-body low-dose CT showed promising findings in terms of specificity and (positive predictive value), regardless of readers’ expertise. This means that the treatment approach would have been confidently adopted in the patients diagnosed with the high-burden disease,” noted lead study author Mohammadreza Chavoshi, MD, and coauthors.

“This modality may obviate performing multiple imaging sessions and high-cost scans in patients diagnosed with the high-burden disease,” wrote lead study author Mohammadreza Chavoshi, MD, who is affiliated with the Department of Radiology at Shariati Hospital and the Tehran University of Medical Sciences in Iran, and colleagues.

For the study, Chavoshi et al examined the use of whole-body, low-dose CT for the diagnosis of osteo-metastasis in 601 patients (mean age, 68.7) with prostate cancer. According to the study, 35.1% of the cohort received imaging for initial staging and 64.9% had imaging to assess the extent of the disease after biochemical recurrence (BCR) of prostate cancer.

For the initial staging group, low-dose CT had a per-patient sensitivity rate ranging between 76.8% and 88.4% with specificity ranging between 98.6% and 99.3%. For patients with BCR, the researchers found a sensitivity range between 83.3% to 90% and a specificity rate between 95.6% and 98.6% for the reviewing radiologists. Overall, low-dose CT demonstrated an 81% to 89.4% sensitivity rate and a 96.6% to 98.5% specificity rate for osteo-metastasis in the study cohort, according to the authors.

While previous research has shown higher sensitivity and specificity for ⁶⁸Ga-PSMA PET/CT in detecting osteo-metastasis (see ref 9 in study), the study authors said whole-body, low-dose CT may provide a viable alternative that is less expensive and is more widely available than ⁶⁸Ga-PSMA PET/CT.

“The high accuracy at the per-patient level indicated that CT could correctly diagnose the presence or absence of metastasis in most patients. However, in clinical management, both in staging and BCR conditions, it is important to know the burden of disease. In this issue, CT still had reliable performance, meaning most patients would receive the proper therapy,” wrote Chavoshi et al.

The study authors noted that the per-lesion analysis for benign lesions with whole-body low-dose CT had significantly lower sensitivity (48.5%-63.3%) as well as lower specificity (82.1%-92.1%). The researchers also found that CT did not detect 30.8% of metastatic lesions in patients without extensive disease.

However, Chavoshi and colleagues noted that current CHAARTED and LATITUDE criteria for prostate cancer do not emphasize precision in determining the number and location of osteo-metastatic lesions as the treatment would be the same for patients deemed to be at high risk. They also noted that whole-body, low-dose CT had only one false diagnosis of a patient with extensive metastasis.

“In the initial staging of prostate cancer patients based on the above-mentioned criteria, whole-body low-dose CT showed promising findings in terms of specificity and (positive predictive value), regardless of readers’ expertise. This means that the treatment approach would have been confidently adopted in the patients diagnosed with the high-burden disease,” noted Chavoshi and colleagues.

References

1. Chavoshi M, Mirshahvalad SA, Zamani S, et al. Whole-body low-dose CT can be of value in prostate cancer decision-making: a retrospective study on 601 patients. Insights Imaging. 2023 Jul 16;14(1):124. doi: 10.1186/s13244-023-01475-w