Observation vs MRI Screening and Pre-emptive Treatment for Spinal Cord Compression in Patients With Prostate Cancer and Spinal Metastases

Routine MRI screening and pre-emptive treatment for malignant clinical spinal cord compression (SCC) is not warranted in patients with asymptomatic castration-resistant prostate cancer (CRPC) and spinal metastases, according to results from the phase 3 PROMPTS trial.

“Early diagnosis of malignant [SCC] is crucial because pretreatment neurological status is the major determinant of outcome. In metastatic [CRPC], SCC is a clinically-significant cause of disease-related morbidity and mortality…Despite the substantial incidence of radiological SCC detected in the intervention group, the rate of clinical SCC in both groups was low at a median of 22 months of follow-up…We recommend that the epidural [SCC] scale be introduced into routine clinical practice because it can be used to determine the presence of early radiological SCC and identifies a high-risk group for subsequent development of clinical SCC,” wrote lead author David Dearnaley, professor emeritus, The Institute of Cancer Research, London, UK, and colleagues.

In the open-label, parallel-group controlled trial, 420 adult patients were recruited from 45 National Health Service hospitals in the UK and randomized in a 1:1 ratio to the control group (observation) or screening MRI. Participants had an Eastern Cooperative Oncology Group performance status of 0 to 2, asymptomatic spinal metastasis, no previous SCC, and no spinal MRI in the past 12 months. The median age was 74 years (IQR 68 to 79). About half (53%) of the patients had normal alkaline phosphatase, and median prostate-specific antigen concentration was 48 ng/mL (IQR 17 to 162).

Participants with radiological SCC were offered pre-emptive treatment by radiotherapy or surgical decompression per the treating physician’s recommendation, and 6-monthly spinal MRI. All patients were followed up every 3 months, and then at month 30 and 36.

The median follow-up was 22 months (IQR 13 to 31); the data cutoff was April 23, 2020. MRI detected radiological SCC in 31% of 200 patients with assessable scans in the intervention group, but time to clinical SCC was not significantly improved with screening (HR 0.64 [95% CI 0.37 to 1.11]; Gray’s test P = .12).

In the control group, the cumulative incidence of clinical SCC at 12 months was 6.7% (95% CI 3.8 to 10.6) compared with 4.3% (2.1 to 7.7) in the intervention group. At 24 months, the rates were 12.6% (8.5 to 17.5) in the control group vs 9.2% in the intervention group (5.8 to 13.7).

The median time to clinical SCC was not reached in either group.

Source:

Dearnaley D, Hinder V, Hijab A, et al. Observation versus screening spinal MRI and pre-emptive treatment for spinal cord compression in patients with castration-resistant prostate cancer and spinal metastases in the UK (PROMPTS): an open-label, randomised, controlled, phase 3 trial. Lancet Oncol. Published online March 10, 2022. doi:10.1016/S1470-2045(22)00092-4.