UROSCAN Year : 2023  |  Volume : 39  |  Issue : 2  |  Page : 175-176  

PROMPTS Trial: Screening spinal magnetic resonance imaging in castration-resistant prostate cancer

Soumya Shivasis Pattnaik
Department of Urology, Vedanayagam Hospital, Coimbatore, Tamil Nadu, India

Date of Submission15-Jan-2023Date of Decision15-Feb-2023Date of Acceptance09-Mar-2023Date of Web Publication31-Mar-2023

Correspondence Address:
Soumya Shivasis Pattnaik
Department of Urology, Vedanayagam Hospital, Coimbatore, Tamil Nadu
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/iju.iju_21_23

  How to cite this article:
Pattnaik SS. PROMPTS Trial: Screening spinal magnetic resonance imaging in castration-resistant prostate cancer. Indian J Urol 2023;39:175-6
   Summary 

The PROMPTS trial[1] is a recently concluded phase 3 trial which was conducted in 45 NHS hospitals in the United Kingdom. It evaluated the role of screening spinal magnetic resonance imaging (MRI) and subsequent treatment of radiological spinal cord compression in asymptomatic patients with metastatic castration-resistant prostate cancer (CRPC) and whether early treatment reduced the incidence of clinical spinal cord compression. This study included patients with an Eastern Cooperative Oncology Group performance status of 0–2, with asymptomatic spinal metastasis without any history of prior spinal cord compression, and no spinal MRI in the past 12 months. Patients were randomized 1:1 into two groups. In one group, screening spinal MRI was done followed by treatment for radiological spinal cord compression (if diagnosed). The other group did not undergo the screening spinal MRI. Patients who were included in the study and had screening detected radiological spinal cord compression were offered treatment in the form of radiotherapy or surgical decompression as recommended by the physician and 6-month spinal MRI was done. All patients were followed up every 3 months, and then at the 30th and 36th months. The study evaluated the incidence of confirmed clinical spinal cord compression and the time taken to develop cord compression.

The trial enrolled 420 patients, 210 in each arm. Screening MRI detected radiological cord compression in 61 (31%) of 200 patients with assessable scans in the intervention group. At a median follow-up of 22 months (interquartile range: 13–31), time to clinical cord compression was not significantly improved with screening. One-year clinical cord compression rates were 6·7% for the control group and 4·3% for the screening and treatment group. Median time to clinical cord compression was not reached in either group.

This study concluded that despite there being a significant incidence of radiological (asymptomatic) spinal cord compression, the rate of clinical spinal cord compression (SCC) in both groups was low at a median follow-up of 22 months. Hence, screening with spinal MRI in patients with asymptomatic CRPC is not warranted.

   Discussion 

The incidence of metastatic carcinoma of prostate is 62/100,000 persons in Europe and 11.5/100,000 persons in India.[2] Spinal cord compression and its clinical manifestation cause significant morbidity. Thirty percent of patients with metastatic CRPC may harbor clinically occult spinal cord compression detectable on MRI.[3] The PROMPTS trial studied the utility of screening spinal MRI to identify asymptomatic radiological spinal cord compression (SCC) and to treat it appropriately before its clinical presentation. However, the time to appearance of clinically significant SCC is not altered significantly by this screening protocol. Despite the presence of radiological SCC, the development of clinical SCC was at a median of 22 months in both groups. Treatment of asymptomatic radiological presence of SCC with radiotherapy or surgery in the treatment group did not alter the time of appearance of clinical disease (cord compression). Although the intervention group had a lower risk of developing clinical cord compression than the control group, the difference was not significant. Patients with radiological cord compression only continued to have a high risk of progression to clinical manifestation of SCC at other spinal sites.

Countries like the UK, where this study was conducted have state-owned health-care systems. Such a routine screening spinal MRI not only adds to the cost but also to the overall stress on the hospitals. PROMPTS trial provides much-needed evidence to all health-care providers from abstaining from routine spinal MRIs.

It is important to identify the subset of patients in the group of metastatic CRPC patients, who would benefit the most from screening spinal MRI and subsequent treatment if needed. Unfortunately, the PROMPTS trial did not investigate this aspect. In a study conducted by Venkitaraman et al.,[3] it was found that serum prostate-specific antigen (PSA) doubling time, initial PSA, and symptom of back pain could be a factor in deciding about the need for spinal MRI screening.

PROMPTS trial is a significant work of research which gives answer to a question which has been in the minds of health-care providers for a long duration of time. This trial not only helps NICE make its guidelines but also enables practitioners to quote statistical data while explaining to their patients regarding the usefulness (or not) of screening spinal MRI.

Financial support and sponsorship: Nil.

Conflicts of interest: There are no conflicts of interest.

 

   References 
1.Dearnaley D, Hinder V, Hijab A, Horan G, Srihari N, Rich P, 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 2022;23:501-13.  
    2.Murthy V, Mallick I, Arunsingh M, Gupta P. Prostate radiotherapy in India: Evolution, practice and challenges in the 21st century. Clin Oncol (R Coll Radiol) 2019;31:492-501.  
    3.Venkitaraman R, Sohaib SA, Barbachano Y, Parker CC, Huddart RA, Horwich A, et al. Frequency of screening magnetic resonance imaging to detect occult spinal cord compromise and to prevent neurological deficit in metastatic castration-resistant prostate cancer. Clin Oncol (R Coll Radiol) 2010;22:147-52.