Conspicuity of prostate cancer lesions diminished by Dutasteride

Eur Radiol. 2017 May 18. doi: 10.1007/s00330-017-4858-0. [Epub ahead of print] PubMed PMID: 28523355.

Short summary 

ADC values and conspicuity of prostate cancer lesions were analysed in 18 men taking dutasteride over a 6 months period and compared to lesions in 19 men taking placebo over the same time period.  

Conclusion

• ADC was higher and conspicuity lower in prostate cancer lesions in men taking dutasteride.

Patient cohort

• Retrospective analysis in 37 men (18 men taking dutasteride; 19 men taking placebo) of a prospective, randomised, dual-blind clinical trial.
• Inclusion criteria:
  • Gleason Score 3+3 or 3+4 in biopsy within preceding < 2years
  • PSA ≤ 15 ng/mL
  • PIRADS score ≥ 4 on initial mpMRI

The New and the Good

• Prospective and randomised analysis on the effect of a frequently taken drug on prostate cancer conspicuity in mpMRI.

Limitations

• Inclusion criteria of GS ≤ 3+4 based on mostly TRUS-Biopsy.
• Small patient cohort.

Possible consequences for clinical practice

• Since taking dutasteride (and finasteride) may negatively influence the detection of PCa, radiologists should be made aware whether their patient is taking these drugs in order to "sensitize" him/her while interpreting the scan by raising his/her sensitivity on calling a lesion "suspicious".

Possible consequences for PIRADS v3

• Regarding the recommendation on needed clinical information prior to reading an exam, the use of 5-α reductase inhibitors should definitely be required.  
• Regarding interpretation and the interpretation algorithm, it may be discussed whether either the imaging features or the suggested algorithm should be differentiated in men taking 5-α reductase inhibitors.
• Especially if quantitative measures, such as absolute ADC-value should find their way into PIRADS v3 (or v4) - which I personally think they should - the use of 5-α reductase inhibitors should be taken into account and according thresholds should be defined.

Future study ideas derived from this paper

• None, except validate by larger patient population. 

Personal Comment

• I was always wondering whether the use of 5-α reductase inhibitors - which in our institution is rarely made known in the clinical information available to us radiologists at the time of the scan - would influence conspicuity of PCa lesions. From now on, I might be biased (I hope for the good) whenever I am reading a scan of a patient taking 5-α reductase inhibitors and may rise my personal sensitivity in these patients.