The oncologic risk of magnetic resonance imaging‐targeted and systematic cores in patients treated with radical prostatectomy
Authors: Gaffney Christopher D. , Tin Amy L. , Fainberg Jonathan , Fine Samson , Jibara Ghalib , Touijer Karim , Eastham James , Scardino Peter , Laudone Vincent , Vickers Andrew J. , Ehdaie Behfar 
Published: August 2023

Background

Magnetic resonance imaging (MRI)‐targeted prostate biopsy (MRI‐biopsy) detects high‐Grade Group (GG) prostate cancers not identified by systematic biopsy (S‐biopsy). However, questions have been raised whether cancers detected by MRI‐biopsy and S‐biopsy, grade‐for‐grade, are of equivalent oncologic risk. The authors evaluated the relative oncologic risk of GG diagnosed by S‐biopsy and MRI‐biopsy.

Methods

This was a retrospective analysis of all patients who had both MRI‐biopsy and S‐biopsy and underwent with prostatectomy (2014–2022) at Memorial Sloan Kettering Cancer Center. Three logistic regression models were used with adverse pathology as the primary outcome (primary pattern 4, any pattern 5, seminal vesicle invasion, or lymph node involvement). The first model included the presurgery prostate‐specific antigen level, the number of positive and negative S‐biopsy cores, S‐biopsy GG, and MRI‐biopsy GG. The second model excluded MRI‐biopsy GG to obtain the average risk based on S‐biopsy GG. The third model excluded S‐biopsy GG to obtain the risk based on MRI‐biopsy GG. A secondary analysis using Cox regression evaluated the 12‐month risk of biochemical recurrence.

Results

In total, 991 patients were identified, including 359 (36%) who had adverse pathology. MRI‐biopsy GG influenced oncologic risk compared with S‐biopsy GG alone (p < .001). However, if grade was discordant between biopsies, then the risk was intermediate between grades. For example, the average risk of advanced pathology for patients who had GG2 and GG3 on S‐biopsy was 19% and 66%, respectively, but the average risk was 47% for patients who had GG2 on S‐biopsy and patients who had GG3 on MRI‐biopsy. The equivalent estimates for 12‐month biochemical recurrence were 5.8%, 15%, and 10%, respectively.

Conclusions

The current findings cast doubt on the practice of defining risk group based on the highest GG. Because treatment algorithms depend fundamentally on GG, further research is urgently required to assess the oncologic risk of prostate tumors depending on detection technique.

Plain Language Summary

Using magnetic resonance imaging (MRI) to help diagnose prostate cancer can help identify more high‐grade cancers than using a systematic template biopsy alone.

However, we do not know if high‐grade cancers diagnosed with the help of an MRI are as dangerous to the patient as high‐grade cancers diagnosed with a systematic biopsy.

We examined all of our patients who had an MRI biopsy and a systematic biopsy and then had their prostates removed to find out if these patients had risk factors and signs of aggressive cancer (cancer that spread outside the prostate or was very high grade).

We found that, if there was a difference in grade between the systematic biopsy and the MRI‐targeted biopsy, the risk of aggressive cancer was between the two grades.