Magnetic resonance imaging targeted biopsy in biopsy-naïve patients and the risk of overtreatment in prostate cancer: a grading issue

OBJECTIVE

To evaluate the impact of applying the 2014 and 2019 International Society of Urological Pathology (ISUP) recommendations on grade group distribution and concordance with radical prostatectomy (RP).

MATERIALS AND METHODS

Overall, 655 biopsy-naïve patients diagnosed by magnetic resonance imaging (MRI) targeted and systematic biopsies for Prostate Imaging Reporting and Data System score ≥3 lesions were identified from a prospectively maintained database from 2016 and 2022. Clinically significant prostate cancer was detected in 249 patients, of whom 69 underwent RP. Wilcoxon signed rank and McNemar's tests were used to compare the ISUP grade group distribution and concordance with RP after applying the 2014 (i.e., highest grade) and 2019 (i.e., global grade) ISUP recommendations, respectively.

RESULTS

Compared to the 2014 ISUP recommendations, the 2019 ISUP recommendations were associated with a significant decrease in ISUP Grade Group 4 (range of difference from -13% to -5%) and an increase in ISUP Grade Group 2 (range of difference from +6% to +11%) in MRI targeted biopsy only, MRI targeted with perilesional biopsies, and MRI targeted with systematic biopsies (all P < 0.01). In patients who underwent RP, a significant decrease in downgrading was observed with all biopsy strategies (range of difference from -19% to -12%; P ≤ 0.008), along with an increase in concordance with RP specimen (range of difference from +12% to +13%; P ≤ 0.02). The use of the 2019 ISUP recommendation was associated with RP specimen a lower treatment burden.

CONCLUSIONS

The use of the 2019 ISUP recommendations mitigates the grade migration induced by MRI targeted biopsy and improves the concordance with the final RP specimen.

The oncologic risk of magnetic resonance imaging-targeted and systematic cores in patients treated with radical prostatectomy

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.

Grade Progression and Intrapatient Tumor Heterogeneity as Potential Contributors to Resistance in Gastroenteropancreatic Neuroendocrine Tumors

Gastroenteropancreatic neuroendocrine neoplasms (NENs) are a heterogenous group of tumors that are incurable when metastatic, regardless of grade. The aim of this article is to understand tumor heterogeneity and grade progression as possible contributors to drug resistance in gastroentropancreatic neuroendocrine tumors (GEP-NETs). Heterogeneity has been observed in the genetic, pathological, and imaging features of these tumors at baseline. Diagnostic challenges related to tumor sampling and the potential for changes in grade over time further confound our ability to optimize therapy for patients. A better understanding of NEN biology and tumor heterogeneity at baseline and over time could lead to the development of new therapeutic avenues.