Are 10-, 10–12-, or > 12-mm prostate biopsy core quality control cutoffs reasonable?

Biopsy core length in white versus African descendant prostate cancer patients

Objective: To explore whether distinct prostate cancer (PCa) prognoses between ethnicities could be explained by diverse characteristics in the prostate biopsy.Methods: Clinical, prostate biopsy and surgical single-institution data of whites and African descendants with similar access to the health system who underwent radical prostatectomy whole gland histopathology within 60 days after biopsy from 2010 to 2011 and followed for 5 years minimum were compared.Results: Among 203 included patients, 153 (75.4%) were whites and 50 (24.6%) were African descendants. The mean patients' age was 63.7 (± 6.8) years. Digital rectal examination (DRE) was suspected of cancer in 45.2% of the patients. The prostate biopsy core length was smaller in African descendants than in whites, overall 11.0 ± 3.2 vs 12.0 ± 2.9 mm, p = 0.037, and without neoplasia, 10.4 ± 3.8 vs 11.7 ± 3.1 mm, p = 0.038, respectively. Also, suspicious DRE showed smaller biopsy core length, overall 11.1 ± 3.2 mm vs 12.4 ± 2.6, p = 0.003, cancer positive 12.0 ± 4.8 mm vs 13.3 ± 3.7, p = 0.022 and negative 10.6 ± 3.6 mm vs 12.2 ± 3.0, p = 0.002. On 81 months median follow-up, more African descendants were lost to follow-up (10%, n = 5 vs 3.9%, n = 6) and the biochemical recurrence rate was the same between the groups (33.3%).Conclusion: In a PCa population with similar access to the health system, prostate biopsy core length in African descendant men is significantly smaller than in whites. This finding is new and may add to the controversial argument of PCa having a worse prognosis in African descendant patients.

T cells CD4+/CD8+ local immune modulation by prostate cancer hemi-cryoablation

PURPOSE

Tumors escape from the immune system by decreasing CD8+ and increasing CD4+ T cells' activity, druggable targets. Thermal ablation might activate tumor-specific T cells by raising the presentation of tumor-specific antigens and hindering tumor negative immune regulation. Our aim was to assess T cell infiltrate pre- and post-cryoablation in a prospective observational study.

METHODS

A total of 240 sextant prostate biopsies cores (12 cores/patient) were collected from 10 unilateral prostate cancer patients (T1c, PSA density < 0.15 ng/dL, Gleason grade group 1, ≤ 2 cancer biopsy cores, and < 50% cancer core involvement) at diagnosis and 12 months after hemi-cryoablation. Cancer-positive (Diag+) and cancer-negative (Diag-) lobes at diagnosis and the same areas 12 months after hemi-cryoablation (Cryo+ and Cryo-, respectively) were explored by immunohistochemistry for infiltrating CD4+ and CD8+ T cells (in 45 random fields per prostate lobe, 400× magnification). The quantitative analysis of cells/mm² and CD4+/CD8+ ratio were performed and compared among Diag+, Diag-, Cryo+, and Cryo- using ImageJ software.

RESULTS

There was a significant increase in tumor-infiltrating CD8+ T cells/mm² in the Cryo+ tissue (mean, SD 0.31, 0.30) compared to Diag+ (0.18, 0.15), p = 0.015; confirmed in prostate acini (hot spots), p = 0.029, in which infiltrating CD4+/CD8+ T cells' ratio decreased after hemi-cryoablation, p = 0.006. Infiltrating CD4+ T cells/mm² presented a trend to decrease in Cryo+ (0.26, 0.27) compared to Diag+ (0.38, 0.32).

CONCLUSIONS

This is the first study to show local immune modulation after prostate cancer cryoablation, characterized by decreasing CD4+/CD8+ T cells' ratio, potential for clinical impact by unleashing the T-cell response to cancer. Future studies are necessary to explore different energies and longer follow-up clinical endpoints.