Background
Despite revisions in 2005 and 2014, the Gleason prostate cancer (PCa) grading system still has major deficiencies. Combining of Gleason scores into a three-tiered grouping (6, 7, 8–10) is used most frequently for prognostic and therapeutic purposes. The lowest score, assigned 6, may be misunderstood as a cancer in the middle of the grading scale, and 3 + 4 = 7 and 4 + 3 = 7 are often considered the same prognostic group.
Objective
To verify that a new grading system accurately produces a smaller number of grades with the most significant prognostic differences, using multi-institutional and multimodal therapy data.
Design, setting, and participants
Between 2005 and 2014, 20 845 consecutive men were treated by radical prostatectomy at five academic institutions; 5501 men were treated with radiotherapy at two academic institutions.
Outcome measurements and statistical analysis
Outcome was based on biochemical recurrence (BCR). The log-rank test assessed univariable differences in BCR by Gleason score. Separate univariable and multivariable Cox proportional hazards used four possible categorizations of Gleason scores.
Results and limitations
In the surgery cohort, we found large differences in recurrence rates between both Gleason 3 + 4 versus 4 + 3 and Gleason 8 versus 9. The hazard ratios relative to Gleason score 6 were 1.9, 5.1, 8.0, and 11.7 for Gleason scores 3 + 4, 4 + 3, 8, and 9–10, respectively. These differences were attenuated in the radiotherapy cohort as a whole due to increased adjuvant or neoadjuvant hormones for patients with high-grade disease but were clearly seen in patients undergoing radiotherapy only. A five–grade group system had the highest prognostic discrimination for all cohorts on both univariable and multivariable analysis. The major limitation was the unavoidable use of prostate-specific antigen BCR as an end point as opposed to cancer-related death.
Conclusions
The new PCa grading system has these benefits: more accurate grade stratification than current systems, simplified grading system of five grades, and lowest grade is 1, as opposed to 6, with the potential to reduce overtreatment of PCa.
Patient summary
We looked at outcomes for prostate cancer (PCa) treated with radical prostatectomy or radiation therapy and validated a new grading system with more accurate grade stratification than current systems, including a simplified grading system of five grades and a lowest grade is 1, as opposed to 6, with the potential to reduce overtreatment of PCa.
Among patients with Gleason score 9-10 prostate cancer, treatment with EBRT+BT with androgen deprivation therapy was associated with significantly better prostate cancer-specific mortality and longer time to distant metastasis compared with EBRT with androgen deprivation therapy or with RP.
Summary
Background
HSD3B1(1245A>C) has been mechanistically linked to castration-resistant prostate cancer by encoding an altered enzyme that augments dihydrotestosterone synthesis. We hypothesized that men inheriting the HSD3B1(1245C) allele would exhibit resistance to androgen deprivation therapy (ADT).
Methods
We determined HSD3B1 genotype retrospectively in men treated with ADT for post-prostatectomy biochemical failure and correlated genotype with long-term clinical outcomes. Patients who received postoperative adjuvant or salvage radiotherapy were eligible, provided they had residual active disease as reflected by continued increase in their PSA after treatment. We analyzed progression-free survival (PFS; primary endpoint), distant metastasis-free survival (DMFS), and overall survival (OS) according to HSD3B1 genotype. Multivariable analyses were performed to assess the independent predictive value of HSD3B1 genotype on outcomes. Results were externally validated in two additional cohorts, including a second post-prostatectomy biochemical failure cohort as well as a metastatic cohort. There was no age limit for eligibility in the primary or validation cohorts.
Findings
The study included 443 patients: 118 in the primary cohort, 137 in the post-prostatectomy validation cohort, and 188 in the metastatic validation cohort. In the primary study cohort, median PFS diminished as a function of the number of variant alleles inherited: 6.6 years in homozygous wild-type men (95% CI, 3.8 to not reached); 4.1 years in heterozygotes (95% CI, 3.0 to 5.5); and 2.5 years in homozygous variant men (95% CI, 0.7 to not reached); P=0.011. Median DMFS likewise decreased according to the number of variant alleles inherited: 9.1 years (95% CI, 7.4 to not reached); 6.8 years (95% CI, 4.3 to 7.4); and 3.6 years (95% CI, 1.0 to 7.3), respectively; P=0.014. Finally, OS diminished with the number of variant alleles inherited: 5-year and 10-year OS 82% (95% CI, 69 to 94) and 55% (95% CI, 35 to 75) in homozygous wild-type men; 74% (95% CI, 62 to 85) and 35% (95% CI, 21 to 49) in heterozygotes; and 58% (95% CI, 30 to 86) and 0% in homozygous variant men; P=0.0064. On multivariable analysis, the hazard ratio (HR) for progression was 1.6 for men with at least one variant allele (95% CI, 1.0 to 2.7; P=0.074), which compared favorably with Gleason score (HR 1.3 for Gleason score 8–10 vs. 6–7; 95% CI 0.8 to 2.0; P=0.31), though neither factor reached statistical significance with the small sample size. The impact of homozygous variant genotype on metastasis (HR 2.8; 95% CI, 1.1 to 6.7; P=0.025) and death (HR 3.5; 95% CI 1.3 to 9.5; P=0.013) was maintained on multivariable analysis. Findings in the external cohorts independently validated the impact of HSD3B1(1245C) on outcomes.
Interpretation
Inheritance of the HSD3B1(1245C) allele that enhances dihydrotestosterone synthesis is associated with prostate cancer resistance to ADT. Our findings nominate HSD3B1 as a powerful genetic biomarker capable of distinguishing men who are a priori ...
Distinguishing radiation necrosis (RN) from tumor recurrence after stereotactic radiosurgery (SRS) for brain metastases is challenging. This study assesses the sensitivity (SN) and specificity (SP) of an MRI-based parameter, the "lesion quotient" (LQ), in characterizing tumor progression from RN. Records of patients treated with SRS for brain metastases between 01/01/1999 and 12/31/2009 and with histopathologic analysis of a subsequent contrast enhancing enlarging lesion at the treated site at a single institution were examined. The LQ, the ratio of maximal nodular cross sectional area on T2-weighted imaging to the corresponding maximal cross sectional area of T1-contrast enhancement, was calculated by a neuroradiologist blinded to the histopathological outcome. Cutoffs of <0.3, 0.3-0.6, and >0.6 have been previously suggested to have correlated with RN, mixed findings and tumor recurrence, respectively. These cutoff values were evaluated for SN, SP, positive predictive value (PPV) and negative predictive value (NPV). Logistic regression analysis evaluated for associated clinical factors. For the 51 patients evaluated, the SN, SP, PPV and NPV for identifying RN (LQ < 0.3) were 8, 91, 25 and 73 %, respectively. For the combination of recurrent tumor and RN (LQ 0.3-0.6) the SN, SP, PPV and NPV were 0, 64, 0 and 83 %. The SN, SP, PPV and NPV of the LQ for recurrent tumor (LQ > 0.6) were 59, 41, 62 and 39 %, respectively. Standard MRI techniques do not reliably discriminate between tumor progression and RN after treatment with SRS for brain metastases. Additional imaging modalities are warranted to aid in distinguishing between these diagnoses.
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