The Oncological and Functional Prognostic Value of Unconventional Histology of Prostate Cancer in Localized Disease Treated with Robotic Radical Prostatectomy: An International Multicenter 5-Year Cohort Study

BACKGROUND AND OBJECTIVE

The impact of prostate cancer of unconventional histology (UH) on oncological and functional outcomes after robot-assisted radical prostatectomy (RARP) and adjuvant radiotherapy (aRT) receipt is unclear. We compared the impact of cribriform pattern (CP), ductal adenocarcinoma (DAC), and intraductal carcinoma (IDC) in comparison to pure adenocarcinoma (AC) on short- to mid-term oncological and functional results and receipt of aRT after RARP.

METHODS

We retrospectively collected data for a large international cohort of men with localized prostate cancer treated with RARP between 2016 and 2020. The primary outcomes were biochemical recurrence (BCR)-free survival, erectile and continence function. aRT receipt was a secondary outcome. Kaplan-Meier survival and Cox regression analyses were performed.

KEY FINDINGS AND LIMITATIONS

A total of 3935 patients were included. At median follow-up of 2.8 yr, the rates for BCR incidence (AC 10.7% vs IDC 17%; p < 0.001) and aRT receipt (AC 4.5% vs DAC 6.3% [p = 0.003] vs IDC 11.2% [p < 0.001]) were higher with UH. The 5-yr BCR-free survival rate was significantly poorer for UH groups, with hazard ratios of 1.67 (95% confidence interval [CI] 1.16-2.40; p = 0.005) for DAC, 5.22 (95% CI 3.41-8.01; p < 0.001) for IDC, and 3.45 (95% CI 2.29-5.20; p < 0.001) for CP in comparison to AC. Logistic regression analysis revealed that the presence of UH doubled the risk of new-onset erectile dysfunction at 1 yr, in comparison to AC (grade group 1-3), with hazard ratios of 2.13 (p < 0.001) for DAC, 2.14 (p < 0.001) for IDC, and 2.01 (p = 0.011) for CP. Moreover, CP, but not IDC or DAC, was associated with a significantly higher risk of incontinence (odds ratio 1.97; p < 0.001). The study is limited by the lack of central histopathological review and relatively short follow-up.

CONCLUSIONS AND CLINICAL IMPLICATIONS

In a large cohort, UH presence was associated with worse short- to mid-term oncological outcomes after RARP. IDC independently predicted a higher rate of aRT receipt. At 1-yr follow-up after RP, patients with UH had three times higher risk of erectile dysfunction post RARP; CP was associated with a twofold higher incontinence rate.

PATIENT SUMMARY

Among patients with prostate cancer who undergo robot-assisted surgery to remove the prostate, those with less common types of prostate cancer have worse results for cancer control, erection, and urinary continence and a higher probability of receiving additional radiotherapy after surgery.

Ductal Prostate Cancers Demonstrate Poor Outcomes with Conventional Therapies

BACKGROUND

Ductal prostate adenocarcinoma (DAC) is a rare, aggressive, histologic variant of prostate cancer that is treated with conventional therapies, similar to high-risk prostate adenocarcinoma (PAC).

OBJECTIVE

To assess the outcomes of men undergoing definitive therapy for DAC or high-risk PAC and to explore the effects of androgen deprivation therapy (ADT) in improving the outcomes of DAC.

DESIGN, SETTING, AND PARTICIPANTS

A single-center retrospective review of all patients with cT1-4/N0-1 DAC from 2005 to 2018 was performed. Those undergoing radical prostatectomy (RP) or radiotherapy (RTx) for DAC were compared with cohorts of high-risk PAC patients.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Metastasis-free survival (MFS) and overall survival (OS) rates were analyzed using Kaplan-Meier and Cox regression models.

RESULTS AND LIMITATIONS

A total of 228 men with DAC were identified; 163 underwent RP, 34 underwent RTx, and 31 had neoadjuvant therapy prior to RP. In this study, 163 DAC patients and 155 PAC patients undergoing RP were compared. Similarly, 34 DAC patients and 74 PAC patients undergoing RTx were compared. DAC patients undergoing RP or RTx had worse 5-yr MFS (75% vs 95% and 62% vs 93%, respectively, p < 0.001) and 5-yr OS (88% vs 97% and 82% vs 100%, respectively, p < 0.05) compared with PAC patients. In the 76 men who received adjuvant/salvage ADT after RP, DAC also had worse MFS and OS than PAC (p < 0.01). A genomic analysis revealed that 10/11 (91%) DACs treated with ADT had intrinsic upregulation of androgen-resistant pathways. Further, none of the DAC patients (0/15) who received only neoadjuvant ADT prior to RP had any pathologic downgrading. The retrospective nature was a limitation.

CONCLUSIONS

Men undergoing RP or RTx for DAC had worse outcomes than PAC patients, regardless of the treatment modality. Upregulation of several intrinsic resistance pathways in DAC rendered ADT less effective. Further evaluation of the underlying biology of DAC with clinical trials is needed.

PATIENT SUMMARY

This study demonstrated worse outcomes among patients with ductal adenocarcinoma of the prostate than among high-grade prostate adenocarcinoma patients, regardless of the treatment modality.

Non-metastatic ductal adenocarcinoma of the prostate: pattern of care from an uro-oncology multidisciplinary group

PURPOSE

To retrospectively review our 20 year experience of multidisciplinary management of non-metastatic ductal prostate cancer (dPC), a rare but aggressive histological subtype of prostate cancer whose optimal therapeutic approach is still controversial.

METHODS

Histologically confirmed dPC patients undergoing primary, curative treatment [radical prostatectomy (RP), external beam radiotherapy (EBRT), and androgen deprivation therapy (ADT)] were included, and percentage of ductal and acinar pattern within prostate samples were derived. Survival outcomes were assessed using the subdistribution hazard ratio (SHR) and Fine-and-Gray model.

RESULTS

From January 1997 to December 2016, 81 non-metastatic dPC fitted selection criteria. Compared to surgery alone, SHR for progression-free survival and cancer-specific mortality were 2.8 (95% CI 0.6-13.3) and 1.3 (95% CI 0.1-16.2) for exclusive EBRT, 2.7 (95% CI 0.6-13.0) and 6.5 (95% CI 0.6-69.8) for adjuvant EBRT, 4.9 (95% CI 0.7-35.5) and 5.8 (95% CI 0.5-65.6) for salvage EBRT post-prostatectomy recurrence, and 3.2 (95% CI 0.7-14.0) and 3.9 (95% CI 0.3-44.1) for primary ADT (P = 0.558; P = 0.181), respectively. Comparing multimodal treatment and monotherapy confirmed the above trends. Local recurrence more typically occurred in pure dPC patients, mixed histology more frequently produced metastatic spread (29.6% relapse in total, P = 0.026).

CONCLUSION

Albeit some limitations affected the study, our findings support the role of local treatment to achieve better disease control and improve quality of life. Different behavior, with typical local growth in pure dPC, higher distant metastatization in the mixed form, might influence treatment response. Given its poor prognosis, we recommend multidisciplinary management of dPC.