Biopsy and implantation of the seminal vesicles

Intensity-modulated radiotherapy for prostate cancer with seminal vesicle involvement (T3b): A multicentric retrospective analysis

OBJECTIVES

No study has reported clinical results of external-beam radiotherapy specifically for T3b prostate cancer. The possibility of escalating the dose to the involved seminal vesicles (ISV) while respecting the dose constraints in the organs at risk is thus so far not clearly demonstrated. The objective of the study was to analyze the dose distribution and the clinical outcome in a large series of patients who received IMRT for T3b prostate cancer.

MATERIALS AND METHODS

This retrospective analysis included all patients who received IMRT and androgen deprivation therapy for T3b prostate cancer, between 2008 and 2017, in six French institutions, with available MRI images and dosimetric data.

RESULTS

A total of 276 T3b patients were included. The median follow-up was 26 months. The median (range) prescribed doses (Gy) to the prostate and to the ISV were 77 (70-80) and 76 (46-80), respectively. The dose constraint recommendations were exceeded in less than 12% of patients for the rectum and the bladder. The 5-year risks of biochemical and clinical recurrences and cancer-specific death were 24.8%, 21.7%, and 10.3%, respectively. The 5-year risks of local, pelvic lymph node, and metastatic recurrences were 6.4%, 11.3%, and 15%, respectively. The number of involved lymph nodes (≤ 2 or ≥ 3) on MRI was the only significant prognostic factor in clinical recurrence (HR 9.86) and death (HR 2.78). Grade ≥ 2 acute and 5-year late toxicity rates were 13.2% and 12% for digestive toxicity, and 34% and 31.5% for urinary toxicity, respectively. The dose to the pelvic lymph node and the age were predictive of late digestive toxicity.

CONCLUSION

IMRT for T3b prostate cancer allows delivery of a curative dose in the ISV, with a moderate digestive toxicity but a higher urinary toxicity. Lymph node involvement increases the risk of recurrence and death.

Stage T3b prostate cancer diagnosed by seminal vesicle biopsy and treated with neoadjuvant hormone therapy, permanent brachytherapy and external beam radiotherapy

OBJECTIVES

To report the long-term results of prostate brachytherapy followed by external beam radiotherapy (EBRT) in men with a positive seminal vesicle biopsy (+SVB).

PATIENTS AND METHODS

In all, 1081 men with localised prostate cancer were treated with permanent brachytherapy, of which 615 had staging SVB and 53 (9.4%) were positive. Higher stage, Gleason score and PSA level were associated with a +SVB (P < 0.001). Patients with +SVB and negative laparoscopic pelvic lymph node dissection, bone and CT scans had 3 months of androgen-deprivation therapy (ADT) followed by ¹⁰³ Pd implant to the prostate (dose 100 Gy) and proximal SVs, and 2 months later 45 Gy EBRT. ADT was continued for a median of 6 months (total ADT 9 months). The mean (range) follow-up was 9 (5-22) years.

RESULTS

Biochemical freedom from failure (computed by the Phoenix definition), freedom from metastasis, and cause-specific survival (CSS) for patients with a negative SVB (-SVB) vs +SVB at 15 years, was 76.3% vs 60.6% (P = 0.001), 95.4% vs 78.2% (P < 0.001), and 95% vs 70.4% (P < 0.001), respectively. Prostate cancer death occurred in 45 of 590 (7.6%) men with a -SVB vs eight of 25 (32%) with a +SVB (odds ratio 5.7, 95% confidence interval 2.35-13.9, P < 0.001). Cox proportion hazard rates (HRs) demonstrated Gleason score (P < 0.001, HR 1.9), stage (P = 0.010, HR 1.42), RT dose (P = 0.013, HR 0.991), and +SVB (P = 0.001, HR 4.48), as significantly associated with CSS.

CONCLUSIONS

Men with a +SVB have inferior CSS compared to those with a -SVB. However, a strategy that included a SVB in high-risk patients and implantation of the SVs in men undergoing combined therapy still yields favourable long-term results.