Advanced Locally Invasive Prostate Cancer with High-Risk Features
This MRI describes a large, highly aggressive prostate cancer with definitive extracapsular extension and bilateral seminal vesicle invasion, representing at minimum stage T3b disease that requires immediate urologic oncology consultation for multimodal treatment planning with curative intent combining radiation therapy and long-term androgen deprivation therapy.
Understanding Your MRI Findings
Your imaging reveals several concerning features that define this as advanced, high-risk prostate cancer:
Lesion Characteristics
- 3.8 cm lesion: This represents a substantial tumor burden involving multiple zones of the prostate (apex, right peripheral zone anterior/mid/posterior, and left peripheral zone mid) 1.
- PI-RADS 5: This is the highest suspicion category on the Prostate Imaging Reporting and Data System, indicating >95% probability of clinically significant cancer requiring treatment 1, 2.
Critical Staging Features
Bilateral Seminal Vesicle Invasion (Stage T3b):
- Seminal vesicle involvement places you in the highest risk category, with only 25% of patients remaining biochemically progression-free at 10 years after surgery alone 1.
- Bilateral involvement indicates extensive local disease spread beyond the prostate capsule 1, 3.
- This finding independently predicts worse prognosis and mandates aggressive multimodal therapy 1.
Grade 3 Extracapsular Extension:
- This indicates tumor has broken through the prostate capsule and is growing into surrounding tissues 1.
- The presence of extracapsular extension in patients with seminal vesicle invasion significantly worsens outcomes, increasing the risk of systemic progression (hazard ratio 1.56) and cancer death (hazard ratio 1.71) 4.
- MRI demonstrates 96% specificity for detecting extracapsular extension, making this a highly reliable finding 3, 5.
Clinical Implications and Risk Stratification
This constellation of findings classifies you as high-risk prostate cancer based on NCCN criteria (T3a or higher stage, regardless of PSA or Gleason score) 1.
Expected Disease Behavior
- High-risk patients with seminal vesicle involvement have a 27-58% risk of disease progression depending on additional risk factors 1.
- The median length of seminal vesicle involvement in surgical series is 1.0 cm, with your bilateral involvement suggesting extensive disease 6.
- Extracapsular extension combined with seminal vesicle invasion confers significantly worse 15-year outcomes: biochemical recurrence-free survival of 29%, systemic progression-free survival of 71%, and cancer-specific survival of 80% without aggressive treatment 4.
Recommended Treatment Approach
Based on current guidelines, surgery alone is insufficient for this stage of disease 1, 3.
Standard of Care Treatment
Definitive radiation therapy combined with long-term androgen deprivation therapy (24-36 months) is the recommended approach 1, 3:
- Radiation therapy: High-dose external beam radiation (78-80+ Gy) using image-guided techniques (3D-CRT/IMRT with daily IGRT) targeting the prostate, proximal 2.0-2.5 cm of seminal vesicles, and potentially pelvic lymph nodes 1, 3, 6.
- Androgen deprivation therapy: Long-term hormonal therapy (24-36 months) started before, during, and continued after radiation significantly improves outcomes in high-risk disease 1.
Why Not Surgery?
- Radical prostatectomy with pelvic lymph node dissection remains an option if predicted probability of lymph node metastasis is ≥2%, but requires adjuvant radiation and hormonal therapy given the adverse pathologic features 1.
- Patients with seminal vesicle invasion and extracapsular extension have significantly increased risks of systemic progression and cancer death even after surgery, necessitating additional treatments 4.
Critical Next Steps
Immediate Actions Required
- Urologic oncology consultation within 1-2 weeks to discuss treatment options and staging completion 1.
- Complete staging workup for high-risk disease 1:
- CT chest/abdomen/pelvis to evaluate for lymph node involvement and distant metastases
- Bone scan to exclude skeletal metastases
- Consider PSMA PET/CT if available, which shows 89% sensitivity for detecting clinically significant disease and may identify occult metastases 2
- Prostate biopsy confirmation if not already performed, as MRI findings must be correlated with histologic Gleason grade to finalize treatment planning 1, 2.
Additional Staging Considerations
- Pelvic lymph node involvement occurs in approximately 6% of cases with seminal vesicle invasion 5.
- Multiparametric MRI with superparamagnetic particles can detect metastatic lymph nodes even when normal-sized, with 88% accuracy 5, 7.
Prognosis and Monitoring
Without treatment, this represents life-threatening disease with high probability of progression to metastatic cancer 1, 4.
With appropriate multimodal therapy (radiation + long-term hormonal therapy):
- Adjuvant hormonal therapy reduces systemic progression risk by 50% (hazard ratio 0.50) and cancer death risk by 43% (hazard ratio 0.57) in patients with adverse pathologic features 4.
- Long-term disease control is achievable in the majority of patients who complete the full treatment course 1.
Follow-up Protocol After Treatment
- PSA monitoring every 3-6 months for the first 5 years, then annually 1.
- Physical examination including digital rectal exam every 3-6 months initially 1.
- Biochemical recurrence defined as PSA rise ≥2 ng/mL above nadir after radiation therapy 1.
Important Caveats
- Active surveillance is absolutely contraindicated for this stage of disease given the definitive radiological stage progression to T3b with bilateral seminal vesicle invasion 1.
- MRI quality matters: These findings assume high-quality multiparametric MRI with proper technique; confirmation with biopsy remains essential 2.
- Treatment must not be delayed: High-risk prostate cancer with seminal vesicle invasion requires prompt initiation of therapy to maximize cure rates 1, 3.