Treatment for T3 N1 Prostate Cancer with Seminal Vesicle and Perineural Involvement
For this 56-year-old man with T3 N1 prostate cancer, the standard treatment is external beam radiotherapy to the prostate and pelvis combined with long-term androgen deprivation therapy (ADT) for at least 24-36 months. 1
Primary Treatment Approach
The presence of lymph node involvement (N1) fundamentally changes the treatment paradigm and makes this a high-risk, node-positive case requiring combined modality therapy:
External beam radiotherapy should be delivered using conformal techniques (IMRT or VMAT with image guidance) to a minimum target dose of 70 Gy in 2.0 Gy fractions to the prostate bed, with inclusion of pelvic lymph nodes in the radiation field 1, 2
Long-term ADT must be continued for 24-36 months in combination with radiation therapy, as this significantly improves local control, reduces disease progression, and improves overall survival in locally advanced disease 3, 1
Consider adding abiraterone plus prednisone for 24 months to the radiation and ADT regimen, as this patient meets criteria for intensified systemic therapy (node-positive disease qualifies as very high-risk), which significantly improves metastasis-free survival (HR 0.54) and overall survival (HR 0.63) 1
Why Surgery Is NOT Recommended
While radical prostatectomy can be considered for T3 disease in highly selected cases, the presence of N1 (node-positive) disease makes surgery inappropriate as primary treatment:
- Prostatectomy should only be undertaken in T3 and pN1 cancers within a randomized clinical trial setting 3
- Radical prostatectomy is specifically not recommended for pN1 high-grade tumors (Gleason score ≥7) 3
- Node-positive disease requires systemic therapy that surgery alone cannot provide 1
Required Staging Before Treatment
Before initiating therapy, complete the following staging workup:
- Bone scan is mandatory given the T3 stage and likely elevated PSA 3
- CT scan of abdomen and pelvis to fully assess extent of nodal disease 3
- Renal ultrasound for patients with T3 cancer 3
- Confirm Gleason score and preoperative PSA level, as these are critical prognostic factors that guide treatment intensity 3, 4
Treatment Protocol Details
Radiation Therapy Specifications:
- Deliver 70-78 Gy to the prostate using conformal techniques 1
- Include pelvic lymph nodes in the radiation field given N1 status 3, 1
- Use intensity-modulated radiotherapy (IMRT) to reduce late toxicity 3, 2
Hormone Therapy Protocol:
- Initiate LHRH analog with antiandrogen coverage for the first 4 weeks to prevent testosterone flare 3
- Continue ADT for minimum 24 months, ideally 36 months for node-positive disease 1
- Consider breast irradiation (8-15 Gy in 1-3 fractions) 1-2 weeks before starting antiandrogen therapy to prevent painful gynecomastia 3
Intensified Systemic Therapy:
- Add abiraterone 1000 mg daily plus prednisone 5 mg twice daily for 24 months, given the node-positive status 1
Prognostic Factors in This Case
The following features in this patient indicate high-risk disease requiring aggressive treatment:
- T3 stage with seminal vesicle involvement indicates locally advanced disease with high risk of progression 3, 4
- N1 (node-positive) disease is an independent adverse prognostic factor requiring long-term ADT 3, 1
- Perineural invasion is an additional adverse prognostic factor, though it does not change the treatment approach 3, 4
Common Pitfalls to Avoid
- Do not use short-course ADT (<24 months) with radiation for T3 N1 disease, as long-term ADT is required for optimal outcomes 1
- Do not consider hormone therapy alone as definitive treatment, as radiation plus ADT provides superior survival compared to ADT alone 3, 1
- Do not pursue radical prostatectomy as primary treatment given the N1 status 3
- Do not use chemotherapy in this nonmetastatic setting, as it is not indicated 1, 4
Follow-Up Monitoring
After completing treatment: