Radiotherapy Approach for High-Risk Prostate Cancer

Standard Treatment Approach

The American Urological Association recommends external beam radiation therapy (EBRT) using intensity modulated radiation therapy (IMRT) techniques to provide highly conformal treatment to the prostate for high-risk prostate cancer patients 1, 2
The National Comprehensive Cancer Network recommends long-term androgen deprivation therapy (ADT) (24-36 months) as an adjunct to radiotherapy for high-risk prostate cancer patients (Strong Recommendation; Evidence Level: Grade A) 2, 3, 4
Pelvic lymph node irradiation should be considered for patients with high-risk disease, as recommended by the National Comprehensive Cancer Network 5, 6
Doses between 78 and 80+ Gy provide improved PSA-assessed disease control for high-risk disease, according to the National Comprehensive Cancer Network 6
Image-guided radiation therapy (IGRT) is required if dose ≥78 Gy to improve oncologic cure rates and reduce side effects, as recommended by the National Comprehensive Cancer Network 6

The American Urological Association suggests that combination therapy of EBRT with brachytherapy (either low-dose or high-dose rate) can be considered to improve coverage of the periprostatic space for high-risk prostate cancer patients 1, 7
The National Comprehensive Cancer Network recommends that the addition of brachytherapy to EBRT has shown reduced risk of recurrence in high-risk patients 7
Analysis of 12,745 high-risk patients found that treatment with brachytherapy plus EBRT lowered disease-specific mortality compared with EBRT alone (HR, 0.77; 95% CI, 0.66–0.90), as reported by the National Comprehensive Cancer Network 7
Trimodality treatment (EBRT + brachytherapy + ADT) has shown excellent outcomes with 9-year progression-free survival and disease-specific survival rates reaching 87% and 91%, respectively, according to the National Comprehensive Cancer Network 7

The European Organisation for Research and Treatment of Cancer (EORTC) trial showed that 36 months of ADT improved 5-year overall survival compared to 6 months (84.8% vs 81.0%, HR 1.42; 95% CI 1.09–1.85) for high-risk prostate cancer patients 3
Neoadjuvant and concurrent ADT for 4–6 months followed by adjuvant ADT for a total of 24-36 months is recommended by the European Organisation for Research and Treatment of Cancer (EORTC) and the American Urological Association 2, 3

Patients should be informed that ADT with radiation increases the likelihood and severity of adverse treatment-related events on sexual function and can cause other systemic side effects (Strong Recommendation; Evidence Level: Grade B), as recommended by the American Urological Association 2, 4

Primary ADT alone (without radiotherapy) is not recommended as standard initial treatment for non-metastatic high-risk prostate cancer, according to the European Organisation for Research and Treatment of Cancer (EORTC) and the National Comprehensive Cancer Network 3, 8
Ensure proper patient selection for brachytherapy, as patients with very large or very small prostate, high IPSS scores, or previous TURP may be at increased risk for side effects, as recommended by the National Comprehensive Cancer Network 6
Post-implant dosimetry should be performed to document the quality of brachytherapy implants, according to the National Comprehensive Cancer Network 6
Daily prostate localization techniques should be used to improve treatment accuracy and reduce side effects, as recommended by the National Comprehensive Cancer Network 6

The National Comprehensive Cancer Network (NCCN) guidelines recommend 44-50 Gy to the pelvic lymph nodes when treating high-risk prostate cancer patients 9, 10
The elective dose is delivered to areas at risk for microscopic nodal involvement, including the obturator, internal and external iliac, presacral, and sacral lymph node regions 9
The elective nodal volume receives this lower dose while the prostate itself receives the higher definitive dose of 75.6-81 Gy, typically using IMRT techniques 10, 11, 12

Pelvic lymph node irradiation is a Category 1 recommendation for high-risk prostate cancer patients, combined with 24-36 months of androgen deprivation therapy 9, 10
High-risk features include: T3-T4 disease, Gleason score 8-10, or PSA >20 ng/mL 9

Pelvic nodal irradiation may be considered for intermediate-risk patients, though it is not mandatory 9, 10
When used, the same elective dose of 44-50 Gy applies, with 4-6 months of concurrent ADT 9, 10

Patients with low-risk prostate cancer should NOT receive pelvic lymph node irradiation 9, 10

Daily image-guided radiation therapy (IGRT) is essential when delivering doses >75 Gy to the prostate to ensure accuracy and minimize toxicity 10
IGRT techniques include CT, ultrasound, implanted fiducials, or electromagnetic tracking 9, 10

Do not use the standard 45-50 Gy nodal dose as a boost dose to grossly involved nodes—these require higher doses of 54-66 Gy if anatomically feasible 13
Avoid treating pelvic nodes in low-risk patients, as this adds toxicity without oncologic benefit 9, 10