As we have seen, SBRT is a preferred therapy for low and intermediate-risk patients (see this link). It is effective, safe, convenient, and relatively inexpensive. However, its use for high-risk patients remains controversial.
Amar Kishan has accumulated data from 8 institutions that have used SBRT for 344 high-risk patients. They were treated as follows:
- They received from 35 Gy-40 Gy in 5 treatments (7-8 Gy per treatment)
- 72% received adjuvant ADT for a median of 9 months
- 19% received elective nodal radiation
After a median follow-up of 49.5 months:
- 4-year biochemical recurrence-free survival (bRFS)was 82%
- Higher dose, longer ADT, and nodal radiation were associated with better bRFS
- 4-year metastasis-free survival was 89%
- Late grade 3 GU toxicity was 2.3%
- Late grade 3 GI toxicity was 0.9%
- Toxicity was associated with dose and ADT use
Although the results of different prospective trials aren't comparable, the following table gives an idea of 4-6 year outcomes of prospective trials of high-risk patients using various therapies.
SBRT = stereotactic body radiation therapy,. External beam radiation (EBRT) concentrated in 5 treatments
NCCN has included SBRT as a reasonable standard-of-care option for high-risk patients (Table 1 Principles of Radiation Therapy PROS-E 3 of 5 in NCCN Physicians Guidelines 3.2020). Due to the pandemic, an international panel of radiation oncologists is recommending that high-risk patients consider its use (see this link).