Copenhagen, Denmark
Onsite/Online

ESTRO 2022

Session Item

Urology
Poster (digital)
Clinical
BIOCHEMICAL RESPONSE AFTER STEREOTACTIC BODY RADIATION THERAPY TRAETMENT FOR PROSTATE CANCER
Jonathan Saavedra Bejarano, Spain
PO-1389

Abstract

BIOCHEMICAL RESPONSE AFTER STEREOTACTIC BODY RADIATION THERAPY TRAETMENT FOR PROSTATE CANCER
Authors:

Jonathan Saavedra Bejarano1, Paula Vicente Ruíz2, Gabriel Campos Rivera1, María Rubio Jiménez1, Mónica Ortiz Seidel3, Ana Illescas Vacas1

1Hospital Universitary Virgen Macarena, Oncology Radiotherapy, Seville, Spain; 2Oncology Radiotherapy, Oncology Radiotherapy, Seville, Spain; 3Hospital Universitary Virgen Macarena, Medical Physical, Seville, Spain

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Purpose or Objective

Stereotactic Body Radiation Therapy (SBRT) is an emerging treatment option for men with localize prostate cancer. Ultrahypofractonation has been shown to be non-inferior to convencional or hypofractionated radiotherapy in terms of biochemical control and toxicity rates. In recent years there has been a growing literature on this regard. Aim of this study is to analyze the PSA kinetics of patient with localized prostate cancer treated with primary curative intent SBRT.

Material and Methods

Between October 2019 and February 2021, 45 patients were treated at one center with SBRT as a curative intent treatment for prostate cancer. 

Results

The mean age of our series was 70,7 years (SD 5,2 years). Gleason was 6 (3 + 3) in 53,3%, Gleason 7 (3 + 4) in 24,4%, Gleason 7 (4 + 3) in 11,2%, Gleason 8 (3 + 5) in 2,2%, Gleason 8 (4 + 4) in 6,7% and Gleason 9 (4 + 5) in 2,2%. Very low risk were 2,2%, 33,3% low risk, 22,2% favorable intermediate risk, 24,4% unfavorable intermediate risk, 11,1% high risk and 6,7% very high risk.

Treatment was scheduled in 5 sessions of 7,25 Gy with a total doses of 36,25 Gy. Overall, 42,2% received concurrent androgen deprivation therapy (ADT).

Median PSA pre-treatment in our series was 7,9 ng/ml (IR 6.5-12.4 ng/ml). After a median follow-up of 15.0 months (IR 11.5-17.0 months), PSA nadir was achieved with a median level of 0,45 ng/ml (0,03-1,50 ng/ml).
Considering men treated by SBRT with the addition of ADT, the median PSA at diagnosis was 8,1 ng/ml (IR 6,6-13,8 ng/ml) while the median PSA nadir during this follow-up was 0,01 ng/ml (IR 0,01-0,14 ng/ml). Analyzing patients who did not receive concurrent ADT, their median PSA at diagnosis was 7,8 ng/ml (IR 6,5-1,0 ng/ml), with a median PSA-nadir of 1,1 ng/ml (IR 0,6-2,1 ng/ml). 

During our study we observed neither PSA bounce nor biochemical recurrence.

PSA nadir <0,3 ng/ml was achieved in 40,0% of our serie; 55,6% nadir <0,5 and 68,9% <1,0 ng/ml.
Assessing the absence or presence of ADT, patients who received exclusively SBRT 57,8% (n = 26), the PSA nadir was <0,3 ng/ml in 3,8%; <0,5 ng/ml in 23,1% and <1,0 ng/ml in 46,2% of patients. In these patients, the mean time from SBRT to nadir was 10,4 months (SD 4,7 months) and a median of 10,5 months (IR 7,0-13,0 months). Patients treated with ADT concomitant to SBRT 24,2% (n = 19), the PSA-nadir was <0,3 in 89,5% and <0,5 in 100% of the patients.

Conclusion

SBRT for prostate cancer reaches low PSA nadir at short-term when prescribed at doses of 36,25 Gy. We did not detect any biochemicalrelapse with a median follow-up of 15 months and bounce effect appears very rare.