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PROSTOX® Testing Information
To help prostate cancer patients avoid toxicity
Radiation treatment is a very effective treatment for prostate cancer.
However, 15% or more of men will experience side effects that may start 6 months or later after treatment, with the most common side effects affecting the urinary system. These side effects are referred to as late genitourinary (GU) toxicity.
Knowing your risk of late GU toxicity can allow you and your doctor to choose the safest course of treatment for you.
PROSTOX Testing
Your physician can order PROSTOX tests if you are a prostate cancer patient who has:
- A localized prostate cancer diagnosis
- Not received radiation therapy to the prostate
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Questions? Read our PROSTOX Testing FAQ or email prostox@miradx.com
What are PROSTOX tests?
PROSTOX tests are genetic tests that can predict a risk of late GU side effects from specific radiation therapy treatment approaches. They look at inherited DNA differences that help identify patients at high versus low-average risk of late GU side effects.
There are two PROSTOX tests available to cover the most common radiation regimens. A patient can take one test or both, depending on the treatment option(s) being considered.
- PROSTOX Ultra - For stereotactic body radiotherapy (SBRT), which consists of 5-7 high doses of radiation to the prostate, usually given over 10 days
- PROSTOX Standard - For conventionally fractionated radiotherapy (CFRT) or moderately hypofractionated radiotherapy (MHFRT), which consists of 20-45 doses of radiation to the prostate given over 4-10 weeks
What will PROSTOX testing tell me?
Each person has a unique set of genetic biomarkers that predict their risk of late GU toxicity, which depends on the type of radiation they receive. For example, the PROSTOX Ultra test identifies biomarkers associated with toxicity from SBRT, while the PROSTOX Standard test identifies biomarkers associated with toxicity from CFRT or MHFRT.
- PROSTOX Ultra - If a patient is found to be High Risk, they have a ~81% chance of developing late GU toxicity from SBRT to the prostate, whereas if they are Low Risk, they have a ~15% risk.1
- PROSTOX Standard - If a patient is found to be High Risk, they have a ~61% chance of developing late GU toxicity from CFRT or MHFRT to the prostate, whereas if they are Low Risk, they have a 10% risk.1
Since the biomarkers for each test are unique, a patient can be “high risk” of toxicity for one type of treatment but not for the other.
This means patients who are at high risk of toxicity to one treatment may still be eligible for radiation therapy using a different, safer method tailored to their genetic profile. In the rare case when a patient is found to be at high risk of toxicity from SBRT, MHFRT and CFRT (only 4% of patients), there are alternative treatment options.
Questions? Read our PROSTOX Testing FAQ or Contact us
Frequently asked questions about PROSTOX Testing
Patient advocates can also find resources here.
General questions about PROSTOX Testing
Accessing PROSTOX Testing
Disclosure: Any discussion of medical management options is for general informational purposes only and does not constitute a medical recommendation. All medical management decisions should be made based on consultation between each patient and his or her healthcare professional.
References
- Based on internal data from patients in clinical trials and real-world clinical settings.
- Kishan AU, et al. Long-term outcomes of stereotactic body radiotherapy for low-risk and intermediate-risk prostate cancer. JAMA Network Open 2019;2:e188006.
- Weidhaas, JB, et al. MicroRNA-based biomarkers of the radiation response in prostate cancer. Journal of Clinical Oncology 38, no. 6_suppl (February 20, 2020) 163-163. DOI: 10.1200/JCO.2020.38.6_suppl.163.
- Kishan AU, et al. Germline variants disrupting microRNAs predict long-term genitourinary toxicity after prostate cancer radiation. Journal for Radiotherapy and Oncology 2022;167:226-232. doi: 10.1016/j.radonc.2021.12.040.
- Kishan AU, Marco N, Ma TM, et al. Application of a genetic signature of late GU toxicity in SCIMITAR, a Post-op SBRT trial. Clin Transl Radiat Oncol. 2023;39doi:10.1016/j.ctro.2023.100594.
- Kishan AU, McGreevy K, Valle L, et.al. Validation and derivation of microRNA-based germline signatures predicting radiation toxicity in prostate cancer. Clin Cancer Res. 2025 Jun 13;31(12):2530-2538. doi: 10.1158/1078-0432.CCR-24-3951.