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PROSTOXTM 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.
PROSTOX can predict an increased risk of late GU toxicity from specific radiation therapies:
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 CFRT
- For conventionally fractionated radiotherapy (CFRT), which consists of 35-45 small doses of radiation to the prostate given over 8-10 weeks
Knowing your risk of late GU toxicity can allow you and your doctor to choose the safest course of treatment for you.
PROSTOX Testing
For a patient considering radiation therapy for treatment of their prostate cancer, a physician can now order PROSTOX if you:
- Have a localized prostate cancer diagnosis
- Have not received radiation therapy to the prostate
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Questions? Read our PROSTOX FAQ or Contact us
What will my PROSTOX results 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 CFRT test identifies biomarkers associated with toxicity from CFRT.
PROSTOX ultra
- If a patient is found to be High Risk, they have a ~75% chance of developing late GU toxicity from SBRT to the prostate, whereas if they are Low Risk they have less than a 10% risk.1-5
PROSTOX CFRT
- If a patient is found to be High Risk, they have a ~72% chance of developing late GU toxicity from CFRT to the prostate, whereas if they are Low Risk they have less than a 5% risk.1,3-5
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 both SBRT and CFRT (only 1%–2% of patients), there are alternative treatment options.
Questions? Read our PROSTOX FAQ or Contact us
Frequently asked questions about PROSTOX
General questions about PROSTOX
Accessing PROSTOX
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
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- 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, et al. Application of a genetic signature of late GU toxicity in SCIMITAR, a Post-op SBRT trial. Clin Transl Radiat Oncol. 2023 Feb 8;39:100594. doi: 10.1016/j.ctro.2023.100594. PMID: 36880064; PMCID: PMC9984404.
- Kishan AU, et al. Validation and Derivation of miRNA-Based Germline Signatures Predicting Radiation Toxicity in Prostate Cancer. Clin Cancer Res 15 June 2025; 31 (12): 2530–2538.
