Every September, Prostate Cancer Awareness Month reminds us that early detection matters. But in prostate cancer, earlier is only part of the story. The harder question is whether we can identify clinically significant disease, localize it precisely, and make the next decision with confidence.
That question matters now more than ever. The American Cancer Society estimates that over 300,000 men in the United States will be diagnosed with prostate cancer in 2026, and over 36,000 will die from the disease. At the same time, prostate cancer is not one uniform disease. Some tumors can be safely monitored. Others need timely, targeted treatment. Better care depends on telling the difference.
MRI changed the pathway – but uncertainty remains
Prostate MRI has changed what happens between an elevated PSA and a biopsy. It can help identify suspicious lesions, guide targeted sampling, and support decisions about whether a biopsy is needed. Current AUA/SUO guidance recognizes that MRI may be used before an initial biopsy to improve detection of Grade Group 2 or higher prostate cancer. PI-RADS gave radiologists a shared framework for interpreting those exams. That was a major step forward. But the read is still largely visual, and performance can vary with the reader, the scanner, the protocol, and the lesion itself. An equivocal region can lead to uncertainty. A broad target can still miss the most aggressive focus. A negative or borderline study may not completely settle the question. This is where quantitative diffusion imaging can add something different: an objective measurement tied to tissue microstructure, not another opinion layered onto the same images.
From a suspicious region to the biologic signal
Diffusion-weighted imaging is central to prostate MRI because densely cellular tumors restrict the movement of water. Conventional apparent diffusion coefficient (ADC) maps compress the behavior of multiple tissue environments into one averaged value per voxel. Cancer, benign tissue, edema, and stroma can all contribute to that average. Restriction Spectrum Imaging (RSI) takes a different approach. It separates diffusion components and isolates the restricted signal associated with densely cellular tissue. The simplest way to say it is: ADC measures the average voxel. RSI isolates the aggressive-cancer signal.
OnQ Prostate uses RSI to generate PACS-ready Restricted Signal Maps and color fusion images that place that signal directly onto the patient’s anatomy. Its quantitative RSI restriction score, or RSIrs, provides an objective biomarker that increases with the probability of clinically significant and higher-risk cancer. In a 2025 multicenter study, RSIrs performed better than conventional ADC and comparably with expert-defined PI-RADS for patient-level detection of clinically significant prostate cancer.
The exact spot, not just the region
For a biopsy, the distinction is practical. PI-RADS can define a region of suspicion. RSI can help identify the strongest restricted signal within that region – a target within the target. That additional localization may help direct the needle toward the tissue most likely to contain clinically significant disease and reduce the risk of sampling a less aggressive portion of a heterogeneous lesion. It also gives the urologist and radiologist a more intuitive image to review together. Instead of relying only on a written impression, the care team can see the same hotspot, discuss the same target, and explain the plan more clearly to the patient. Only biopsy can definitively confirm a diagnosis, but imaging can make the path to that biopsy more intentional.
The value does not end at diagnosis
A useful imaging biomarker should do more than help with the first decision. It should remain relevant as the patient moves through care. For men on active surveillance, serial MRI is often used to look for change, but qualitative comparisons can be difficult across readers and time points. Research has shown that RSI can add predictive value for upgrading beyond standard PI-RADS assessment. A reproducible quantitative biomarker creates the possibility of following one objective signal over time – surveillance decisions with less guesswork- while helping identify when a repeat biopsy may be most important.
For focal therapy and radiation therapy, location and boundaries matter. The treatment team needs to know not only that a lesion exists, but where the highest-risk focus is and how it relates to the surrounding anatomy. Clearer lesion conspicuity and quantitative information can support patient selection, target definition, treatment planning, and post-treatment assessment.
Awareness changes what happens next
Prostate Cancer Awareness Month should absolutely encourage men to understand their risk and talk with their physicians about screening. It should also push the clinical community to ask what happens after an abnormal result. Was the MRI acquired well? Can the clinically significant disease be distinguished from benign change? Can the physician see the target clearly? If surveillance is chosen, is there an objective baseline that can be followed?
At Cortechs.ai, we developed OnQ Prostate to help answer those questions with advanced diffusion imaging that is clinically ready, automated, and integrated into the existing workflow. OnQ Prostate complements standard prostate MRI, PI-RADS, clinical findings, and biopsy; it does not replace them. Its role is to add clearer visualization and objective quantitative information where uncertainty still affects care.
That is the opportunity in front of us: not AI for AI’s sake, and not simply more imaging. It is better information at the moments that matter – deciding whether to biopsy, where to target, when to continue surveillance, and how to plan treatment. This September, the message is simple: finding prostate cancer early matters. Finding the cancer that matters is what makes early detection useful.
References
1. American Cancer Society: Key Statistics for Prostate Cancer. 2026 estimates
2. Wei JT, et al. Early Detection of Prostate Cancer: AUA/SUO Guideline Part II. J Urol. 2023;210(1):54-63
3. Rojo Domingo M, et al. Restriction Spectrum Imaging as a Quantitative Biomarker for Prostate Cancer. J Urol. 2025
4. Besasie BD, et al. RSI-MRI to Improve Prostate Cancer Imaging in Men on Active Surveillance. J Urol. 2021;206(1):44-51
5. Cortechs.ai: OnQ Prostate – Bringing Quantitative MRI to Prostate Imaging. March 11, 2026
