A positive LucenceINSIGHT test indicates the presence of circulating tumor DNA (ctDNA) associated with prostate cancer in your blood. If a CT scan was negative, it is important to understand that CT scans are generally better at finding larger tumors or cancer that has spread to lymph nodes and bones, rather than early-stage cancer within the prostate itself.
Based on standard clinical pathways and the nature of liquid biopsies, the next steps typically involve more specialized imaging and a physical biopsy to confirm the findings.
1. Multiparametric MRI (mpMRI)
In Singapore’s clinical practice (and globally), a Multiparametric MRI is usually the gold standard next step when cancer is suspected but a CT scan is clear.
Why: Unlike a CT, an mpMRI provides very high-resolution images of the prostate tissue. It can identify small, "suspicious" lesions that a CT scan would almost certainly miss.
The Result: It will give you a PI-RADS score (1 to 5). A score of 4 or 5 strongly suggests that a targeted biopsy is necessary.
2. Prostate Biopsy (Fusion Biopsy)
A liquid biopsy like Lucence suggests cancer exists, but a tissue biopsy is the only way to officially diagnose it and determine the "Gleason Score" (how aggressive the cancer is).
MRI-Ultrasound Fusion Biopsy: If the mpMRI shows a suspicious spot, doctors use "fusion" technology to overlay the MRI images onto a real-time ultrasound, allowing them to aim the needle exactly at the area of concern.
Transperineal Biopsy: This is now the preferred method in Singapore over the older transrectal method, as it has a lower risk of infection.
3. PSA and PSA Density
Your doctor will likely look at your PSA (Prostate-Specific Antigen) levels alongside the Lucence result.
PSA Density: They may calculate your PSA level relative to the size of your prostate. A high density often triggers a biopsy even if imaging is inconclusive.
4. Specialist Consultation (Urologist)
If you haven't already, you should see a Urologist. They will perform a Digital Rectal Exam (DRE) to feel for any physical irregularities that scans might have missed.
Why did the CT scan fail to detect it?
It is quite common for a CT scan to be negative in early-stage prostate cancer. CT scans use X-rays to look for structural changes and "gross" disease (large masses). Early prostate cancer often doesn't change the shape of the prostate enough for a CT to see it.
Important Note: A "Detected" result on a liquid biopsy is a signal to investigate further, not a definitive diagnosis. It is possible for these tests to detect very early-stage or low-grade "indolent" cancers that may only require "Active Surveillance" (watching and waiting) rather than immediate surgery or radiation.
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