An essential part of planning treatment for prostate cancer (PCa) is determining its size and location. Where and how big is it? If the tumor is found early when it is small and contained within the gland, it is called localized. In this case, the patient is a candidate for a local treatment with curative intent—which is a fancy way of saying that removing or destroying the tumor before it has begun to spread offers very high chances of 100% cancer control.

Local treatments can be tailored to the extent of the tumor, depending not only on tumor size and location, but also on additional clinical factors such as patient age, family history, PSA at the time of diagnosis, PI-RADS score, Gleason score, and genomics (if testing was done). When all factors are taken into account, the treatment should “match” the extent and aggression level of the disease. From least aggressive to most aggressive treatments, choices range from focal ablation, partial gland ablation (larger area than focal but less than whole gland), and whole gland treatment by surgery or radiation.

However, PCa can be very sneaky. A bulky, aggressive tumor that occupies much of the gland, or that has grown along the edge of the prostate capsule brings suspicion that some has escaped the gland and begun growing elsewhere. If this occurs, it is called advanced, meaning tumor activity beyond the prostate into the tissue surround it, nearby structures like the bladder, or nearby lymph nodes. Finally, if tumor activity is present in more remote locations such as bones or other organs, it is called metastasis or simply mets.

The old days: ruling out prostate cancer spread

It wasn’t that long ago that newly diagnosed patients, especially those with PSA greater than 10, were routinely sent for CT scans and bone scans. This was done to rule out tumor advance or spread in order to verify the patient was a candidate for a localized treatment. Though these were not the most reliable or sensitive tests, they were certainly better than nothing. The American Cancer Society (ACS) states:

A CT scan uses x-rays to make detailed, cross-sectional images of your body. This test isn’t often needed for newly diagnosed prostate cancer if the cancer is likely to be confined to the prostate based on other findings (DRE result, PSA level, and Gleason score). Still, it can sometimes help tell if prostate cancer has spread into nearby lymph nodes.

“Sometimes” is not the most reassuring statistic. As for conventional bone scans done by bone scintigraphy, they are also being replaced by MRI because scintigraphy for PCa has a high rate of false positives,^[i] and MRI is more sensitive. As ACS explains, “A bone scan might suggest cancer in the bone, although other non-cancerous conditions such as arthritis can sometimes look similar on the scan. To be sure, other tests, such as plain x-rays, CT or MRI scans, or even a bone biopsy, might be needed.” Clearly, something better is needed to be confident as to whether a localized treatment is in a patient’s best interest. If not, the treatment strategy must be more generalized and aggressive.

The new MRI world

Thankfully, detecting PCa activity beyond the prostate in tissue as well as bones can be accomplished using whole body MRI. A comprehensive review of published literature was conducted by a research team from MD Anderson Cancer Center (Houston, TX). They found that not only was whole body MRI at least as good, if not better, than CT for detecting lymph node involvement, it also exceeded bone scintigraphy in identifying bone mets.^[ii] Importantly, whole body MRI involves a single scanning session, which is not only convenient from a patient perspective, it also helps reduce the anxiety of scheduling then waiting for two different test results. (Of note, the only imaging superior for detecting clinically significant PCa plus bone mets is a hybrid called PSMA PET/MRI, which requires a specialized radiotracer.^[iii])

The Sperling Prostate Center is proud to offer whole body MRI for the evaluation of possible tumor extension beyond the prostate gland. Just as important, if our 3T multiparametric MRI identifies only PCa contained in the gland, Dr. Sperling can discuss all localized treatment options, including our focal ablation methods using either Focal Laser Ablation (FLA) or TULSA. Contact us for more information.

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

References

[i] Mohseninia N, Zamani-Siahkali N, Harsini S et al. Bone Metastasis in Prostate Cancer: Bone Scan Versus PET
Imaging. Semin Nucl Med. 2024 Jan;54(1):97-118.
[ii] Fang AM, Gregg JR, Pettaway C, Ma J et al. Whole-body MRI for staging prostate cancer: a narrative review. BJU
Int. 2024 Sep 22.
[iii] Barbosa FG, Queiroz MA, Nunes RF et al. Clinical perspectives of PSMA PET/MRI for prostate cancer. Clinics (Sao Paulo). 2018 Sep 21;73(suppl 1):e586s.