Practice Updates in Prostate Cancer Imaging - Episode 17

Patient Profile 5: IMRT for Adenocarcinoma

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Dr Lawrence Saperstein describes the patient profile of a 78-year-old man with a history of intensity-modulated radiation therapy for adenocarcinoma.

Neal Shore, MD, FACS: Let’s go to your case, Larry. Can you review it for us?

Lawrence Saperstein, MD: This is a 78-year-old man with a history of IMRT [intensity-modulated radiation therapy] in 2010 for Gleason 6 adenocarcinoma with no androgen deprivation therapy. In May 2012, a repeat prostate biopsy shows, Gleason 8 adenocarcinoma. He underwent cryoablation. In December 2012, PSA [prostate-specific antigen] nadir was 0.6 ng/mL. In January 2020, PSA rose to 3.1 ng/mL. In March 2021, repeat biopsy was negative for tumor, and a recent PSA rose to 7.2 ng/mL. What do you do next?

Neal Shore, MD, FACS: What’s going through your mind for this guy, Steven? He has failed radiation, failed salvage cryoablation, and a rapid PSA doubling time.

Steven Finkelstein, MD, DABR, FACRO: I’d want to explore next-generation imaging to see if this guy has disease in many years passed. His PSA has now doubled. It looks like a PSA doubling time of around 10 months—all worrisome factors. I’m hoping that next slide is going to show a nice PSMA [prostate-specific membrane antigen] PET [positron emission tomography].

Lawrence Saperstein, MD: On the left, we have a single image of maximum-intensity projection rendering. We see physiological uptake and several markedly avid lymph nodes in the upper and lower pelvis. We’ll go to the right side, where we have a diffused PET/CT image, and we see markedly radiotracer avid lymph nodes. Just below that demonstrates how small those lymph nodes are, probably in the range of 2 to 3 mm. By conventional imaging this would be read as normal.

Steven Finkelstein, MD, DABR, FACRO: I want to make 1 comment as a radiation oncologist. For the panelists, do you think this got radiated back in 2012? Do you think this would be included in a standard field? The answer for me would be no. We are seeing these findings with arrows, where it becomes very perirectal presacral. Whenever we’re doing radiation oncology, we always think about the things we want to hit and avoid. The balance isn’t something that we classically want to cover so close to. We always try to avoid the rectum when we’re doing prostate cancer–specific radiation therapy. It’s going to be interesting to see these patterns of failure. We keep seeing disease and think, “That’s not an area we usually cover.” Now it’s 10 years later, there’s that 1 cell that became 2, became 4, became 8. That gives it enough years, and suddenly with appropriate imaging you can find sites of disease.

Could you treat this today with radiation therapy? You need to be able to find the previous radiation fields and make sure what was covered and what was not covered. But there’s a potential that this was not disease that was ever covered. You can go back and get radiation therapy in select cases but, my goodness, there are multiple spots of disease in the pelvis. You got radiation before. Not all radiation is the same in the way that not all surgeries are the same. I encourage those watching this to encourage radiation oncologists to review those previous plans with what disease is seen on imaging.

Neal Shore, MD, FACS: Those are excellent points. Hopefully the treating physician at the time would be able to go back and get the radiation plan that was performed.

Transcript edited for clarity.