Prostate Cancer Case Review: Biochemical Recurrence and a Rib Lesion

In "Prostate Cancer Case Review: Biochemical Recurrence and a Rib Lesion," the panel reviews a 76-year-old with biochemical recurrence whose PSMA PET reveals an indeterminate rib lesion.

Dr. Yonover presents the first case: a 76-year-old man diagnosed with metastatic prostate cancer seven years earlier, now with a rising PSA after stopping androgen deprivation therapy due to intolerable side effects. Conventional CT showed no visceral or convincing bony metastases, so a gallium-68 PSMA PET was ordered to clarify disease extent given his biochemical changes. Dr. Ghesani presents imaging showing a prior fluorine-based scan with uptake in the right third rib without a clear anatomic correlate, while a follow-up gallium scan six months later showed resolution of that finding. Dr. Yonover explains that a solitary rib lesion without other findings, especially on a fluorine-based tracer, raises his suspicion for an indeterminate bone lesion rather than true metastasis, and that comparing tracers can sometimes help adjudicate ambiguous findings despite insurer pushback. Given the patient's stable PSA and preference to remain off ADT, he says he would feel comfortable continuing surveillance rather than pursuing metastasis-directed radiation that could expose the patient to unnecessary toxicity. Dr. Mendel agrees he would not treat this lesion, noting that convincing rib metastases are typically larger and more intensely PSMA-avid, and that he would want to know the patient's PSA doubling time before deciding. He describes a parallel scenario common in his own practice: post-prostatectomy patients with a rising, low PSA and a negative PET scan, where he still frequently orders pelvic MRI, sometimes finding and biopsying local recurrences, and generally proceeds with salvage radiation to the prostate bed even when imaging is negative. Dr. Ghesani closes by reinforcing the value of reformatting images into sagittal and coronal planes near the anastomosis, where bladder activity can otherwise obscure subtle disease, and by noting that fluorine tracers preferentially localize to bone while gallium is more likely to be shunted to the liver.

Our next episode, "Prostate Cancer Case Review: PSMA PET Before Definitive Therapy," turns to a high-risk, newly diagnosed patient weighing surgery against radiation.