After an initial favorable response to ADT, a significant fraction of patients with advanced prostate cancer will develop CRPC with a median time to androgen independence of 14 to 30 months [130]. Patients invariably progress to a castration-resistant state in which the cancer will grow despite low levels of serum testosterone [131]. More than 90% of patients with CRPC have bone metastases [132]. Morbidity and mortality from prostate cancer is typically the result of metastatic CRPC. CRPC represents the lethal form of the disease and carries a poor prognosis with a median survival of <2 years for those with metastatic disease [133]. In this setting, imaging is not done for detection or diagnosis of disease, but the role shifts to one of monitoring response to therapy. Bone Scan Bone metastases are common in late-stage metastatic prostate cancer, particularly CRPC. Bone scan in this setting with PSA >60 ng/mL is greatly increased in yield compared to Variants 1 and 2. Bone scan can reflect changes in disease status post-treatment, and successfully treated metastases can become negative, which usually is accompanied by a corresponding marked decrease in serum PSA level. Bone scan can show a flare phenomenon after treatment initiation that could lead to false interpretation as progression [134]. Bone scan and CT are often performed as complimentary modalities, the pair serving as an alternative to specialized PET examinations (choline or fluciclovine). CT Chest, Abdomen, and Pelvis With advanced disease, nodal metastases progress in size and become diagnosable by CT. In this setting, CT is useful in following response of known enlarged metastatic lymphadenopathy to treatment. CT is useful in Post-Treatment Follow-up of Prostate Cancer detecting visceral metastases; liver metastases in particular are the most common visceral metastasis, and CT is very accurate for that evaluation [135].
Post Treatment Follow up of Prostate Cancer. After an initial favorable response to ADT, a significant fraction of patients with advanced prostate cancer will develop CRPC with a median time to androgen independence of 14 to 30 months [130]. Patients invariably progress to a castration-resistant state in which the cancer will grow despite low levels of serum testosterone [131]. More than 90% of patients with CRPC have bone metastases [132]. Morbidity and mortality from prostate cancer is typically the result of metastatic CRPC. CRPC represents the lethal form of the disease and carries a poor prognosis with a median survival of <2 years for those with metastatic disease [133]. In this setting, imaging is not done for detection or diagnosis of disease, but the role shifts to one of monitoring response to therapy. Bone Scan Bone metastases are common in late-stage metastatic prostate cancer, particularly CRPC. Bone scan in this setting with PSA >60 ng/mL is greatly increased in yield compared to Variants 1 and 2. Bone scan can reflect changes in disease status post-treatment, and successfully treated metastases can become negative, which usually is accompanied by a corresponding marked decrease in serum PSA level. Bone scan can show a flare phenomenon after treatment initiation that could lead to false interpretation as progression [134]. Bone scan and CT are often performed as complimentary modalities, the pair serving as an alternative to specialized PET examinations (choline or fluciclovine). CT Chest, Abdomen, and Pelvis With advanced disease, nodal metastases progress in size and become diagnosable by CT. In this setting, CT is useful in following response of known enlarged metastatic lymphadenopathy to treatment. CT is useful in Post-Treatment Follow-up of Prostate Cancer detecting visceral metastases; liver metastases in particular are the most common visceral metastasis, and CT is very accurate for that evaluation [135].