Unusual Presentation of Solitary Penile Metastasis of Prostate Cancer on 68 Ga-PSMA PET/CT.

ABSTRACT: A 75-year-old patient was referred with biochemical recurrence for prostate cancer. The patient underwent 68 Ga-PSMA (prostate-specific membrane antigen) PET/CT scan, which revealed a focal PSMA activity in the proximal left lateral penile margin. Although a subsequent ultrasound did not identify the abnormality, MRI pelvis revealed a 10-mm lesion in the left proximal corpus cavernosum. This lesion was consistent with metastatic acinar adenocarcinoma of the prostate on postresection histopathology. This unusual presentation of asymptomatic, histopathology-proven, penile solitary metastases was documented 3 years after robotic-assisted laparoscopic prostatectomy and pelvic external beam radiotherapy.

PET/CT in treatment response assessment in lung cancer. When should it be recommended?

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. Different treatment options are now possible both for surgical candidates and for those NSCLC patients deemed not suitable for surgery. Despite the treatments available, only a limited number of less advanced stages are potentially curable, with many patients suffering local recurrence or distant metastases. FDG-PET/CT is commonly used in many centers for post-treatment evaluation, follow-up, or surveillance; Nonetheless, there is no clear consensus regarding the indications in these cases. Based upon the results of a literature review and local expertise from a large lung cancer unit, we built clinical evidence-based recommendations for the use of FDG-PET/CT in response assessment. We found that in general this is not recommended earlier than 3 months from treatment; however, as described in detail the correct timing will also depend upon the type of treatment used. We also present a structured approach to assessing treatment changes when reporting FDG-PET/CT, using visual or quantitative approaches.