ASCO GU 2019: Oligometastatic Disease: Tumor Board - A Radiation Oncologist Perspective by Gert de Meerleer, MD

San Francisco, CA (UroToday.com) In this tumor board session on oligometastatic disease, a prostate cancer case was presented by Dr. Montorsi to an esteemed panel consisting of a urologic oncologist, two medical oncologists, and two radiation oncologists, and the different perspectives of the case were presented.  Dr. Gert de Meerleer provided the radiation oncologist perspective.  The case presented was a 59-year-old male with no history of smoking or alcohol and a medical history that was significant for hypertension only, with a Charlson comorbidity score of 1 and a BMI of 23. The patient had no prior surgical history and no family history of prostate cancer.

The case was presented by Dr. Montorsi, which was an actual patient seen in his center. This was a 59-year-old male with no history of smoking or alcohol and a medical history that was significant for hypertension only, with a Charlson comorbidity score of 1 and a BMI of 23. The patient had no prior surgical history and no family history of prostate cancer.

The patient underwent a digital rectal examination demonstrating a T3 disease, with a total PSA of 8 ng/ml, and a prostatic health index of 62. The patient also underwent a 1.5 Tesla multiparametric MRI in another institution, which demonstrated a PIRADS 5 lesion with evidence of left seminal vesicle involvement in T2-weighted sequences with concomitant restricted diffusion at the ADC map. Furthermore, there was evidence of enlarged lymph nodes at the T1 sequence, at the right obturator (12 mm) and right external iliac (14 mm). The patient went on to have a transrectal targeted and systematic biopsy which revealed 10/15 cores positive for Gleason 7 (4+3) disease.

Dr. Meerleer began his discussion with the recommended staging imaging tests for prostate cancer patients. According to both American and European guidelines, this patient should undergo both a CT scan of the abdomen and pelvis and a bone scan. Bone metastases can occur everywhere, with 80% of them being osteoblastic, 15% osteolytic, and 15% is mixed with osteoblastic and osteolytic features. However, the rate of equivocal cases in bone scans is quite high, and this can be improved if using a SPECT/CT scan instead, reducing the equivocal rate from 61% to 8%! 

Dr. Meerleer continued and stated that there is as light advantage to using whole-body MRI over CT and bone scans, with a sensitivity and specificity of 86% and 98%, respectively, for the bone scan and CT scan, compared to 98-100% sensitivity and 98%-100% specificity of the MRI. No difference was noted when comparing MRI to CT in the identification of positive node disease. Both modalities had a sensitivity and specificity of 42% and 82%, respectively. Nodes are suspected of being positive when they are above 10 mm (for oval nodes) and above 8 mm (for round nodes). A high positive predictive value for CT and MRI is noted only when the lymph nodes are larger than 1.5 cm.

Another evolving option is the 68 Ga-PSMA PET/CT scan, but the data is still being evaluated and studied. Currently, the only gold standard that is available for identification of positive lymph nodes is performing surgical pelvic lymphadenectomy.



Presented by: Gert de Meerleer, MD, University Hospitals Leuven, Belgium

Written By: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre @GoldbergHanan at the 2019 American Society of Clinical Oncology Genitourinary Cancers Symposium, (ASCO GU) #GU19, February 14-16, 2019 - San Francisco, CA



email news signup