A Follow-up Report
Duke K. Bahn, M.D.
Director, Prostate Institute of America, Ventura, CA
This is a follow-up report to the live demonstration of prostate ultrasound and biopsy that was performed at PCRI conference on September 7, 2013.
Biopsy: Due to the strong possibility of the cancer extension out towards the neurovascular bundle and the main tumor volume appears much larger than the original biopsy report, a limited targeted and staging biopsy was performed.
Biopsy Report: The report showed Gleason 7=3+4 at the left base, mid and extending towards the apex. Up to 64% of the tissue cores showed the cancer compared to 30% by the initial biopsy. In addition, the left neurovascular bundle was also positive for the cancer extension (sign of ECE). However, the left seminal vesicle was negative for cancer extension. A small volume Gleason 6 cancer was seen at the right mid gland (dotted arrow) as on the initial biopsy.
Assessment: Due to the confirmation of ECE (neurovascular bundle invasion confirmed), it is now T3a stage malignancy. With Gleason grade 7, more than 50% tissue core invasion in one of the specimen, and significant degree of blood supply at the cancer (neovascularity) site, this cancer is not a low risk disease. It is an intermediate to high risk disease. Active surveillance is not an option for him, especially at age of 58. He should seriously consider a proper loco-regional therapy.
Biopsy: His initial biopsy was systemic blind biopsy, taking two tissue cores from right and left bases, right and left mid and right and left apices of the prostate, all together 12 cores taken. This ultrasound clearly depicts a lesion at the right mid towards the apex. There is a good possibility that this lesion was not recognized and was not biopsied initially. Tissue specimens were obtained from the both bases due to the known cancer in these regions, even though it was not visible on ultrasound. Proper targeted tissue cores were obtained from the lesion at the mid to apex of the prostate since it most likely the main tumor, the “Index” tumor.
Biopsy report: This biopsy was not able to duplicate the known small volume cancers at both bases of the prostate that is known as Gleason 6 malignancies (<5% invasion). These must be too small to be seen and compatible with clinically insignificant “latent” malignancies.
However, the lesion seen on this ultrasound study was a Gleason grade 6 cancer with 20% tissue core invasion, means it is much larger cancer than other two known cancers. It is indeed the “index tumor”.
Assessment: This index tumor was missed by the systemic blind biopsy. The index tumor is fortunately Gleason grade 6 and not a large volume (20%). Combining two sets of biopsy reports, it is a pathological T2c, but clinical T1c stage disease. His cancer belongs to low-intermediate risk group. He can consider active surveillance management, at least, for the time being. In that case, he needs a close PSA watch every three month and repeat ultrasound in 6 month. By doing so, we can clearly view the PSA trend and more importantly the known index tumor can be monitored objectively with color-Doppler ultrasound. If there is no evidence of disease progression, he can stay on active surveillance. If not, he should consider a proper loco-regional treatment.
These two cases illustrate the importance of proper ultrasound evaluation and targeted staging biopsy. Without correct cancer grade and staging information, it would be almost impossible to make an appropriate management decision.