For those who are relying on biopsy data alone for thier information on a treatment are in for a surprise.
This article posted on the New Prostate Cancer Infolink show the inaccurracy of biopsies alone.
Additional staging methods such as Color doppler, MRIS, and poloidy analysis, PAP and PCA3 are other staging tools to better help in getting a clearer picture.
new, detailed, correlative analysis of pathologic data from saturation biopsies as compared to the actual pathology of radical prostatectomy (RP) specimens has demonstrated that 90 percent of patients with apparent unilateral prostate cancer on biopsy really had bilateral disease.
Falzarano et al. set out to determine whether, at their institution, saturation needle biopsies (SBx) could predict prostate cancer location in RP specimens with a high degree of accuracy. Their data was based on 72 patients, all of whom received an SBx according to the following protocol: traditional sextant cores as well as 10 or more additional biopsy cores (i.e., a minimum of 16 biopsy cores in total). All 72 patients went on to have an RP, and after the RP a single pathologist mapped the tumor outlines, determined the number of prostate cancer foci, and assessed the patients’ Gleason scores, and pathologic stages.
The results of this study can be summarized as follows:
- The median age of the patients was 60 years
- The median PSA level of the patients was 5.6 ng/ml.
- SBx detected bilateral disease in 33 men and unilateral disease in 39 men.
- All cases shown to have bilateral prostate cancer by SBx also had bilateral disease at RP.
- 35/39 patients (89.7 percent) shown to have unilateral prostate cancer by SBx were shown to have bilateral disease at RP.
- 12 potentially clinically significant prostate cancer tumors were missed by SBx in 11/35 patients.
- 2/12 had a Gleason scoreof 6
- 10/12 had a Gleason score of 7
- 11/12 were stage pT2
- 1/12 was stage pT3.
The original objective of this study was to investigate the potential of saturation biopsy as a method to identify patients who were suitable candidates for focal therapy. And it is likely that the advocates for focal therapy willl repond to these data by saying that the investigators didn’t take enough biopsy cores. The authors concluded that, “A negative SBx does not confirm the absence of cancer in the corresponding side of the gland and cannot be used as single determinant when considering a patient for focal treatment.”
The “New” Prostate Cancer InfoLink has a larger concern, which is the accuracy of any biopsy as a means to diagnose clinically significant prostate cancer.
This study was conducted by researchers at a well-respected, major medical center by individuals with (we assume) considerable expertise in prostate biopsy and subsequent evaluation of the biopsy materials. Despite this, there were unable to find bilateral prostate cancer in 35/39 patients and the unidentified cancer was potentially clinically significant in 31 percent (11/12) of those cases.
We have long known that prostate cancer biopsy is not the most accurate diagnostic tool. Between 25 and 40 percent of patients may be upgraded after surgery as compared to their original biopsy findings. However, the current study is suggestive of the idea that a significant proportion of all potentially clinically significant prostate cancers may be being missed entirely on biopsy.
For The “New” Prostate Cancer InfoLink, this is just one more very clear indication that the current state of technology used to find and diagnose prostate cancer is inadequate. It is bad enough that we have such difficulty determining who actually needs treatment and who can be monitored by some form of expectant management. But this study suggests that we may be “missing” the chance to diagnose thousands of men each year because of inadequate technology.
We do not believe that we immediately need to start biopsying every patient under MRI guidance. (Indeed the data supporting such an idea is still less than fully convincing.) What we need is a much clearer acceptance on the part of advocates, physicians, and researchers that better tools are essential if we are to assure ourselves that we are identifying early the men who are most at risk for progressive disease and who can and should be treated with curative intent while their cancer is still potentially curable.
JohnT