Prostate biopsy DNA content predicts need for treatment
MedWire News: Certain DNA content measurements found in the diagnostic biopsies of prostate cancer patients can indicate subsequent conversion to an unfavorable biopsy necessitating the need for treatment, study findings show.
“Specifically, a BA excess of optical density [OD] and cancer-tissue [CA] standard deviation of OD were significant both univariately and multivariately for predicting unfavorable biopsy conversion,” explain Robert Veltri (The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA) and colleagues.
The study included 71 patients participating in an expectant management program, involving annual surveillance of low-grade prostate cancer. All men had both benign-adjacent (BA) and cancer-tissue (CA) present in their diagnostic biopsies.
In all, 39 participants developed an unfavorable biopsy during a median of 3.7 years surveillance, defined as a Gleason score of 7 or higher, Gleason pattern 4 or 5, three or more cores involved with cancer, or any core containing more than 50% cancer.
The men’s annual biopsy specimens were measured for DNA variance using Feulgen staining. The ability of gray value (maximum/minimum, skewness, and excess) and OD measurements to predict conversion to unfavorable biopsy was evaluated.
Univariate analysis showed that an excess of OD in BA and the standard deviation of OD in CA were each significant predictors for unfavorable biopsy conversion, with hazard ratios of 2.58 and 5.36, respectively.
After multivariate analysis BA excess of OD and CA standard deviation of OD remained significant both as continuous and dichotomized variables. Patients with BA excess of OD and standard deviation of OD in CA had a 3.12-fold and 5.88-fold increased risk for an unfavorable biopsy, respectively, compared with men without these DNA content measurements.
The researchers then stratified patients according to their specific DNA measurements, and found that those with a BA excess of OD above 25.0 and a CA standard deviation of OD above 4.0 had the highest risk for an unfavorable biopsy.
“DNA alteration in both BA and CA of prostate cancer is a significant event representing the up-regulation of proliferation-related genes, including transcription factors,” write Veltri and colleagues in the BJU International.
The team believes that future research in this area will change the way expectant management of prostate cancer patients is performed, using “DNA content measurements in combination with other molecular biomarkers to assess the prognosis of low-grade low-stage prostate cancer.”
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By Sarah Guy