Ploidy Analysis
June, 2000
An analysis of the tumor cells DNA content, or ploidy, is a valuable prognostic tool. Normal DNA is comprosed of a pair of chromosome, and is thus termed “diploid.” Diploid status is more commonly associated with tumors of a low to moderate Gleason score, whereas abnormal ploidy (aneuploid) status is more commonly associated with tumors of a higher Gleason score. However, this is not a hard and fast rule.
The landmark paper from the Mayo Clinic in Rochester, Minnesota substantiates the value of the ploidy analysis, although other prostate cancer centers dispute its significance. The importance of ploidy as an independent prognostic factor is clearly demonstrated by Lerner, et al.13 In this paper, Lerner, et al examined the 5-year relapse rates in patients undergoing RP and having “apparent” OCD. When the data were analyzed below with respect to PSA, GS and ploidy status, a significantly higher rate of disease relapse was seen in patients with non-diploid tumors.
|
Table 6: Risk Factors for Progression in Patients with Prostate Cancer Treated with Radical Prostatectomy with Apparent Pathologically Organ-Confined Disease |
|
% of patients with progression within 5 years |
|||||
|
PSA |
GS |
Diploid |
Anuploid |
Tetraploid* |
Unknown |
|
< 10 ng/ml |
5 |
8% |
15% |
- |
10% |
|
6 |
15% |
30% |
- |
16% |
|
|
7 |
30% |
42% |
- |
34% |
|
|
8-10 |
42% |
61% |
- |
34% |
|
|
> 10 |
5 |
15% |
30% |
- |
16% |
|
6 |
30% |
61% |
42% |
34% |
|
|
7 |
42% |
61% |
- |
34% |
|
|
8-10 |
61% |
61% |
- |
59% |
|
* Tetrapolid = duplicate set of chromosomes (a type of aneuploidy)
References:
Lerner SE, Blute ML, Bergstrahl EJ, et al: Analysis of risk factors for progression in patients with pathologically confined prostate cancers after radical retropubic prostatectomy. J Urol 156:137-43, 1996.
