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Exploring total PSA and free testosterone distributions and linear correlations in groups and subgroups of operated prostate cancer patients according to the total PSA/FT ratio, by Antonio B. Porcaro, MD, et al.
In the first paper of the present study we have shown that:
- prostate cancer biology is related to serum levels of both free testosterone (ft) and total PSA, the former as representing the stimulating growth factor and the latter as expressing the product of cancer activity, and
- PSA production is linearly related to FT, and the PSA to FT ratio may be considered as the growth rate parameter expressing cancer biology.(1)
In the second part of the study,(2) we explored the role of the pretreatment total PSA to ft ratio (PSA/ft) as a marker for assessing the pathologic independent factors for metastasis-free survival after radical prostatectomy, such as the pathologic Gleason sum (pGS), and levels of tumor extension (pT), and we demonstrated that:
- the PSA/FT ratio was strongly associated with pT and pGS,
- the PSA/ft ratio ≥0,40 was strongly associated with large extensive and high grade cancers, such as pT3b+4 and pGS8/9,
- prostate cancer patients may be clustered in 3 different prognostic groups according to the PSA/FT ratio: low risk (PSA/FT ≤0.20), intermediate risk (PSA/FT > 0,20 and ≤0,40), and high risk (PSA/FT > 0,40 and ≤1,5).
Our opinion was that the PSA/ft ratio may have an effective role as a marker in the natural history of prostate cancer.
In this communication we showed that significantly lower levels of free testosterone have been detected in prostate cancer patients with extensive disease and the mean of total PSA significantly increased as PSA/ft, pT, and pG ranked higher (see Figures 1-2 and Table 1 ). Free testosterone distributions were significantly different in the pT2, pT3a and pG≤6 subgroups; surprisingly their means decreased as the psa/ft ratio increased and this trend was also seen in the pG=7(3+4) – pG≥7 groups where the p-value was not significant (see Table 2 ). PSA distriibutions were always highly significant in the different pT and pG subgroups clustered according to the psa/ft ratio and the means increased as the psa/ft ratio ranked up (see Figure 3 and Table 2 ). The present study showed that, according to the PSA/ft prognostic ratio approach, ft was a significant predeictor of PSA in all the groups and subgroups (see Tables 3-4 ) except for the pT3a+4(psa/ft>0.40) where the slope of the regression line did not correlate (b1/ft = 0.28 and p-value = 0,45). Interestingly, the pT3a+4 group (see Figure 4 ) included only 13% and 26% of patients with PSA/ft ≤0.20 and >0.20≤0.40 respectively, suggesting that these subgroups are outliers, and this might impact the results of the univariate and regression analysis.
Considering the significant results in the different pG subgroups (see Figure 5 and Table 3-4 ), we think that the small number of observations might impact negatively on the ft univariate analysis which failed to show different significant distributions in both pG=7 and pG≥7 subgroups. The slope of ft predicting PSA was always significant for the different pathology prognostic subgroups and these findings suggestive for different clusters of the prostate cancer population (see Figures 4-6 and also Tables 3-6 ).
References:
- Porcaro AB, Migliorini F, Petrozziello A, et al.: Investigative clinical study on prostate cancer: on the role of the pretreatment total PSA to free testosterone ratio in selecting different biology groups of prostate cancer patients. Int Urol Nephrol. 42(3): 673-681, 2009.
- Porcaro AB, Monaco C, Romano M, et al. Investigative clinical study on prostate cancer part II: on the role of the pretreatment total PSA to free testosterone ratio as a marker assessing prostate cancer prognostic groups after radical retropubic prostatectomy. Urol Int. 85 (2): 152- 158, 2010.
Written by:
Antonio B. Porcaro,1 Aldo Petrozziello,3 Mario Romano,2 Teodoro Sava,4 Claudio Ghimenton,5 Beatrice Caruso,6 Filippo Migliorini,1 Stefano Zecchini Antoniolli,1 Emanuele Rubilotta,1 Vincenzo Lacola,1 Carmelo Monaco,1 and Luigi Comunale1 as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Department of Urology,1 Department of Radiation Oncology,2 Department of Internal Medicine – Section Endocrinology,3 Department of Medical Oncology,4 Department of Pathology,5 Department of Laboratory6 - Azienda Ospedaliera Universitaria Integrata, Ospedale Civile Maggiore, Verona, Italy
UroToday.com Prostate Cancer Section