Does PSADT calculation make sense when testosterone is increasing

[dac500]

During ADT break PSA increases as testosterone increases. How relevant calculation of PSADT is when testosterone is increasing?

[Tall_Allen]

It depends what your trigger is for ending your vacation.

[timotur]

There's some studies on PSA-DT and recurrence and whether it's a meaningful measure along with absolute PSA....

ncbi.nlm.nih.gov/pmc/articl...

PSA kinetics in relapsed or advanced prostate cancer

Prostate cancer patients treated by surgery or radiotherapy typically experience a decrease in PSA to a stable nadir. If PSA subsequently rises, the patient is said to have relapsed. Various investigators have examined whether the rate of this PSA rise is prognostic. Indeed, one of the first references to PSA doubling time was in a paper examining PSA changes at relapse [6].

An early indication that PSA kinetics at relapse predicted subsequent mortality included 94 patients with recurrence after radiotherapy. The risk of prostate cancer death within five-years of relapse was 50% for patients with a PSA doubling time of 12 months or less compared to 10% for patients with a doubling time greater than 12 months[7]. Other authors have clearly demonstrated that PSA doubling time adds information to other available predictors. Pound et al. created an algorithm for calculating risk of metastasis after relapse following radical prostatectomy. For patients with Gleason less than 8, though not for those with Gleason 8+, PSA doubling time strongly separated risk of subsequent metastasis, even after adjusting for time between surgery and relapse [8]. Freedland et al. similarly reported that PSA doubling time has a very strong influence on the risk of cancer-specific death after relapse in surgical patients. In a multivariable model, doubling times < 3 months and 3 – 8.9 months were associated with hazard ratios of 25 and 8 respectively; in comparison, the hazard ratio for a high Gleason score was 1.35 [9]. PSA doubling time has now been incorporated into predictive models for use at the time of relapse [10, 11].

There is also evidence that PSA kinetics can be of benefit for making treatment decisions after relapse. In a cohort of over 1000 men with relapse after radical prostatectomy, Moul et al. analyzed the risk of metastasis for patient receiving early compared to delayed androgen deprivation therapy. Early treatment was only found to be more effective in high risk patients, defined in terms of either Gleason grade or short PSA doubling time[12].

The relationship between PSA kinetics and disease progression in patients with metastatic and castrate-resistant prostate cancer is less clear than at the time of relapse. Still, a preponderance of data suggests that a short doubling time is associated with a poorer prognosis in patients with castration-resistant prostate cancer. In a typical study, PSA doubling time was analysed for 250 patients on chemotherapy. Median survival was 16.5 months in patients with a doubling time lower than the median (45 days) compared to 26 months for patients with longer doubling times[13]. Similar findings have been reported by other investigators[14] although in some cases, the association between doubling time and survival has been relatively modest[15].

[pjoshea13]

In the off phase of IADT, PSA is likely to rise as T increases. According to Dr. Myers, the PSA will settle down when T rises above the hypogonadal cut-off (350 ng/dL.) However, this likely happens when T is at Morgentaler's saturation point - about 250 ng/dL, I believe.

When I write "PSA will settle down", it is the PSADT that will settle down. Before then, the PSADT is meaningless IMO.

-Patrick

[Hidden in reply to pjoshea13]

What is the significance of Morgentaler's saturation point?

[pjoshea13 in reply to Hidden]

It is the level of T required to 'saturate' the androgen receptors in the body. According to Morgentaler, additional testosterone will have no further effect on proliferation.

[JPnSD]

If a high risk RP patient went to Undetectable (.01) at the start of ADT...maintained it through and post RT for a year...where would that patient fall risk wise if some level of PSA became detectable upon starting an ADT vacation? Would you use doubling time for readings below 1 or 2? (eg .01,.02, .04, .08). Are these levels significant for restarting ADT?