Radiotherapy & second primary malignancies.

[pjoshea13]

New study below.

My prostatectomy [RP] of 14.5 years ago was not successful & so I had salvage radiation. I was told that there would be an increased risk of a second cancer - but not within the first 5 years. At that time I was not thinking beyond 5 years, & extra risk after 5 years was not a consideration - besides, the immediate potential benefit of radiation presumably exceded any future risk.

Close to 10 years after the RP I had a colonoscopy. Naturally, I was very interested in any evidence of problems in areas that had received radiation. The pictures showed tissue that looked remarkably healthy.

In the new study, a second primary malignancy (SPM) is defined as a bladder or rectal tumor. It occurs to me that the supplements I have used against PCa, dismissed as resulting only in expensive urine (& presumably expensive bowel movements too), might have reduced my risk for bladder or rectal cancer. Who knows - but for those who have received radiation in those areas, it's worth thinking about IMO.

The new study compared SPMs for radiotherapy (RT) as primary treatment versus RP.

"A total of 579,608 patients met inclusion criteria, and 51.8% of the cohort was treated with RT."

There was an increase in risk with RT, of course, but an increase in risk of 80% at 10 years, say, doesn't necessarily translate to big numbers. (However, the SPM mortality rate approached 30%).

What was unexpected was that younger men had higher risk in spite of "similar median follow-up times"

"At 10 years, SPM-specific mortality occurred in 28.9% of patients treated with RT, though {overall survival} with SPM was worse in the youngest patients"

Age & risk factor:

<55 ... 1.88

55-64 ... 1.60

65-74 ...1.40

≥ 75 ... 1.27

Any ideas?

-Patrick

ncbi.nlm.nih.gov/pubmed/302...

Urol Oncol. 2018 Sep 21. pii: S1078-1439(18)30209-6. doi: 10.1016/j.urolonc.2018.06.007. [Epub ahead of print]

The impact of age at the time of radiotherapy for localized prostate cancer on the development of second primary malignancies.

Krasnow RE1, Rodríguez D2, Nagle RT3, Mossanen M4, Kibel AS4, Chang SL4.

Author information

1

Department of Urology, MedStar Washington Hospital Center, Washington, DC. Electronic address: [e-mail].

2

Department of Urology, Massachusetts General Hospital, Boston, MA.

3

Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA.

4

Center for Surgery and Public Health, Division of Urology, Brigham and Women's Hospital, Harvard Medical School Boston, MA.

Abstract

PURPOSE:

There is a known increased risk of second primary malignancy (SPM) in patients with prostate cancer (CaP) treated with radiotherapy (RT). It is unclear how age at diagnosis influences the risk of SPMs.

MATERIALS AND METHODS:

Using the 1973 to 2013 Surveillance, Epidemiology, and End Results Program, we studied the impact of age on SPMs (defined as a bladder or rectal tumor) after localized CaP treatment with radical prostatectomy (RP) or RT. SPM risk was compared using inverse probability of treatment weighting (IPTW)-adjusted cumulative incidence function and competing-risk proportional hazard models. Overall survival (OS) in patients with SPM was compared using Kaplan Meier and Cox regression analyses.

RESULTS:

A total of 579,608 patients met inclusion criteria, and 51.8% of the cohort was treated with RT. The 10- and 20-year cumulative incidences of competing risk (IPTW adjusted) of SPMs were 1.9% (95%CI = 1.8-1.9%) and 3.6% (95%CI = 3.4-3.7%) after RP vs. 2.7% (95%CI = 2.6-2.8%) and 5.4%(95%CI = 5.3-5.6%) after RT. IPTW-adjusted competing risk hazard ratio (HR) of SPM after RT compared to RP was increased in the entire cohort (HR 1.46; 95%CI = 1.39-1.53, P < 0.001) and was highest in the youngest patients: Age <55 HR = 1.83 (95% confidence interval [CI] = 1.49-2.24, P<0.001), Age 55 to 64 HR = 1.66 (95%CI = 1.54-1.79, P < 0.001), Age 65-74 HR = 1.41 (95%CI = 1.33-1.48, P < 0.001), Age ≥75 HR = 1.14 (95%CI = 0.97-1.35, P = 0.112). At 10 years, SPM-specific mortality occurred in 28.9% of patients treated with RT, though OS with SPM was worse in the youngest patients: Age <55 HR = 1.88 (95%CI = 1.25-2.81, P= 0.002), Age 55-64 HR = 1.60 (95%CI = 1.42-1.81, P < 0.001), Age 65-74 HR = 1.40 (95%CI = 1.30-1.52, P < 0.001), Age ≥ 75 HR = 1.27 (95%CI = 1.06-1.53, P = 0.009). All of the age categories had similar median follow-up times.

CONCLUSION:

At 10 years there is a 1.8% increased incidence of SPM after RT compared to RP, of which <30% of RT-treated patients with an SPM die as a result of a SPM. However, the risk of SPMs was greatest among younger men treated with RT for localized CaP, and this relationship could not be explained solely by follow-up time, latency time, or life expectancy. An improved understanding of those at the highest risk of SPMs may help tailor treatment and surveillance strategies.

Copyright © 2018 Elsevier Inc. All rights reserved.

KEYWORDS:

Abbreviations used: SPM, second primary malignancy; Age factors; BT, brachytherapy; CI, confidence interval; CSS-SPM, cancer specific survival of a SPM; CaP, prostate cancer; EBRT, External beam radiotherapy; HR, hazard ratio; IPTW, inverse probability of treatment weighting; IRR, incidence rate ratios; OS, overall survival; Prostatectomy; Prostatic neoplasms; RP, radical prostatectomy; RR, relative risks; RT, radiotherapy; Radiotherapy; SEER, Surveillance, Epidemiology and End Results Program registry; SIR, standardized incidence ratios; Second primary neoplasms; Survival analysis

PMID: 30249519 DOI: 10.1016/j.urolonc.2018.06.007

[cesanon]

"reduced my risk for bladder or rectal cancer. '

The problem is that there is a troubling but logical case that they can increase the risk as well.

[Hidden in reply to cesanon]

"The problem is that there is a troubling but logical case that they can increase the risk".?

I think you need to back that statement up with evidence. In other words, stop spreading pure BS.

[cesanon in reply to Hidden]

I actually did a few months ago. It is a peer reviewed article authored by James Watson, the Nobel prize winner.

Do a search on his name and on Royal Society and you should be able to find it.

It is stock full of data and citations. Much more than you can find for the other side of the argument.

[pjoshea13 in reply to cesanon]

Well, I believe that Jim Watson was arguing against antioxidants because they interfere with ROS, but those who use such supplements for cancer do so at big enough doses to create ROS. This has been discussed here a number of times - pro-oxidant doses. Many PCa studies, as a final step, will introduce NAC which invariably abrogates any benefit. This is done to demonstrate that ROS is an essential element of the anti-cancer effect of such supplements.

-Patrick

[cesanon in reply to pjoshea13]

"This has been discussed here a number of times - pro-oxidant doses. "

I don't recollect ever reading about this. Could you please explain a bit more... and how you know what will constitute a pro-oxident dose?

What is nac?

[softwaremom00]

My Dad had radiotherapy for his prostate cancer. This was some years ago. He did get a secondary cancer . .a sarcoma in the area of the radiation(this cancer took his life quickly).. I wonder if his work in the nuclear industry should have been a consideration when thinking about the therapy.(He worked with reactors.) The radiation oncologists never asked about it and at the time we did not think about it. Hugs and prayers for all of you cancer warriors out there.

(I am on this forum for my husband.. neuroendocrine prostate cancer.. but my dad had it too)

[j-o-h-n in reply to softwaremom00]

to softwaremom00:

Your Dad* made a great daughter... (*Throw in MOM too).

Good Luck and Good Health.

j-o-h-n Friday 09/28/2018 5:05 PM EDT