Vasectomy and prostate cancer

[Guest guest]

Hi All,

The available pdf for the below study that prospectively associates low-grade

prostate cancer with vasectomies provides some more details, as shown below.

Hormone factors come to mind, since CRers tend to have lower levels of sex

hormones,

but seemed to be not considered or associated directly with the cancers. Highly

sexually active males may be at risk.

Definitions are:

stage = The extent to which cancer has spread from its original site to other

parts

of the body. Usually denoted by a number from Stage 1 (least severe) to Stage 4

(more advanced). Different lymphoma types have different criteria for staging.

grade ... tumour... Solid or cystic ... of high differentiation or low grade.

Gleason's tumour grade = A classification of adenocarcinoma of the prostate by

evaluation of the pattern of glandular differentiation; the tumour grade, know

as

Gleason's score, is the sum of the dominant and secondary patterns, each

numbered on

a scale of 1 to 5.

Rohrmann S, Paltoo DN, Platz EA, Hoffman SC, Comstock GW, Helzlsouer KJ.

Association of Vasectomy and Prostate Cancer Among Men in a land Cohort.

Cancer Causes Control. 2005 Dec;16(10):1189-1194.

PMID: 16215869

.... followed since 1989. On a questionnaire mailed in 1996... hazard ratios (HR)

....

HR for prostate cancer for men who had had a vasectomy was 2.03 (95% CI:

1.24-3.32).

Risk of low-grade disease (HR=2.87; 95% CI 1.49-5.54), but not high-grade

disease

(HR=0.99; 95% CI 0.36-2.76), was higher in men who had had a vasectomy. No

statistically significant associations were observed for low- or high-stage

disease.

The association for vasectomy was more pronounced in men who were 40 years at

the

time of vasectomy (HR=2.63; 95% CI 1.40-4.94) than in men who were younger at

vasectomy. ... The results from this prospective study suggest a positive

association between vasectomy and prostate cancer, especially low-grade disease.

.... About 12% of married men have had a vasectomy

and are generally under the age of 40 years when the

procedure is performed ...

.... Table 2.Hazard ratios a (HR)and 95%con & #64257;dence intervals (CI) for

prostate

cancer by vasectomy status among 3373 men in the CLUE II study,1996-2004

=================

No vasectomy Vasectomy

==================

All cases/person-years 51/20,211 27/7785

HR (95%CI)1.0 2.03 (1.24-3.32)

Low-stage cases b /person-years 17/20,211 6/7785

HR (95%CI)1.0 1.47 (0.55-3.90)

High-stage cases b/person-years 11/20,211 4/7785

HR (95%CI)1.0 1.52 (0.46-5.06)

Low-grade cases c/person-years 22/20,211 18/7785

HR (95%CI)1.0 2.87 (1.49-5.54)

High-grade cases c/person-years 19/20,211 5/7785

HR (95%CI)1.0 0.99 (0.36-2.76)

================================

a Estimated from a proportional hazards regression model after adjusting for

age

as a continuous variable.

b Low-stage cases =SEER stage 1 or 2;high-stage cases =SEER stage 3 or 4.

c Low-grade cases =Gleason sum <7;high-grade cases =Gleason sum =/>7.

.... Table 3.Hazard ratios a (HR)and 95%con & #64257;dence intervals (CI)for

prostate

cancer according to age at vasectomy and time since vasectomy among 3330 b men

in

the CLUE II Study,1996-2004

================

No vasectomy----

================

----Age at vasectomy

----<40 years of age =/>40 years of age

===============

Cases/person years 51/20,211 14/5556 12/1854

HR (95%CI)1.00 1.77 (0.93-3.37)2.63 (1.40-4.94)

Time since vasectomy

<20 years ago =/>20 years ago

Cases/person years 51/20,211 7/3107 19/4294

HR (95%CI)1.00 2.21 (0.92-5.34)2.03 (1.19-3.47)

===============

a Estimated from proportional hazards regression models after adjusting for

age

as a continuous variable.

b Information on age at vasectomy is missing for 43 men who had had a vasectomy.

.... Given the hypothesis that some of the cases with missing

stage are men with early stage disease,in a sensitivity

analysis,we included the men with missing stage along

with the early stage cases and observed a statistically

signi & #64257;cant association between vasectomy and low-stage

prostate cancer

---

.This result is

similar to the association of vasectomy with low-grade

prostate cancer. ...

.... Potential confounders that we

could not address in this study include androgen levels ... Men

who have higher testosterone levels might be more likely

to be sexually active and undergo vasectomy to control

fertility. Although circulating testosterone concentra-

tions have not been consistently linked to prostate cancer

risk [23 ], androgens are permissive for prostate cancer

development. ... Men who are

sexually more active may be more likely to acquire sex-

ually transmitted diseases than men who are less sexually

active. Unaccounted for associations of vasectomy with

androgen levels and STDs might lead to a very modest

overestimation in the RR of prostate cancer. ....

Al Pater, PhD; email: old542000@...

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