On 2016 Oct 11, David Keller commented:

Frequent ejaculation is associated with lower incidence of prostate cancer: how frequent is frequent enough?

Kotb and colleagues conclude in this review that "frequent" ejaculation is associated with reduced incidence of prostate cancer.[1] This finding begs the question: how frequent is "frequent"? Two of the reviewed studies provided relevant answers.

A study of 2,338 men found that men who averaged 5 or more ejaculations per week in their 20's had only 2/3 the risk of later developing prostate cancer, compared with men who ejaculated less frequently.[2]

Another study, of 29,342 men, found the lifetime relative risk of prostate cancer for men reporting 21 or more ejaculations per month (about 5 ejaculations per week) was 33% lower compared to men reporting 4 to 7 ejaculations per month (about 1 to 2 ejaculations per week).[3]

Kotb and colleagues do not present any data on whether ejaculation rates significantly higher than 5 times per week are associated with even lower risk of prostate cancer, or whether the benefit maxes out at a certain rate.

References

1: Kotb AF, Beltagy A, Ismail AM, Hashad MM. Sexual activity and the risk of prostate cancer: Review article. Arch Ital Urol Androl. 2015 Sep 30;87(3):214-5. doi:10.4081/aiua.2015.3.214. PubMed PMID: 26428643.

2: Giles GG, Severi G, English DR, et al. Sexual factors and prostate cancer. BJU Int 2003; 92:211-6.

3: Leitzmann MF, Platz EA, Stampfer MJ, Willett WC,Giovannucci E. Ejaculation frequency and subsequent risk of prostate cancer. JAMA. 2004; 291:1578- 86.

On 2016 Oct 11, David Keller commented:

Frequent ejaculation is associated with lower incidence of prostate cancer: how frequent is frequent enough?

Kotb and colleagues conclude in this review that "frequent" ejaculation is associated with reduced incidence of prostate cancer.[1] This finding begs the question: how frequent is "frequent"? Two of the reviewed studies provided relevant answers.

A study of 2,338 men found that men who averaged 5 or more ejaculations per week in their 20's had only 2/3 the risk of later developing prostate cancer, compared with men who ejaculated less frequently.[2]

Another study, of 29,342 men, found the lifetime relative risk of prostate cancer for men reporting 21 or more ejaculations per month (about 5 ejaculations per week) was 33% lower compared to men reporting 4 to 7 ejaculations per month (about 1 to 2 ejaculations per week).[3]

Kotb and colleagues do not present any data on whether ejaculation rates significantly higher than 5 times per week are associated with even lower risk of prostate cancer, or whether the benefit maxes out at a certain rate.

References

1: Kotb AF, Beltagy A, Ismail AM, Hashad MM. Sexual activity and the risk of prostate cancer: Review article. Arch Ital Urol Androl. 2015 Sep 30;87(3):214-5. doi:10.4081/aiua.2015.3.214. PubMed PMID: 26428643.

2: Giles GG, Severi G, English DR, et al. Sexual factors and prostate cancer. BJU Int 2003; 92:211-6.

3: Leitzmann MF, Platz EA, Stampfer MJ, Willett WC,Giovannucci E. Ejaculation frequency and subsequent risk of prostate cancer. JAMA. 2004; 291:1578- 86.