J Sex Med. 2013 Dec;10(12):3129-34. doi: 10.1111/jsm.12319. Epub 2013 Sep 9.
Breast cancer development in transsexual subjects receiving cross-sex hormone treatment.

"We researched the occurrence of breast cancer among transsexual persons 18-80 years with an exposure to cross-sex hormones between 5 to >30 years. Our study included 2,307 male-to-female (MtF) transsexual persons undergoing androgen deprivation and estrogen administration (52,370 person-years of exposure)"

"Among MtF individuals one case was encountered, as well as a probable but not proven second case."

"The number of people studied and duration of hormone exposure are limited but it would appear that cross-sex hormone administration does not increase the risk of breast cancer development, in either MtF or FtM transsexual individuals. Breast carcinoma incidences in both groups are comparable to male breast cancers. Cross-sex hormone treatment of transsexual subjects does not seem to be associated with an increased risk of malignant breast development."

The TRANSSEXUAL PHENOMENON
Harry Benjamin, M.D. (FROM THE 1960'S)

"In my own clinical material of 152 male transsexuals, 141 of whom were treated with medium to fairly large doses of estrogen, some over several years, no incident of breast or any other cancer was observed. One may argue that these are mostly young men, less apt to develop a malignancy. The experiences of urologists, however, who treated elderly and old men with even much larger doses of estrogen for cancer of the prostate, must then be recalled. With the exception of one disputed case of breast cancer (it may have been a metastasis of the prostatic cancer) reported in the medical literature, no such incident was observed in hundreds if not thousands of cases. In a personal communication from Dr. Elmer Belt, one of the outstanding and most experienced urologists in the country, he said:

In regard to the taking of Stilbestrol as a cause for cancer of the breast, we have placed several hundred
men on this material (I imagine if we were to search our records we would find the number to be in
excess of two thousand) and in all of these cases we have not seen a single occurrence of cancer of the
breast, although the dosages we used were of a very high level."

You can show this to your doctors. They can't tell you ever again that they refuse to increase dose or what not because of the risk of breast cancer. Mammography also seems useless for us. Very encouraging results indeed. Especially considering the doses and forms of estrogen used in the past vs the safer forms we use today and MUCH lower doses.

There has been a fair amount of breast cancer in my family, although it hasn't been linked to a particular genetic marker. Still, I have thought long and hard about that issue, and it more than anything has given me pause in pursuing HRT in recent years. Strangely, it was surviving another type of cancer (colon) a few years back that started to put everything into perspective for me. I had that moment where I realized that life is short, and you might as well live it as you, instead as somebody else. Yes, I am apprehensive about breast cancer, but with regular screenings, the risk is manageable. The psychological and emotional trauma of doing nothing is what became my real fear.

As shown, breast cancer is extremely rare in transsexual women and colon cancer risk actually decreases due to estrogen treatment in women.

From European Journal of Endocrinology (2011) 164 635–642
A long-term follow-up study of mortality in transsexuals
receiving treatment with cross-sex hormones

"The decreased mortality rate for colon cancer, also observed in the Women's Health Initiative
(14), is similarly remarkable, but also this needs confirmation in further studies. We did not observe
any cases of breast cancer in the population studied, neither in MtF nor in FtM, in agreement with the low
prevalence of breast cancer in the literature."

From BMJ 2012;345:e6409 doi: 10.1136/bmj.e6409 (Published 9 October 2012)
Effect of hormone replacement therapy on cardiovascular events in recently postmenopausal
women: randomised trial

"the effects of hormone replacement therapy were believed to be beneficial, owing to a reduction in risk of cardiovascular disease, osteoporosis, and colon cancer.1"

Everything I have read states that the evidence is inconclusive at best. There simply hasn't been enough research done. Logic tells me that if you have more breast tissue than you otherwise would have without HRT, then the risk would be at least slightly higher. I weighed that against the immediate medical dangers of not transitioning (severe alcohol abuse/depression/self hatred) and it was a perfectly acceptable risk for me.

Hi everyone.

I'm new to this site and awaiting HRT.  Hopefully in a couple weeks.

I found this topic intriging and wanted to add a little comment.  Below is a good web link to a site that discusses breast cancer and the causes etc.

http://www.breastnotes.com/bc/bc.htm

I strongly believe in what is said that cancer risk is greatly increased by women whereing ras and not allowing the breasts and tissue to function naturally.  There are great articles in the web link and they show pics and discuss the incidence of breast cancer from a time before the bra was invented to present day. 

There is information about what causes sagging of the breast and that bras are more the culprit that the solution.  Bras do not allow the Copper ligaments to properly strengthen and therefore gravity comes in and pulls everything downwards. 

My 2 cents....hope it helps.