Long-term safety of HRT

Introduction
HRT and being trans appears safer for trans men than trans women. Trans men had similar mortality rates to the general population, with no added risk of cancer, cardiovascular events or osteoporosis. For trans women, total mortality was 51% higher than in population due to suicide, AIDS, cardiovascular disease, drug abuse and other causes. Trans women aren't at a higher risk of cancer, but do suffer from osteoporosis, alarming rates of cardiovascular problems and lifestyle risk factors.

Most medical articles report risks only for "MTFs" and "FTMs," so little is reported medically about non-binary transgender health. Hopefully this is still useful to y'all.

Cardiovascular Health
Trans men are at no higher risk of embolism, thrombosis or other cardiovascular events than the general male population. In the study above, 6% of trans women experienced embolism and another 6% suffered other cardiovascular problems after ~11 years on HRT on average.

Use of Ethinyl estradiol, an older synthetic estrogen and still a common birth control medication, was an independent, three-fold risk of cardiovascular death. (Do not use birth control to transition!! It may kill you.)

Ovarian Cancer

 * The incidence of ovarian cancer in transgender men is not known. There are roughly five cases reported medically. It seems very rare, but may be underreported.

Breast Cancer

 * In a study of 5,135 transgender veterans from 1996-2013, breast cancer in MTF or FTM patients receiving HRT did not occur at a greater rate than the general population.

Testicular Cancer

 * Hearsay, but this Reddit thread is slightly worrisome.

Other Cancers
In trans women, total mortality from cancer was not significantly different from the general population, but lung cancer and leukemia were significantly more frequent. Total mortality and types of cancer in trans men were roughly equivalent to the general population.