[Internal endocrine therapy of breast cancer]

Additive endocrine therapy of breast cancer was first initiated by androgen treatment through intramuscular administration which proved to be effective in about 25% of trial cases. It was followed by another trial of massive administration of estrogens mainly to patients of more than 60 years of age, and this showed a similar efficacy. Under these circumstances, additive endocrine therapy's position was established as a special therapy for advanced breast cancer. Breast cancer patients have a considerably longer period of progress after disease recurrence than in other types of cancer, so oral androgens were developed for treating recurrent breast cancer patients at home. However, the side effects of androgens (e.g., virilization, hepatic disorders) presented problems with Long-term administration. Since then more androgens with less side effects have been developed which have contributed to the remarkable progress of androgen therapy. On the other hand, recently an anti-estrogen was found which specifically antagonizes estrogen and has few side effects. Additive endocrine therapy's reputation has improved with the emergence of this anti-estrogen agent. Another study has also been started on a progesterone agent which is completely different from conventional sex hormone agents. Anti-estrogen agent is widely accepted for post-operative adjuvant endocrine therapy of breast cancer taking over as the conventional post-operative adjuvant chemotherapy, and also as a partner of chemo-endocrine therapy.