[In Process Citation]
OBJECTIVE: Endometriosis is one of the most common benign gynaecological diseases. Its aetiology is uncertain and there are many unanswered questions about its pathogenesis and treatment. MATERIAL AND METHODS: Medline search of relevant publications. RESULTS: Particularly the early stages of endometriosis, usually located in the peritoneum, are metabolically highly active and, even from the start, set in motion a vicious circle of progressive organ destruction, adhesions and inflammatory processes. This can lead to chronic cyclic or acyclic pains and/or sterility. Invasiveness and potential for progression are based on the secretion of prostaglandin derivatives and numerous cytokines which, together with the gradual failure of immune resistance and the local hormonal environment, usually dominated by oestrogen, are responsible for the progressive nature of around 50% of endometriosis cases. The estimated incidence of active, progressive endometriosis is 21,000 new cases per year in Germany, placing it on a par with prostate cancer. Subtle microscopic and morphological grading of the activity of the lesions is crucial to the choice of treatment. Early results of clinical trials indicate that the highest pregnancy rates and the lowest recurrence rates at follow-up can be achieved with individualised hormonal and surgical treatment of active endometriosis, even for mild or minimal endometriosis, in comparison with the laparoscopic removal of lesions alone. CONCLUSIONS: The combined use of hormonal and surgical treatment could become the new gold standard for treating active endometriosis.