Ovarian cysts and when they do not need to be removed

cisti ovariche

This is properly termed “watchful waiting”. When ovarian cysts are diagnosed, most of them, the simple and undoubtedly benign ones, can be monitored without removing them surgically. The procedure can be postponed to a later date, if necessary, because the mass has grown (which happens in no more than five percent of cases). Therefore “if the ultrasound scan was performed properly, this kind of strategy does not involve any risk for the woman,” explained Robert Fruscio, a gynaecologist at San Gerardo hospital in Monza and Italian principal investigator in a study featured in the journal The Lancet Oncology, which concluded that today many women end up in the operating theatre even when it is not necessary.


Ovarian cysts are fairly common and they account for between ten and twenty percent of all gynaecological conditions. Being closely related to the structure and function of the ovaries, they most often occur in women of childbearing potential and they are predominantly benign. In other words, they can be eliminated over a couple of menstrual cycles, without requiring any therapy. This is because, in most cases, they are caused by simple changes in the function of the follicles, the spherical bodies that contain the maturing egg cell and the normal corpora lutei. Although ovarian cysts almost never cause symptoms, when they are present they consist in intense discomfort, pain during sexual intercourse and menstrual cycle irregularities (skipped or very heavy periods, pain).


Doctors usually prescribe women experiencing these symptoms a transvaginal ultrasound scan, the most appropriate method for establishing whether the lesion is benign or malignant. Simple ovarian cysts do not need to be remove surgically, as many of them disappear spontaneously or, in any case, they do not affect the woman’s health.

A study conducted by an international group by enrolling almost two thousand women with ovarian cysts who were monitored regularly by transvaginal ultrasound showed that, in the two years following enrolment in the study, the cysts disappeared spontaneously in 80 percent of cases.

The complication rate proved to be very low, less than one percent. “Having reassuring data for offering women monitoring by ultrasound instead of surgery means avoiding the potential complications of procedures that, in the light of the results of this study, are not necessary,” added Fabio Landoni, director of the obstetrics and gynaecology clinic of the hospital in Brianza.


Researchers believe that the data obtained do not justify resorting to surgery, which has complications, such as intestinal perforation, in between 3% and 15% of cases. A scenario that is therefore more likely than that assumed as a possible exacerbation of a benign cyst, i.e. its rupture, twisting inside the ovary and evolution towards malignancy. On the other hand, surgery is necessary when a large cyst (with a diameter of more than five centimetres) is suspected of being malignant, is symptomatic or is cause for concern to the woman. Ovarian cysts are almost always removed with a laparoscopic procedure if the woman is of child-bearing potential and has therefore not completed her reproductive cycle. This spares the ovary and only the diseased part is removed.


According to Taymaa May and Amit Oza of the Princess Margaret Cancer Center in Toronto (Canada), authors of an editorial comment on the study, “this paper focuses on a crucial matter that involves many women and poses a common challenge in clinical practice. The conservative management of ovarian tumours classified as benign by ultrasound is still the gold standard.” Functional ovarian cysts differ from endometrial cysts, which can be recognised on ultrasound scans by their dark colour (they contain blood). They also have a different composition, as endometriomas develop from the cells of the endometrium (the mucous membrane of the uterus) that travel to other sites (the Fallopian tubes or ovaries) and result in these growths.

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Risk of complications in patients with conservatively managed ovarian tumours (IOTA5): a 2-year interim analysis of a multicentre, prospective, cohort study, The Lancet Oncology

Conservative management of adnexal masses, The Lancet Oncology