Unnecessary ovarian surgery should be avoided

Researchers have monitored close to 2 000 women to see how benign changes to the ovaries develop if they are left untreated. The results, published in the journal Lancet Oncology, show that follow-up using ultrasound instead of surgery does not increase the risk of complications. The researchers behind the study think that their findings justify a review of the way in which public healthcare treats changes to the ovaries.

“A reduction in the number of women undergoing surgery for benign changes to the ovaries could lead to fewer women suffering surgical complications, which are sometimes very severe, and associated discomfort. In addition, the costs to public healthcare would diminish”, says Lil Valentin, professor at Lund University and consultant physician at Skåne University Hospital.

Surgical risks

Many types of tumours can occur in the ovaries. The vast majority are benign. The most common are fluid-filled blisters known as cysts, but tumours consisting only of solid tissue, known as nodules, can also form.

Since the late 1990s, together with colleagues from other countries including Belgium, Lil Valentin who led the study, has been researching how public healthcare could distinguish between benign and malign cysts and nodules in the ovaries in order to avoid unnecessary surgical interventions.

“Surgery in the treatment of changes to the ovaries entails a risk of complications and troublesome side-effects, which can negatively affect the patient’s quality of life. For example, adhesions may form which can lead to ileus or chronic pain, and for women of child-bearing age, there is a risk of fertility problems”, explains Lil Valentin.

“In public healthcare, surgery is still very often recommended in case of changes to the ovaries which are considered benign. This is because physicians assume that there is a risk of complications such as torsion, where the ovary twists itself so that the blood supply is cut off, or that a cyst will burst. Our study shows that follow-up of benign changes to the ovaries using ultrasound instead of surgery does not increase the risk of complications. Rather the contrary, as we avoid surgical intervention which itself carries an increased risk of complications.”

Follow-up using ultrasound examinations

Medical imaging such as ultrasound, computer-assisted tomography and magnetic resonance imaging, is increasingly used in public healthcare and it is increasingly common for changes to the ovaries to be detected by chance in women with no gynaecological symptoms.

The alternative to surgery is an approach known as watchful waiting, which means regular monitoring of the disease process. In the study, the size and appearance of benign changes were monitored through regular ultrasound examinations. Often, the cysts disappeared spontaneously and no treatment was required.

“Ultrasound enables an incredibly accurate assessment of whether a change to the ovary is benign or malign, but it requires expertise and experience”, says Lil Valentin.

Study of development over time

“In order to measure the risk, we looked at what happened over time to the patients, in a two-year period. The study was conducted at several hospitals in Europe and the US where many different physicians have different levels of expertise, enabling us to generalise the results”.

One in five women had changes that disappeared spontaneously. 16 per cent underwent surgery, and the most common cause was pain or discomfort and the patient’s own wish for surgery. Only seven women, 0.4 per cent, were diagnosed with ovarian cancer.

“The results indicate that the risk of malignancy, i.e. cancerous tumours, and acute complications is very small. Instead of operating on patients in whom changes to the ovaries assessed as benign were discovered by chance, public healthcare should follow up these patients with ultrasound examinations as an alternative.”


  • Every year, 13 out of 100 000 women in Sweden will be diagnosed with ovarian cancer. In 2016, according to the Swedish national quality register of gynaecological surgery (Gynop-registret) 5 008 operations for benign changes to the ovaries were carried out, but there could be more as the register is not exhaustive.

  • The researchers’ study is the largest so far of how benign changes (cysts and nodules) in the ovaries develop if they are left completely untreated, known as the natural course. Over two years, the researchers monitored 1 919 symptom-free women with an average age of 48 who proved to have benign changes in the region of the ovaries when examined through vaginal ultrasound. They were followed up with regular ultrasound examinations after three months and, if the benign changes had not developed, after a further six months and thereafter once per year.

  • The results presented in the study are an interim analysis with statistics for follow-up over two years. The next analysis is planned for 2022 when all the women in the study will have been followed up for at least five years.

  • The international multi-centre study includes researchers from several countries besides Sweden: Belgium, the UK, Italy, France, Spain, the USA and others.

  • The largest centre is in Malmö with 500–600 patients who also have the best follow-up at a rate of 97 per cent. The study was made possible by support from the Swedish Research Council.

    Source: Lil Valentin

This article was originally published on Lund University's website.

The study published in the Lancet Oncology