Low-grade serous ovarian cancer guide

LGSOC is usually treated first with aggressive surgery, called tumor-debulking or cytoreductive surgery. People have better outcomes when this surgery is performed by a specialist gynaecological cancer surgeon, called a gynaecologic oncologist. The goal of surgery is to determine the extent to which the cancer has spread and remove all visible cancer.

Surgery usually involves the removal of both ovaries and fallopian tubes (salpingo-oophorectomy), the uterus and cervix (hysterectomy), and the omentum (omentectomy). The omentum is a fatty bit of tissue at the top of the abdomen that does not perform a vital function but in ovarian cancer is a frequent location of cancer cells.

The surgical procedure will provide comprehensive staging information (where small samples of the surrounding areas are surgically removed) to determine the spread, or metastasis, of the cancer.

Depending on the extent of metastasis, some of the bowel, liver, lymph nodes, or other organs may also be removed.

If part of the bowel needs to be removed, sometimes a stoma (alternative opening in the abdomen to remove feces) needs to be created. This may be temporary or permanent. If this is a possibility, the surgeon will usually discuss it prior to surgery.

Surgical removal of both the ovaries and the uterus causes infertility.

In stage IA-IC, if the cancer is contained within one ovary, fertility-sparing surgery where just the affected ovary is removed (with conservation of the other ovary and/or uterus), may be possible. Uncommonly, even in cases of stage II-III LGSOC, a normal ovary and/or uterus may be preserved. However, the risks associated with this management and any pregnancy are unknown and should be discussed with your gynaecological oncologist.

For women who do have a retained ovary, periodic monitoring with ultrasound is recommended, in addition to the routine monitoring discussed later in this guide.

Women who retain their uterus and/or cervix should continue cervical screening as per local guidelines.

Fertility treatment to extract eggs prior to or following surgery may be an option. Some doctors believe that the treatment used to stimulate the ovary to produce eggs may encourage LGSOC growth but there is not currently enough evidence on this subject. An aromatase inhibitor (such as letrozole) can be given with gonadotropins during treatment to reduce exposure to estrogen, without compromising the effectiveness of fertility treatment.

If you are interested in fertility-sparing surgery or egg extraction talk to your gynaecological oncologist to see if you are a candidate for this type of procedure and consider consulting with a reproductive endocrine infertility subspecialist.

Some people newly diagnosed with LGSOC have very extensive disease, and initial cytoreductive surgery may not be able to remove all or most of the tumours. In these situations, neoadjuvant treatment followed by interval cytoreductive surgery and then further systemic therapy (such as chemotherapy and/or hormone therapy) may be considered.

Neoadjuvant therapy is when treatment is given prior to surgery with the intention of shrinking the cancer. In contrast to HGSOC, the threshold for offering neoadjuvant treatment in patients with LGSOC is very high, meaning it should only be offered when surgery is unlikely to remove all or most of the visible cancer; or in individuals who have significant co-morbidities (other serious medical conditions) where surgery is not safe or in their best interest. This is because LGSOC often has a suboptimal response, i.e. doesn’t respond as well to chemotherapy as HGSOC does.

Depending on the experience your doctor has with LGSOC, it may be worth seeking a second opinion before starting neoadjuvant treatment; ideally, you want to see a provider who has experience specifically with LGSOC.

Currently, the standard neoadjuvant treatment consists of chemotherapy (carboplatin and paclitaxel), however, in 2022, results from a small clinical trial suggested that fulvestrant (a type of hormone therapy) combined with abemaciclib (a CDK4/6 inhibitor) may be more effective than chemotherapy. This was a small trial, and it may be difficult to draw conclusions because of its size. You should speak to your oncology team if you want to know more.

Treatment will vary as a result of the stage at diagnosis.

Stage I

If the cancer is diagnosed at stage IA or IB, surgery may be the only treatment that is required. If the cancer is diagnosed at stage IC, surgery alone, or three to six rounds of IV paclitaxel/carboplatin chemotherapy or hormone therapy are options.

Stage IA and IB

Surgery may be the only treatment that is required

Stage IC

Options include:

• Surgery alone
• Three to six rounds of paclitaxel/carboplatin chemotherapy +/- followed by hormone therapy
• Hormone therapy

Stages II – IV

Most people receive either:

• Six rounds of carboplatin and paclitaxel chemotherapy followed by hormone therapy (most commonly an aromatase inhibitor, e.g., letrozole or anastrozole), or
• Hormone therapy on its own (most commonly an aromatase inhibitor, e.g., letrozole or anastrozole), or
• Six rounds of carboplatin and paclitaxel chemotherapy with bevacizumab (a type of antiangiogenic therapy that blocks new blood vessels from forming in tumours, which may prevent the cancer from growing or cause it to shrink; also called Avastin) during and after completion of chemotherapy.

In 2026 a clinical trial called NRG-GY019 published results showing chemotherapy followed by a type of hormone therapy called letrozole works better than letrozole alone for stage 2-4 LGSOC, when there is visible cancer remaining after surgery. Listen to a Podcast with clinical trial lead Dr Amanda Fader on YouTube or Spotify discussing the findings.

Aromatase inhibitors are given alone post-menopause. If an ovary is retained in pre-menopause, a GnRH agonist like Zoladex will be used to induce medical menopause, in addition to an aromatase inhibitor.

The optimal length of time for receiving hormone therapy is unknown, and the general advice is that people should continue taking it for as long as it keeps working.

Learn more about hormone therapy in our guide to hormone therapy.

Clinical studies are a type of research for which people with low-grade serous ovarian cancer and low-grade serous peritoneal cancer can volunteer. They help doctors gain a better understanding of how to treat low-grade serous ovarian cancer (LGSOC).

Clinical studies include clinical trials and observational studies. They can be for newly diagnosed, recurrence or any point from diagnosis.

For more information visit our clinical trials page.

Genetic testing provides doctors with further information that can sometimes identify additional treatment and clinical trial options for people with ovarian cancer.

There are two main types of genetic tests commonly performed in patients with LGSOC:

BRCA testing

Mutations of the BRCA gene occur in fewer than 6% of LGSOC cases and are thought to be incidental, rather than contributory, to the development of the cancer. However, because BRCA mutations can be hereditary and therefore have implications for both an individual and a family’s risk of cancer, testing is often recommended. This is usually performed via a blood test, and sometimes through a saliva test. At the time of writing, there is no data on the use of PARP inhibitors (a targeted treatment approved for HGSOC in women with BRCA mutations) in BRCA-mutated LGSOC.

Genomic Tumour Profiling

More extensive genetic testing of the tumour is possible through some hospitals, and is also offered via some commercial tests such as Foundation One and Caris Life Sciences. Testing is usually done on a preserved sample of tumour, like that routinely removed during cancer surgery. The most commonly found mutations in LGSOC are mutations in the KRAS, NRAS, or BRAF genes.

Generally speaking, the initial treatment of LGSOC is not changed by the results of the tumour testing. However, in recurrence, the results can sometimes influence treatment choice or the availability of clinical trials.

Before considering supplements and complementary therapies, people should always discuss them with their gynaecological oncologist, medical oncologist, and/or pharmacist.

Some complementary therapies can reduce the effectiveness of cancer treatments or increase the risk of complications.

For general information about common herbs, vitamins, and supplements and their efficacy and safety in a cancer setting, see Memorial Sloan Kettering Cancer Center’s online guide and database About Herbs, Botanicals, and Other Products.