Small cell carcinoma of the ovary hypercalcemic type (SCCOHT) is a very rare type of cancer. It most commonly affects people in their early 20s. Infants and people in their 40s may develop the disease.

SCCOHT begins in one ovary and may spread to other parts of the body. In a small subgroup of patients, this cancer type is related with hypercalcemia (high calcium levels).

Each year, about 40 to 50 people in the United States are diagnosed with SCCOHT.

Causes of Small Cell Carcinoma of the Ovary Hypercalcemic Type

SCCOHT is caused by a change (mutation) in the SMARCA4 gene, which can be inherited from a parent. The majority of SCCOHT patients are not born with this change. It is only found in the tumor cells.

A mutation in the SMARCA4 gene or the related SMARCB1 gene also causes another rare type of cancer called malignant rhabdoid cancer. This type of cancer occurs in young children. Some pediatric cancer experts believe that even though most people with SCCOHT are young adults, doctors should treat their cancer closely to how they treat rhabdoid cancers.

The Adolescent and Young Adult Cancer Center at Cincinnati Children’s provides expert care for SCCOHT. We work to meet the unique needs of young adults with this type of cancer.

Symptoms of Small Cell Carcinoma of the Ovary Hypercalcemic Type

SCCOHT symptoms usually develop quickly and without much warning. The most common symptom is a mass, bloating or pain in the lower abdomen.

Diagnosing Small Cell Carcinoma of the Ovary Hypercalcemic Type

SCCOHT is so rare that many primary care doctors, OB-GYN specialists and even some cancer doctors are not familiar with it. This can lead to an incorrect or delayed diagnosis.

Diagnosing SCCOHT requires:

  • Imaging scans. These include ultrasound, magnetic resonance imaging (MRI) and computed tomography (CT).
  • Pathology testing. This includes a minor surgery to get cells from the tumor. A doctor looks at the cells under a microscope.
  • Genetic testing. This can find the presence of the SMARCA4 mutation in the tumor and in the blood.

SCCOHT Stages

After confirming the diagnosis of SCCOHT, the cancer doctor will do more imaging studies and blood tests. The goal is to see whether the cancer has spread from the ovaries. This helps determine the “stage” of SCCOHT:

  • Stage 1-2: The tumor has not spread beyond the ovaries.
  • Stage 3: The tumor has spread to other areas in the abdomen and pelvis. But no cancer cells are found in the blood, bones or other organs, such as the brain.
  • Stage 4: The tumor has spread through the bloodstream beyond the abdomen and pelvis to other organs.

Experts generally recommend routine monitoring for patients with inherited changes of SMARCA4. But that may vary depending on a patient’s unique situation. Most often this includes ovarian ultrasound studies and blood work.

Treatment for Small Cell Carcinoma of the Ovary Hypercalcemic Type

Cancer experts personalize SCCOHT treatment based on many factors. One factor is how much the cancer has spread. The treatment plan may include some or all of the following:

  • Surgery. The first surgery is to remove as much of the tumor as possible. The surgeon will also look to see if the cancer has spread. This may involve removing one or both ovaries and the fallopian tubes. A “second look” surgery after chemotherapy removes any remaining cancer from the abdomen and pelvic area.
  • Chemotherapy to kill the cancer. This treatment involves a combination of six different drugs.
  • Autologous bone marrow transplant. Hopefully, chemotherapy and surgery help patients achieve a stage called “minimal residual disease.” This means only a small number of cancer cells remain in the body. Once that occurs, the goal is to build on this progress with additional high doses of chemotherapy. The patient will need a bone marrow transplant before the additional chemotherapy starts. The bone marrow transplant infuses the body with healthy, blood-forming stem cells that will protect the bone marrow from chemotherapy’s effects.
  • Radiation therapy to kill the cancer. This is not always needed.

During the “second look” surgery, the surgeon may provide a treatment called hyperthermic intraperitoneal chemotherapy, or HIPEC. This delivers high doses of heated chemotherapy to the abdomen and pelvis to get rid of the remaining cancer cells.

People with stages 3 or 4 SCCOHT need more aggressive treatment than those with stage 1 and 2.

How is this treatment different from what an “adult care” center provides?

Doctors in the adult care setting are likely to treat SCCOHT as they would ovarian cancers that are more common in older people.

Some pediatric cancer doctors (including those at Cincinnati Children’s) take a more aggressive approach. They recognize how similar SCCOHT is to other childhood cancers such as rhabdoid tumors. These other cancers respond better to more aggressive treatment. This is why they recommend a more aggressive course of therapy for SCCOHT. This may include surgery, high-dose chemotherapy, bone marrow transplant and radiation therapy.

An effective treatment plan includes support from a team of different kinds of specialists. The care team includes cancer doctors, bone marrow therapy specialists, fertility specialists, surgeons, endocrinologists (hormone specialists), genetic counselors, pathologists, nurses and many other expert providers.

Fertility Concerns for People with Small Cell Carcinoma of the Ovary Hypercalcemic Type

Treatment for SCCOHT usually involves surgery to remove at least one ovary. It is important for patients to understand how SCCOHT and its treatment may affect their hormones and fertility.

Genetic testing can help guide the conversation. Test results will show if the SCCOHT tumor contains a germline change. This means the change causing SCCOHT was inherited from one parent. If this is the case, the second ovary is at risk for SCCOHT. It should be removed as well (even if it doesn’t show signs of disease). Additional genetic testing can help family members better understand their risk for SCCOHT.

If there is no germline change in the tumor, the care team will explain options for fertility preservation. This may include ovarian tumor cryopreservation. This method involves removing the egg-producing portion of the ovary (the ovarian cortex) before cancer treatment begins. The ovarian cortex is frozen and stored. It can be transplanted later to make pregnancy possible.

What Is the Prognosis for People with Small Cell Carcinoma of the Ovary Hypercalcemic Type?

SCCOHT treatment has come a long way. Scientists are studying new and more effective treatment possibilities. When SCCOHT is detected early, before it spreads beyond the ovary, the cure rate is between 70 and 80%. Once the tumor has spread beyond the ovary, treatment is usually less successful. An aggressive approach offers the most promise for people with more advanced SCCOHT.