The rarest type of ovarian cancer, small cell carcinoma of the ovary (SCCO) progresses rapidly and is often detected late. Because of this, doctors may find it difficult to treat.

Small cell carcinoma of the ovary (SCCO) is a very rare, aggressive subtype of ovarian cancer. It mainly affects young individuals and has symptoms that are similar to other types of ovarian cancer.

Early detection is crucial for a positive outlook. However, the outlook for a person with this type of cancer is often poor.

This article defines SCCO and explores its types, symptoms, and prevalence. It also discusses SCCO diagnosis, treatment options, risk factors, and outlook for someone with the condition.

Shadow of a leaf on a person's back -1.Share on Pinterest
Serge Filimonov/Stocksy

SCCO is the rarest of the four subtypes of ovarian cancer. It makes up less than 0.1% of all ovarian cancers.

This form of cancer is aggressive, fast growing, and primarily affects individuals in their 20s.

SCCO is characterized by the presence of small, round cancer cells resembling those found in small cell lung cancer. However, researchers are not certain whether the cells in SCCO are from ovarian epithelial cells, stromal cells or germ cells.

Typically, this type of cancer starts in the ovaries. It may then spread to the abdomen, pelvis, or other parts of the body.

There are two main subtypes of SCCO, including:

Small cell carcinoma of the ovary hypercalcemic type (SCCOHT)

Each year, approximately 40–50 people in the United States are diagnosed with this subtype of ovarian cancer.

Young women in their teens and twenties are more likely to receive an SCCOHT diagnosis. According to a review of studies, the average age at diagnosis was 23.9 years.

Because this form of cancer is more resistant to chemotherapy, it tends to have a poorer long-term outlook.

Approximately two-thirds of patients with SCCO also have hypercalcemia, or higher than normal calcium levels in the blood.

Small cell carcinoma of the ovary pulmonary type (SCCOPT)

This type of SCCO is less common than the hypercalcemic type. It affects less than 1% of individuals with ovarian cancer.

SCCOPT affects people ages 28–85 years. However, it usually occurs in perimenopausal or postmenopausal individuals, with a median age of 59.

The symptoms of SCCO can be similar to other types of ovarian cancer. This can make it difficult to detect early.

Common symptoms may include:

  • abdominal pain
  • bloating
  • changes in bowel habits

Due to the lack of specific symptoms, SCCO is often diagnosed at an advanced stage. Diagnosis typically involves a combination of imaging studies, such as CT scans and MRIs. Doctors may also perform a biopsy to confirm the presence of small cell carcinoma cells.

SCCO is an exceptionally rare form of ovarian cancer, making up less than 0.01% of all ovarian cancers. Its rarity makes it challenging to conduct large-scale studies and gather comprehensive data.

However, it is crucial for healthcare professionals to be aware of SCCO and its distinct characteristics. This can help individuals receive a diagnosis as early as possible.

Currently, there is no definitive treatment for SCCO because the underlying cause is not fully understood. Treatment options will depend on the stage of cancer and the overall health of the individual.

Depending on the type, a person may require a multidisciplinary approach to treatment. This can include:

A 2019 study investigated the best treatment protocols for people with hypercalcemic SCCO. It concluded that a combination of surgery, chemotherapy and radiotherapy produced better survival rates than surgery and chemotherapy alone.

Given its rarity, the risk factors contributing to the development of SCCO are not fully understood. However, ongoing research suggests that risk factors linked to other types of ovarian cancer may increase the likelihood of its occurrence.

Common risk factors for SCCO may include:

  • age
  • family history
  • reproductive history
  • genetics
  • hypercalcemia

The outlook for a person with SCCO is generally difficult to define. This is due to the condition’s aggressive nature and the tendency for late-stage diagnosis.

The overall survival rate for SCCO is relatively low compared to other types of ovarian cancer, at about 10%. This figure reaches 30% when the tumor is stage 1A.

The long-term survival rate of SCCOHT is 30% in early-stage cases.

SCCOPT tends to have a poor outlook, with an overall survival rate of 2 years after diagnosis.

Individual outcomes can vary based on several factors. These include the stage at diagnosis, the type of SCCO, and the effectiveness of the chosen treatment.

Small cell carcinoma of the ovary (SCCO) is a rare and aggressive form of ovarian cancer. It poses unique challenges for diagnosis and treatment, as symptoms can be difficult to identify.

There are two main subtypes of SCCO: SCCOHT and SCCOPT. Each type requires different treatments. However, treatment usually involves a combination of surgery, chemotherapy, and sometimes radiation therapy.