Clear cell carcinoma (CCC), also sometimes called clear cell cancer, is a rare type of tumor characterized by cells that are clear or pale in color. These cells have a solid boundary and tend to be either filled with fluid or glycogen, a form of glucose. This type of cell can be found in many different types of tumors, but they are often found in the female reproductive system and lower urinary tract.
Areas of the Body Affected by CCC
Carcinoma tumors arise from epithelial cells, which are cells that make up the surface of body tissue and cavities. Clear cell carcinoma, therefore, can be found throughout the body in both men and women — in the breasts; on the skin; in the lower urinary tract, particularly the kidney; or the organs of the female reproductive system, including the ovaries, vaginal tract, and uterus.
Clear cell renal carcinoma, also known as renal cell carcinoma (RCC), originates in the renal tubules of the kidney. These are the small tubes that remove waste products from the blood. RCC is a very common type of kidney tumor; nine out of ten kidney tumors are of this type, and seven out of ten of RCC tumors are clear cell tumors.
In the ovaries, clear cell ovarian cancer is also known as clear cell adenocarcinoma and clear cell mesonephroma. Only about 6% of ovarian cancers are of this type, but half of those cases are fatal. Clear cell ovarian cancer is difficult to detect with a routine examination and is often caught only in the later stages.
Signs and Symptoms
Clear cell carcinoma symptoms vary considerably from person to person, and depending on where the tumor is located. Cancers of the kidney may show signs including abdominal pain, difficulty urinating or blood in the urine, pain or burning with urination, and/or pain or disruption during bowel movements. Tumors in the female reproductive system may also cause pain in the abdomen and pelvic region. Other signs may include fatigue, loss of appetite, or weight loss.
Causes
While there are various risk factors, including heredity and smoking, that are associated with CCC, the main cause is unknown. It is more common in female patients whose mothers took the drug diethylstilbestrol (DES) during pregnancy. DES is a synthesized non-steroidal estrogen that was prescribed to women from 1938 to 1971 to prevent miscarriage. In the United States, the FDA declared in 1971 that the drug was not safe to use during pregnancy, because it was causing a high incidence of health problems in the children that resulted from those pregnancies.
It is estimated that there are over 10 million DES mothers and daughters in the US. Among women exposed to DES in utero, CCC usually develops in the late teens and 20s, but it has been known to appear when the women are in their 30s and 40s. Researchers believe that the hormonal changes during puberty may activate the cancer. Though DES is associated with this form of cancer generally, it is not believed that DES exposure is a risk factor for clear cell ovarian cancer.
Treatment
Once CCC has been positively confirmed, treatment can range from surgery to chemotherapy and radiation. Various treatment plans can be carried out on the affected areas, including cryoablation, which is the freezing of cancer cells with a metal probe; targeted drug therapy; and immunotherapy. Most tumors are malignant and are considered to be a high-grade cancer, but often have a high survival rate.