Cervical cancer begins in the cells lining the cervix, which is the lower part of the uterus. If left untreated, cervical cancer can spread to other parts of the body. The first place cervical cancer usually spreads is to nearby tissues and organs in the pelvis.
Lymph Node Metastasis
One of the most common places for cervical cancer to spread is to the lymph nodes in the pelvis. Lymph nodes are small, bean-shaped glands that are part of the body’s immune system. There are clusters of lymph nodes located throughout the body. The pelvic lymph nodes are located in the pelvic region near the cervix.
Cancer cells can break away from the original cervical tumor and travel through the lymphatic system to lymph nodes in the pelvis. When cancer cells spread to lymph nodes, it is called lymph node metastasis. Pelvic lymph node metastasis is found in 15-20% of women with early stage cervical cancer and up to 40% of women with advanced stage cervical cancer.[1]
Women with small cervical tumors located only in the cervix have around a 15% chance of cancer spreading to the pelvic lymph nodes. For larger tumors that have grown deeper into the cervical wall or spread to surrounding tissues, the risk of pelvic lymph node metastasis increases to 20-40%.
There are several groups of pelvic lymph nodes that cervical cancer may spread to:[2]
- External iliac nodes – located along the external iliac artery and vein in the pelvis
- Internal iliac nodes – located along the internal iliac artery and vein deep in the pelvis
- Obturator nodes – located near the obturator muscles in the pelvis
- Common iliac nodes – located where the external and internal iliac nodes meet
- Parametrial nodes – located in the parametrium beside the cervix
- Sacral nodes – located near the sacrum in the pelvis
Pelvic lymph node metastasis is one of the most important factors in determining the stage and treatment options for cervical cancer. Imaging tests like CT scan, MRI, and PET scan can detect enlarged lymph nodes that may contain cancer.
Spread to Nearby Organs
In addition to lymph nodes, cervical cancer can also directly spread into nearby tissues and organs inside the pelvis. This is called local extension or direct extension.
Some of the nearby areas cervical cancer may invade include:[3]
- Vagina
- Parametrium – connective tissue around the uterus
- Uterus
- Fallopian tubes
- Ovaries
- Bladder
- Rectum
- Pelvic sidewall
As the cancer grows larger in the cervix, it can push directly into adjacent pelvic structures. Symptoms like bleeding after intercourse, pelvic pain, or blood in the urine can occur if the cancer invades into the vagina, bladder, or rectum.
Advanced cervical cancer may also lead to a non-cancerous condition called hydronephrosis, where one or both kidneys become enlarged and swollen as a tumor presses on the ureter tubes connecting the kidneys to the bladder. This can cause pain in the back or side.
Local extension into nearby pelvic organs is more common in larger stage II or III tumors. Fortunately, many women are diagnosed in early stage I while the cancer is still small and confined to the cervix. In these cases, the chances of direct local spread are much lower.
Hematogenous Spread
Another way cancer can spread from the cervix is through the bloodstream. This is known as hematogenous metastasis. Cancer cells can break off from the tumor and enter small blood vessels or lymphatic channels. They can then circulate through the body and form new tumors far from the original site.
Common sites for cervical cancer to spread hematogenously include:[4]
- Lungs
- Liver
- Bones
- Distant lymph nodes
Lung metastases occur in around 3-5% of women with cervical cancer. Bone metastases are also found in approximately 3-4% of cases. The liver, adrenal glands, brain, and other organs are less common sites.
Hematogenous spread is more likely if the primary cancer is larger and has grown into blood vessels or lymphatic channels. However, even small cervical tumors can metastasize through the bloodstream. Advanced imaging scans like PET/CT can help detect subtle areas of cancer spread.
While distant metastasis is concerning, cervical cancer still tends to spread in a step-wise fashion. Pelvic lymph nodes and adjacent pelvic structures are typically affected earlier than distant organs like the lungs or liver.
Key Points
In summary, the key points about where cervical cancer spreads first include:
- Pelvic lymph nodes are the most common initial site of metastasis. The rate of lymph node spread correlates with larger tumor size.
- Direct extension into nearby pelvic organs like the vagina, bladder, or rectum may occur, especially with larger stage II/III tumors.
- Hematogenous spread through the bloodstream to the lungs, liver, bones, or other distant sites is less common than local pelvic spread.
- Even small, early stage cervical cancers can metastasize distantly in some cases.
- Imaging tests like CT, MRI, and PET scans can detect cervical cancer metastasis in many patients.
Prognosis and Survival
The prognosis and survival rates for cervical cancer depend heavily on whether it has spread to other sites:[5]
| Stage | 5-year Survival Rate |
|---|---|
| Stage I | 80-90% |
| Stage II | 55-65% |
| Stage III | 25-35% |
| Stage IV | 10-15% |
The highest cure rates occur for stage I cancer confined to the cervix. Once the cancer spreads regionally to lymph nodes or surrounding organs, survival declines significantly. And metastatic stage IV cervical cancer has the poorest prognosis.
But these statistics reflect outcomes with standard treatments. Advances in radiation, chemotherapy, surgery, and targeted therapies are helping improve survival, even in metastatic cervical cancer.
Treatment Options
Treatments for cervical cancer are tailored based on the stage, tumor size, lymph node status, and other factors. Common treatments include:[6]
- Surgery – Hysterectomy and removal of local structures invaded by cancer. May include pelvic lymph node dissection.
- Radiation – External beam radiation and/or brachytherapy to kill cancer cells.
- Chemotherapy – Cytotoxic drugs like cisplatin given systemically.
- Targeted therapy – Drugs like bevacizumab (Avastin) that block tumor blood vessel growth.
- Immunotherapy – Medications that help the body’s immune system recognize and attack cancer cells.
Early stage cancers may be treated with surgery or radiation alone. More advanced cancers often benefit from combining modalities like chemotherapy plus radiation.
If cancer has spread to distant lymph nodes or organs, chemotherapy and targeted therapies become more important to try to control the spread. Radiation can help shrink tumors to relieve symptoms as well.
Clinical trials offer another option to access the latest treatments not yet widely available. With more research, the outlook for metastatic cervical cancer is improving.
Conclusion
In conclusion, the earliest and most common site of metastasis for cervical cancer is to the lymph nodes in the pelvis. Direct local extension into adjacent pelvic structures is also more likely to occur before distant spread to organs like the lungs or liver. But even early stage cervical cancers can sometimes metastasize through the bloodstream. Modern imaging tests can detect the majority of recurrences and metastases. While cervical cancer metastasis worsens the prognosis, long-term survival is possible with current treatments. Continuing advances in surgery, radiation, chemotherapy, and targeted therapies provide hope for improving cure rates at all stages of cervical cancer spread.