Mapping the Disease: Diagnosis, Pathology, and Staging

Confirming a diagnosis of cervical squamous cell carcinoma (SCC) involves more than just a single test. It is a process of gathering evidence from tissue samples, detailed imaging, and clinical exams to create a complete map of the disease. This “map” is your stage, and it helps your care team determine the most effective treatment path for you.

Confirming the Diagnosis

The first step is always a tissue sample to confirm the presence of cancer cells. This is usually done through a cervical biopsy or a LEEP (Loop Electrosurgical Excision Procedure), which uses a thin wire loop to remove a larger piece of tissue ^[1].

Once the tissue is under a microscope, a pathologist looks for specific markers to support the diagnosis of SCC and to distinguish it from “look-alike” cancers, such as endometrial cancer that has moved downward:

• p16: In HPV-associated cervical SCC, this marker usually shows a “block-like” or diffuse pattern ^[2].
• p40, p63, and CK5/6: These are markers that support the cells are indeed squamous cells ^[2][3].
• Margins: If you had a LEEP, the report will state if the edges (margins) are clear. “Negative margins” mean no cancer cells were found at the edge of the removed tissue—though this does not guarantee the rest of the cervix is completely clear of disease ^[4].

Diagnostic “Look-Alikes”

Occasionally, it can be difficult to tell if a cancer started in the cervix or the lining of the uterus (endometrium). Doctors use a combination of MRI scans to see where the bulk of the tumor is located and special stains like PAX8 or ER/PR (hormone receptors) to help identify the site of origin ^[3][5].

The Role of Imaging: Seeing the Full Picture

Under the current FIGO 2018 staging guidelines, imaging plays a vital role in determining your stage ^[6]. Imaging is highly individualized based on your stage, examination, and local practice; not everyone needs every scan.

1. Pelvic MRI: This is the gold standard for looking at the “local” area. It helps doctors measure the exact size of the tumor and see if it has grown into nearby tissues like the parametrium (the tissue surrounding the uterus) or the vagina ^[7][8].
2. FDG-PET/CT: This scan looks at the whole body. It uses a small amount of radioactive sugar to find active cancer cells. It is particularly good at spotting if cancer has spread to lymph nodes or distant organs, and is most often used when nodal disease is suspected ^[9][10]. Keep in mind that PET scans can sometimes show “false positives” if a lymph node is just inflamed from a common infection.

Understanding FIGO 2018 Staging

Cervical cancer staging is unique because it combines what the doctor sees during an exam with what the scans and pathology show. If your stage is based on imaging, you might see a small “r” (radiologic) next to it; if it is based on surgery, you will see a “p” (pathologic) ^[6][9].

Stage I: Confined to the Cervix

• Stage IA: The tumor is microscopic.
  • IA1: Invades the tissue up to 3 mm deep ^[6].
  • IA2: Invades more than 3 mm and up to 5 mm deep ^[6].
• Stage IB: The tumor is larger or deeper (sometimes microscopic if deep, but often visible to the naked eye), yet still confined to the cervix.
  • IB1: Less than 2 cm ^[6].
  • IB2: Between 2 cm and less than 4 cm ^[6].
  • IB3: 4 cm or larger ^[6].

Stage IIIC: The Lymph Node Factor

A major change in recent years is how we handle lymph nodes. If cancer is found in the lymph nodes in the back of the abdomen (retroperitoneal nodes), the cancer is classified as Stage IIIC, regardless of how small the tumor on the cervix is ^[6][11].

• Stage IIIC1: Cancer is found in the pelvic lymph nodes ^[6].
• Stage IIIC2: Cancer is found in the para-aortic lymph nodes (higher up, near the large artery called the aorta) ^[6].

The Concept of “Stage Migration”

Because our imaging (like PET scans) has become so much better at finding tiny spots of cancer in lymph nodes, many patients who would have been called “Stage I” or “Stage II” in the past are now called Stage IIIC ^[12][13]. This is called stage migration.

Stage IIIC is an advanced, node-positive category. This generally changes your radiation fields and systemic treatment planning ^[14]. However, it is important to understand that your individual prognosis still varies substantially depending on the original size of the primary tumor, the number of nodes involved, and whether the nodes were confirmed by pathology or just seen on a scan ^[15][16].

Other Stages Briefly

• Stage II: Cancer has spread beyond the cervix to the upper vagina or parametrium, but not to the pelvic wall.
• Stage III (A/B): Cancer has spread to the lower third of the vagina or to the pelvic wall, or causes kidney blockage.
• Stage IV: Cancer has spread to the bladder/rectum (IVA) or distant organs like the lungs (IVB).