Cervical cancer is a serious but often highly treatable disease, particularly when detected early. Staging the cancer is a fundamental step that determines the extent of the disease and guides the entire treatment plan. Stage 1 is the earliest invasive stage, meaning the cancer is strictly confined to the cervix itself and has not spread to lymph nodes or distant organs. This localized nature gives patients diagnosed at this stage a significantly better outlook compared to later-stage diagnoses.
Defining Stage 1 Cervical Cancer
Stage 1 cervical cancer represents the first stage where malignant cells have invaded the underlying connective tissue, known as the stroma. The International Federation of Gynecology and Obstetrics (FIGO) staging system classifies this disease globally, focusing on the depth of invasion and tumor size. Stage 1 is defined as carcinoma strictly confined to the cervix.
This early stage is split into two main groups, 1A and 1B, reflecting differences in tumor size and depth. Stage 1A, or microinvasive carcinoma, refers to cancer identified only microscopically. This group is divided based on the measurement of stromal invasion, which is the depth the cancer has grown into the cervical tissue.
Stage 1A1 is the least invasive, with stromal invasion measuring no more than 3 millimeters (mm) and a horizontal spread of 7 mm or less. Stage 1A2 is defined by a slightly deeper invasion, between 3 mm and 5 mm in depth, but still with a maximum horizontal spread of 7 mm.
Stage 1B encompasses lesions larger than the microscopic criteria of 1A or those clinically visible. These cancers have invaded more than 5 mm into the stroma but remain confined entirely to the cervix. This group is further categorized by the tumor’s largest dimension.
Stage 1B1 includes tumors measuring 2 centimeters (cm) or less, while Stage 1B2 includes tumors between 2 cm and 4 cm. The largest Stage 1 cancer is 1B3, defined as a tumor greater than 4 cm in its greatest dimension, still limited only to the cervix.
How Stage 1 is Diagnosed
Diagnosis of Stage 1 cervical cancer typically begins with routine screening, such as a Pap test, which detects abnormal cells, or an HPV test. If abnormal results are found, a colposcopy is performed, which uses a magnifying device to examine the cervix. During this procedure, any suspicious areas are sampled with a biopsy.
To accurately stage the cancer, especially for the microscopic 1A sub-stages, a more extensive tissue sample is required. This is often achieved through a cone biopsy, which removes a cone-shaped piece of tissue from the cervix. This procedure allows a pathologist to precisely measure the depth of stromal invasion and the horizontal spread, which is necessary to assign the specific 1A1 or 1A2 stage.
For larger lesions, a punch biopsy confirms cancer, but imaging studies are necessary to ensure the cancer has not spread beyond the cervix. MRI and PET scans are often used to assess tumor size and confirm the absence of spread to nearby lymph nodes or other pelvic structures. The final staging determination relies on all clinical, imaging, and pathological information, though pathology findings supersede imaging when determining depth and spread.
Treatment Options for Stage 1
Treatment for Stage 1 cervical cancer is highly individualized and primarily depends on the sub-stage of the disease and the patient’s desire for future fertility. Since the cancer is localized, surgery is the main treatment approach for most Stage 1 cases. For the very earliest stage, 1A1, a cone biopsy is often used not only for diagnosis but also for treatment if the margins of the removed tissue are cancer-free.
If the patient wishes to preserve the ability to have children, a cone biopsy with negative margins may be sufficient for Stage 1A1. For slightly deeper Stage 1A2 cancers, or when the cancer is found to have invaded blood or lymph vessels, a more extensive surgery may be needed, such as a radical trachelectomy. This procedure removes the cervix and the upper part of the vagina while leaving the uterus intact, allowing for potential future pregnancy.
When fertility preservation is not a consideration, a hysterectomy is the most common approach for Stage 1A. A simple hysterectomy, which removes the uterus and cervix, is often adequate for 1A1, while a modified radical hysterectomy, which also removes the surrounding tissue and lymph nodes, is typically used for 1A2.
For larger Stage 1B tumors, the standard treatment is a radical hysterectomy and the removal of pelvic lymph nodes. Tumor size (1B2 or 1B3) determines the extent of surgical dissection and the potential need for additional treatment. Chemoradiation may be used as the primary treatment if a patient cannot undergo surgery or if high-risk features, such as positive margins or lymph node involvement, are found after surgery.
Prognosis and Follow-Up Care
The prognosis for Stage 1 cervical cancer is highly favorable because the disease is caught before spreading beyond the cervix. The 5-year survival rate for localized cervical cancer, which includes all Stage 1 cases, is approximately 91%, though many studies report rates as high as 90% to 95%.
After completing initial treatment, a patient transitions into the follow-up care phase, which involves regular monitoring for recurrence. The schedule for these post-treatment visits is typically frequent in the first two to three years, as this is the period when recurrence is most likely. Follow-up usually includes physical examinations, pelvic exams, and periodic testing.
The goal of this intensive surveillance is to detect any potential return of the cancer as early as possible. As more time passes without recurrence, the frequency of follow-up visits generally decreases.