Patients diagnosed with Stage I uterine cancer have cancer that has not spread outside the uterus.
Stage IA is cancer confined to the inner layer of cells of the uterus (endometrium). Stage IB is cancer that invades less than one half of the muscle wall of the uterus. Stage IC is cancer that invades more than one half of the muscle wall of the uterus.
Stage I uterine cancer is curable with surgery alone for the majority of patients. Optimal treatment may require additional therapeutic approaches in selected situations. Thus, it is important for patients to be treated at a medical center that can offer multi-modality treatment from gynecologic oncologists and radiation oncologists.
The standard treatment for stage I uterine cancer is a total abdominal hysterectomy (removal of the uterus) and bilateral salpingo-oophorectomy (removal of the fallopian tubes and ovaries) with or without removal of the pelvic and para-aortic lymph nodes. Despite complete surgical resection of all cancer, 5-20% of patients will experience recurrence of their cancer. This is because some patients with stage I cancer have microscopic cancer cells, called micrometastases, that have spread outside the uterus and therefore were not removed by surgery. These cancer cells cannot be detected with any of the currently available tests. The presence of these micrometastases causes relapses that follow treatment with surgery alone. Following surgery, some patients may benefit from additional treatment (adjuvant therapy) to decrease the risk of cancer recurrence. There is a progressive increase in local and distant cancer recurrences in patients with stage IA, IB and IC disease and in patients with well, moderately and poorly differentiated cancers following treatment with surgery alone. To learn more about surgery, go to Surgery & Uterine Cancer.
Adjuvant therapy is the delivery of cancer treatment following local treatment with surgery and may include chemotherapy, radiation therapy and/or biologic therapy. Although it is still being evaluated in clinical trials, many patients with stage IB and IC uterine cancer are often treated with adjuvant radiation therapy. When the uterus is surgically removed, the cut ends of the vagina are surgically sewn together forming a “vaginal cuff”. The vaginal cuff is a common site of local cancer recurrence following treatment with surgery alone. The goal of radiation therapy is to eradicate any remaining cancer cells after surgery. Adjuvant radiation therapy may consist of brachytherapy and/or external beam radiation. Women with stage I uterine cancer treated with surgery and postoperative radiation therapy have a 5-year survival of 80-90% and a local cancer recurrence rate of only 4-8%.
Adjuvant External Beam Radiation Therapy: External beam radiation therapy (EBRT) is given via machines called linear accelerators, which produce high-energy external radiation beams that penetrate the tissues and deliver the radiation dose deep into the areas where the cancer resides.
A large clinical trial that involved 715 women with stage I uterine cancer compared treatment with surgery alone or treatment with surgery followed by adjuvant external beam radiation therapy. These women had deep invasion of the muscle wall of the uterus and/or had high-grade (more aggressive) types of cancer. The cancer recurrence rates were 4% for patients treated with surgery and radiation and 14% for patients treated with surgery alone. Survival rates, however, were 81% for treatment with surgery and adjuvant radiation therapy and 85% for surgery alone. Although patients treated with surgery and radiation experienced fewer cancer recurrences, patients treated with surgery alone survived longer. This is because there were more side effects in women treated with radiation therapy. The doctors concluded that postoperative radiation therapy reduced local recurrences of cancer following surgery for stage I uterine cancer, but did not improve survival.
Adjuvant Brachytherapy: Brachytherapy treatment involves the placement of a radioactive isotope into the vagina and may have fewer side effects than external beam radiation. Brachytherapy delivers radiation therapy at a very high dose rate in 3 weekly treatments to the “vaginal cuff” region. Brachytherapy without external beam radiation therapy has been used to prevent local recurrences after surgery. In a clinical trial that involved 102 women with stage IB and IC uterine cancer who were treated with brachytherapy following surgery, cancer recurrences occurred in 7% of women, 4% of which were local recurrences. Of the 3 local recurrences, only one occurred in the vaginal cuff. The survival at 5 years was 84%. Brachytherapy alone appeared very effective for preventing local cancer recurrences without the major side effects associated with external beam radiation.
Researchers in Florida have also evaluated outcomes of 396 women with stage I uterine cancer treated with hysterectomy, lymph node dissection and brachytherapy. Following treatment, 5-year survival was 100% for patients with stage IA cancer, 97% for patients with stage IB cancer and 93% for patients with stage IC cancer. All cancer recurrences occurred at distant sites that would not have been treated in an external beam radiation field. These studies suggest that brachytherapy alone is as effective for the treatment of stage I uterine cancer as external beam radiation therapy.
However, since these clinical trials did not directly compare brachytherapy to brachytherapy plus hysterectomy, it remains unknown whether hysterectomy plus brachytherapy definitely improves survival compared to surgery alone. This is because treatment of a local cancer recurrence in patients initially treated with surgery can be accomplished with additional surgery and/or radiation. A strategy utilizing initial treatment with surgery alone followed by additional surgery or radiation therapy only for the 5-20% of patients who experience a local cancer recurrence would spare the majority of women with stage IB and IC uterine cancer from radiation treatment. For patients who do not receive radiation therapy, frequent examinations are necessary because 5-20% of patients will experience a local cancer recurrence following treatment with surgery alone. It is important to detect recurrences early.