According to a recent article published in the Journal of the American Medical Association (JAMA), radiation following surgery improves survival in patients with stage I endometrial cancer.
Endometrial cancer refers to cancer of the uterus, or womb. Endometrial cancer is the most frequently diagnosed gynecologic cancer in the U.S. Fortunately, long-term survival rates are high for cancers detected and treated early.
Stage I endometrial cancer refers to cancer that has not spread outside the uterus. Stage IC is cancer that invades more than one half of the muscle wall of the uterus.
Standard treatment for stage I endometrial cancer includes 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 removal of all visible cancer, 5%-20% of patients will experience recurrence. These recurrences are caused by undetectable cancer cells that remain in the body following surgery.
Adjuvant radiation therapy refers to radiation that is administered following surgery. The radiation is aimed near the site of the original cancer and is used to kill any possible remaining cancer cells. Although clinical trials have demonstrated improved outcomes with the use of adjuvant radiation therapy for stage I endometrial cancer, this treatment has remained controversial.
Researchers from the University of Utah medical center and the Huntsman Cancer Institute recently evaluated data from clinical trials evaluating adjuvant radiation therapy in the treatment of stage I endometrial cancer. The trials included 21,249 women with stages IA-IC endometrial cancer. All of women had undergone initial surgery to remove their cancer. Nearly 20% went on to receive adjuvant radiation therapy. Outcomes between patients who received surgery only were compared to those who received surgery plus radiation therapy.
Overall, patients with stage IC endometrial cancer had improved survival with adjuvant radiation therapy:
- Survival at 10 years for women with stage IC grade I (least aggressive) cancer who were treated with radiation therapy was 92% for those under 56 years, 76% for those between 56 and 75 years of age, and 59% for those older than 75 years.
- Survival at 10 years for women with stage IC grade I cancer who did not receive radiation therapy was 69% for those younger than 56 years, 72% for those between 56 and 75 years of age, and 42% for those older than 75 years.
- Survival at 10 years for women with stage IC grade 3-4 (more aggressive) cancer who were treated with radiation therapy was 86% for those under 56 years, 51% for those between 56 and 75 years of age, and 27% for those 75 years or older.
- Survival at 10 years for women with stage IC grade 3-4 cancer who did not receive radiation therapy was 77% for those under 56 years, 42% for those between 56 and 75 years, and 11% for those over the age of 75 years.
- Survival at 5 years was also significantly improved across all age groups of women with stages IC grade I or grades 3-4 cancer who were treated with radiation therapy.
The researchers concluded that adjuvant radiation therapy provides a survival benefit at 5 and 10 years across all age groups of women diagnosed with stages IC grade I or grades 3-4 endometrial cancer. Women diagnosed with stage IC endometrial cancer should speak with their physicians regarding their individual risks and benefits of adjuvant radiation therapy.
Reference: Lee C, Szabo A, Shrieve D, Macdonald K, Gaffney D. Frequency and Effect of Adjuvant Radiation Therapy Among Women with Stage I Endometrial Adenocarcinoma. Journal of the American Medical Association. 2006;295:389-397.