Guideline Details the Role of Postoperative Radiotherapy for Endometrial Cancer

The American Society for Radiation Oncology (ASTRO; Fairfax, VA, USA) has published the new guideline, “The Role of Postoperative Radiation Therapy for Endometrial Cancer: An ASTRO Evidence-Based Guideline,” and the executive summary was published in the May-June 2014 issue of Practical Radiation Oncology (PRO), the official clinical practice journal of ASTRO.

ASTRO’s Guidelines Panel of 17 leading gynecologic specialists compiled and reviewed extensive data from 330 studies from MEDLINE, EMBASE, and the Specialized Register of the Cochrane Gynaecological Cancer Review Group published from 1980 to 2011. The data population chosen for the guideline was defined as women of all races, age 18 or older, with stage I-IV endometrial cancer of any histologic type or grade. The studies included patients who underwent a hysterectomy followed by no adjuvant therapy, or pelvic and/or vaginal brachytherapy with or without systemic chemotherapy. The panel identified five key questions about the role of adjuvant radiation therapy and developed a set of recommendations to address each question.

The first key question addresses which patients with endometrioid endometrial cancer require no further therapy after hysterectomy. For patients with no residual disease in the hysterectomy specimen in spite of positive biopsy or grade 1 or 2 tumors with either no invasion or < 50% myometrial invasion, especially when no other high-risk features are present, no adjuvant radiation therapy is a reasonable alternative. Patients with grade 3 tumors without myometrial invasion or grade 1 or 2 tumors with < 50% myometrial invasion and higher risk factors such as age > 60 and/or lymphovascular space invasion could reasonably be treated with or without vaginal cuff brachytherapy.

Key question 2 examines which patients with endometrioid endometrial cancer should receive vaginal cuff radiation. Evidence demonstrates that cuff brachytherapy is as effective as pelvic radiation therapy at preventing vaginal recurrence for patients with (1) grade 1 or 2 cancers with ≥ 50% myometrial invasion or (2) grade 3 tumors with < 50% myometrial invasion. Vaginal cuff brachytherapy is preferred to pelvic radiation in patients with these risk factors, in particular in patients who have had comprehensive nodal evaluation.

Key question 3 details which women should receive postoperative external beam radiation. Patients with early stage endometrial cancer which is grade 3 with ≥ 50% myometrial invasion or cervical stroma invasion are felt to benefit from pelvic radiation to reduce the risk of pelvic recurrence. Patients with grade 1 or 2 tumors with ≥ 50% myometrial invasion may also benefit from pelvic radiotherapy to decrease pelvic recurrence rates if other risk factors are presents such as age > 60 years and/or lymphovascular space invasion. For patients with positive nodes or involved uterine serosa, ovaries/fallopian tubes, vagina, rectum, or bladder, the best available evidence suggests that treatment should include external beam radiation therapy as well as adjuvant chemotherapy. Chemotherapy or radiation therapy alone may be considered for some patients based on pathologic risk factors for pelvic recurrence.

Key question 4 addresses when brachytherapy should be used in addition to external beam radiation. The panel noted that data is lacking to validate the use of brachytherapy after pelvic radiation and that retrospective studies show little conclusive findings of a benefit, albeit with small patient numbers. Use of vaginal brachytherapy in patients also undergoing pelvic external beam radiation may not typically be necessary, unless risk factors for vaginal recurrence are present.

Key question 5 scrutinizes how radiation therapy and chemotherapy should be integrated in the management of endometrial cancer. The panel concluded that the best available evidence suggests that concurrent chemoradiation followed by adjuvant chemotherapy is specified for patients with positive nodes or involved uterine serosa, ovaries/fallopian tubes, vagina, bladder or rectum. Alternative sequencing strategies with external beam radiation and chemotherapy are also acceptable. Chemotherapy or radiation therapy alone may be considered for some patients based on pathologic risk factors for pelvic recurrence.

“Several trials on the role of radiation therapy in endometrial cancer have been reported in the past five years, seeking to clarify this topic; however these trials have been interpreted in different ways, leading to inconsistent treatment recommendations,” said Ann Klopp, MD, PhD, and Akila N. Viswanathan, MD, MPH, co-chairs of the ASTRO Endometrial Guideline Panel. “This guideline provides recommendations to help ensure patients receive the best possible care and to help patients and doctors make informed decisions about treatment options.”

Related Links:
American Society for Radiation Oncology