For women with grade 3-4A endometrial cancer who have positive nodes or other pelvic-area involvement (eg, uterine serosa, ovaries or fallopian tubes, vagina, bladder, or rectum), ASTRO recommends EBRT combined with adjuvant chemotherapy as a “reasonable option.”
Interestingly, ASCO emphasizes that the best evidence supports use of chemotherapy for these patients, but that adding EBRT can be considered reasonable. Use of EBRT alone or chemotherapy alone may be of benefit but has weaker supporting evidence, according to ASTRO.
The emphasis of the recommendations may reflect the specific interests of the two groups; the takeaway for oncologists is that adjuvant chemotherapy plus EBRT is a reasonable and beneficial option for women with later stage disease, but chemotherapy alone appears to convey more survival benefit than EBRT alone.
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Perhaps the major question of interest to both ASTRO and ASCO is how to integrate chemotherapy and radiation therapy in the treatment of non-metastatic endometrial cancer.
ASTRO gives a strong recommendation to concurrent chemoradiation, followed by adjuvant chemotherapy for women with high-risk early stage or advanced disease (ie, stage 1-3).
ASCO, on the other hand, states that there are limited data supporting concurrent chemoradiation, and emphasizes that chemotherapy has potential benefit for women with high-risk early stage or advanced endometrial cancer, such as those with positive nodes or locoregional involvement.
ASCO cites several prospective trials comparing adjuvant chemotherapy with EBRT that have shown a survival benefit with chemotherapy versus EBRT for women with later-stage or high-risk disease, albeit at the cost of higher rates of acute toxicity.
In a pooled analysis of women with stage 1-3 disease, sequential adjuvant chemotherapy and EBRT improved progression-free survival versus radiation therapy alone.
Other studies, however, have shown that the two treatment approaches deliver similar benefit or have failed to show additional benefit with the addition of chemotherapy to radiotherapy, suggesting a definitive answer remains elusive.
The hope is that results of ongoing prospective trials, such as GOG-0249, GOG-0258, and PORTEC-3, will further elucidate the potential benefit of chemotherapy and radiotherapy for women with high-risk early stage or advanced endometrial cancer.
In summary, ASCO’s endorsement of the ASTRO guidelines for adjuvant radiotherapy for endometrial cancer provides additional guidance for clinicians treating these patients.
Key takeaways are the lack of survival benefit with adjuvant EBRT in early stage disease, the preference for vaginal brachytherapy over EBRT for locoregional control in high- or intermediate-risk disease, and the benefit of adjuvant chemotherapy with or without concurrent EBRT for women with high-risk early stage or advanced disease.
- Meyer LA, Bohlke K, Powell MA, et al. Postoperative radiation therapy for endometrial cancer: American Society of Clinical Oncology Clinical Practice Guideline Endorsement of the American Society for Radiation Oncology evidence-based guideline. J Clin Oncol. July 6, 2015. [Epub ahead of print] pii: JCO.2015.62.5459.
- American Cancer Society. Cancer Facts and Figures, 2015. Atlanta: American Cancer Society; 2015.
- Klopp A, Smith BD, Alektiar K, et al. The role of postoperative radiation therapy for endometrial cancer: Executive Summary of an American Society for Radiation Oncology evidence-based guideline. Pract Radiat Oncol. 2014;4(3):137-144.