Endometrial cancer is most commonly diagnosed at an early stage. Unfortunately, there is a trend toward the diagnosis of more advanced disease, for which cure is rare, and this is an important contributing factor toward the overall increasing mortality trend for endometrial cancer.
Dr. Emma C. Rossi
Histology is a major risk factor for advanced disease. For example, serous carcinoma, which accounts for approximately only 10% of all endometrial cancer diagnoses, comprises 25% of cases of advanced cases. Similarly, carcinosarcoma, a cell type known to be particularly aggressive, is relatively overrepresented among cases of advanced disease.
Advanced endometrial cancer includes cases of stage III (involvement of lymph nodes, ovaries, and vagina) and stage IV disease (with direct extension into pelvic viscera and distant metastases). In most cases of stage III disease, extrauterine metastases are microscopic and are detected only at the time of surgical staging. Bulky nodal disease within the pelvic and para-aortic nodal basins is less common but associated with worse prognosis than for patients with microscopic nodal metastases. Stage IV disease usually presents with peritoneal spread of disease including carcinomatosis, omental disease, and involvement of the small and large intestine.
Once advanced, endometrial cancer requires more than surgery alone, relying heavily on adjuvant therapies to achieve responses, particularly systemic therapy with platinum and taxane chemotherapy. In some cases, molecularly targeted therapy (such as trastuzumab for serous carcinomas that demonstrate overexpression of HER2) has been shown to be superior in efficacy.1 Surgery may involve either radical nodal dissections to the infrarenal aortic basin, and/or peritoneal debulking procedures similar to that required for ovarian cancer. Perhaps because of patterns of disease distribution so similar to ovarian cancer, historically, sequencing of therapy focused on radical primary debulking surgery (PDS) followed by chemotherapy.
In 2000, a retrospective series from Johns Hopkins University documented the outcomes of 65 patients with advanced endometrial cancer who had undergone primary debulking surgery followed by chemotherapy.2 They noted that survival was directly associated with degree of cytoreduction, with the best outcomes seen for those patients whose surgery resulted in no gross residual disease. Following these data, PDS with complete resection of all disease became the goal of primary therapy.
However, unlike ovarian cancer (which shares a similar disease distribution with advanced endometrial cancer) patients with endometrial cancer are more obese, older, and typically have more comorbidities. Therefore, radical primary debulking surgeries may be associated with poor patient perioperative outcomes, and feasibility of complete cytoreduction, particularly in very obese patients, can be limited. For this reason, neoadjuvant chemotherapy (NACT) has been explored as an option. The potential virtue of NACT is that it allows for tumor deposits to decrease in size, or be eliminated, prior to surgery, resulting in a less morbid procedure for the patient.
Observed outcomes for NACT relative to PDS are mixed. When small series have compared the two for the treatment of advanced serous endometrial cancer, NACT was associated with decreased perioperative morbidity, with similar overall survival observed.3,4
However, in larger series exploring patients within the National Cancer Database (a collection of over 1,500 hospitals accredited by the Commission on Cancer) outcomes appear different for the two approaches.5,6 While PDS was initially associated with worse survival, at approximately 5-6 months from diagnosis, this changed and survival was observed to be consistently superior for this group. These data suggest that patients undergoing primary surgical cytoreduction may experience an early mortality risk, possibly secondary to the impact of surgery, but that if they are to survive beyond this point, they experience better outcomes. While the researchers attempted to control for risk factors of poor outcomes that might have systematically differed between the two groups, this specific database is limited in its ability to account for all fundamental differences between them. Only approximately 15% of women with advanced endometrial cancer were offered NACT during those time periods. This observation alone suggests that this likely represents a group specially selected for their poor candidacy for upfront debulking surgery, and inherently increased risk for death from all causes.
The question remains, is NACT appropriate for all patients or just those who are considered poor surgical candidates? Could all patients benefit from the decreased morbidity associated with surgery after NACT without compromising survival? Randomized controlled trials are necessary to answer this question as they are the only way to ensure that risk factors for poor outcomes (such as histology, disease distribution, medical comorbidities) are equally distributed among both groups.
In the meantime, gynecologic oncologists should take a cautious approach to decision making regarding sequencing of surgery and chemotherapy in the setting of a new diagnosis of advanced endometrial cancer. Arguably more important than surgical interventions, access to molecularly targeted systemic therapy is likely to bring the best outcomes for advanced endometrial cancer. Carboplatin and paclitaxel are the current gold standard of care for frontline systemic therapy; however, response rates with this regimen are less favorable for endometrial cancer than for ovarian cancer. Work is being done to test novel therapies against actionable targets to use as alternatives or as adjuncts to traditional chemotherapy regimens. In doing so, clinicians are learning to distinguish endometrial cancers by more than simply their histologic features, but also by their molecular profiles.
Advanced endometrial cancer is a serious disease with high lethality. Future research should focus on ways to ensure toxicities of therapy, including surgery, are minimized while improving upon existing poor clinical outcomes.
Dr. Rossi is assistant professor in the division of gynecologic oncology at the University of North Carolina at Chapel Hill. She has no financial disclosures.
References
1. Fader AN et al. J Clin Oncol 2018;36(20):2044-51.
2. Bristow RE et al. Gynecol Oncol 2000;78(2):85-91.
3. Bogani G et al. Tumori 2019;105(1):92-97.
4. Wilkinson-Ryan I et al. Int J Gynecol Cancer. 2015;25(1):63-8.
5. Tobias CJ et al. JAMA Netw Open 2020;3(12):e2028612.
6. Chambers LM et al. Gynecol Oncol 2021;160(2):405-12.