Patients with the risk factors summarized in Table 35.10 account for 35% of the overall population with endometrial cancer, but 89% of the observed hematogenous, lymphatic, and peritoneal relapses. Importantly, 46% of the patients considered at risk subsequently experienced a recurrence in one or more of the three sites, compared with only 2% of patients not judged to be at risk based on these criteria (p <0.001). The identification of subgroups of patients at risk for the different patterns of recurrence would allow postoperative treatment targeted to the predicted areas of tumor dissemination. The recurrence sites predicted by risk factors would presuppose different adjuvant treatment strategies. Patients at risk for hematogenous or peritoneal recurrence would potentially benefit from systemic cytotoxic treatment,while patients at risk for lymphatic or vaginal recurrence would potentially benefit from radiation treatment directed at areas at risk.
Modalities of Postoperative Treatment
Observation Patients with grades 1 and 2 lesions without myometrial invasion or any of the above risk factors (Table 35.10) have an excellent prognosis and require no postoperative therapy. In a GOG study, there were no recurrences and a 100% disease-free 5-year survival rate in the 91 patients in this category, 72 of whom received no additional treatment after hysterectomy (132). Other investigators reported equally favorable results with only surgical therapy in similar patients (282,283).
Vaginal Vault Radiation Vaginal brachytherapy is an attractive alternative to externalradiation therapy (ERT).High-dose rate (HDR) brachytherapy is well tolerated with low rates of severe or chronic complications.
Table 35.10 Rates of Recurrence at 5 Years According to the Different Risk Categories for 915 Patients
CSI, cervical stromal invasion. aCSI, nonendometrioid histologic subtype, positive lymph nodes, or positive result on peritoneal cytologic evaluation.bExcluding vaginal recurrences. cFor at least one of the three categories of recurrence (i.e. hematogenous, lymphatic, or peritoneal).
From Mariani A, Dowdy SC, Keeney GL, et al. High-risk endometrial cancer subgroups: candidates for target-based adjuvant therapy. Gynecol Oncol 2004;95:120–126.
Vaginal control rates with the more convenient, better-tolerated HDR brachytherapy are comparable to control rates with the lengthier low-dose rate (LDR) brachytherapy. Pearcey and Petereit established the HDR dosing of 21 Gy to 5-mm depth in threefractions as the standard brachytherapy dose, providing local control rates of 98% to 100% (284). Additional retrospective data demonstrate 98% to 100% vaginal control rates with HDR in high risk early-stage endometrial cancer (285,286). Retrospective data suggestthat the vaginal relapse rate after brachytherapy averages 4% to 5% (Table 35.11) and this is similar to the 5-year vaginal failure rate of 3.5% reported among the highest-risk patients who received ERT in PORTEC-1 (135,282,285,287– 291).