New Treatments for Endometrial Cancer. Part 4
Now this is based on three-year follow-up. Surgical resection alone yields an 89% three year survival. Surgery followed by pelvic radiation in this group yields a 96% three-year survival. The basis for that is this study, GOG protocol 99. It did not include any of the IIIa patients but it did include all the patients with stage I disease who had myometrial invasion. Patients with stage II disease, that is cervix involvement, all of these patients – 390 of them – were subjected to a randomization after surgery to either no further therapy or pelvic radiation. This was reported at the site of the gynecologic oncology meeting about a year-and-a-half ago, 390 patients in the study. The progression-free survival at three years was 88% on the group that got surgery only, 96% on the group that got adjuvant radiation. The overall survival at three years, 89% versus 96% and those differences are statistically significant. There was also a significant reduction in the incidence of vaginal recurrence, from 17 recurrences down to 3 with pelvic radiation. So we recommend that the intermediate risk group receive pelvic radiation if their reason for being intermediate includes either cervix involvement or myometrial invasion.
Now for patients at high risk for recurrence, these include the patients who are stage III by virtue of the involvement of the vagina or the pelvic or periaortic lymph nodes. And also stage IVa patients. Those who are stage IV by virtue of involvement of the bladder or rectal mucosa. If you do surgery only on these patients, that is do a TAH – total abdominal hysterectomy – and bilateral salpingo-oophorectomy, a complete resection of gross disease, relapse rates exceed 50%. Now the truth is, nobody knows the definitive best treatment for this group. We don’t have any large prospective randomized trials, but currently what’s recommended is resection of all gross disease, radiation to areas that were involved with disease and then the issue of whether systemic therapy is indicated is currently under study. The gynecologic oncology group has done two phase II trials showing that there is some reason to believe that abdominal pelvic radiation is active in this setting, and also showing that there is reason to believe that a combination of doxorubicin and cisplatin is active. What’s currently being done within the GOG is a phase III trial comparing these two approaches. Patients on this study have either stage III or stage IVa disease, that is bladder or rectal mucosal involvement for stage IV. They are subjected to a total abdominal hysterectomy, bilateral salpingo-oophorectomy, and tumor de-bulking so that nothing bigger than 2 cm remains. The tumor must be confined to the abdomen or pelvis and the patient must have had no prior therapy other than possibly progestins. They are randomized to receive either abdominal pelvic radiation or a combination of doxorubicin and cisplatin. That study is ongoing at the present time. But until that trial is completed, the standard of care is surgical resection of all gross disease if at all possible, followed by radiation to involved areas.