AT THE ANNUAL MEETING ON WOMEN’S CANCER
NATIONAL HARBOR, MD. (FRONTLINE MEDICAL NEWS) – Patients with endometrial cancer should not receive adjuvant chemotherapy or radiotherapy solely because they have isolated tumor cells in their sentinel lymph nodes, Marie Plante, MD, said during an oral presentation at the annual meeting of the Society of Gynecologic Oncology.
In a single-center prospective cohort study, about 96% of patients with endometrial cancer were alive and progression free at 3 years, a rate which resembles those reported for node-negative patients, said Dr. Plante of Laval University, Quebec City. Moreover, all 10 patients who did not receive adjuvant therapy remained alive and progression free during follow-up, she said. “Patients with isolated tumor cells carry an excellent prognosis,” she added. “Adjuvant treatment should be tailored based on uterine factors and histology and not solely on the presence of isolated tumor cells in sentinel lymph nodes.”
Pathologic ultrastaging has boosted the detection of low-volume metastases, which comprise anywhere from 35% to 63% of nodal metastases in patients with endometrial cancer. Clinicians continue to debate management when this low-volume disease consists of isolated tumor cells (ITC), defined as fewer than 200 carcinoma cells found singly or in small clusters. Finding ITC in endometrial cancer is uncommon, and few studies have examined this subgroup, Dr. Plante noted.
She and her associates evaluated 519 patients who underwent hysterectomy, salpingo-oophorectomy, lymphadenectomy, or sentinel lymph node mapping for endometrial cancer at their center between 2010 and 2015. Pathologic ultrastaging identified 31 patients with ITC (6%), of whom 11 patients received adjuvant chemotherapy, 14 received pelvic radiation therapy, and 10 underwent only brachytherapy or observation, with some patients receiving more than one treatment. Another 54 patients in the cohort had metastatic disease, including 43 patients with macrometastasis and 11 with micrometastasis.
Stage, not treatment, predicted progression-free survival (PFS), Dr. Plante emphasized. After a median follow-up period of 29 months, the estimated 3-year rate of PFS was significantly better among patients with ITC (96%), node-negative disease (88%), or micrometastasis (86%) than among those with macrometastasis (59%; P = .001), even though macrometastasis patients received significantly more chemotherapy (P = .0001).
Rates of PFS did not statistically differ between the ITC and node-negative groups, Dr. Plante noted. The single recurrence in an ITC patient involved a 7 cm carcinosarcoma that recurred despite adjuvant chemotherapy and radiation therapy. There were no recurrences among patients with endometrioid histology.
Among ITC patients who received no adjuvant treatment, half had stage IA endometrial cancer and half were stage IB, half were grade 1 and half were grade 2, all had endometrioid histology, and seven (70%) had evidence of lymphovascular space invasion, Dr. Plante said. All remained alive and progression free at follow-up.
Ultrastaging should only be performed if a sentinel lymph node is negative on initial hematoxylin and eosin stain and if there is myoinvasion, commented Nadeem R. Abu-Rustum, MD , chief of the gynecology service at Memorial Sloan Kettering Cancer Center, New York, who was not involved in the study. “Ultrastaging increases positive-node detection by about 8%,” he said during the scientific plenary session at the conference. “Finding positive nodes can change management, and we have to be careful not to overtreat.”
Ongoing research is examining the topography and anatomic location of ITC in sentinel lymph nodes, Dr. Abu-Rustum said. In the meantime, he advised clinicians to consider any ultrastaging result of ITC in context. “When modeling the risk of ITCs, don’t look at them in isolation. Don’t be ‘node-centric,’ ” he advised. “Look at the uterine factors and the overall bigger picture.”
Dr. Plante did not acknowledge external funding sources. Dr. Plante and Dr. Abu-Rustum reported having no conflicts of interest.