An interesting study where the authors performed a post hoc analysis of randomized trials using molecular classification of endometrial cancers. There was good evidence to omit RT for those with POLE mutations and def-MMR. There seems to be a higher degree of benefit in those with a p53 mutation.
The molecular classification of endometrial cancer (EC) has proven to have prognostic value and is predictive of response to adjuvant chemotherapy. Here, we investigate its predictive value for response to external beam radiotherapy (EBRT) and vaginal brachytherapy (VBT) in early-stage endometrioid EC (EEC).
Data of the randomized PORTEC-1 trial (n = 714) comparing pelvic EBRT with no adjuvant therapy in early-stage intermediate-risk EC and the PORTEC-2 trial (n = 427) comparing VBT with EBRT in early-stage high-intermediate-risk EC were used. Locoregional (including vaginal and pelvic) recurrence-free survival was compared between treatment groups across the four molecular classes using Kaplan-Meier’s methodology and log-rank tests.
A total of 880 molecularly classified ECs, 484 from PORTEC-1 and 396 from PORTEC-2, were included. The majority were FIGO-2009 stage I EEC (97.2%). The median follow-up was 11.3 years. No locoregional recurrences were observed in EC with a pathogenic mutation of DNA polymerase-ε (POLEmut EC). In mismatch repair–deficient (MMRd) EC, locoregional recurrence-free survival was similar after EBRT (94.2%), VBT (94.2%), and no adjuvant therapy (90.3%; P = .74). In EC with a p53 abnormality (p53abn EC), EBRT (96.9%) had a substantial benefit over VBT (64.3%) and no adjuvant therapy (72.2%; P = .048). In EC with no specific molecular profile (NSMP EC), both EBRT (98.3%) and VBT (96.2%) yielded better locoregional control than no adjuvant therapy (87.7%; P < .0001).
The molecular classification of EC predicts response to radiotherapy in stage I EEC and may guide adjuvant treatment decisions. Omitting radiotherapy seems to be safe in POLEmut EC. The benefit of radiotherapy seems to be limited in MMRd EC. EBRT yields a significantly better locoregional recurrence-free survival than VBT or no adjuvant therapy in p53abn EC. VBT is the treatment of choice for NSMP EC as it is as effective as EBRT and significantly better than no adjuvant therapy for locoregional tumor control.
For patients with local recurrences of endometrial cancer, XRT alone is extremely effective, and the addition of cisplatin does not offer any benefit while increasing toxicity. These patients with low-grade and vaginal recurrences have a good prognosis and most should be treated with XRT alone.
Initial results from the DUO-E study in metastatic endometrial cancer. The preliminary report suggests that maintenance durvalumab and maintenance durvalumab + olaparib were superior to standard observation after systemic carbo/taxol. As the trial data matures, the question will be: is this in all patients or driven by those with dMMR or HDR mutations?
This is another possibility for maintenance therapy. It will require further study.
Large phase III study of carbo/taxol+pembro x 6 followed by pembro alone x 14 cycles in metastatic endometrial cancer. There was a benefit in both pMMR and dMMR patients, although the magnitude was unsurprisingly higher in those with dMMR. OS results are still pending, and carcinosarcoma-type histology was excluded. This combination has been approved and is on NCCN as a cat-1 recommendation.
Chemo + IO may become the SOC for 1L treatment of met-endometrial adenoCa. For pembro + chemo, there was a 70% lower risk of disease progression in dMMR and a 46% lower risk in pMMR compared to placebo + chemo. For pMMR patients, the impact on 2L therapy responses will need to be considered carefully, as lenvantinib + pembro has been found to be superior to either agent alone after chemo.
FCS Hematology Oncology Review creates a platform for our physician network to observe the most recent articles and studies available in the oncology and hematology world. By sharing these articles we are building our wealth of knowledge of new observations and treatments as they come available.
