Adjuvant treatment in early-stage endometrial cancer: context-dependent impact of somatic CTNNB1 mutation on recurrence-free survival

p53 Abnormal (Copy Number High) Endometrioid Endometrial Carcinoma Has a Prognosis Indistinguishable From Serous Carcinoma

Among the 4 molecular subgroups of endometrial carcinoma, the p53 abnormal (copy number high) subgroup has the worst prognosis; however, the histologic characteristics of this subgroup are not well established. Also, it is not well established whether low-grade tumors can belong to the p53 abnormal molecular subgroup and if so, what is the prognostic significance of the p53-mutated molecular subgroup in low-grade tumors. In the current study, we included 146 p53-mutated endometrial carcinomas and performed molecular subgrouping either based on a combination of immunohistochemical studies for p53 and MMR protein expression and POLE mutation testing (81 cases) or based on array-based and sequencing-based technologies (65 cases). We excluded cases that belonged to the POLE mutant or MSI molecular subgroups and only studied p53 abnormal (molecular subgroup) endometrial carcinomas (125 cases). In 71 cases, the molecular subgroup was determined by a combination of immunohistochemical studies and POLE mutation testing, and in 54 cases by array-based and sequencing-based methods. We reviewed 1 to 2 representative digital slides from each case and recorded the morphologic characteristics as well as clinical, treatment, and survival follow-up data. Overall, 47 cases were classified as endometrioid carcinoma, 55 serous carcinoma, and 23 other histotypes. Eight cases were FIGO 1, 21 were FIGO 2, and 91 were FIGO 3. A significant proportion of the cases (24.2%) were histologically classified as low-grade (FIGO 1 or 2) endometrioid carcinoma. There was no morphologic characteristic that showed prognostic implication. There was no significant difference in survival among different histotypes (P=0.60). There was no significant difference in survival among low-grade endometrioid (FIGO 1 or 2) versus high-grade (FIGO 3) tumors (P=0.98). Early-stage (stage I), low-grade tumors showed no significant survival advantage over early-stage, high-grade tumors (P=0.16) and this was more evident in FIGO 2 tumors. Although not statistically significant, the FIGO 2 tumors showed a trend toward worse survival than FIGO 3 tumors. Among the cases with available treatment data, more patients with early-stage high-grade tumors received adjuvant treatment, compared to patients with early-stage low-grade tumors, possibly explaining this trend (P=0.03). In conclusion, the findings of our study suggest that low-grade p53 abnormal endometrioid endometrial carcinomas (especially FIGO 2 tumors) have an aggressive course, with a prognosis similar to high-grade tumors. Furthermore, our study suggests that patients who had early-stage low-grade p53 abnormal disease might have been undertreated because of the "low-grade" histotype.

Effects of radiotherapy on the survival of patients with stage IA and low-grade stage IB uterine endometrioid carcinoma

The present study aimed to evaluate the effects of radiotherapy on the overall survival of patients with primary stage IA, grade I-III uterine endometrioid carcinoma or stage IB, grade I-II uterine endometrioid carcinoma. A total of 7504 patients with stage IA, grade I-III uterine endometrioid carcinoma, and 857 patients with stage IB, grade I-II uterine endometrioid carcinoma were collected for the present study. Following propensity score matching (PSM), statistical analysis was performed for the equalized number of patients with stage IA, grade I-III uterine endometrioid carcinoma (n = 383) and patients with stage IB, grade I-II uterine endometrioid carcinoma (n = 330). For patients with primary stage IA, grade I-III uterine endometrioid carcinoma, radiotherapy was found to promoted a reduced 5-year overall survival rates [hazard ratio (HR), 1.726; 95% confidence interval (CI), 1.456-2.046; P < 0.05]. In patients with primary stage IB, grade I-II uterine endometrioid carcinoma, no significant differences were observed in the 5-year overall survival rates between radiotherapy and no radiotherapy groups (P = 0.059). In conclusion, radiotherapy may not improve 5-year overall survival for patients with primary stage IA, grade I-III or stage IB, grade I-II uterine endometrioid carcinoma.

Adjuvant radiation therapy in early-stage endometrial cancer with abnormal beta-catenin expression is associated with improved local control

OBJECTIVES

Emerging data suggests that abnormal (nuclear) β-catenin expression in some settings is associated with poorer outcomes. Our study aimed to verify the significance of abnormal β-catenin expression in early-stage endometrial cancer patients and determine if adjuvant radiation therapy (RT) improves local control.

METHODS

We identified 213 patients with FIGO 2018 stage I-II endometrioid endometrial cancer who underwent surgery from 2009 to 2021 with β-catenin expression assessed. Vaginal, regional, and distant recurrences were analyzed using competing risk methods, and overall survival was analyzed using Kaplan-Meier.

RESULTS

Median follow up was 53.2 months; 6.9% experienced vaginal, 8.2% regional, and 7.4% distant recurrence. For the entire cohort, abnormal β-catenin expression was significantly associated with vaginal recurrence and remained significant on multivariate analysis (p = 0.03). There were 114 patients in the no specific molecular profile (NSMP) subgroup, and abnormal β-catenin expression was present in 46.5%. In the NSMP subgroup, abnormal β-catenin expression was associated with increased rates of vaginal recurrence (p = 0.06). Abnormal β-catenin expression in the NSMP subgroup was significant on multivariate analysis for vaginal recurrence (p = 0.04). RT significantly decreased vaginal recurrences in the entire cohort in patients with abnormal β-catenin expression (0%) versus wild type expression (17.5%; p = 0.03). In the NSMP subgroup 0% of patients who received RT versus 20.9% of patients who did not receive RT experienced a vaginal recurrence (p = 0.03).

CONCLUSION

Use of adjuvant RT for stage I-II NSMP endometrial cancer with abnormal β-catenin expression improved local control. RT should be considered in these patients to decrease risk of vaginal recurrences.

Mechanisms of mutant β-catenin in endometrial cancer progression

Endometrial carcinoma (EC) is the most diagnosed gynecological malignancy in Western countries. Both incidence and mortality rates of EC have steadily risen in recent years. Despite generally favorable prognoses for patients with the endometrioid type of EC, a subset of patients has been identified with decreased progression-free survival. Patients in this group are distinguished from other endometrioid EC patients by the presence of exon 3 hotspot mutations in CTNNB1, the gene encoding for the β-catenin protein. β-catenin is an evolutionarily conserved protein with critical functions in both adherens junctions and Wnt-signaling. The exact mechanism by which exon 3 CTNNB1 mutations drive EC progression is not well understood. Further, the potential contribution of mutant β-catenin to adherens junctions' integrity is not known. Additionally, the magnitude of worsened progression-free survival in patients with CTNNB1 mutations is context dependent, and therefore the importance of this subset of patients can be obscured by improper categorization. This review will examine the history and functions of β-catenin, how these functions may change and drive EC progression in CTNNB1 mutant patients, and the importance of this patient group in the broader context of the disease.