Investigating the Relationship between the Dose to the Recto-Vaginal Reference Point and Vaginal Stenosis among Cervical Cancer Patients Treated at a North American Academic Institution

PURPOSE/OBJECTIVE(S)

In the treatment of locally advanced cervical cancer (LACC) with image-guided brachytherapy, there are limited data concerning the optimal vaginal dose constraints to minimize risk of vaginal stenosis (VS). While the dose to the recto-vaginal reference point (RV-RP) has been reported to be associated with VS, the EMBRACE dose constraint of 65Gy is a higher value than we typically measure at our institution. We hypothesize that there may be an association between the dose to the RV-RP and VS at lower values than previously reported.

MATERIALS/METHODS

Following IRB approval, data were collected for 87 LACC patients treated at a single institution between 12/2012 - 4/2022 with available CTCAEv4.0 VS scores and minimum follow-up of 4 months. Only patients treated with tandem/ring or tandem/ovoid applicators, with or without interstitial needles, were included. Perineal template and cylinder-based applications were excluded. Dose to the RV-RP was retrieved from the treatment planning system. Primary endpoint was grade 2 or higher (G ≥ 2) VS. The Kaplan-Meier method was used to estimate the cumulative incidence of VS. The log-rank test and multivariable Cox proportional-hazards regression were used to evaluate the association between dose to the RV-RP with VS G ≥ 2.

RESULTS

The cohort median age was 48 (IQR 38-61). 59 patients (68%) were stage I or II (FIGO 2009) and 28 (32%) were stage III. Ethnicity was Hispanic or Latino in 20 patients (23%). Technique was predominantly tandem/ring (78%), high-dose-rate (79%), and intracavitary without interstitial needles (83%). The most common dose-fractionation was 28Gy in 4 fractions (following 45Gy to the pelvis). The median cumulative HR-CTV D90% dose was 83.1Gy (IQR 79.7 - 86.5). Median dose to the RV-RP was 51.1Gy (IQR 49.2 - 55.8). Only 9 patients (10%) had a dose to the RV-RP higher than 65Gy (max 71.1). Median follow-up was 22.6 months (range: 4.2 - 114). The 2-year incidence of VS G ≥ 2 was 24.4%. Dose to the RV-RP was associated with VS G ≥ 2. The 2-year incidence of VS G ≥ 2 for patients with RV-RP dose <51 vs ≥51Gy was 13.1% vs 34.6% (p = 0.038). On multivariable regression, dose to the RV-RP ≥51Gy (HR 2.94 CI 1.16 -7.48, p = 0.024), Hispanic or Latino ethnicity (HR 3.71 CI 1.38 - 9.99, p = 0.01), and stage III (HR 2.33 CI 1.06 - 5.12, p = 0.035) were significantly associated with increased risk of VS G ≥ 2.

CONCLUSION

We observed a statistically significant association between the dose to the RV-RP and VS G ≥ 2, when stratified by our median dose to the RV-RP of 51Gy, which is lower than the dose constraint of 65Gy previously reported by EMBRACE. These findings may be partially explained by differences in patient demographics or brachytherapy technique. Further investigation of the relationship between the dose to the RV-RP and development of VS G ≥ 2 across broader populations is warranted.

Prognostic Impact of Mismatch Repair Deficiency on Stage I-II Endometrioid Endometrial Cancer Treated with Adjuvant Radiation Therapy: A Multi-Institutional Analysis

PURPOSE/OBJECTIVE(S)

To report the impact of mismatch repair (MMR) status on outcomes in patients with stage I-II endometrioid endometrial cancer (EEC).

MATERIALS/METHODS

This is a multi-institutional retrospective cohort study across 11 institutions. Preliminary data from 7 centers is available for analysis. Patients with known MMR status and stage I-II EEC status post-surgical staging treated with adjuvant radiation therapy were included. Overall survival (OS) and recurrence-free survival (RFS) rates were estimated by the Kaplan-Meier method. Univariate and multivariate analyses were performed by Cox proportional hazard models for OS/RFS. Statistical analyses were conducted using statistical software.

RESULTS

A total of 573 patients with median age at diagnosis of 65 years (Interquartile Range (IQR) 58-71) were eligible. Most patients were White (79%), had FIGO 2009 Stage I (89.7%) and FIGO grade 1-2 (74.7%). MMR deficiency (dMMR) was reported in 191 patients (33%) while 382 patients (67%) had preserved MMR (pMMR). External beam radiation therapy (EBRT) +/- vaginal brachytherapy (VBT) was delivered to 124 patients (21.6%) while 449 patients (78.4%) received VBT alone. After a median follow-up of 41 months ((IQR) 28-60 months), the estimated OS and RFS rates for the entire cohort were 95.1% and 85%, respectively. On univariate analysis, age >65 (p < 0.001), grade 3 (p < 0.001), presence of lymphovascular space invasion (LVSI) (p = 0.039) and deep myometrial invasion (p = 0.03) were associated with worse OS. The OS was inferior in the dMMR group, however, it did not reach significance (92% vs 96.1%, p = 0.06). On multivariate analysis, older age (p < 0.001) and grade 3 (p = 0.002) were the only predictors for worse OS. On univariate analysis for RFS, age >65 (p = 0.02), grade 3 (p = 0.018) and dMMR (72.9% vs 91%, p < 0.001) were associated with worse RFS. On multivariate analysis, age >65 (p = 0.015) and dMMR (p < 0.001) were significant predictors of worse RFS.

CONCLUSION

Preliminary data from 7 out of 11 participating institutions showed that dMMR status leads to significantly decreased RFS in patients with early-stage EEC. While awaiting the results of NRG GYN020 and RAINBO prospective trials, this large study suggests that treatment intensification could be warranted in patients with dMMR early-stage EEC.

PD04-03: Sexual Dysfunction in Premenopausal Women with Breast Cancer: Prevalence and Severity

Background: Sexual dysfunction is reported after chemotherapy and endocrine therapies. However, the prevalence and severity of sexual dysfunction in premenopausal women undergoing therapy for both local and metastatic disease is not well defined. This study was performed in order to understand the impact of contemporary breast cancer treatment on the prevalence and severity of sexual health in premenopausal women.

Methods: We developed a survey that includes a previously validated questionnaire, the Female Sexual Function Index (FSFI), as well as an established measure of health-related quality of life (the EuroQol EQ-5D), and disease-specific items to characterize sexual dysfunction and its causes based on literature review and expert consultations. Anonymous administration of the surveys was conducted in outpatient clinic waiting areas of the Breast Cancer Center at Memorial Sloan-Kettering Cancer Center (MSKCC), under an IRB waiver of consent.

Results: 372 consecutively approached premenopausal women with breast cancer of any stage, undergoing treatment were each queried once. The mean age was 47. 87% reported current or past hormonal treatment, and 86% reported current or past chemotherapy (76% adjuvant; 24% for metastatic disease). Sexual dysfunction attributed to breast cancer or its treatment, defined as an FSFI score &lt;26, was reported by 75% of respondents with a mean score of 16.3. Among these women, 79% of patients considered their sexual symptoms to be bothersome, with 51% noting moderate or severe levels of bother (score &gt;=5/10). In a multivariate analysis, metastatic disease, development of amenorrhea from cancer treatment, antidepressant use and poorer overall health were each significantly associated with worse FSFI scores. Lower FSFI scores were also significantly associated with worse health-related quality of life.

Conclusion: Sexual dysfunction is prevalent in premenopausal women treated for breast cancer and should be discussed with patients as a potential adverse effect of therapy. Assessment of sexual symptoms throughout treatment and beyond may facilitate the use of potential interventions such as lubricants, dilators, treatment modification and counseling.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD04-03.