Determining the Optimal Sequence of Immunotherapy and Lymph Node Irradiation among Patients with Cancer: A Propensity Score Matched Analysis

PURPOSE/OBJECTIVE(S)

Immunotherapy (IT) and lymph node irradiation (LNI) are essential cancer treatment modalities. In combination, the optimal sequence to enhance tumor response is poorly understood. While LNI depletes radiosensitive IT-related immune cells, LNI also provides an immunostimulatory effect by shedding tumor neoantigens in the microenvironment. Here we aim to 1) assess IT and LNI sequence patterns among patients with common cancers, 2) evaluate propensity score (PS) matched overall survival (OS) between IT first and LNI first treatments, and 3) compare OS by cancer site.

MATERIALS/METHODS

A PS matched retrospective cohort study was conducted using the National Cancer Database. The primary endpoint was OS (time from diagnosis to death). Patients age ≥18 years with breast, GI (pancreas, colorectal, liver), GU (prostate, kidney, bladder), lung, lymphoma, melanoma, and oral cavity cancers were included. All patients underwent both IT and LNI and those with incomplete treatment timing were excluded. IT followed by LNI (IT first) was compared to LNI followed by IT (LNI first). PS were performed with 1:1 matching and a standard mean difference cutoff of 0.1 for covariate balancing. PS matched age, stage, comorbidity index, facility type, and upfront lymph node surgery. Unadjusted Kaplan-Meier (KM) estimates with log-rank tests assessed OS. Multivariable Cox proportional hazard (CPH) models adjusted for patient demographics compared IT first versus LNI first with adjusted hazard ratios (aHR) and 95% confidence intervals (95% CI). Models were stratified by cancer site.

RESULTS

A total of 23,238 patients treated with IT and LNI were included, 88% of patients underwent IT first. Median (interquartile range [IQR]) age and follow-up were 57 (48-66) years and 39 (27-53) months, respectively. Cancers included 74% breast, 8% oral cavity, 6% GI, 5% lymphoma, 4% lung, 2% GU, and 1% melanoma. Median (IQR) weeks to treatment were 7 (4-13) for IT first and 8 (4-17) for LNI first. On unadjusted analysis, OS was significantly inferior with LNI first for overall (p<.0001), breast (p<.0001), GI (p = .004), lymphoma (p = .0003), and oral cavity cancer (p = .005). There were no significant differences in OS for GU, lung, and melanoma. On PS matched adjusted CPH analysis, LNI first had significantly higher risk of death overall (aHR = 3.2, 95% CI = 3.0-3.4), compared to IT first. PS matched cancer stratified analyses found OS was significantly inferior with LNI first for breast (aHR = 1.5, 95% CI = 1.2-1.8), GI (aHR = 1.2, 95% CI = 1.1-1.4), GU (aHR = 1.3, 95% CI = 1.0-1.8), lymphoma (aHR = 1.8, 95CI = 1.3-2.6), and oral cavity cancer (aOR = 1.3, 95% CI = 1.1-1.5).

CONCLUSION

PS matched analyses revealed superior OS for patients receiving IT first then LNI for breast, GI, GU, lymphoma, and oral cavity cancers. These findings suggest the importance of an intact immune system prior to IT. Future prospective studies are warranted to validate these findings.

Racial Disparities in Brachytherapy Treatment among Women with Cervical and Endometrial Cancers: A United States Cohort Study between 2004 and 2017

PURPOSE/OBJECTIVE(S)

Brachytherapy (BT) improves clinical outcomes among women with cervical and endometrial cancers. Recent trends found decreasing BT rates in the United States; however, racial/ethnic differences have not been investigated completely. Here we aim to analyze 1) variations in BT practice patterns, 2) racial differences of BT, and 3) predictors of BT by race among women with cervical and endometrial cancers in the United States.

MATERIALS/METHODS

A retrospective cohort of women with endometrial and cervical cancers in the US was evaluated using the National Cancer Database, between 2004 and 2017. Primary endpoint was treatment with BT. Women ≥18 years of age were included for FIGO Stage IA-IVA, non-surgically treated cervical cancers and high intermediate risk (PORTEC-2 and GOG-99 definition) or FIGO Stage II-IVA endometrial cancers. Racial groups were in accordance with federal guidelines including Asian, American Indian and Alaska Native (AIAN), Black, Native Hawaiian and other Pacific Islander (NHPI), and White. BT practice patterns and trends over time were evaluated by race. To identify predictors of BT by race, logistic regression calculated adjusted odds ratios (aOR) and 95% confidence intervals (95% CI) after assessing for multicollinearity.

RESULTS

A total of 13,857 women with cervical cancer and 140,942 women with endometrial cancer were included. Median follow-up was 69 months. Median (IQR) age was 53 (43-63) years for cervical cancer and 64 (57-72) years for endometrial cancer. Most cervical cancers were Stage III (44%), squamous cell carcinoma (88%), and lymphovascular space invasion (LVSI) positive (49%). Most endometrial cancers were Stage IB (45%), endometrioid histology (82%), and LVSI-positive (50%). Between 2004 and 2017, endometrial cancer BT increased (34% to 57%). BT rates for cervical cancer ranged from 65% NHPI, 63% Asian, 62% White, 59% AIAN, and 57% Black. BT rates for endometrial cancer ranged from 26% Black, 25% White, 25% Asian, 21% AIAN, and 20% NHPI. By race, only Black women with cervical cancer were significantly less likely to receive BT (aOR = 0.8; 95% CI = 0.7-0.9), compared to White women. Only NHPI women with endometrial cancer were less likely to receive BT (aOR = 0.7; 95% CI = 0.5-1.0), compared to White women. Community cancer center treatment was the only factor associated with a decreased odds of BT for both Black women with cervical cancer (aOR = 0.7; 95% CI = 0.6-0.9) and NHPI women with endometrial cancer (aOR = 0.3; 95% CI = 0.1-0.8), compared to academic centers.

CONCLUSION

In this study of women diagnosed with endometrial and cervical cancers with stages known to benefit from BT, NHPI women with endometrial cancer and Black women with cervical cancer were less likely to receive brachytherapy compared to White women. Community engagement is needed to increase BT access for patients treated at community cancer centers to ensure equitable gynecologic cancer care.

Gene regulatory networks controlling temporal patterning, neurogenesis, and cell-fate specification in mammalian retina

Gene regulatory networks (GRNs), consisting of transcription factors and their target sites, control neurogenesis and cell-fate specification in the developing central nervous system. In this study, we use integrated single-cell RNA and single-cell ATAC sequencing (scATAC-seq) analysis in developing mouse and human retina to identify multiple interconnected, evolutionarily conserved GRNs composed of cell-type-specific transcription factors that both activate genes within their own network and inhibit genes in other networks. These GRNs control temporal patterning in primary progenitors, regulate transition from primary to neurogenic progenitors, and drive specification of each major retinal cell type. We confirm that NFI transcription factors selectively activate expression of genes promoting late-stage temporal identity in primary retinal progenitors and identify other transcription factors that regulate rod photoreceptor specification in postnatal retina. This study inventories cis- and trans-acting factors that control retinal development and can guide cell-based therapies aimed at replacing retinal neurons lost to disease.