Racial and socioeconomic disparities in survival among women with advanced-stage ovarian cancer who received systemic therapy

In the present analysis of women diagnosed with advanced-stage ovarian cancer who received systemic therapy, we observed that the risk of all-cause mortality among Black women was 12% higher than among White women. The increased risk of all-cause mortality observed in Black women spans all age groups and encompasses the low and mid SES categories, further emphasizing the disparity between Black and White women. Conversely, Hispanic women had a lower overall risk of all-cause mortality, across all models, compared to White women. However, there was no evidence of effect modification between race/ethnicity, age, CCI, surgery, and SES groups. These results emphasize the need to address racial disparities in the survival of advanced-stage ovarian cancer, as racial disparities persist even among women who have all received systemic treatment.

Our results are consistent with prior research suggesting that racial disparities in ovarian cancer survival persist, even when all women received systemic treatment [18, 24, 25]. A cohort study among members of Kaiser Permanente Northern California found that Black women experienced poor survival rates compared to White women, even when both groups had equal access to care and received the same systemic therapy (specifically adjuvant first-line therapy of carboplatin and paclitaxel) [18]. The study also reported that Black women were more likely to have rare histological types of ovarian cancer, similar to the findings of our study (grouped in the “Other or NOS histological types” category) [18]. However, even among more rare histological types, such as malignant ovarian germ cell tumors, poorer survival was still found among Black women compared to their White counterparts, despite having similar adjuvant treatment patterns (including surgery, radiation, and chemotherapy) [24]. Another study using NCDB data reported that Black women were more likely to receive neoadjuvant chemotherapy before surgery (which the authors define as the initiation of chemotherapy between 1 and 120 days before interval debulking surgery), as opposed to primary surgery plus adjuvant chemotherapy. This finding may be due to extensive tumor burden or prediction of poor surgical performance, yet Black women still experienced lower survival compared to their White counterparts [26, 27]. Our study’s findings support this conclusion, as we found that the disparity between Black and White women persisted even among women who only received primary surgery. However, our study adds to the existing literature as we found that the racial disparity in advanced-stage ovarian cancer persists despite receipt of systemic therapy. Furthermore, our study adds to the literature showing that the Black-White disparity in ovarian cancer survival persist, even among equivalent chemotherapy receipt [18]. Our study also found that Black women in the low- and mid-SES groups, but not the high SES groups, exhibited poorer survival rates compared to all other racial/ethnic groups. However, Hispanic women within the same SES groups demonstrated better survival rates compared to White women. Similarly, Park et al. found that Black women had poorer survival rates while Hispanic women had better 5-year survival rates across histological types compared to White women [28]. This study, along with other studies on racial disparities in ovarian cancer, is consistent with the ‘Hispanic Paradox’ phenomenon. Despite facing socioeconomic barriers to health, Hispanic individuals have similar or better survival than their White counterparts [29, 30]. Additional studies are needed to evaluate the ethnic differences that might contribute to survival outcomes among women with ovarian cancer [30, 31].

Several clinical differences may also play a significant role in the Black-White disparity in ovarian cancer survival. Our study found that the Black-White disparity persisted even among women who did not report any comorbidities. This finding indicates that healthcare disparities, such as access to and utilization of healthcare resources, as well as other clinical factors, may be at play [32, 33]. For instance, a study from the Ovarian Cancer in Women of African Ancestry consortium found that nulliparity, body mass index, and postmenopausal hormone therapy duration were all independent mediators in the racial disparity in ovarian cancer survival [32]. Biological differences may also contribute to the racial disparity in ovarian cancer, as the highest levels of mutations in micro-RNA (miRNA) genes, which can lead to dysregulation of miRNA processing or degradation, have been found among African American women [34]. Additionally, Black women with ovarian cancer are more likely to have a high expression of immune cells, which is associated with a favorable response to immunotherapy, [35‐37] yet they are less likely to be enrolled in clinical trials involving immunotherapy [38]. Therefore, there are most likely clinical and biological factors that remain unaddressed, contributing to the racial disparities in the survival of advanced-stage ovarian cancer, regardless of treatment receipt.

Our study has several strengths. First, it included a large sample size from the NCDB, which undergoes strict quality control measures to ensure high-quality standardized data [19]. Additionally, we were able to adjust for many potential confounders, including demographic, comorbidities, treatment, and tumor characteristics. Furthermore, we were able to make a composite measure of SES to evaluate its role in survival disparities. We comprehensively evaluated the effect modification by age, SES, CCI, and receipt of surgery. However, our study had limitations that need to be considered. First, although the NCDB covers approximately 70% of the U.S. population, the results may not be generalizable to all women with advanced-stage ovarian cancer, as women treated at Commission on Cancer (CoC) accredited facilities may have different sociodemographic characteristics than women treated at non-CoC accredited facilities [19]. Second, the NCDB only records first-course treatments, meaning that patients who receive systemic therapy after their primary treatment were not able to be included in our study nor could we evaluate neoadjuvant versus adjuvant chemotherapy [19]. Furthermore, NCDB reports systemic therapy as chemotherapy, hormone therapy, immunotherapy, or hematologic transplant and endocrine procedures; however, we did not examine hematologic transplant and endocrine procedures nor does the definition specify targeted therapy. Lastly, we were not able to evaluate ovarian cancer-specific death, as the database only records vital status and not the specific causes of death. Despite these limitations, our study allowed us to evaluate disparities in race/ethnicity and SES among women with advanced-stage ovarian cancer who have received systemic therapy while maintaining sufficient power.