Minority Participation in Gynecologic Oncology Group (GOG) Studies. Issue 9 (September 2015) - Scalici, Jennifer
Abstract ABSTRACT Cancer mortality rates have declined significantly in the United States since the 1990s. There has been about a 10% reduction in death in women alone. Despite this reduction, 5-year overall survival at each stage of diagnosis remains significantly lower for black patients compared with whites. The primary factors underlying cancer racial disparities are likely multifactorial and include clinical features, environmental factors, socioeconomic factors, and differences in tumor biology. Racial differences have been reported in incidence of several malignancies, including endometrial, ovarian, and cervical cancers and uterine sarcoma. A review of death rates in advanced/recurrent endometrial cancer showed that black women in the United States were 60% to 80% more likely to die of endometrial cancer when controlling for other variables such as performance status, disease stage, tumor grade and histology, and the treatment provided. Black patients with cervical cancer have the highest death compared with all racial or ethnic groups, and there is racial disparity in ovarian cancer death rates as well. The gap in racial disparity for mortality from all cancers have widened over the past few decades. The observed enrollment of black patients in clinical trials is substantially lower than that of white women. It has been suggested that enrollment of minority populations into clinical trials is critical to adequately describe true racial disparity for gynecologic malignancies. Without adequately studying minority populations, it is difficult to gain significant insight into the potential factors that contribute to well-described disparities and enhance understanding of the burden of gynecologic cancer in minority patients. The aim of this study was to evaluate minority participation in published Gynecologic Oncology Group (GOG) clinical trials. Articles published from 1985 to 2013 were reviewed. Minority enrollment was stratified by tumor site, tumor and study type, and year published. Data variables also included patient demographics and surgicopathology. Using the Centers of Disease Control and Prevention (CDC) age-adjusted incidence for race, expected and observed ratios of racial participation were calculated. Data were abstracted and reviewed from 445 GOG publications involving 67, 568 patients. Racial breakdown was provided for 38% (n = 170) of these studies involving 45, 259 patients and was as follows: 83% white (n = 37, 617), 8% black (n = 3686), and 9% other (n = 3956). Ovarian trials (n = 202) were the most common studies accounting for 45% of those reviewed. The most common type of trials published, comprising 65% of all studies, was phase 2 studies (n = 290). There was a steady decline in the proportion of black patients enrolled when evaluating the quartiles of publication year. Inclusion of racial breakdown was not reported prior to 1994 (years 1985 to 1993; 0 publications). There was a 2.8-fold reduction in black enrollment over time. The percentage enrolled dropped from 16% in 1994 to 2002 to 5.8% from 2009 to 2013 (P < 0.01). Observed enrollment of black patients into GOG clinical trials utilizing CDC age-adjusted incidence was significantly less than expected. Compared with expected enrollment, observed black enrollment was15-fold lower in ovarian trials. Other tumor types with less than expected enrollment were endometrial (10-fold lower), cervical (4.5-fold lower), and sarcoma (5.2-fold lower); each comparison was P < 0.001. These findings show that observed enrollment of black patients into GOG studies based on age-adjusted incidence was lower than expected for a variety of tumor types. Despite emphasis on minority participation in clinical trials, there has been decrease in enrollment of black patients over time.