Cancer-related Disparities: Weathering the Perfect Storm Through Comprehensive Cancer Control Approaches

During the last two decades extraordinary progress in developing and using effective cancer prevention strategies, early detection interventions, and cancer treatments has been made. This progress has resulted in an overall decline in mortality rates for all cancers combined. Nonetheless, cancer is the second most common cause of death in the United States. Although cancer is a diagnosis that many survive, cancer experiences across populations may vary considerably. These differences in cancer experiences have created an unequal disease burden that presents distinct professional and moral challenges to our nation. Many cancer control plans suggest specific strategies that prioritize eliminating cancer-related disparities. This article describes certain cancer-related disparities in the United States and gives several examples of how communities and disenfranchised populations are using comprehensive cancer control (CCC) approaches to eliminate these disparities. One or two interventions are highlighted in each example.

Geographic variation in breast cancer mortality for white and black women: 1986-1995

Breast cancer mortality rates have decreased during the last 20 years in the United States overall. However, declines in breast cancer mortality rates differ among individual states. This analysis ranked states from the highest to the lowest percentage change in mortality between 1986 to 1990 and 1991 to 1995. Data on white and black females were analyzed separately. Among white women, the 10 states showing the greatest percentage change in mortality during those two periods had the greatest baseline mortality in the 1986-to-1990 period. Similarly, the 10 states with the lowest percentage change in mortality had the lowest mortality rate in 1986 to 1990. In contrast, among black women, the top 10 states ranked by percentage change in mortality included either a decline or an increase. The disparities in mortality rates by state likely depend on the stage of disease at diagnoses, socioeconomic status, access to care, and adequacy of medical care.

Tumor variants by hormone receptor expression in white patients with node-negative breast cancer from the surveillance, epidemiology, and end results database

PURPOSE

Hormone receptor expression (presence-positive or absence-negative) may reflect different stages of one disease or different breast cancer types. Determining whether hormone receptor expression represents one or more breast cancer phenotypes would have important paradigmatic and practical implications.

METHODS

Breast cancer records were obtained from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database. The study included 19,541 non-Hispanic white women with node-negative breast cancer. Standard tumor cell characteristics and breast cancer-specific survival were analyzed by independent estrogen receptor (ER+ and ER-), independent progesterone receptor (PR+ and PR-), and joint ERPR expression (ER+PR+, ER+PR-, ER-PR+, and ER-PR-).

RESULTS

Age frequency density plots by hormone receptor expression showed two overlapping breast cancer populations with early-onset and/or late-onset etiologies. Independent ER+ and PR+ phenotype were associated with smaller tumor sizes, better grade, and better cancer-specific survival than ER- and PR- breast cancer types. Joint ERPR phenotype exhibited biologic gradients for tumor size, grade, and cancer-specific survival, which ranked from good to worse for ER+PR+ to ER+PR- to ER-PR+ to ER-PR-.

CONCLUSION

Variations of standard tumor cell characteristics and breast cancer-specific survival by hormone receptor expression in white patients with node-negative breast cancer suggested two breast cancer phenotypes with overlapping etiologies and distinct clinical features.

A Phase II study of high-dose tamoxifen in patients with hormone-refractory prostate cancer

Micromolar concentrations of tamoxifen inhibit the activity of protein kinase C and were recently shown to inhibit prostate cancer cell growth in preclinical studies. Because micromolar concentrations can be attained with high-dose therapy, the clinical activity of high-dose tamoxifen was evaluated in patients with metastatic adenocarcinoma of the prostate. Between December 1993 and February 1997, 30 patients with hormone-refractory metastatic adenocarcinoma of the prostate were continuously administered tamoxifen at 160 mg/m2/day. Therapy was continued until disease progression. All study patients had failed prior treatment with combined androgen blockade, had castrate levels of testosterone, and were heavily pretreated, having received a median of three prior regimens. The average steady-state plasma concentration of tamoxifen was 2.96+/-1.32 microM (mean +/- SD). Grade 3 neurotoxicity was observed in 29% of patients and was rapidly reversible and readily managed with dose modification. Otherwise, grade 3 toxicities were rare. One partial response (80% decline in prostate-specific antigen) was observed (3.3%), whereas disease stabilization was observed in six patients (20%), for a combined partial response/stable disease response rate of 23%. Median time to progression was 2.1 months, and median survival time was 10.5 months. High-dose tamoxifen therapy was well tolerated and associated with micromolar concentrations of tamoxifen in human plasma, and it demonstrated activity, albeit limited, in a heavily pretreated patient cohort with hormone-refractory prostate cancer. These findings suggest that further investigation of the role of protein kinase C modulation in prostate cancer is warranted.

Geographic, age, and racial variation in the treatment of local/regional carcinoma of the prostate

PURPOSE

Prostate cancer is one of the most common cancers in men. Incidence rates increase with age and are substantially higher in black men than white men. This study examines the variations in the use of radical prostatectomy and radiation by geographic area, age, and race.

MATERIALS AND METHODS

Data from the National Cancer Institute's Surveillance, Epidemiology, and End-Results Program (SEER) were used to examine treatment differences. Current treatments generally consist of prostatectomy, radiation, or careful observation for clinically localized or regional disease.

RESULTS

The age-adjusted proportion of men, age 50 and older, who received radical prostatectomy increased sharply between 1984 and 1991, from 11.0% to 32.3% among men with local/regional disease. The choice of treatment varied widely by geographic regions. In 1991, the proportion that received prostatectomy was highest in Utah (47.8%) and lowest in Connecticut (22.5%) among men with localized and regional disease. The increase in radical prostatectomy was not limited to younger men. Although the rates increased for blacks, black men had lower age-adjusted rates of prostatectomy than whites in all years of the study.

CONCLUSION

The SEER data show a clear trend toward more aggressive treatment, especially prostatectomy. However, the proportion of black men who received prostatectomy was substantially lower than that of white men and this disparity does not appear to be changing.

Assuring access to state-of-the-art care for U.S. minority populations: the first 2 years of the Minority-Based Community Clinical Oncology Program

BACKGROUND

The Minority-Based Community Clinical Oncology Program (MBCCOP) was initiated in September 1990 to expand the National Cancer Institute's (NCI's) clinical trials network to minority populations. Institutions, organizations, and/or physician groups that had more than 50% of new cancer patients from minority groups were eligible to participate. There has been no previous evaluation of the MBCCOP.

PURPOSE

This study was designed to describe the early implementation of the MBCCOP and identify the challenges that have emerged in developing a network aimed at increasing the participation of minority populations in clinical trials.

METHODS

Data were taken from primary and secondary sources, including site visits and patient log data, that described performance of 12 MBCCOP centers initially funded in September 1990. Accrual was measured by the number of credits earned per MBCCOP for patients enrolled in research protocols for cancer treatment or for prevention and control, which includes activities such as early detection, pain control, and rehabilitation. These accrual credits, assigned by the NCI, were based on the complexity of the protocol and the amount of resources expected to be required for accrual of patients by the MBCCOP.

RESULTS

Data for the first 2 years of the MBCCOP showed that 344 patients were accrued to trials of treatment protocols from June 1, 1990, to May 31, 1991, and this number increased to 470 during the second accrual year, June 1, 1991, to May 31, 1992. Similarly, accrual of patients to cancer prevention and control studies increased from 256 in 1990-1991 to 423 in 1991-1992. More than 70% of the MBCCOP patients entered in studies were from minority populations. The proportion of eligible MBCCOP patients entered into treatment protocols was identical with that experienced by the initial Community Clinical Oncology Program (CCOP). Results also demonstrated that MBCCOP centers operate in an environment characterized by socio-economic decline and limited resources, both having substantial effects on the implementation of clinical trials among minorities. While minority patients are willing to participate in clinical trials, there are profound barriers involving language, logistics, and the appropriateness of available protocols. Participating physicians, nurses, and support personnel report a high level of agreement with program goals and have developed unique approaches to meeting the challenges faced in the implementation of this program.

CONCLUSIONS

The MBCCOPs have demonstrated their ability to participate in clinical trials. Evaluation reveals, however, that they are emerging organizations influenced by factors endemic to the community they serve and their own structure. The MBCCOPs are confronting substantial challenges, yet they provide an important link to the overall NCI clinical trials network.

A pilot study of sequential therapy with zidovudine plus acyclovir, dideoxyinosine, and dideoxycytidine in patients with severe human immunodeficiency virus infection

A pilot study was initiated to explore a sequential combination antiretroviral regimen in 21 patients with AIDS or advanced human immunodeficiency virus (HIV) infection, who had received little or no prior anti-HIV therapy. The mean entry CD4 cell count was 184/mm3. Patients received 3-week cycles consisting of zidovudine plus acyclovir, dideoxyinosine, and dideoxycytidine for 1 week each. Overall, the regimen was well tolerated for up to 3 years. The principal toxicities were anemia, nausea, and vomiting; 1 patient developed retinal lesions. The mean CD4 cell count reached a peak of 64 cells/mm3 above baseline at week 8 (P = .005 compared to baseline) and remained above baseline for > 40 weeks. Patients also gained weight and had decreases in serum HIV p24 antigen. Eight patients developed opportunistic infections or tumors. Only 4 patients died during 3 years of follow-up. This regimen appears to be generally tolerable and to have anti-HIV activity. Additional studies will be needed, however, to learn how to best combine the available agents in patients with HIV infection.

Measures of renal function in patients with cisplatin-related chronic renal disease

Twenty-seven patients with advanced stage refractory ovarian cancer were studied to determine if chronic stable cisplatin-related renal dysfunction was present. Medical histories were examined to determine the types of therapy previously received as well as the total previous platinum doses received that ranged from 200 to 2,100 mg/m2. Standard assessments of renal function were made prior to administering current chemotherapy or immunotherapy to the patient, which included 24-hour creatinine clearance, serum creatinine, and blood urea nitrogen (BUN). For patients with a 24-hour creatinine clearance of less than 60 mL/minute, serum creatinine was highly variable (range: 0.9 to 2.0 mg/dL) and was not related to the degree of diminution in the 24-hour creatinine clearance value. Conversely, for patients with a serum creatinine of less than 1.5, the 24-hour creatinine clearance values varied by almost three-fold, ranging between 46 and 120 mL/minute. Two patients with serum creatinines of less than 1 had creatinine clearances of less than 50 mL per minute. Similarly, BUN measurements did not correlate with 24-hour creatinine clearance values, and the 24-hour creatinine clearance value was not related to the total cumulative platinum dose. We conclude that patients who receive substantive doses of cisplatin may experience chronic stable cisplatin-related renal dysfunction and that serum creatinine cannot be relied on to assess the degree of renal compromise. In such patients, we recommended that the 24-hour creatinine clearance value should be used when medical management is influenced by renal function.