The impact of ethnicity and insurance status on stage of cancer at diagnosis and overall survival of breast cancer

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Background: Major advances in early diagnosis and treatment of breast cancer (BC) have been achieved with significant declines in mortality. However, not all segments of the United States population have experienced equal benefits from this progress. Though ethnic disparities in BC outcome have been attributed to lack of adequate health insurance, the differences in outcome when insurance and socioeconomic status are similar still exist. We elected to examine the effect of insurance status at diagnosis, and whether race is an independent risk of poor outcome in a population from a community-based cancer database.

Methods: A retrospective study on BC among patients aged 18 to 64 years were identified, between 1993 and 2005, using data from the Tumor Registry at Hurley Medical Center in Flint, Michigan. Patient’s characteristics included age, race, stage at diagnosis, and primary payer. Insurance status was classified as uninsured/Medicaid, private insurance, and Medicare disability (Medicare under age 65). The 5-year overall survival (OS) was calculated, in respect to patient ethnicity, and compared between the three insurance groups using Fisher’s exact test.

Results: A total of 779 patients have been identified with diagnosis of BC. 147 patients were excluded due to incomplete data. 632 patients were analyzed. African Americans were 228 (36%), Caucasians 391 (62%), and other ethnicities 13 (2%). Mean age at diagnosis was (49.21) for African Americans versus (51.35) for Caucasians (p = 0.002). African Americans were more likely to present at advanced stage (III, IV) than Caucasians (17% versus 10%, p = 0.017). However, this difference was not statistically significant when adjusting for insurance status. Although both ethnicities had similar OS in respect of their insurance group, patients with Medicaid/uninsured had significantly lower OS compared to patients with Medicare disability (p = 0.006) and private insurance (p < 0.0001) respectively.

Conclusions: Uninsured/Medicaid patients with breast cancer have worse outcome when compared to patients with Medicare or private insurance. Ethnicity is not an independent risk factor of advanced stage at diagnosis and poorer outcome.

Ethnic disparity of treatment initiation in women diagnosed with breast cancer

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Background: Despite the major advances in early detection and treatment of breast cancer (BC), African American women, continued to have a higher mortality rates than Caucasians. Many studies have failed to identify a key factor to explain racial disparities in breast cancer outcome. These disparities persist even after controlling for insurance and socioeconomic settings. Data about delays in treatment initiation are limited and inconclusive. We intend to compare the time from diagnosis to the initiation of treatment between African American and Caucasian women diagnosed with BC in a single community-based cancer registry.

Methods: Women aged 18 to 64 years with breast cancer were identified, between 1993 and 2009, using data from the Tumor Registry at Hurley Medical Center in Flint, Michigan. Patient’s characteristics obtained include age at diagnosis, race, stage, date of diagnosis, and date of treatment initiation. All patients were previously insured or became insured after diagnosis. Time from diagnosis to the initiation of treatment was calculated in days and compared between African American and Caucasian women using t-test.

Results: A total of 1016 patients have been identified with diagnosis of BC. 23 patients were excluded due to missing data. 993 patients were analyzed. African Americans were 355 (36%), Caucasians 617 (62%), and other ethnicities 21 (2%). Mean age at diagnosis was (48.9) for African Americans versus (51.45) for Caucasians (p = 0.005). African American women were more likely to present with advanced stage (III, IV) than Caucasians (18% versus 12%, p = 0.009). African American women had significant delay in the treatment initiation of BC compared to Caucasians (31.11 versus 21.52 days, p < 0.0001).

Conclusions: African American women were diagnosed with breast cancer at younger age and more advanced disease than Caucasians. African American women experienced significant delay in the initiation of therapy after diagnosis compared to Caucasians. However, the impact of an average delay of 10 days in treatment on overall survival is unknown. The exact explanation of this disparity is yet to be determined.

The effect of statins on overall survival of breast cancer

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Background: Observational studies have raised the possibility that use of statins may reduce the incidence and overall risk of cancer. In contrast, some randomized trials have consistently shown no effect of statins at cancer incidence or mortality. However, data about the potential effect of statins on overall survival of breast cancer are limited. We intend to examine the role of statins at overall survival of women diagnosed with breast cancer.

Methods: A retrospective observational study was conducted from 1993 to 2007, using data from McLaren Regional Medical Center in Flint, Michigan on women diagnosed with breast cancer. Patient's characteristics including age at diagnosis, race, stage and use of statin with dosage were recorded. Patients with coronary artery disease were excluded to eliminate the confounding effect. The three-year overall survival was considered the primary outcome. Results:s A total of 392 women diagnosed with breast cancer were identified. 146 patients were on statins therapy prior to diagnosis (group 1), and 246 patients were not on statins (group 2). African American percentage was 7%. Mean age at diagnosis was 65 for both groups. Atorvastatin was the most used treatment with a dose of 20 mg daily. Patients were classified according to the TNM staging system of breast cancer as stage I, II, III, IV (58%, 31%, 8%, 3%) for group 1, and (62%, 32%, 4%, 2%) for group 2 respectively. The 3-year stage-specific survivals were calculated and compared between the two groups using Fisher's exact test (Table). Overall survival was not statistically significant between the two groups.

Conclusions: Our study did show that statins do not affect the three-year overall survival of breast cancer at early stages, but it may improve the outcome at advanced stages. A larger national data review is warranted.

[Table: see text]

The effect of chemotherapy on overall survival of stage II colon cancer

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Background: Surgical resection of local colon cancer is the only curative treatment, at the same time adjuvant chemotherapy is clearly shown to be beneficial as the standard of care for node positive disease (stage III) colon cancer. However the role of chemotherapy for stage II colon cancer treatment is still conflicting. We aim to compare the overall survival rate of stage II colon cancer patient's with and without chemotherapy.

Methods: A retrospective observational study was conducted from 1990-2006. Patients with stage II colon cancer were included. Patient's characteristics including age, gender, common site of involvement, histology patterns, overall survival rate and treatment with chemotherapy were recorded.

Results: A total of 138 consecutive patients were identified from 1990-2006. The median age was 68 (21-91) year, males (44%), African Americans (47.6%). The most common sites of the primary tumor were sigmoid and cecum (22.4%) each. Adenocarcinoma being the most common pathology. Majority of the patients (86.2%) were found to have T 3 tumors. Of the patients that received chemotherapy (29/44) 66% had an overall survival rate of three years or more, whereas (53/94) 57% of the patients who did not receive chemotherapy had a survival rate of three years or more. The difference of survival rates between the two groups of patients was not statistically significant.

Conclusions: The role of chemotherapy in stage II colon ancer is still controversial. There was no significant difference in overall survival between the two groups who did and did not receive chemotherapy; thus more studies are warranted to explore the factors that predict the survival of stage II colon cancer.

No significant financial relationships to disclose.

Potentiation of 2-chlorodeoxyadenosine activity by bryostatin 1 in the resistant chronic lymphocytic leukemia cell line (WSU-CLL): association with increased ratios of dCK/5'-NT and Bax/Bcl-2

The activities of 2-chlorodeoxyadenosine (2-CdA) metabolizing enzymes, deoxycytidine kinase (dCK) and cytosolic 5'-nucleotidase (5'-NT) were measured in control and bryostatin 1 treated CLL cells using an EBV-negative WSU-CLL cell line. This cell line was established from a patient with CLL resistant to fludarabine. The results revealed a significant increase in dCK activity in bryostatin 1 treated cells at 48 and 72 h compared with the control. 5'-NT activity decreased significantly at 48 h. The ratio of dCK to 5'-NT activity was significantly increased in bryostatin 1 treated WSU-CLL cells after 48 h. WSU-CLL cells treated with bryostatin 1 exhibited an increase in the percentage of apoptotic and dead cells from control levels of 16% to 40%. This percentage was further increased to 67% following the addition of 11.2 microM 2-CdA to WSU-CLL cells pretreated with bryostatin 1. Results from Western blot analysis indicate that WSU-CLL cells express high levels of Bcl-2, Bcl-xL and c-myc, and a low level of Bax. p53 in untreated WSU-CLL cells is undetectable. WSU-CLL cells treated with bryostatin 1 showed a significant increase in the ratio of Bax to Bcl-2. To demonstrate that the bryostatin 1 mediated enhancement of 2-CdA efficacy was not restricted to in vitro cell culture, we have studied the tumor growth delay of WSU-CLL xenografts treated with placebo, bryostatin 1, 2-CdA, and bryostatin 1 followed by 2-CdA. SCID mice given bryostatin 1 at 75 microg x kg(-1) x d(-1) for 5 days followed by 30 mg x kg(-1) x d(-1) 2-CdA for 5 days in two cycles, had significantly improved tumor growth delay (P = 0.05). We conclude that bryostatin 1 is not only capable of inducing apoptosis by itself, but also sensitizes de novo resistant WSU-CLL cells to the chemo-therapeutic effects of 2-CdA. The bryostatin 1-induced increased ratio of dCK/5'-NT activity and an increased ratio of Bax/Bcl-2 are at least two mechanisms through which this natural compound is able to potentiate the anti-tumor activity of 2-CdA in otherwise resistant CLL cells.

Sequential treatment of human chronic lymphocytic leukemia with bryostatin 1 followed by 2-chlorodeoxyadenosine: preclinical studies

We have previously reported that bryostation 1 (Bryo 1) induces differentiation of chronic lymphocytic leukemia (CLL) in vitro to a hairy cell (HC) stage. This study tests the hypothesis that Bryo 1-differentiated CLL cells are more susceptible to 2-chlorodeoxyadenosine (2-CdA) than parent CLL cells. A recently established EBV-negative CLL line (WSU-CLL) from a patient resistant to chemotherapy including fludarabine was used to test this hypothesis. Both Bryo 1 (10-1000 nM) and 2-CdA (5.6-22.4 microM) exhibited a dose-dependent growth inhibitory effect on the WSU-CLL cell line. In vitro, the sequential exposure to Bryo 1 (100 nM for 72 h) followed by 2-CdA (11.2 microM) resulted in significantly higher rates of growth inhibition than either agent alone. Changes in immunophenotype, enzymes, lipids, proteins, and the DNA of WSU-CLL cells were studied before and after Bryo 1 treatment. Bryo 1 induced a positive tartrate-resistant acid phosphatase reaction and two important markers, CD11c and CD25, after 72 h of culture, confirming the differentiation of CLL to HC. The Fourier transformation infrared spectroscopic analysis showed that the amount of membrane lipids significantly increased in Bryo 1-treated cells compared to controls after 24 h, whereas the protein content, as well as the DNA content, decreased. This finding supports the change of CLL to HC. To evaluate the in vivo efficacy of Bryo 1 and 2-CdA, we used a xenograft model of CLL in WSU-CLL-bearing mice with severe combined immune deficiency. s.c. tumors were developed by injection of 10(7) WSU-CLL cells, and fragments were then transplanted into a new batch of severe combined immunodeficient mice. Bryo 1 and 2-CdA at the maximum tolerated doses (75 micrograms/kg i.p. and 30 mg/kg s.c., respectively) were administered to the mice at different combinations and schedules. The survival in days, the tumor growth inhibition ratio, the tumor growth delay, and the log10 kill of the mice treated with Bryo 1 followed by 2-CdA were significantly better than the control and other groups. We conclude that the sequential treatment with Bryo 1 followed by 2-CdA resulted in higher antitumor activity and improved animal survival.

Establishment of a human B-CLL xenograft model: utility as a preclinical therapeutic model

Chronic lymphocytic leukemia (CLL), a proliferative disease of mature looking B lymphocytes, is the commonest leukemia in western countries. It remains incurable by available treatment modalities. We report on the establishment of a permanent, EBV-negative, B-CLL line (WSU-CLL) from the peripheral blood of a patient with CLL. The cells grow as suspension in liquid culture, express IgG lambda and other B cell markers and show lg heavy and light gene rearrangements. Karyotypic analysis shows 45,X,del(3)(p14;p24),t(4;12;12) (q31;q22;p13), t(5;12) (q31;p13), add(16)(q24)X2, t(18;21) (q12;p12). WSU-CLL forms colonies when grown on soft agar. A xenograft model was established by injecting the WSU-CLL cells subcutaneously (s.c.) in severe combined immune deficient (SCID) mice. When the s.c. tumor was transplanted in vivo to other SCID mice, the success rate was 100% with a doubling time of 7.3 days. The CLL-SCID xenograft model was used to test the efficacy of selected standard chemotherapy drugs and new therapeutic agents against WSU-CLL. The cell line and the xenograft described can be used as a model to facilitate the development of new therapeutic agents against CLL in man.