LOS ANGELES - While the incidence of breast cancer among African-American women is lower than the rest of the population, those who do have the disease tend to be younger, present at a later stage, and have worse five-year survival rates. Research presented this week at the American Society for Therapeutic Radiology and Oncology (ASTRO) meeting indicates that African-American women are more prone to disease relapse after breast-conserving therapy.
Nevertheless, lead author Dr. Meena Moran emphasized that breast-conserving therapy should still be discussed as a reasonable treatment option for African-American women who are determined to keep their breasts intact.
"While we have also demonstrated that African-American patients have higher local recurrence rates after breast-conserving therapy, we believe that conserving surgery and radiation therapy remains a reasonable option, provided the clinical scenario is appropriate," Moran said during her presentation.
Moran and colleagues reviewed 27 years' worth of records for 2,371 women treated for early-stage breast cancer with conserving surgery, whole-breast radiation, plus a boost dose to the tumor bed (total median dose of 64 Gy). The women also received regional node radiotherapy and adjuvant systemic therapy. Additionally, p53 expression was analyzed in 444 patients. The patients were followed up for a median of seven years.
Moran and her co-authors are from Yale University School of Medicine in New Haven, CT, and the Robert Wood Johnson Medical School at the University of Medicine and Dentistry of New Jersey in New Brunswick.
Previous studies have shown that socioeconomic and access-to-care disparities exist between African-American and Caucasian women, but Moran noted that in this particular patient population there was no statistically significant difference in detection method by racial group (45% of cancer found with mammography alone in African-American and Caucasian women), surgical results (8.4 lymph nodes removed in African-American patients, 7.9 in Caucasian patients), and the percentage of positive surgical margin (12% in African Americans, 9% in Caucasians).
Also, the percentage of patients receiving chemotherapy and tamoxifen did not differ significantly by race, Moran stated, nor did the frequency of the regimens used.
While there was no difference in the family history of breast cancer, 20% of the African-American women were younger than age 40 at presentation versus 12% of Caucasian women. Thirty-two percent of African-American women had T2 pathologic status and 32% had positive nodal status. In comparison, 18% of Caucasian women had T2 pathologic status and 24% had positive nodal status. Finally, 32% of the African Americans were p53 positive versus 13% of the Caucasians.
Also, on follow-up, there were race-related differences in distant relapse: 20% for African-American women versus 17% in Caucasian women. Nodal relapse occurred in 6% of the African-American patients and 2% of the Caucasian patients. Lastly, overall breast relapse occurred in 17% of the African Americans compared with 13% of the Caucasians.
"When we preformed a multivariate analysis, taking into account age at diagnosis, T stage, nodal status, and margin status, we found that nodal relapse and breast relapse remained significantly higher for (African-American) women, with a relative risk of 3.14 for nodal relapse and a relative risk of 1.63 for breast relapse," Moran said.
Again, Moran stressed that the results should not be interpreted to mean that African-American women were ineligible for breast-conserving therapy. Instead, radiation oncologists and other treating physicians should be aware of the risk of locoregional relapse and take steps to manage these risks, including ensuring negative margin status, delivering adequate doses to the tumor bed, breast, and regional lymph nodes, as well as treating the axilla.
During the ASTRO discussion, Dr. Lori Pierce from the University of Michigan in Ann Arbor cautioned against making treatment decisions based on race alone. Instead, she said biological factors needed to be taken into consideration, such as the tendency for African-American women to have triple-negative tumors (ER-negative, PR-negative, HER2/neu-negative).
Moran said her group is currently conducting an assay-based study that will further analyze relapse rates among triple-negative patients. Other issues that the team will look at with future research are other biological differences between Caucasian and African-American women, the types of chemotherapeutic agents used, and compliance with treatment and follow-up.
By Shalmali Pal
AuntMinnie.com staff writer
October 31, 2007
Related Reading
White women receive adjuvant breast cancer therapy more often than blacks, October 17, 2007
Estrogen receptor-negative breast cancer more common in African Americans, September 6, 2007
Racial variations found in breast cancer type an, August 23, 2007
Breast cancer incidence linked to hormone therapy and mammography use, August 7, 2007
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