Others face a diagnosis of multicentric disease, where multiple tumors have formed independently in the breast. Standard radiation treatment is not tailored to the number of tumors found in the breast, so patients with multifocal or multicentric disease do not receive radiation after mastectomy and if they undergo lumpectomy, they receive the same dose and extent as patients presenting with a single mass.
Though previous researchers have analyzed data on patients with this type of breast cancer, “there has never been any good consensus on whether or not having multifocal or multicentric breast cancer leads to higher recurrence rates, or whether there’s any difference in survival,” says Tiffany Tam, MD, an attending physician in the Radiation Oncology Department at Fox Chase Cancer Center, who will present new findings about this on October 30 at the American Society for Radiation Oncology’s 54th Annual Meeting.
Tam led a team of Fox Chase physicians in a retrospective study designed to investigate those differences in outcomes. They found no statistically significant difference in overall survival or distant recurrence, where the cancer spreads to other organs or tissues. However, local recurrence—having cancer return to the same area from which it was surgically removed—occurred more than 2.5 times more often among patients with multifocal/multicentric disease, compared to patients with a single tumor.
Tam and her colleagues analyzed the medical records of 112 women who were treated for multifocal or multicentric breast cancer at Fox Chase between 1983 and 2010. They compared outcomes data from those patients with data from 263 women treated for unifocal disease during the same period. Patients from the two groups were matched by age, gender, and stage at diagnosis. The researchers incorporated data on hormone-receptor status, type of surgery, age, grade, stage, and other therapies into their analyses. Males, patients with ductal carcinoma in situ (DCIS) and metastatic disease were all excluded from the study.
Overall survival rates and rates of distant recurrence were roughly equal between both groups. When the researchers accounted for all the variables, they found that multifocal or multicentric breast cancer patients were diagnosed with local recurrences about 2.6 times as often as patients with unifocal disease. In addition, patients with multiple tumors had shorter periods of disease free survival, which is the amount of time that passes after treatment and before cancer is detected again.
Tam says she was motivated to do the study after treating patients diagnosed with multifocal or multicentric disease. “They don’t have any other indications for radiation, post-mastectomy, and I wondered whether or not multifocal or multicentric disease should be considered in the decision to offer radiation,” she says.
The new study won’t change clinical practice guidelines, Tam says, but it suggests that the number of tumors found in the breast should be considered—along with other risk factors when considering radiation therapy.
“Even though this study suggests having multifocal or multicentric disease leads to increase local recurrence, we can’t say that definitely. It’s an additional factor that oncologists can consider,” Tam adds. It’s not clear whether or not patients with this type of disease have a more aggressive form of cancer or if they have some other risk factor that makes them more susceptible to developing multiple tumors.
Those patients may benefit from radiation therapy following mastectomy, for example, to reduce the likelihood of local recurrence, though larger studies are needed to weigh the possible benefits against possible harms.
Tam’s coauthors include Penny Anderson, Tianyu Li, Lori Goldstein, Richard Bleicher, Marcia Boraas, Elin Sigurdson, Paula Ryan, and Shelly Hayes from Fox Chase.
Fox Chase Cancer Center, part of the Temple University Health System, is one of the leading cancer research and treatment centers in the United States. Founded in 1904 in Philadelphia as one of the nation’s first cancer hospitals, Fox Chase was also among the first institutions to be designated a National Cancer Institute Comprehensive Cancer Center in 1974. Fox Chase researchers have won the highest awards in their fields, including two Nobel Prizes. Fox Chase physicians are also routinely recognized in national rankings, and the Center’s nursing program has received the Magnet status for excellence three consecutive times. Today, Fox Chase conducts a broad array of nationally competitive basic, translational, and clinical research, with special programs in cancer prevention, detection, survivorship, and community outreach. For more information, call 1-888-FOX-CHASE or 1-888-369-2427.