WASHINGTONPalpable and nonpalpable breast cancers differ in a variety of inherent characteristics, reported Kristin Skinner, MD, of the University of Southern California Norris Comprehensive Cancer Center, Los Angeles. She presented her study results at the 54th Annual Cancer Symposium of the Society of Surgical Oncology.
Nodal involvement had been known to occur twice as often in palpable as in nonpalpable breast cancers, Dr. Skinner commented. To investigate whether inherent differences separate these tumors from nonpalpable cancers, the researchers reviewed a prospective database of T1 breast cancers dating back to 1981.
Of the 1,263 cancers in the database, 859 (68%) were palpable and 404 (32%) were not. The cancers did not differ in distribution between ductal and lobular types. The database contained no data on the size of the patients’ breasts. Size of tumors was determined by 3-dimensional reconstruction of pathologic samples.
The investigators compared the two types of cancer for a variety of characteristics, including tumor size, receptor status, HER-2/neu status, nodal status, multifocality, multicentricity, presence of lymphovascular invasion and extensive intraductal component, mitotic and nuclear grades, ploidy, and S-phase.
The examination of the pathologic characteristics showed that the palpable cancers had larger size, less multicentricity, less multifocality, more nuclear abnormalities, and more metastatic potential, she said.
At 8 years, the breast-cancer-specific survival of patients with palpable tumors, adjusted for stage, was significantly worse than that of patients with nonpalpable tumors, 87% vs 95%, respectively.
Most breast cancer diagnoses still result from palpation, despite improvements in mammography, Dr. Skinner noted.