Survey of ASCO members on management of sentinel node micrometastases in breast cancer: variation in treatment recommendations according to specialty.

BACKGROUND: American Society of Clinical Oncology (ASCO) guidelines recommend axillary dissection (ALND) as the primary treatment for sentinel node micrometastases (SNMM) in breast cancer. We hypothesized that variation exists in adherence to these guidelines and management of SNMM as a result of the medical specialty of the treating physician.
METHODS: A questionnaire was e-mailed to 2511 active members of ASCO who specialize in breast cancer and who are board certified in surgery, medical oncology, or radiation oncology. Questions covered treatment of SNMM and factors influencing clinical decisions. Survey responses were analyzed by the Kruskal-Wallis and Fisher's exact test.
RESULTS: Of 612 questionnaires viewed by recipients, 537 (88%) were completed by 382 medical oncologists, 100 surgeons, and 55 radiation oncologists. Most (98.5%) regarded SNMM as clinically important. Unexpectedly, ALND for SNMM was recommended by only 23% of surgeons, 23% of medical oncologists, and 15% of radiation oncologists (no statistically significant intergroup difference). Factors identified as important in selecting patients for ALND were tumor size, age, tumor grade, lymphovascular invasion, and size of metastases. Most respondents in each specialty (89% overall) would consider adjuvant chemotherapy for primary tumors <1 cm if SNMM were present. Tumor size, age, size of metastases, estrogen receptor/progesterone receptor status, HER-2 neu status, and gene expression profile would influence this decision. Radiation oncologists (76%) were more likely than medical oncologists (57%) or surgeons (47%) to consider axillary radiation instead of ALND for SNMM (P = 0.0021).
CONCLUSIONS: Guidelines recommending ALND for SNMM are not being followed by most of the ASCO members we surveyed.