Journal of the National Cancer Institute Advance Access published online on June 27, 2007
JNCI Journal of the National Cancer Institute, doi:10.1093/jnci/djm026
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BRIEF COMMUNICATION |
Rising Incidence Rates of Breast Carcinoma With Micrometastatic Lymph Node Involvement
Affiliations of authors: Surveillance Research Program, Division of Cancer Control and Population Sciences, National Cancer Institute, Bethesda, MD (DPCF, LAR, BKE); Department of Clinical Epidemiology, Aarhus University Hospital, Denmark (DPCF); Office of Healthcare Inspections, Office of Inspector General, U.S. Department of Veterans Affairs, Washington, DC (LXE)
Correspondence to: Deirdre P. Cronin-Fenton, PhD, Department of Clinical Epidemiology, Aarhus University Hospital, Ole Worms Alle 1150, 8000 Aarhus C, Denmark (e-mail: dc{at}dce.au.dk).
We investigated the increased incidence of early-stage breast cancer with micrometastatic lymph node involvement. Breast cancer incidence trends from 1990 through 2002 in the US Surveillance, Epidemiology, and End Results Program catchment area were analyzed. Joinpoint regression was used to show the annual percentage change (APC) in breast cancer incidence trends. The overall incidence of breast cancer among women aged 50–64 years increased 1.8% (95% confidence interval [CI] = 1.4% to 2.2%) per annum from 1990 through 2002 but decreased in all other age groups. Stage IIA and stage IIB tumor incidence increased (APC for stage IIA from 1996 to 2002 = 61.9%, 95% CI = 51.1% to 73.4%, and APC for stage IIB from 1998 to 2002 = 53.7%, 95% CI = 20.6% to 96.0%). The incidence of micrometastatic lymph node involvement for stage IIA and stage IIB tumors increased during the 1990s, especially after 1997 (APC = 17.3% for both stages), more for estrogen receptor–positive than estrogen receptor–negative disease. Increased use of mammography screening partly explains the increased incidence of early-stage breast cancer. Increases in small tumors with micrometastatic lymph node involvement may be attributable to the increased use of the sentinel lymph node biopsy in community practice.
| CONTEXT AND CAVEATS Prior knowledge The effect of the recent increase in the use of sentinel lymph node biopsy on the incidence of breast cancer with micrometastatic lymph node involvement was unknown. Study design Regression analysis was used to identify trends in the incidence of breast cancer according to stage and lymph node involvement based on data from the Surveillance, Epidemiology, and End Results Program. Contribution Increases in the incidence of breast cancer with micrometastatic lymph node involvement were identified that were consistent with an effect of increased detection due to more widespread use of sentinel lymph node biopsy in recent years. Implications The results of this study predict that as the use of sentinel lymph node biopsy continues to increase, the incidence of breast cancer with lymph node metastases will increase in parallel. Limitations The study was conducted without the knowledge as to which patients underwent sentinel lymph node biopsy and without the information on trends in the use of the procedure that would be needed for a more conclusive assessment of the effects of sentinel lymph node biopsy on breast cancer diagnosis.
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Manuscript received November 30, 2006; revised April 26, 2007; accepted May 23, 2007.
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J Natl Cancer Inst 2007 99: 981.
J Natl Cancer Inst 2007 99: 981.