Background: Cancer incidence trends use by health officials in order to program evaluations and development of cancer control strategies. The trends of cancer incidence have used to evaluate programs and develop the cancer control strategies. The aim of this study is to analyze changes of breast cancer incidence trends in Isfahan city using joinpoint regression models.
Materials and methods: The study was based on all cases of breast cancer reported among women residing in the city of Isfahan for the period 2001-2010. Age-standardized rates were calculated for each tumor characteristics, using the direct method. Joinpoint regression was used to provide estimated annual percentage change.
Results: A plot of the age-specific rates of breast cancer showed an increase in all age groups from 30 to 69 years and sharp increase in the incidence of breast cancer confined to estrogen receptor-positive and progesterone receptor-positive tumors and the significant change (2003) by progesterone receptor(-) tumors. The analysis by tumor size and grade, incidence rates decreased for tumors >5 cm by 10.6% since 2006.7 and for poorly differentiated tumor by 26.1% since 2007.8. No decrease in incidence was observed for group of proportion of positive lymph nodes to lymph node surgery ≥25%. The proportion of positive lymph node to surgery node ≤25% (nonsignificant) was upward.
Conclusion: The trend of incidence rates with tumor size ≤2, well-differentiated tumor grade, moderately differentiated tumor grade, positive estrogen and progesterone hormone receptors was upward. The pattern of breast cancer can help to cancer prevention and prognosis, selecting the best type of surgery.
Keywords: Age trend; breast cancer; incidence; joinpoint regression; tumor characteristics.