Risk of subsequent invasive breast carcinoma after in situ breast carcinoma in a population covered by national mammographic screening

Abstract

Sweden was the first country to establish a nationwide breast cancer screening service. We used the Swedish Family-Cancer Database to evaluate the risk of invasive carcinoma after in situ carcinoma of the breast. Risk estimates for contralateral and ipsilateral invasive malignancies following age and histology specific in situ breast carcinomas were calculated using Poisson's regression analysis. The agreement between concordant and discordant morphologies of invasive and in situ breast cancer was measured using the kappa statistic. Women with in situ breast cancer showed a relative risk of 2.03 for contralateral and 3.94 for ipsilateral invasive breast cancer. The risk was higher for in situ carcinomas diagnosed before the age of 50 years and after lobular in situ breast cancers. A comparison of the risks during the past decades suggested that the risk of ipsilateral breast cancer has increased in Sweden but that of contralateral breast cancer has remained unchanged. In situ and the subsequent invasive breast cancers did not seem to share their morphologies.

Increased risk of second malignancies after in situ breast carcinoma in a population-based registry

“…In Sweden, the risk of second breast cancer increased at the beginning of the screening period and only decreased after long implementation of national screening (Rawal et al, 2005). Thus, in the coming decades, we might observe a decrease in the risk of second cancer after BCIS.…”

“…A higher risk of second breast cancer has been found among in situ and malignant breast cancer patients diagnosed before the age of 50 years (Rawal et al, 2005;Soerjomataram et al, 2005b). This is partly due to genetic predisposition, which usually becomes manifest at a relatively young age.…”

“…Women with previous breast cancer are known to carry a two-fold increased risk of second cancer in comparison to the general population (Rubino et al, 2003;Soerjomataram et al, 2005a). Studies assessing the risk of second cancer following the diagnosis of BCIS (breast carcinoma in situ) are however scarce or only focused on the risk of second breast cancer (Habel et al, 1997;Warnberg et al, 2000;Claus et al, 2003;Levi et al, 2005;Rawal et al, 2005). …”

“…An increased risk of 2.0 -7.2 for breast cancer following the diagnosis of BCIS has been reported (Franceschi et al, 1998;Rawal et al, 2005), the probability that a breast cancer will develop in BCIS patients being 26% after 20 years of follow-up (Levi et al, 2005). This is as high as the risk of second breast cancer found for patients with malignant breast carcinoma (Chen et al, 2001).…”

The occurrence of invasive cancers following a diagnosis of breast carcinoma in situ

“…The most common form of treatment is lumpectomy, with or without radiotherapy, although women with a more diffuse pattern of BCIS may undergo mastectomy. A number of previous studies have focused on the risk of second breast cancer following a diagnosis of BCIS (Habel et al, 1997;Wärnberg et al, 2000;Claus et al, 2003;Levi et al, 2005;Rawal et al, 2005), with estimates of relative risk generally of the order of two-to fivefold. Few studies have looked at the occurrence of subsequent invasive cancers at other sites (Ward et al, 1992;Franceschi et al, 1998;Soerjomataram et al, 2006), and these were based on relatively small numbers of cases.…”