Absence of Anaplastic Large Cell Lymphoma Cases in a Large Cohort of Danish Women with Breast Implants: Results of a Nationwide, Population-Based Study,

An increased risk of alk-negative T- cell anaplastic large cell lymphoma (T-ALCL) in women with silicone breast implants has recently been suggested. Several small series and case-reports have been published, but, so far, only one analytical epidemiological population-based study has specifically addressed this hypothesis (de Jong et al, JAMA, 2008).

We identified a nationwide cohort of Danish women, who underwent breast implant surgery for any reason (cosmetic or reconstruction) at public hospitals or in private clinics. Data including civil registry number and date of surgery were obtained from the Danish National Hospital Register (1977–2009) and from The Danish Registry for Plastic Surgery of the Breast (1999–2009) and eight private clinics of plastic surgery (1973–1995).

The civil registry number, assigned to all Danish citizens by the Central Population Registry (CPR), encodes gender and date of birth, and secures valid linkage to population-based registries in Denmark.

Identification of lymphoma cases was performed by combined linkages to the Danish Cancer Registry and the Danish Lymphoma Group (LYFO). This combined strategy was applied in order to maximize catchment of incident lymphoma cases (capture-recapture analysis).

We identified a cohort of 18,356 women, who underwent breast implant surgery between 1973–2009. The vast majority of breast implants were silicone gel-filled implants. Among study-subjects, 11,380 underwent surgery for strictly cosmetic reasons, while 6,976 received breast implants as part of a breast reconstruction secondary to breast cancer. The number of non-Hodgkin lymphoma (NHL) and T-ALCL cases expected in the general female population of Denmark was 350/year and 10/year in the study period.

The total person-years for the study-cohort (162699,5 years)were multiplied by the estimated incidence rates for T-ALCL in the breast (3/100.000.000 person-years)to ascertain the expected number (0,005) of ALCL in the breast among cohort members.

The total number of NHL cases observed was 60. There were no cases of ALCL in the study-cohort and none had an implant-near localization.

This is a comprehensive epidemiologic study addressing the specific issue of the possible association between T-ALCL and breast implants. Our large nationwide cohort study does not support a major association between T-ALCL lymphomas and breast implants either implanted for cosmetic reasons in otherwise healthy recipients or for reconstructive purposes in women previously treated for breast cancer. Due to the rarity of this condition, additional population-based analyses are needed to further evaluate potential biological procedure-related or implant-specific associations. An extended analysis of pooled data from different Nordic countries is ongoing.

No relevant conflicts of interest to declare.