medwireNews: Women with permanent silicone-filled breast implants have an increased risk of developing anaplastic large-cell lymphoma in the breast (breast-ALCL) compared with other individuals, research confirms.
Using data from a nationwide pathology registry in the Netherlands, the investigators found that 32 of 43 women with a primary diagnosis of breast-ALCL had received an ipsilateral breast implant compared with just one of 146 women with other types of non-Hodgkin breast lymphoma, giving a significant odds ratio of 421.8.
"Our relative risk estimate of over 400, implying an attributable risk approaching 100%, is highly suggestive of a direct or indirect causal role of the breast implant in breast implant-associated [BIA-]ALCL", say Daphne de Jong, from VU University Medical Center in Amsterdam, the Netherlands, and co-workers.
The team estimated that 3.3% of women aged 20–70 years in the Netherlands have breast implants. The cumulative risk of BIA-ALCL in the general population was calculated to be 0.35 cases per million by age 75 – for women with implants, the cumulative risk increased to 29 cases per million at age 50 years and 82 cases per million at age 70 years.
The type of implant received was known for 28 of the breast-ALCL patients; 82% of these were macrotextured implants despite this type of implant making up just 45% of Dutch sales between 2010 and 2015, the researchers observe in JAMA Oncology.
In all, the number needed to treat with implants to cause one case of breast-ALCL before age 75 years was calculated to be 6920, although the investigators were unable to determine risk by implant type.
Possible causal factors include a local inflammatory response to silicone or bacteria adherent to the implant surface, or a genetically increased risk of lymphoma associated with an inflammatory response to implants, they add.
Recognising that their study findings "affect a relatively large group of women", Daphne de Jong et al recommend comprehensive counselling on the risk of breast implant-associated ALCL for women considering breast implants and use of alternative breast procedures for key patient groups, such as those undergoing mastectomy to treat or reduce the risk of breast cancer.
The investigators also call for improved postmarket monitoring and registry programmes for breast implants. "Collaboration between international research groups, registries, and governmental organizations to pool multidisciplinary data on BIA-ALCL cases and breast implant prevalence are essential to support these efforts", they write.
While agreeing on the need for systematic capture of information on the risk and nature of BIA-ALCL, the authors of an accompanying comment emphasize that the absolute risk associated with breast implants "remains extremely low".
"With most women who are newly diagnosed with BIA-ALCL being successfully treated with implant removal and capsulectomy alone, the number needing systemic antilymphoma treatment or developing life-threatening complications of BI-ALCL is even lower", say Colleen McCarthy and Steven Horwitz, from Memorial Sloan Kettering Cancer Center in New York, USA.
de Boer M, van Leeuwen FE, Hauptmann M, et al. Breast implants and the risk of anaplastic large-cell lymphoma in the breast. JAMA Oncol; Advance online publication 4 January 2018. doi:10.1001/jamaoncol.2017.4510
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