As noted, though, the absolute risk of ALCL with silicone breast implants is exceedingly small. The authors calculate that just 0.1 to 0.3 cases per 100,000 women with implants would arise per year.

"These findings must be considered preliminary and hypothesis-generating and are not strong enough to definitively conclude that breast implants predispose women to non-Hodgkin lymphoma," Dr. Andrew M Evens and Dr. Brian C-H Chiu, from Northwestern University, Chicago, write in an accompanying editorial.

"However," they add, "given that silicone is immunogenic, further evaluation of breast implant-related lymphoma is warranted, particularly by studies with statistical power, sufficient follow-up, and information on other factors."