The US Food and Drug Administration (FDA) has acknowledged reports of squamous cell carcinoma (SCC) of the breast as well as lymphomas associated with postmastectomy breast implants.
Findings from a large cohort study suggest the incidence of SCC is negligible. The analysis found one case of SCC among nearly 57,000 women who had undergone breast implant reconstruction over 421,227 person-years of follow-up.
The authors also confirmed the known risk of breast implant–associated anaplastic large-cell lymphoma (ALCL), identifying five cases in the population, which was considered a “significantly elevated” risk.
Although patients with breast cancer who are eligible for mastectomy should be counseled on the risks for cancer after implant reconstruction, patients “should not be dissuaded from pursuing implant-based reconstruction because of the risk of SCC,” lead author Connor J. Kinslow, MD, of Columbia University, New York City, and colleagues concluded.
SCC cases associated with breast implants are distinct from breast implant-associated ALCL, the authors noted, explaining that this lymphoma “is the subject of a black box warning on all saline- and silicone gel–filled breast implants since 2020.”
The results were published April 19 in a Research Letter in JAMA Surgery.
Last September, a safety communication from the FDA highlighted reports of SCC and other lymphomas associated with breast implants. The FDA said it was aware of less than 20 cases of SCC.
Following the safety communication, Kinslow and colleagues assessed SCC risk among 56,785 women who underwent cancer-directed mastectomy with implant reconstruction for breast tumors.
Women in the cohort were diagnosed between 2000 and 2018 and included in the Surveillance, Epidemiology, and End Results (SEER) 17 database. Patients had a median age of 51 years; most (84%) where White, 8.1% were Black, 7.4% were Asian or Pacific Islander, 0.4% were American Indian/Alaska Native, and race was unknown in 0.4%.
Across 421,227 person-years of follow-up, the team identified one case of SCC, corresponding to an incidence rate of 2.37 per million person-years vs an expected incidence of 1.02 per million person-years in the general population. Although the 2.33 standardized incidence ratio (SIR) “appeared elevated vs the general population,” it was “not significant given the low incidence” (95% CI, 0.06 – 13.0).
The team also identified five cases of breast implant–associated ALCL. That corresponded to an incidence rate of 11.9 per million person-years compared with an expected incidence of 0.29 per million person-years — for a significantly elevated SIR of 40.9. The authors also noted more than 1000 reported cases of breast implant–associated ALCL previous as well as a robust association with implants.
Regarding SCC, “whether the observed elevated risk is associated with the implants is difficult to interpret because it is based on only 1 case and wide [confidence intervals],” the authors say. But, overall, “we found that the incidence rate of SCC was extraordinarily low and of minimal public health concern.”
JAMA Surg. Published online April 19, 2023. Research Letter
Sharon Worcester, MA, is an award-winning medical journalist based in Birmingham, Alabama, writing for Medscape, MDedge and other affiliate sites. She currently covers oncology, but she has also written on a variety of other medical specialties and healthcare topics. She can be reached at [email protected] or on Twitter: @SW_MedReporter
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