Risk of Anaplastic Large Cell Lymphoma After Post-Mastectomy Implant-Reconstruction for Breast Cancer

Abstract

Approximately one in eight women in the United States is diagnosed with breast cancer and eligible for mastectomy with implant reconstruction. Although it has been suggested that patients with breast cancer or those who are at high risk for breast cancer may have an increased risk of anaplastic large cell lymphoma (ALCL) after breast implantation, no studies have explored the association in this population. Our objective was to determine the relative and absolute risks of breast ALCL after post-mastectomy implant reconstruction for breast cancer compared with the general population.This population-based study obtained incidence data on breast ALCL in the general population from the Surveillance, Epidemiology, and End Results (SEER) program from 2000 - 2017. Patients who underwent post-mastectomy implant reconstruction for primary breast cancer from 2000 - 2016 were identified and followed through 2017. Because breast implant-associated ALCL has been documented as early as 2 months after implantation, patients with less than two months of follow-up were excluded. Observed-to-expected ratios for breast ALCL were derived from multiple primary - standardized incidence ratios in the study population versus the general U.S. population after adjusting for age, sex, race, anatomical site, and year of diagnosis. For external validation, we compared the number of cases of breast ALCL diagnosed in SEER with the estimated number of FDA-reported cases over a similar time period.The incidence rate of breast ALCL in the general U.S. female population was 0.08 - 0.12 per 1,000,000 persons per year and was rising. 52,882 women were identified that received post-mastectomy implant reconstruction for primary breast cancer and were followed for a median of 69 months, including 10,979 patients with follow-up time greater than or equal to 10 years (range 2 - 215 months). After adjusting for demographical characteristics of the cohort, the expected incidence rate of breast ALCL was 0.25 - 0.34 per 1,000,000 persons per year versus an observed rate of 5.8 - 8.7 per 1,000,000 persons per year (standardized incidence ratio 23.4 [95% confidence interval 2.8 - 84.7]). These findings corresponded well with FDA-reported cases; 353 SEER versus 333 FDA cases, respectively.Although breast cancer patients who receive post-mastectomy implant reconstruction are at increased risk of breast ALCL, the absolute risk remains extremely low. Furthermore, the risk does not appear to be increased compared to patients that receive implantation (for cosmesis or reconstruction) in previously reported literature.