Disparities in the Occurrence of Long-Term Effects of Bone Marrow Suppression after Treatment in Adolescent Young Adult Breast Cancer Survivors.

BACKGROUND: Many adolescent and young adult (AYA) patients with breast cancer (BC) receive adjuvant therapy as initial treatment, with long-term bone marrow suppression as a potential complication, but no studies have evaluated the impact of race/ethnicity on the development of bone marrow suppression in AYA BC survivors. PATIENTS AND METHODS: Female patients ages 15-39 years diagnosed with BC (2006-2018) and surviving ≥ 2 years were identified from the California Cancer Registry and linked to statewide hospitalization data. We estimated the cumulative incidence of developing late effects of bone marrow suppression, such as leukopenia, anemia, thrombocytopenia, bleeding, and infection/sepsis, during hospital discharge diagnoses present ≥ 2 years after diagnosis. We examined the impact of sociodemographic and clinical factors on late effects using multivariate Cox proportional hazards regression. RESULTS: Of 11,293 patients, 42.8% were non-Hispanic (nH) White, 28.8% Hispanic, 19.5% nH Asian/Pacific Islander, and 7.5% nH Black. In multivariable analyses, nH Blacks had the highest risk (versus nH Whites) of anemia [hazard ratio (HR) 1.72, 95% confidence interval (CI) 1.47-2.02], leukopenia (HR 1.56, CI 1.14-2.13), thrombocytopenia (HR 1.46, CI 1.08-1.99), major infection/sepsis (HR 1.64, CI 1.4-1.92), and bleeding (HR 1.89, CI 1.39-2.58). Hispanics had a higher risk of developing anemia (HR 1.17, CI 1.04-1.32), bleeding (HR 1.4, CI 1.12-1.76), and major infections/sepsis (HR 1.36, CI 1.21-1.52). Asian/Pacific Islanders had only a higher risk of developing bleeding (HR 1.33, CI 1.03-1.72). Patients from a low neighborhood socioeconomic status had a 20% higher risk of infection/sepsis (HR 1.21, CI 1.1-1.34), but there were no associations for the other late effects. CONCLUSIONS: We identified that AYAs of nH Black, Hispanic, and Asian/Pacific Islander race/ethnicity are at an increased risk of several late effects after adjuvant therapy compared with nH White patients. From these data, providers can implement early/frequent screening of hematologic late effects in these high-risk survivors.

Serine proteases and protease-activated receptor 2 mediate the proinflammatory and algesic actions of diverse stimulants.

BACKGROUND AND PURPOSE: Although serine proteases and agonists of protease-activated receptor 2 (PAR2) cause inflammation and pain, the spectrum of proteases that are activated by proinflammatory and algesic stimuli and their contribution to inflammatory pain are uncertain. EXPERIMENTAL APPROACH: Enzymic assays and selective inhibitors were used to characterize protease activity in mice after intraplantar injections of formalin, bradykinin, PAR2 activating peptide (AP) or vehicle. The capacity of these proteases and of recombinant mouse trypsin 4 to cleave fragments of PAR2 and to activate PAR2 in cell lines was determined. Protease inhibitors and par2 (-/-) mice were used to assess the contributions of proteases and PAR2 to pain and inflammation. KEY RESULTS: Intraplantar injection of formalin, bradykinin or PAR2-AP led to the activation of proteases that were susceptible to the serine protease inhibitor melagatran but resistant to soybean trypsin inhibitor (SBTI). Melagatran inhibited mouse trypsin 4, which degraded SBTI. Proteases generated in inflamed tissues cleaved PAR2-derived peptides. These proteases and trypsin 4 increased [Ca(2+) ]i in PAR2-transfected but not in untransfected cells, and melagatran suppressed this activity. Melagatran or PAR2 deletion suppressed oedema and mechanical hypersensitivity induced by intraplantar formalin, bradykinin and PAR2-AP, but had no effect on capsaicin-induced pain. CONCLUSIONS AND IMPLICATIONS: Diverse proinflammatory and algesic agents activate melagatran-sensitive serine proteases that cause inflammation and pain by a PAR2-mediated mechanism. By inducing self-activating proteases, PAR2 amplifies and sustains inflammation and pain. Serine protease inhibitors can attenuate the inflammatory and algesic effects of diverse stimuli, representing a useful therapeutic strategy.