Multiple factors affect risk of competing mortality among patients with HNC. Risk stratification would be useful to identify patients most likely to benefit from treatment intensification.
PURPOSE
To test the hypothesis that increased pelvic bone marrow (BM) irradiation is associated with increased hematologic toxicity (HT) in cervical cancer patients undergoing chemoradiotherapy (CRT), and to develop a normal tissue complication probability (NTCP) model for HT.
METHODS AND MATERIALS
We tested associations between hematologic nadirs during CRT and the volume of BM receiving ≥ 10 and 20 Gy (V10 and V20) using a previously developed linear regression model. The validation cohort consisted of 44 cervical cancer patients treated with concurrent cisplatin and pelvic radiotherapy. Subsequently, these data were pooled with 37 identically treated patients from a prior study, forming a cohort of 81 patients for NTCP analysis. Generalized linear modeling was used to test associations between hematologic nadirs and dosimetric parameters, adjusting for body mass index. Receiver operating characteristic curves were used to derive optimal dosimetric planning constraints.
RESULTS
In the validation cohort, significant negative correlations were observed between white blood cell count (WBC) nadir and V10 (regression coefficient (β)=−0.060, p=0.009) and V20 (β=−0.044, p=0.010). In the combined cohort, the (adjusted) β estimates for log(WBC) vs. V10 and V20 were: −0.022 (p=0.025) and −0.021 (p=0.002), respectively. Patients with V10 ≥ 95% were more likely to experience grade ≥ 3 leukopenia (68.8% vs. 24.6%, p<0.001) as were patients with V20 > 76% (57.7% vs. 21.8%, p=0.001).
CONCLUSIONS
These findings support the hypothesis that HT increases with increasing pelvic BM volume irradiated. Efforts to maintain V10 < 95% and V20 < 76% may reduce HT.
Background
African American (AA) men in the general US population are more than twice as likely to die of prostate cancer (PC) compared with non‐Hispanic white (NHW) men. The authors hypothesized that receiving care through the Veterans Affairs (VA) health system, an equal‐access medical system, would attenuate this disparity.
Methods
A longitudinal, centralized database of >20 million veterans was used to assemble a cohort of 60,035 men (18,201 AA men [30.3%] and 41,834 NHW men [69.7%]) who were diagnosed with PC between 2000 and 2015.
Results
AA men were more likely to live in regions with a lower median income ($40,871 for AA men vs $48,125 for NHW men; P < .001) and lower high school graduation rates (83% for AA men vs 88% for NHW men; P < .001). At the time of diagnosis, AA men were younger (median age, 63.0 years vs 66.0 years; P < .001) and had a higher prostate‐specific antigen level (median, 6.7 ng/mL vs 6.2 ng/mL; P < .001), but were less likely to have Gleason score 8 to 10 disease (18.8% among AA men vs 19.7% among NHW men; P < .001), a clinical T classification ≥3 (2.2% vs 2.9%; P < .001), or distant metastatic disease (2.7% vs 3.1%; P = 0.01). The 10‐year PC‐specific mortality rate was slightly lower for AA men (4.4% vs 5.1%; P = .005), which was confirmed in multivariable competing‐risk analysis (subdistribution hazard ratio, 0.85; 95% CI, 0.78‐0.93; P < .001).
Conclusions
AA men diagnosed with PC in the VA health system do not appear to present with more advanced disease or experience worse outcomes compared with NHW men, in contrast to national trends, suggesting that access to care is an important determinant of racial equity.
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