Sinoatrial Node Dose Is Associated With Worse Survival in Patients Undergoing Definitive Stereotactic Body Radiation Therapy for Central Lung Cancers.

PURPOSE: Our purpose was to evaluate the clinical consequences of sinoatrial node (SAN) and atrioventricular node (AVN) irradiation in patients undergoing stereotactic body radiation therapy (SBRT) for central non-small cell lung cancer (NSCLC) tumors. METHODS AND MATERIALS: A single-institutional retrospective review of patients with primary NSCLC undergoing definitive SBRT for centrally located thoracic tumors from February 2007 to December 2021 was performed. The SAN and AVN were contoured in accordance with a published contouring atlas, and the maximum dose (Dmax) and mean dose (Dmean) for each structure were calculated. Sequential log rank testing between the 50th and 90th percentiles was used to identify potential cutoff values for the corresponding dosimetric parameters and overall survival. RESULTS: Among 93 eligible patients, the median age was 72.5 years (IQR, 66.6-78.3), and median follow-up was 32.4 months (IQR, 13.0-49.6). The median SAN Dmax and Dmean were 95 cGy (range, 9-5394) and 58 cGy (range, 7-3168), respectively. The median AVN Dmax and Dmean were 45 cGy (range, 4-2121) and 34 cGy (range, 3-1667), respectively. Candidate cutoff values for SAN Dmax and Dmean were 1309 and 836 cGy, respectively. No associations between AVN parameters and survival outcomes were identified. Upon multivariate Cox regression, the SAN Dmax cutoff (hazard ratio [HR], 2.03 [1.09-3.79]; P = .026) and SAN Dmean cutoff (HR, 2.22 [1.20-4.12]; P = .011) were significantly associated with overall survival. For noncancer-associated survival, the SAN Dmax cutoff trended toward significance (HR, 2.02 [0.89-4.57]; P = .092), and the SAN Dmean cutoff remained significantly associated (HR, 2.34 [1.05-5.18]; P = .037). CONCLUSIONS: For patients undergoing SBRT for NSCLC, SAN Dmax and Dmean were significantly associated with worse overall survival using cut-off values of 1309 and 836 cGy, respectively. Further studies examining the effect of SAN irradiation during SBRT are warranted.

Severe Oral Mucositis After Intensity-Modulated Radiation Therapy for Head and Neck Cancer.

Importance: Oral mucositis (OM) is a common and debilitating adverse effect observed in patients with head and neck cancer (HNC) receiving radiation therapy (RT). Previous studies examining associations between OM and clinical outcomes were performed in the era of 3-dimensional conformal RT planning with low rates of concurrent chemotherapy, and thus may not reflect current practice. Objective: To prospectively assess patient-reported OM and identify its associations with clinical outcomes and quality of life. Design, Setting, and Participants: This cohort study performed at a single institution included 702 consecutive patients who underwent definitive or adjuvant intensity-modulated RT (IMRT) for primary HNC from February 9, 2015, to May 27, 2022. Data were analyzed from November 28, 2022, to August 18, 2023. Main Outcomes and Measures: Severity of OM was assessed based on highest reported mouth and throat soreness (MTS) score during radiotherapy according to the Oral Mucositis Weekly Questionnaire-Head and Neck Cancer survey, which was administered weekly during IMRT. Linear mixed models were used to compare mean MTS scores grouped by disease site and chemotherapy regimen. Fisher exact tests and 1-way analysis of variance tests were performed to identify associations between severity of OM and clinical outcomes. Results: Among 576 eligible patients, the median age was 62.5 (IQR, 56.3-69.1) years, and 451 patients (78.3%) were men. In terms of race and ethnicity, 6 patients (1.0%) were American Indian or Alaska Native; 2 (0.3%), Asian; 31 (5.4%), Black; 8 (1.4%), Hispanic or Latino; 509 (88.4%), White; and 28 (4.9%), unknown. The most common treatment site was oropharynx (268 [46.5%]), and most patients received concurrent chemotherapy (464 [80.6%]). By the end of treatment, 360 patients (62.5%) developed severe OM and 568 (98.6%) developed some degree of OM. Linear mixed models found no significant differences in OM between HNC disease sites. Groups with greater highest severity of OM reported had higher rates of measured outcomes (listed respectively by MTS score 0, 1, 2, 3, and 4): feeding tube placement (0%, 3.6% [2 of 56], 6.6% [10 of 152], 14.7% [40 of 272], and 21.6% [19 of 88]; P = .001), hospitalization (12.5% [1 of 8], 10.7% [6 of 56], 15.1% [23 of 152], 23.9% [65 of 272], and 28.4% [25 of 88]; P = .02), opiate use (0%, 19.6% [11 of 56], 42.8%[65 of 152], 61.4% [167 of 272], and 64.8% [57 of 88]; P < .001) and experienced greater weight loss (median, -0.7 [IQR, -1.7 to -0.4] kg; median, 3.9 [IQR, 1.1 to 6.1] kg; median, 5.0 [IQR, 2.2 to 7.7] kg; median, 4.7 [IQR, 2.1 to 7.7] kg; and median, 7.7 [IQR, 2.8 to 10.6] kg; P < .001). Conclusions and Relevance: In this cohort study of patients with HNC, 62.5% developed severe OM. Higher severity of OM was associated with feeding tube placement, hospitalization, opiate use, and weight loss. Improvements in OM prevention and management are needed.

A dual tracer [11C]PBR28 and [18F]FDG microPET evaluation of neuroinflammation and brain energy metabolism in murine endotoxemia.

BACKGROUND: Brain metabolic alterations and neuroinflammation have been reported in several peripheral inflammatory conditions and present significant potential for targeting with new diagnostic approaches and treatments. However, non-invasive evaluation of these alterations remains a challenge. METHODS: Here, we studied the utility of a micro positron emission tomography (microPET) dual tracer ([11C]PBR28 - for microglial activation and [18F]FDG for energy metabolism) approach to assess brain dysfunction, including neuroinflammation in murine endotoxemia. MicroPET imaging data were subjected to advanced conjunction and individual analyses, followed by post-hoc analysis. RESULTS: There were significant increases in [11C]PBR28 and [18F]FDG uptake in the hippocampus of C57BL/6 J mice 6 h following LPS (2 mg/kg) intraperitoneal (i.p.) administration compared with saline administration. These results confirmed previous postmortem observations. In addition, patterns of significant simultaneous activation were demonstrated in the hippocampus, the thalamus, and the hypothalamus in parallel with other tracer-specific and region-specific alterations. These changes were observed in the presence of robust systemic inflammatory responses manifested by significantly increased serum cytokine levels. CONCLUSIONS: Together, these findings demonstrate the applicability of [11C]PBR28 - [18F]FDG dual tracer microPET imaging for assessing neuroinflammation and brain metabolic alterations in conditions "classically" characterized by peripheral inflammatory and metabolic pathogenesis.

Trends in Postoperative Intensity-Modulated Radiation Therapy Use and Its Association With Survival Among Patients With Incompletely Resected Non-Small Cell Lung Cancer.

Importance: National guidelines allow consideration of postoperative radiation therapy (PORT) among patients with incompletely resected non-small cell lung cancer (NSCLC). However, there is a paucity of prospective data because recently completed trials excluded patients with positive surgical margins. In addition, unlike for locally advanced NSCLC, the role of intensity-modulated radiation therapy (IMRT) for PORT remains unclear. Objective: To evaluate trends of IMRT use for PORT in the US and the association of IMRT with survival outcomes among patients with incompletely resected NSCLC. Design, Setting, and Participants: This retrospective cohort study used data from the National Cancer Database for patients diagnosed between January 2004 and December 2019 with incompletely resected NSCLC who underwent upfront surgery with positive surgical margins followed by PORT. Exposures: IMRT vs 3D conformal radiation therapy (3DCRT) for PORT. Main Outcomes and Measures: The main outcome was overall survival. Multivariable Cox proportional hazards regression assessed the association of IMRT vs 3DCRT with overall survival. Multivariable logistic regression identified variables associated with IMRT. Propensity score matching (1:1) was performed based on variables of interest. Results: A total of 4483 patients (2439 men [54.4%]; median age, 67 years [IQR, 60-73 years]) were included in the analysis. Of those, 2116 (47.2%) underwent 3DCRT and 2367 (52.8%) underwent IMRT. Median follow-up was 48.5 months (IQR, 31.1-77.2 months). The proportion of patients who underwent IMRT increased from 14.3% (13 of 91 patients) in 2004 to 70.7% (33 of 471 patients) in 2019 (P < .001). IMRT was associated with improved overall survival compared with 3DCRT (adjusted hazard ratio, 0.84; 95% CI, 0.78-0.91; P < .001). Similar findings were observed for 1463 propensity score-matched pairs; IMRT was associated with improved 5-year overall survival compared with 3DCRT (37.3% vs 32.2%; hazard ratio, 0.88; 95% CI, 0.80-0.96; P = .003). IMRT use was associated with receipt of treatment at an academic facility (adjusted odds ratio [aOR], 1.15; 95% CI, 1.00-1.33; P = .049), having T4 stage tumors (aOR, 1.50; 95% CI, 1.13-1.99; P = .005) or N2 or N3 stage tumors (aOR, 1.25; 95% CI, 1.04-1.51; P = .02), and receipt of pneumonectomy (aOR, 1.35; 95% CI, 1.02-1.80; P = .04). Conclusion and Relevance: This cohort study found that use of IMRT for PORT among patients with incompletely resected NSCLC increased in the US from 2004 to 2019 and was associated with improved survival compared with 3DCRT. Further studies are warranted to investigate the role of different radiation therapy techniques for PORT.