Imaging micrometer-sized aerosol particles with digital holography.

Small particles that are trapped, deposited, or otherwise fixed can be imaged by digital holography with a resolution approaching that of optical microscopy. When such particles are in motion as an aerosol, a comparable resolution is challenging to achieve. Using a simplified bi-telecentric lens system, we demonstrate that 1µm free-flowing aerosol particles can be imaged at the single-particle level using digital in-line holography. The imaging is demonstrated with an aerosol of 1µm polystyrene latex microspheres and a ragweed pollen aerosol.

Re-irradiation versus systemic therapy for the management of local-regionally recurrent head and neck cancer.

PURPOSE: The optimal management of local-regionally recurrent head and neck cancer that is not amenable to surgical resection is uncertain. We sought to compare outcomes among patients treated with and without re-irradiation in this setting. METHODS AND MATERIALS: A review of institutional registries identified 65 patients with local-regionally recurrent squamous cell carcinoma of the head and neck who were ineligible for surgery. Forty patients (62 %) opted for re-irradiation with the remaining 25 patients (38 %) undergoing initial systemic therapy alone. All patients had measurable disease. Forty-three patients (66 %) were male and twenty-two (33 %) were female. The median age at the time of recurrence was 59 years (range, 39-84 years). The most common primary sites of disease were the oropharynx, (n = 25), oral cavity (N = 19), and nasopharynx (n = 11). The median interval from completion of prior radiation to the diagnosis of recurrent disease was 35 months (range, 2-102 months). RESULTS: Re-irradiation improved 2-year overall survival, (32 % versus 11 %), progression-free survival (31 % versus 7 %), and local-regional control (39 % versus 3 %) compared to systemic therapy alone (p < 0.05, for both). The likelihood of developing any new grade 3+ toxicity was significantly higher among patients treated by re-irradiation compared to those treated by systemic therapy (53 % vs. 28 %, p < 0.001). There were 3 treatment-related fatalities, all of which occurred in the re-irradiation group. The incidence of grade 3+ late toxicity was 48 % and 12 % for patients in the re-irradiation and systemic therapy cohorts, respectively (p < 0.001). CONCLUSION: Although re-irradiation improved overall survival compared to systemic therapy for appropriately selected patients with local-regionally recurrent head and neck cancer, the relatively high risk of toxicity must be considered.

Integrating Overall Survival and Tumor Control Probability Models to Predict Local Progression After Brain Metastasis Radiosurgery.

Purpose: Stereotactic radiosurgery (SRS) for brain metastases is frequently prescribed to the maximum tolerated dose to minimize the probability of local progression. However, many patients die from extracranial disease prior to local progression and may not require maximally aggressive treatment. Recently, improvements in models of SRS tumor control probability (TCP) and overall survival (OS) have been made. We predicted that by combining models of OS and TCP, we could better predict the true risk of local progression after SRS than by using TCP modeling alone. Methods and Materials: Records of patients undergoing SRS at a single institution were reviewed retrospectively. Using established TCP and OS models, for each patient, the probability of 1-year survival [p(OS)] was calculated, as was the probability of 1-year local progression [p(LP)]) for each treated lesion. Joint-probability was used to combine the models [p(LP,OS)=p(LP)*p(OS)]. Analyses were conducted at the individual metastasis and whole-patient levels. Fine-Gray regression was used to model p(LP) or p(LP,OS) on the risk of local progression after SRS, with death as a competing risk. Results: At the patient level, 1-year local progression was 0.08 (95% CI, 0.03-0.15), median p(LP,OS) was 0.13 (95% CI, 0.07-0.2), and median p(LP) was 0.29 (95% CI, 0.22-0.38). At the metastasis level, 1-year local progression was 0.02 (95% CI, 0.01-0.04), median p(LP,OS) was 0.05 (95% CI, 0.02-0.07), and median p(LP) was 0.10 (95% CI, 0.07-0.13). p(LP,OS) was found to be significantly associated with the risk of local progression at the patient level (P = .048) and metastasis level (P = .007); however, p(LP) was not (P = .16 and P = .28, respectively). Conclusions: Simultaneous modeling of OS and TCP more accurately predicted local progression than TCP modeling alone. Better understanding which patients with brain metastases are at risk of local progression after SRS may help personalize treatment to minimize risk without sacrificing efficacy.

A Pilot Study of Pembrolizumab Combined With Stereotactic Ablative Radiotherapy for Patients With Advanced or Metastatic Sarcoma.

OBJECTIVES: Immunotherapy with immune checkpoint inhibitors has shown only limited success in the management of metastatic soft tissue sarcoma. Overall response rates (ORR) with single agent pembrolizumab were 18% and median PFS was 18 weeks on the clinical trial SARC028. One strategy to improve the responses to immunotherapy is with stereotactic body radiation therapy (SBRT), which can enhance the antitumor CD8 T cell response through the release of tumor-specific antigens, potentially priming a more diverse class of T cell receptors. METHODS: This is a phase 0, pilot prospective study taking place at a single center with 2 arms. In Arm A, patients are treated with pembrolizumab 400 mg IV infusion on day 1 of a 42-day cycle. Stereotactic body radiation therapy (SBRT) is delivered in 1-5 fractions starting on C1D15-28 and given every other day. In Arm B, patients who have started an immune checkpoint inhibitor within 60 days are treated with SBRT in addition to the current therapy. RESULTS: In this study we outline testing the feasibility of adding SBRT to pembrolizumab. CONCLUSION: The ultimate goal of combination therapy is improved overall response, including tumors not treated with SBRT. This trial can be found registered online: NCT05488366.

Consolidation Osimertinib Versus Durvalumab Versus Observation After Concurrent Chemoradiation in Unresectable EGFR-Mutant NSCLC: A Multicenter Retrospective Cohort Study.

INTRODUCTION: Durvalumab improves survival when used as consolidation therapy after chemoradiation (CRT) in patients with stage III NSCLC. The optimal consolidation therapy for patients with EGFR-mutant (EGFRmut) stage III NSCLC remains unknown. METHODS: In this multi-institutional, international retrospective analysis across 24 institutions, we evaluated outcomes in patients with stage III EGFRmut NSCLC treated with concurrent CRT followed by consolidation therapy with osimertinib, durvalumab, or observation between 2015 and 2022. Kaplan-Meier method was used to estimate real-world progression-free survival (rwPFS, primary end point) and overall survival (secondary end point). Treatment-related adverse events (trAEs) during consolidation treatment were defined using Common Terminology Criteria for Adverse Events version 5.0. Multivariable Cox regression analysis was used. RESULTS: Of 136 patients with stage III EGFRmut NSCLC treated with definitive concurrent CRT, 56 received consolidation durvalumab, 33 received consolidation osimertinib, and 47 was on observation alone. Baseline characteristics were similar across the three cohorts. With a median follow-up of 46 months for the entire cohort, the median duration of treatment was not reached (NR) for osimertinib (interquartile range: NR-NR) and was 5.5 (interquartile range: 2.4-10.8) months with durvalumab. After adjusting for nodal status, stage III A/B/C, and age, patients treated with consolidation osimertinib had significantly longer 24-month rwPFS compared to those treated with durvalumab or in the observation cohorts (osimertinib: 86%, durvalumab: 30%, observation: 27%, p < 0.001 for both comparisons). There was no difference in rwPFS between the durvalumab and the observation cohorts. No significant difference in overall survival across the three cohorts was detected, likely due to the limited follow-up. Any-grade trAE occurred in 52% (2 [6.1%] grade ≥3) and 48% (10 [18%] grade ≥3) of patients treated with osimertinib and durvalumab, respectively. Of 45 patients who progressed on consolidation durvalumab, 37 (82%) subsequently received EGFR tyrosine kinase inhibitors. Of these, 14 (38%) patients developed trAEs including five patients with pneumonitis (14%; 2 [5.4%] grade ≥3) and five patients with diarrhea (14%; 1 [2.7%] grade ≥3). CONCLUSIONS: This study suggests that among patients with stage III unresectable NSCLC with a sensitizing EGFR mutation, consolidation osimertinib was associated with a significantly longer rwPFS compared to durvalumab or observation. No unanticipated safety signals were observed with consolidation osimertinib.

Refining Target Volume Coverage After Parotidectomy for Cutaneous Squamous Cell Carcinoma: Omission of the Cervical Neck From the Radiation Field.

Purpose: For patients without pathologic evidence of cervical disease after neck dissection for cutaneous squamous cell carcinoma involving the parotid region, inclusion of the ipsilateral cervical neck in the postparotidectomy radiation volume is routinely performed. We report our experience with selective avoidance of the ipsilateral neck for patients undergoing postoperative radiation to the parotid bed. Methods and Materials: From January 2014 to December 2023, a total of 30 consecutive patients underwent postoperative radiation after parotidectomy for cutaneous squamous cell carcinoma involving the parotid area. All patients had previously had a neck dissection confirming pathologic N0 disease. Treatment was delivered using intensity modulated radiation therapy to a median dose of 60 Gy (range, 56-66 Gy). The radiation target volumes included the parotid bed only, with deliberate avoidance of the ipsilateral cervical neck. The median pathologic tumor size of the parotid tumor was 3.3 cm (range, 0.2-9.4 cm). Final pathologic evaluation showed positive microscopic margins in 8 patients (27%), perineural invasion in 17 patients (57%), and facial nerve involvement in 6 patients (20%). Results: There were no isolated nodal failures. One patient developed an ipsilateral neck recurrence approximately 8 months after completion of radiation therapy. This occurred 2 months subsequent to the development of local recurrence. The 5-year actuarial rates of local (parotid) control, neck control, and overall survival were 87%, 97%, and 76%, respectively. Conclusions: Omission of the ipsilateral neck from the parotid volume does not compromise disease control for pathologically N0 patients undergoing postoperative radiation for cutaneous squamous cell carcinoma involving the parotid region. Practical implications are discussed.

The Correlation Between Lymphocyte Nadir and Radiation Therapy for Soft Tissue Sarcoma: Defining Key Dosimetric Parameters and Outlining Clinical Significance.

Purpose: The objectives of this study were to identify key dosimetric parameters associated with postradiation therapy lymphopenia and uncover any effect on clinical outcomes. Methods and Materials: This was a retrospective review of 69 patients (between April 2010 and January 2023) who underwent radiation therapy (RT) as a part of curative intent for soft tissue sarcoma (STS) at a single academic institution. All patients with treatment plans available to review and measurable absolute lymphocyte count (ALC) nadir within a year after completion of RT were included. Results: Median follow-up was 22 months after the start of RT. A decrease in lymphocyte count was noted as early as during treatment and persisted at least 3 months after the completion of RT. On multivariable linear regression, the strongest correlations with ALC nadir were mean body dose, body V10 Gy, mean bone dose, bone V10 Gy, and bone V20 Gy. Five-year overall survival was 60% and 5-year disease-free survival was 44%. Advanced T-stage, chemotherapy use, use of intensity-modulated RT, lower ALC nadir, and the development of grade ≥2 lymphopenia at nadir were associated with worse overall survival and disease-free survival. Conclusions: Post-RT lymphopenia was associated with worse outcomes in STS. There were associations between higher body V10 Gy and bone V10 Gy and lower post-RT ALC nadir, despite the varying sites of STS presentation, which aligns with the well-known radiosensitivity of lymphocyte cell lines. These findings support efforts to reduce treatment-related hematopoietic toxicity as a way to improve oncologic outcomes. Additionally, this study supports the idea that the effect of radiation on lymphocyte progenitors in the bone marrow is more significant than that on circulating lymphocytes in treatments with limited involvement of the heart and lung.

Severity of Financial Toxicity for Patients Receiving Palliative Radiation Therapy.

Introduction: Financial toxicity has negative implications for patient well-being and health outcomes. There is a gap in understanding financial toxicity for patients undergoing palliative radiotherapy (RT). Methods: A review of patients treated with palliative RT was conducted from January 2021 to December 2022. The FACIT-COST (COST) was measured (higher scores implying better financial well-being). Financial toxicity was graded according to previously suggested cutoffs: Grade 0 (score ≥26), Grade 1 (14-25), Grade 2 (1-13), and Grade 3 (0). FACIT-TS-G was used for treatment satisfaction, and EORTC QLQ-C30 was assessed for global health status and functional scales. Results: 53 patients were identified. Median COST was 25 (range 0-44), 49% had Grade 0 financial toxicity, 32% Grade 1, 15% Grade 2, and 4% Grade 3. Overall, cancer caused financial hardship among 45%. Higher COST was weakly associated with higher global health status/Quality of Life (QoL), physical functioning, role functioning, and cognitive functioning; moderately associated with higher social functioning; and strongly associated with improved emotional functioning. Higher income or Medicare or private coverage (rather than Medicaid) was associated with less financial toxicity, whereas an underrepresented minority background or a non-English language preference was associated with greater financial toxicity. A multivariate model found that higher area income (HR .80, P = .007) and higher cognitive functioning (HR .96, P = .01) were significantly associated with financial toxicity. Conclusions: Financial toxicity was seen in approximately half of patients receiving palliative RT. The highest risk groups were those with lower income and lower cognitive functioning. This study supports the measurement of financial toxicity by clinicians.

Transmission Bottleneck Size Estimation from De Novo Viral Genetic Variation.

Sequencing of viral infections has become increasingly common over the last decade. Deep sequencing data in particular have proven useful in characterizing the roles that genetic drift and natural selection play in shaping within-host viral populations. They have also been used to estimate transmission bottleneck sizes from identified donor-recipient pairs. These bottleneck sizes quantify the number of viral particles that establish genetic lineages in the recipient host and are important to estimate due to their impact on viral evolution. Current approaches for estimating bottleneck sizes exclusively consider the subset of viral sites that are observed as polymorphic in the donor individual. However, these approaches have the potential to substantially underestimate true transmission bottleneck sizes. Here, we present a new statistical approach for instead estimating bottleneck sizes using patterns of viral genetic variation that arise de novo within a recipient individual. Specifically, our approach makes use of the number of clonal viral variants observed in a transmission pair, defined as the number of viral sites that are monomorphic in both the donor and the recipient but carry different alleles. We first test our approach on a simulated dataset and then apply it to both influenza A virus sequence data and SARS-CoV-2 sequence data from identified transmission pairs. Our results confirm the existence of extremely tight transmission bottlenecks for these 2 respiratory viruses.

Racial disparities in the timely receipt of adjuvant radiotherapy for head and neck cancer.

PURPOSE: To evaluate the influence of socioeconomic and demographic factors which might predict for excessive delays in the receipt of adjuvant radiotherapy for head and neck cancer. METHODS AND MATERIALS: The medical records of 430 consecutive patients referred for adjuvant radiation after surgical resection for squamous cell carcinoma of the head and neck were reviewed. The number of days from surgery to initiation of radiation was recorded. To study the variability in which adjuvant radiation was delivered, descriptive statistics were used to determine the percentage of patients who deviated from starting treatment beyond the recommended benchmark of 42 days. The chi-square statistic was used to compare differences in proportion among subsets. A Cox proportional hazards model was constructed to perform a multi-variate analysis to identify factors which independently influenced the likelihood for non-adherence. RESULTS: The interval between surgery and the start of radiation therapy ranged from 5 to 128 days (mean, 36 days). The mean number of days from surgery to radiation therapy was 31 days, 35 days, 40 days, and 42 days for Caucasians, Asians, Latino, and Black patients (p = 0.01). In all, 359 of 430 patients (83 %) started adjuvant radiation within 42 days. The proportion of patients who initiated radiation therapy within 42 days of surgery was 91 %, 86 %, 71 %, 65 %, and 80 % for Caucasians, Asians, Latinos, Blacks, and Native Hawaiian/Pacific Islanders, respectively (p < 0.001). Patient characteristics associated with higher odds of non-adherence to the timely receipt of adjuvant radiation therapy within then 42-day benchmark from surgery to radiation included race ([OR] = 4.23 95 % CI (1.30-7.97), non-English speaking status ([OR] = 2.38, 95 % CI: 0.61-4.50), and low socioeconomic status ([OR] = 1.21, 95 % CI: 1.01-1.86). CONCLUSION: Underrepresented minorities are more likely to experience delays in the receipt of adjuvant radiation for head and neck cancer. The potential underlying reasons are discussed.

Posttreatment Surveillance Imaging After Radiation for Head and Neck Cancer.

Importance: The role of surveillance imaging after treatment for head and neck cancer is controversial and evidence to support decision-making is limited. Objective: To determine the use of surveillance imaging in asymptomatic patients with head and neck cancer in remission after completion of chemoradiation. Design, Setting, and Participants: This was a retrospective, comparative effectiveness research review of adult patients who had achieved a complete metabolic response to initial treatment for head and neck cancer as defined by having an unequivocally negative positron emission tomography (PET) scan using the PET response criteria in solid tumors (PERCIST) scale within the first 6 months of completing therapy. The medical records of 501 consecutive patients who completed definitive radiation therapy (with or without chemotherapy) for newly diagnosed squamous cell carcinoma of the head and neck between January 2014 and June 2022 were reviewed. Exposure: Surveillance imaging was defined as the acquisition of a PET with computed tomography (CT), magnetic resonance imaging (MRI), or CT of the head and neck region in the absence of any clinically suspicious symptoms and/or examination findings. For remaining patients, subsequent surveillance after the achievement of a complete metabolic response to initial therapy was performed on an observational basis in the setting of routine follow-up using history-taking and physical examination, including endoscopy. This expectant approach led to imaging only in the presence of clinically suspicious symptoms and/or physical examination findings. Main Outcome and Measures: Local-regional control, overall survival, and progression-free survival based on assignment to either the surveillance imaging or expectant management cohort. Results: This study included 340 patients (mean [SD] age, 59 [10] years; 201 males [59%]; 88 Latino patients [26%]; 145 White patients [43%]) who achieved a complete metabolic response during this period. There was no difference in 3-year local-regional control, overall survival, progression-free survival, or freedom from distant metastasis between patients treated with surveillance imaging vs those treated expectantly. Conclusions and Relevance: In this comparative effectiveness research, imaging-based surveillance failed to improve outcomes compared with expectant management for patients who were seemingly in remission after completion of primary radiation therapy for head and neck cancer.

Transmission bottleneck size estimation from de novo viral genetic variation.

Sequencing of viral infections has become increasingly common over the last decade. Deep sequencing data in particular have proven useful in characterizing the roles that genetic drift and natural selection play in shaping within-host viral populations. They have also been used to estimate transmission bottleneck sizes from identified donor-recipient pairs. These bottleneck sizes quantify the number of viral particles that establish genetic lineages in the recipient host and are important to estimate due to their impact on viral evolution. Current approaches for estimating bottleneck sizes exclusively consider the subset of viral sites that are observed as polymorphic in the donor individual. However, allele frequencies can change dramatically over the course of an individual's infection, such that sites that are polymorphic in the donor at the time of transmission may not be polymorphic in the donor at the time of sampling and allele frequencies at donor-polymorphic sites may change dramatically over the course of a recipient's infection. Because of this, transmission bottleneck sizes estimated using allele frequencies observed at a donor's polymorphic sites may be considerable underestimates of true bottleneck sizes. Here, we present a new statistical approach for instead estimating bottleneck sizes using patterns of viral genetic variation that arose de novo within a recipient individual. Specifically, our approach makes use of the number of clonal viral variants observed in a transmission pair, defined as the number of viral sites that are monomorphic in both the donor and the recipient but carry different alleles. We first test our approach on a simulated dataset and then apply it to both influenza A virus sequence data and SARS-CoV-2 sequence data from identified transmission pairs. Our results confirm the existence of extremely tight transmission bottlenecks for these two respiratory viruses, using an approach that does not tend to underestimate transmission bottleneck sizes.

Timing of chemotherapy and radiation delivery for patients receiving chemoradiation for head and neck cancer: When does "concurrent" mean concurrent?

PURPOSE: To analyze practice patterns focusing on variations in the timing of chemotherapy relative to radiation in patients treated with concurrent chemoradiation for head and neck cancer. METHODS AND MATERIALS: The medical records of 302 consecutive adult patients treated with concurrent chemoradiation for head and neck cancer between April 2014 and February 2022 were reviewed. After excluding 38 patients who received non-platinum-based regimens, induction chemotherapy, and/or had non-squamous cell histology, a total of 264 patients formed the primary population. To study the variability in which concurrent chemoradiation was delivered, descriptive statistics were used to determine the percentage of patients who deviated from starting chemotherapy and radiation on the same day. The chi-square statistic was used to compare differences in proportion among various subsets. A Cox proportional hazards model was then used to perform a multi-variate analysis to identify factors which independently influenced the likelihood for non-adeherence. RESULTS: Among the 264 patients, a total of 187 patients (70.8%) had chemotherapy and radiation started on the same day with 171 of these (91.4%) receiving chemotherapy prior to radiation delivery. On multivariate analysis, both non-Caucasian ethnicity (OR: 1.13, 95% C.I. 1.01-1.20) and being non-English speaking (OR: 1.39; 95% C.I. 1.18--1.51) was significantly associated with greater likelihood of the receipt of radiation and chemotherapy on different days. CONCLUSION: Significant variation exists in the timing of chemotherapy relative to radiation for concurrent chemoradiation in the clinical setting. The potential repercussions on outcome warrante further invesigtation and are discussed.

The comparative morphology of the musculature controlling the pectoral free rays in scorpaenoid fishes.

Free rays are ventral pectoral fin rays (lepidotrichia) that are free of the pectoral fin webbing. They are some of the most striking adaptations of benthic fishes. Free rays are used for specialized behaviors such as digging, walking or crawling along the sea bottom. Studies of pectoral free rays have focused on a small number of species, most notably the searobins (Family Triglidae). Previous research on the morphology of the free rays has emphasized their functional novelty. We hypothesize that the more extreme specializations of the pectoral free rays in searobins are not precisely novel, but are part of a broader range of morphological specializations that are associated with the pectoral free rays in suborder Scorpaenoidei. We perform a detailed comparative description of the intrinsic musculature and osteology of the pectoral free rays in three families of scorpaenoid fishes: Hoplichthyidae, Triglidae, and Synanceiidae. These families vary in the number of pectoral free rays and the degree of morphological specialization of those rays. As part of our comparative analysis, we propose significant revisions to earlier descriptions of both the identity and function of the musculature associated with the pectoral free rays. We focus particularly on the specialized adductors that are important for walking behaviors. Our emphasis on the homology of these features provides important morphological and evolutionary context for understanding the evolution and function of free rays within Scorpaenoidei and other groups.

Impact of Treatment Modalities upon Survival Outcomes in Skull Base and Clival Chordoma: An NCDB Analysis.

Objectives Skull base chordomas are locally aggressive malignant tumors derived from the notochord remnant. There are limited large-scale studies examining the role and extent of surgery and radiation therapy. Design Analysis of the National Cancer Database (NCDB) was performed to evaluate the survival outcomes of various treatments, and to assess for predictors of overall survival (OS). Participants This is a retrospective, population-based cohort study of patients diagnosed with a clival/skull base chordoma between 2004 and 2015 in the NCDB. Main Outcome Measures The primary outcome was overall survival (OS). Results In all, 468 cases were identified. Forty-nine percent of patients received surgery and 20.7% had positive margins. Mean age at diagnosis was 48.4 years in the surgical cohort, and 55% were males. Of the surgical cohort, 33.8% had negative margins, 20.7% had positive margins, and 45.5% had unknown margin status. Age ≥ 65 (hazard ratio [HR]: 3.07; 95% confidence interval [CI]: 1.63-5.76; p < 0.001), diagnosis between 2010 and 2015 (HR: 0.49; 95% CI: 0.26-0.90; p = 0.022), tumor size >5 cm (HR: 2.29; 95% CI: 1.26-4.15; p = 0.007), and government insurance (HR: 2.28; 95% CI: 1.24-4.2; p = 0.008) were independent predictors of OS. When comparing surgery with or without adjuvant radiation, no survival differences were found, regardless of margin status ( p = 0.66). Conclusion Surgery remains the mainstay of therapy. Advanced age (>65 years), large tumor size, and government insurance were predictors of worse OS. Whereas negative margins and the use of adjuvant radiation did not appear to impact OS, these may very well reduce local recurrences. A multidisciplinary approach is critical in achieving optimal outcomes in this challenging disease.

How time-scale differences in asymptomatic and symptomatic transmission shape SARS-CoV-2 outbreak dynamics.

Asymptomatic and symptomatic SARS-CoV-2 infections can have different characteristic time scales of transmission. These time-scale differences can shape outbreak dynamics as well as bias population-level estimates of epidemic strength, speed, and controllability. For example, prior work focusing on the initial exponential growth phase of an outbreak found that larger time scales for asymptomatic vs. symptomatic transmission can lead to under-estimates of the basic reproduction number as inferred from epidemic case data. Building upon this work, we use a series of nonlinear epidemic models to explore how differences in asymptomatic and symptomatic transmission time scales can lead to changes in the realized proportion of asymptomatic transmission throughout an epidemic. First, we find that when asymptomatic transmission time scales are longer than symptomatic transmission time scales, then the effective proportion of asymptomatic transmission increases as total incidence decreases. Moreover, these time-scale-driven impacts on epidemic dynamics are enhanced when infection status is correlated between infector and infectee pairs (e.g., due to dose-dependent impacts on symptoms). Next we apply these findings to understand the impact of time-scale differences on populations with age-dependent assortative mixing and in which the probability of having a symptomatic infection increases with age. We show that if asymptomatic generation intervals are longer than corresponding symptomatic generation intervals, then correlations between age and symptoms lead to a decrease in the age of infection during periods of epidemic decline (whether due to susceptible depletion or intervention). Altogether, these results demonstrate the need to explore the role of time-scale differences in transmission dynamics alongside behavioral changes to explain outbreak features both at early stages (e.g., in estimating the basic reproduction number) and throughout an epidemic (e.g., in connecting shifts in the age of infection to periods of changing incidence).

The Role of Chemotherapy Plus Immune Checkpoint Inhibitors in Oncogenic-Driven NSCLC: A University of California Lung Cancer Consortium Retrospective Study.

Introduction: There is a paucity of data on immune checkpoint inhibitors (ICIs) plus doublet chemotherapy (C) in patients with advanced lung cancer whose tumor harbors an actionable mutation. We sought to provide insight into the role of this combination in relation to chemotherapy alone in this patient population. Methods: We conducted a retrospective study at the five University of California National Cancer Institute-designated Comprehensive Cancer Centers. The primary end point was progression-free survival (PFS). Secondary end points included overall survival (OS) and significant adverse events. Adverse events in patients who received a tyrosine kinase inhibitor (TKI) post-ICI were also captured. Results: A total of 246 patients were identified, 170 treated with C plus ICI and 76 treated with C alone. Driver alterations included EGFR (54.9%), KRAS (32.9%), ALK (5.3%), HER2/ERBB2 (2.9%), ROS1 (1.2%), MET (1.2%), RET (0.8%), and BRAF non-V600 (0.8%). The overall PFS and OS hazard ratios were not significant at 1.12 (95% confidence interval 0.83-1.51; p = 0.472) and 0.86 (95% confidence interval: 0.60-1.24, p = 0.429), respectively. No significant differences in PFS or OS were observed in the mutational subgroups. Grade 3 or greater adverse events were lower in the C plus ICI group. The multivariate analysis for PFS and OS revealed a performance status (Eastern Cooperative Oncology Group) score of 2, and previous TKI treatment was associated with poorer outcomes with C plus ICI. Conclusions: Our study suggests that patients with oncogenic-driven NSCLC, primarily those with EGFR-driven tumors, treated with a TKI should not subsequently receive C plus ICI. Analysis from prospective clinical trials will provide additional information on the role of ICIs in this group of patients.