Availability of Primary Care Physicians and Racial Disparities in Colorectal Cancer-Related Mortality in the United States

INTRODUCTION

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the United States (US), however racial disparities in outcomes persist. We sought to assess the correlation of availability of primary care physicians (PCPs) and racial disparities in CRC-related mortality.

METHODS

We studied the correlation between age-adjusted incidence and mortality rates of CRC among all 50 states and the District of Columbia (D.C.) from the Center for Disease Control (CDC) Wide-Ranging Online Data for Epidemiologic Research (WONDER) with the number of actively practicing PCPs in all 50 states and D.C. from the Association of American Medical Colleges (AAMC) State Physician Workforce Data Report. Pearson's coefficient was used to study correlations and the two-sample t test was used for comparing state-level PCP/CRC ratios between the two groups. Statistical analysis was performed using VassarStats.

RESULTS

The mean AAMR per 100,000 population for CRC was significantly higher among AA versus White populations (t = 5.79, p < 0.001). Higher state-wide PCP per CRC case ratio correlated with lower state-wide CRCrelated mortality (r = -0.36, p = 0.011). The mean PCP per CRC case ratio was significantly lower among AA compared to White populations (t = -15.95, p < 0.0001). Higher PCP per CRC case ratio correlated with lower CRC-related mortality among both White (r = -0.64, p < 0.0001) and AA (r = -0.57, p = 0.0002) populations.

CONCLUSIONS

These findings suggest that racial disparities in CRC-related mortality may at least in part be related to lower availability of PCPs. Efforts focused on the development of strategies focused on improving access to primary care may help bridge racial disparities in CRC-related outcomes.

Association of lifestyle-related risk factors with incidence and mortality rates of colorectal cancer among adolescents and young adults (AYA) in the United States

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Background: Incidence of colorectal cancer (CRC) among adolescents and young adults (AYA) is increasing. A significant proportion of adolescents and young adults (AYA) with colorectal cancer (CRC) lack traceable genetic risk factors. We sought to study the impact of lifestyle-related risk factors on the incidence and mortality of CRC in these patients. Methods: We extracted data on crude incidence and mortality rates of CRC (reported per 100,000 population) for ages 15-39 years in all 50 U.S. states and District of Columbia from the Center for Disease Control (CDC) WONDER database (1999-2018). Data on risk factors such as obesity, physical activity, alcohol and tobacco abuse and nutrition were obtained from the Behavioral Risk Factor Surveillance System (BRFSS, 2020). Correlations were analyzed using Pearson’s co-efficient. p < 0.05 was considered statistically significant. Statistical analysis was performed using VassarStats. Results: Median crude incidence and mortality rates of CRC in AYA in the US from 1999-2018 were 3.8 (IQR 3.2, 4.4) and 0.7 (IQR 0.5,0.9) per 100,000 population respectively. States with higher age-adjusted prevalence of obesity per 100,000 had higher incidence (r = 0.36, p = 0.01) and mortality rates (r = 0.49, p = 0.0002) of CRC in AYA population. States with a higher age-adjusted prevalence of adherence to recommended weekly aerobic activity had lower incidence (r = -0.4515, p = 0.001) and mortality (r = -0.569, p < 0.0001) rates. While states with higher age-adjusted prevalence of tobacco abuse had higher incidence rate of CRC (r = 0.33, p = 0.02), there was no correlation with mortality rates (r = 0.24, p = 0.09). Higher prevalence of alcohol consumption was associated with decreased mortality rate (r = -0.44, p = 0.001), with no impact on incidence rate (r = -0.16, p = 0.26). States with lower daily consumption of fruits had higher incidence (r = 0.37, p = 0.01) and mortality rates (r = 0.59, p < 0.0001). No correlation of daily consumption of vegetables with incidence (r = -0.1516, p = 0.29) and mortality (r = 0.18, p = 0.22) rates was noted. Conclusions: In the current analysis, higher prevalence of obesity, lower rates of aerobic activity and lower daily consumption of fruits were strongly associated with increased incidence and mortality rates. The impact of tobacco abuse and alcohol consumption was more variable. Apart from improving access to genetic testing and counseling, efforts aimed at mitigating the rise of CRC incidence among AYA should also focus on traditional lifestyle-related risk factors.

Detection of microsatellite instability-high (MSI-H) by liquid biopsy predicts robust and durable response to immunotherapy in patients with pancreatic cancer

Clinical trials reporting the robust antitumor activity of immune checkpoint inhibitors (ICIs) in microsatellite instability-high (MSI-H) solid tumors have used tissue-based testing to determine the MSI-H status. This study assessed if MSI-H detected by a plasma-based circulating tumor DNA liquid biopsy test predicts robust response to ICI in patients with pancreatic ductal adenocarcinoma (PDAC). Retrospective analysis of patients with PDAC and MSI-H identified on Guardant360 from October 2018 to April 2021 was performed; clinical outcomes were submitted by treating providers. From 52 patients with PDAC +MSI-H, outcomes were available for 10 (19%) with a median age of 68 years (range: 56-82 years); the majority were male (80%) and had metastatic disease (80%). Nine of 10 patients were treated with ICI. Eight out of nine patients received single-agent pembrolizumab (8/9), while one received ipilimumab plus nivolumab. The overall response rate by Response Evaluation Criteria in Solid Tumors was 77% (7/9). The median progression-free survival and overall survival were not reached in this cohort. The median duration of treatment with ICI was 8 months (range: 1-24), and six out of seven responders continued to show response at the time of data cut-off after a median follow-up of 21 months (range: 11-33). Tissue-based MSI results were concordant with plasma-based G360 results in five of six patients (83%) who had tissue-based test results available, with G360 identifying one more patient with MSI-H than tissue testing. These results suggest that detecting MSI-H by a well-validated liquid biopsy test could predict a robust response to ICI in patients with PDAC. The use of liquid biopsy may expand the identification of PDAC patients with MSI-H tumors and enable treatment with ICI resulting in improved outcomes.

SMAD4 loss is associated with response to neoadjuvant chemotherapy plus hydroxychloroquine in patients with pancreatic adenocarcinoma

SMAD4, a tumor suppressor gene, is lost in up to 60%–90% of pancreatic adenocarcinomas (PDAs). Loss of SMAD4 allows tumor progression by upregulating autophagy, a cell survival mechanism that counteracts apoptosis and allows intracellular recycling of macromolecules. Hydroxychloroquine (HCQ) is an autophagy inhibitor. We studied whether HCQ treatment in SMAD4 deficient PDA may prevent therapeutic resistance induced by autophagy upregulation. We retrospectively analyzed the SMAD4 status of patients with PDA enrolled in two prospective clinical trials evaluating pre‐operative HCQ. The first dose escalation trial demonstrated the safety of preoperative gemcitabine with HCQ (NCT01128296). More recently, a randomized trial of gemcitabine/nab‐paclitaxel +/− HCQ evaluated Evans Grade histopathologic response (NCT01978184). The effect of SMAD4 loss on response to HCQ and chemotherapy was studied for association with clinical outcome. Fisher’s exact test and log‐rank test were used to assess response and survival. Fifty‐two patients receiving HCQ with neoadjuvant chemotherapy were studied. Twenty‐five patients had SMAD4 loss (48%). 76% of HCQ‐treated patients with SMAD4 loss obtained a histopathologic response greater than or equal to 2A, compared with only 37% with SMAD4 intact (p = 0.006). Although loss of SMAD4 has been associated with worse outcomes, in the current study, loss of SMAD4 was not associated with a detriment in median overall survival in HCQ‐treated patients (34.43 months in SMAD4 loss vs. 27.27 months in SMAD4 intact, p = 0.18). The addition of HCQ to neoadjuvant chemotherapy in patients with PDA may improve treatment response in those with SMAD4 loss. Further study of the relationship among SMAD4, autophagy, and treatment outcomes in PDA is warranted.

Patterns of disease progression to checkpoint inhibitor immunotherapy in patients with stage IV non-small cell lung cancer

INTRODUCTION

The purpose of this study was to assess patterns of disease progression for patients with metastatic non-small cell lung cancer (NSCLC) on checkpoint inhibitor immunotherapy.

METHODS

This single centre, retrospective study included all patients diagnosed with Stage IV NSCLC from 2015 to 2019 who received at least 2 cycles of immunotherapy, with or without concurrent chemotherapy. Immune RECIST criteria were used to assess patterns of disease progression, and progression-free survival (PFS), excluding irradiated tumours. The chi-square and log-rank tests assessed for associations between baseline clinical characteristics and progressive disease in initial sites only (vs. new or combined sites), and PFS, respectively.

RESULTS

Among 143 eligible patients with a median follow-up of 11 months, 97 (68%) developed disease progression. Of these, 67 patients (69.1%) progressed only at initial disease site(s), 10 patients (10.3%) progressed only at new disease site(s), and 20 patients (20.6%) progressed in both initial and new sites. Rates of disease progression based on tumour location were higher for liver (64%) and lung metastases (61%) than for other metastatic sites (33-36%) or the primary tumour (24%). Only higher PD-L1 expression (P = 0.002) and absence of lung metastasis (P = 0.048) at baseline were associated with improved PFS. No baseline characteristics significantly impacted the probability of initial disease site-only progression, though a trend was observed for untreated primary tumour (72% vs. 56%, P = 0.169).

CONCLUSIONS

The dominant pattern of disease progression is in the initial sites of disease alone, suggesting a potential role for local radiation therapy as a complementary treatment modality to immunotherapy.

Patterns of disease progression to checkpoint inhibitor immunotherapy in patients with stage IV non-small cell lung cancer

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Background: The purpose of this study was to assess patterns of disease progression for patients with metastatic non-small cell lung cancer (NSCLC) on checkpoint inhibitor immunotherapy in order to help guide effective use of targeted radiation therapy to sites of gross disease most likely to progress. Methods: This single center, retrospective study included all patients diagnosed with Stage IV NSCLC between June 2015 and February 2019 who received at least 2 cycles of nivolumab, pembrolizumab, or atezolizumab, with or without concurrent chemotherapy. Immune RECIST criteria were used to assess patterns of disease progression, and progression-free survival (PFS), excluding irradiated tumors. Descriptive statistics were used to report baseline patient and tumor characteristics. The Chi square and log-rank tests were used to determine whether any baseline clinical characteristics were associated with progressive disease in initial sites only (vs. new or combined sites), and PFS, respectively. Factors assessed included initial metastatic sites, tumor histology, performance status, PD-L1 expression, untreated primary tumor, history of brain metastasis, number of metastatic sites involved, and use of concurrent chemo-immunotherapy. Results: Among 143 eligible patients with a median follow-up of 11 months, 97 (68%) developed disease progression. Of these, 67 patients (69.1%) progressed only at initial disease site(s), 10 patients (10.3%) progressed only at new disease site(s), and 20 patients (20.6%) progressed in both initial and new sites. Rates of disease progression based on tumor location were higher for liver (64%) and lung metastases (61%) than for other metastatic sites (33-36%) or the primary tumor (24%). Only higher PD-L1 expression ( p= 0.002) and absence of lung metastasis ( p= 0.048) at baseline were associated with improved PFS. No baseline characteristics significantly impacted the probability of initial disease site-only progression, though a trend was observed for untreated primary tumor (72% vs. 56%, p= 0.169). Conclusions: The dominant pattern of disease progression for patients with metastatic NSCLC on checkpoint inhibitor immunotherapy is in the initial sites of disease alone, whereas only 10% of patients progressed in new disease site(s) alone, suggesting a potential role for local radiation therapy as a complementary treatment modality. Pre-treatment patient and tumor characteristics did not predict patients most likely to benefit.

Association of SMAD4 loss with response to neoadjuvant chemotherapy with the autophagy inhibitor hydroxychloroquine in patients with pancreatic adenocarcinoma

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Background: SMAD4, a tumor suppressor gene, is inactivated or deleted in 60-90% of pancreatic adenocarcinomas (PDA). Loss of SMAD4 allows tumor progression by limiting cell cycle arrest and apoptosis and increasing metastases. SMAD4 deficient PDA cells are resistant to radiotherapy by upregulation of autophagy, a cell survival mechanism that allows intracellular recycling of macromolecules and organelles. Hydroxychloroquine (HCQ) is a known autophagy inhibitor, suggesting that HCQ treatment in SMAD4 deficient PDA may prevent therapeutic resistance induced by autophagy upregulation. Methods: We retrospectively analyzed the SMAD4 status of PDA patients enrolled in two prospective clinical trials evaluating preoperative HCQ. The first dose escalation trial demonstrated the safety of preoperative gemcitabine with HCQ ( NCT01128296 ). More recently, a randomized trial of gemcitabine/nab-paclitaxel +/- HCQ evaluated Evans Grade histopathologic response ( NCT01978184 ). Immunohistochemistry of resected specimens for SMAD4 was previously performed. Patients not treated at the max HCQ dose (n = 5), not resected (n = 2) or with SMAD4 staining unavailable were excluded (n = 10). The effect of SMAD4 loss on response to HCQ and chemotherapy was studied for association with clinical outcome. Fisher’s exact test and log-rank test were used to assess response and survival. Results: 52 patients receiving HCQ with neoadjuvant chemotherapy and 24 patients receiving neoadjuvant chemotherapy alone were studied. Of the HCQ group, 25 patients had SMAD4 loss (48%), compared with 15 control patients (63%, p = 0.32). 76% of HCQ treated patients with SMAD4 loss obtained a histopathologic response ≥2A, compared to only 37% with SMAD4 intact (p = 0.006). In the control group, loss of SMAD4 was associated with a nonsignificant detriment in 3 year OS (25% vs. 78%, p = 0.3) that was less apparent in patients treated with HCQ (46% vs. 47%, p = 0.18). Conclusions: The addition of HCQ to neoadjuvant chemotherapy in PDA may improve treatment response in patients with SMAD4 loss. Further study of the relationship between SMAD4, autophagy and treatment outcomes in PDA is warranted.

Low-Dose Acyclovir Prophylaxis for Varicella zoster Reactivation in Autologous Hematopoietic Cell Transplantation Recipients

Varicella zoster virus (VZV) reactivation after autologous hematopoietic cell transplantation (auto-HCT) may be observed in a quarter of patients. Currently, prophylactic use of acyclovir 800 mg twice daily or valacyclovir 500 mg twice daily is recommended for prophylaxis against VZV reactivation for at least one-year post-HCT, with continued use recommended in immunosuppressed recipients. Acyclovir dosing regimens vary between institutions despite the noted recommendations. In this single-center, retrospective study, recipients of auto-HCT who received at least one year of low-dose antiviral prophylaxis defined as the equivalent of acyclovir 400 mg orally twice daily or valacyclovir 500 mg daily were included. The primary objective of this study was to assess the incidence of VZV reactivation with low-dose acyclovir/valacyclovir prophylaxis in autograft recipients. One hundred and eighty patients undergoing auto-HCT between April 2008 and March 2015 were included. Patients received low-dose acyclovir, for a median duration of 55.5 months (range 12–100). There were no occurrences of VZV reactivation while patients were on these drugs. However, 2 patients (1.1%) had VZV reactivation after discontinuation of therapy, occurring 18.8 and 14 months from transplant and 6.7 and 2 months after stopping prophylaxis, respectively. Our retrospective analysis found low-dose antiviral prophylaxis with oral acyclovir 400 mg twice daily or valacyclovir 500 mg daily to be effective in preventing VZV reactivation in auto-HCT recipients.

Single versus double-unit transfusion: Safety and efficacy for patients with hematologic malignancies

OBJECTIVES

Although hemoglobin thresholds for red blood cell (RBC) transfusion have decreased, double-unit RBC transfusion practices persist. We studied the effects switching from predominantly double-unit to single-unit RBC transfusions had on utilization and clinical outcomes for malignant hematology patients.

METHODS

Retrospective chart review compared malignant hematology patients before and after implementing single-unit RBC transfusion policy. Hemoglobin threshold was 8.0 g/dL for both groups. RBC utilization metrics included number of RBC units transfused, RBC units transfused per admission, and number of transfusion episodes. Clinical outcomes included length of stay, 30-day mortality, and outpatient RBC transfusion 30-days post-discharge.

RESULTS

Baseline hemoglobin was similar in both groups. The single-unit group was transfused with fewer RBC units per admission (5.1 vs 4.5, P = 0.01) than the double-unit group, but had more transfusion episodes per admission (4.1 vs 2.7, P < 0.001). After implementing single-unit policy, a 29% reduction in RBC utilization was observed. Mean hemoglobin at discharge was lower in the single-unit group (8.9 vs 9.5 g/dL, P = 0.005). No significant differences in length of stay or 30-day mortality were observed.

CONCLUSION

Transfusing malignant hematology patients with single RBC units is safe and efficacious. Electronic provider order systems facilitating RBC transfusion requests provide excellent adherence to transfusion policy.

Altered structural and functional connectivity of the insula in functional dyspepsia

BACKGROUND

Functional dyspepsia (FD) is a common functional gastrointestinal disease. Neuroimaging studies have identified that insula is involved in the pathogenesis of FD. However, less is known about structural and functional connectivity of insula in FD.

METHODS

In this study, 67 FD patients and 46 healthy controls (HCs) underwent structural MRI, resting-state functional MRI, diffusion tensor imaging (DTI) scans, and clinical assessment. We used the 3 neuroimaging modalities to investigate structural and functional connectivity of insula between FD patients and HCs, and we examined relationships between the neuroimaging findings and clinical symptoms.

KEY RESULTS

Compared with HCs, (i) FD patients had decreased gray matter density in right insula according to voxel-based morphometry method, which region was targeted as region of interest for further analysis of structural and functional connectivity; (ii) FD patients had lower connection probability in right anterior insula with right thalamus, right internal capsule (IC), and right external capsule (EC); (iii) FD patients had decreased functional connectivity of the right anterior insula with right thalamus and right pregenual anterior cingulate cortex (pACC); and (iv) FD patients had negative correlation between disease duration and the functional connectivity of right anterior insula with thalamus.

CONCLUSIONS AND INFERENCES

The present findings reveal that alterations of structural and/or functional connectivity of right anterior insula with regions, including thalamus, IC, EC, and pACC, may be mainly implicated in abnormalities of visceral sensory processing and related affective responses in FD patients. Finally, this study could enhance understanding of the pathophysiology of FD.

Adult Sporadic Burkitt's Lymphoma Presenting with Rapid Development of Peritoneal Lymphomatosis

Sporadic Burkitt's Lymphoma (BL) is a highly aggressive form of non-Hodgkin's lymphoma which requires prompt diagnosis and treatment. Though usual presentation involves abdominal lymphadenopathy with possible solid organ involvement, sporadic BL can rarely present with peritoneal lymphomatosis. We present a unique case with rapid evolution of BL presenting as peritoneal and omental lymphomatosis with hepatic lesions and pelvic and pericardial adenopathy.

Get1p and Get2p are required for maintenance of mitochondrial morphology and normal cardiolipin levels

Cardiolipin (CL) is the signature phospholipid of mitochondrial membranes. CL deficiency leads to defects in mitochondrial function. Using a targeted synthetic lethality screen to identify defects that exacerbate CL deficiency, we determined that deletion of mitochondrial morphology genes in cells lacking CL leads to severe growth defects. We show that ER membrane proteins Get1p and Get2p are required for maintaining normal levels of CL. We propose that these proteins regulate the level of CL by maintaining wild type-like tubular mitochondrial morphology. The genetic interactions observed in this study identify novel physiological modifiers that are required for maintenance of CL levels and mitochondrial morphology.

Swallowing Outcomes for T1-T4 Oropharyngeal Cancers Treated with TORS: Preliminary Experience

Objectives:

1) Assess swallowing function longitudinally using standardized questionnaires in a cohort of oropharyngeal cancer patients treated with transoral robotic surgery (TORS). 2) Compare the effect of tumor T-stage on swallowing outcomes.

Methods:

A prospective, institutional review board (IRB)-approved database of all patients undergoing TORS for oropharyngeal cancer at a tertiary-care academic institution was queried from November 2010-October 2012. Demographic data as well as longitudinal assessment of swallowing outcomes were collected. Standardized questionnaires included: University of Washington Quality of Life question 5 (UW-QOLq5), MD Anderson Dysphagia Inventory (MDADI), and Functional Oral Intake Scale (FOIS). Two-sided Wilcoxon signed-rank tests were used to compare baseline values with corresponding 1, 3, 6, and 12 months post-surgery. Two-sided Wilcoxon rank-sum tests were used to test for differences between T-stages.

Results:

Thirty-nine patients were studied with a mean age of 60.7 (42-92). T-stages included: T1 n = 14, T2 n = 15, T3 n = 6, T4 n = 4. No significant differences were detected at any time between patients with T1-T2 and T3-T4 stage disease on UW-QOLq5, MDADI, or FOIS. Compared to baseline, UW-QOLq5 measures were significantly lower at 1 month ( P = 0.0156), but not at 3 or 6 months. MDADI overall scores were significantly lower than baseline at 1 month ( P = 0.0134), but not at 3, 6, or 12 months. Compared to baseline, FOIS measures were significantly lower at 1 month ( P <.0001), and remained significantly lower at 3 ( P <.0001), 6 ( P <.0001), and 12 months ( P = 0.0039).

Conclusions:

Results suggests that while swallowing status declines immediately after TORS, it can be expected to approach baseline within 3 months post-surgery.

Head and Neck Cancer Screenings in Suburban/Urban Populations in Michigan: Need for More Education

Objectives:

1) Assess self-reported risk factors and knowledge gaps regarding head and neck cancer (HNC) risk factors in a multi-ethnic urban versus suburban population. 2) Improve education regarding behavioral risk factors for HNC, including regarding the transmission of human papillomavirus (HPV).

Methods:

The current sample includes a total of 118 individuals who presented for free HNC screenings across urban and suburban sites. Ninety-eight consented to complete behavioral risk questionnaires assessing for knowledge regarding HNC, ancestry, smoking/tobacco use, alcohol use, and sexual history.

Results:

Mean age was 56.63 years old (SD = 14.22, range 23 to 85), 60.2% female, predominantly African American (53.1%), Caucasian (42.7%), and other (4.1%). Those residing in an urban environment were more likely to be African American χ2(1, N = 98)=23.334, P < 0.001, have a history of treatment for some other cancer χ2(1, N=98)=6.063, P = 0.01, be a current smoker χ2(2, N=98)=5.885, P = 0.05, report more cumulative years consuming alcohol t(85)=2.050, P = 0.04, be willing to volunteer to promote awareness χ2(1, N=98)=4.866, P = 0.02, and feel the program increased their knowledge regarding HNC χ2(1, N=98)=4.726, P = 0.03, than those in a suburban environment.

Conclusions:

Free HNC screenings and related education are well received by a racially diverse urban population. HNC screenings should include evaluation of behavioral risk and specific knowledge associated with HNC.

Cardiolipin and mitochondrial phosphatidylethanolamine have overlapping functions in mitochondrial fusion in Saccharomyces cerevisiae

The two non-bilayer forming mitochondrial phospholipids cardiolipin (CL) and phosphatidylethanolamine (PE) play crucial roles in maintaining mitochondrial morphology. We have shown previously that CL and PE have overlapping functions, and the loss of both is synthetically lethal. Because the lack of CL does not lead to defects in the mitochondrial network in Saccharomyces cerevisiae, we hypothesized that PE may compensate for CL in the maintenance of mitochondrial tubular morphology and fusion. To test this hypothesis, we constructed a conditional mutant crd1Δpsd1Δ containing null alleles of CRD1 (CL synthase) and PSD1 (mitochondrial phosphatidylserine decarboxylase), in which the wild type CRD1 gene is expressed on a plasmid under control of the TET(OFF) promoter. In the presence of tetracycline, the mutant exhibited highly fragmented mitochondria, loss of mitochondrial DNA, and reduced membrane potential, characteristic of fusion mutants. Deletion of DNM1, required for mitochondrial fission, restored the tubular mitochondrial morphology. Loss of CL and mitochondrial PE led to reduced levels of small and large isoforms of the fusion protein Mgm1p, possibly accounting for the fusion defect. Taken together, these data demonstrate for the first time in vivo that CL and mitochondrial PE are required to maintain tubular mitochondrial morphology and have overlapping functions in mitochondrial fusion.