Association between pathologic response and survival after neoadjuvant therapy in lung cancer

Neoadjuvant immunotherapy plus chemotherapy improves event-free survival (EFS) and pathologic complete response (0% residual viable tumor (RVT) in primary tumor (PT) and lymph nodes (LNs)), and is approved for treatment of resectable lung cancer. Pathologic response assessment after neoadjuvant therapy is the potential analog to radiographic response for advanced disease. However, %RVT thresholds beyond pathologic complete response and major pathologic response (≤10% RVT) have not been explored. Pathologic response was prospectively assessed in the randomized, phase 3 CheckMate 816 trial (NCT02998528), which evaluated neoadjuvant nivolumab (anti-programmed death protein 1) plus chemotherapy in patients with resectable lung cancer. RVT, regression and necrosis were quantified (0-100%) in PT and LNs using a pan-tumor scoring system and tested for association with EFS in a prespecified exploratory analysis. Regardless of LN involvement, EFS improved with 0% versus >0% RVT-PT (hazard ratio = 0.18). RVT-PT predicted EFS for nivolumab plus chemotherapy (area under the curve = 0.74); 2-year EFS rates were 90%, 60%, 57% and 39% for patients with 0-5%, >5-30%, >30-80% and >80% RVT, respectively. Each 1% RVT associated with a 0.017 hazard ratio increase for EFS. Combining pathologic response from PT and LNs helped differentiate outcomes. When compared with radiographic response and circulating tumor DNA clearance, %RVT best approximated EFS. These findings support pathologic response as an emerging survival surrogate. Further assessment of the full spectrum of %RVT in lung cancer and other tumor types is warranted. ClinicalTrials.gov registration: NCT02998528 .

Abstract LB531: The addition of IFNα and 5-Aza-2'deoxycytidine treatments to a dendritic cell-targeting DNA vaccine enhance the expression of Th1-related genes and the infiltration of CD11c+ CD8+ T-cells

Background: DNA vaccines fusing the chemokine MIP-3α (CCL20), which binds to CCR6 on immature dendritic cells (DCs), to melanoma-associated antigens have enhanced anti-tumor immunity and efficacy compared to vaccines lacking the chemokine. To further enhance the therapeutic effects of the vaccine, our laboratory has added type-I interferon (IFNα) and 5-Aza-2’-deoxycitidine (5Aza) to the therapy. Here, we report that the efficacy seen in this combination results in deeper intratumoral penetration of CD8+ cells, enhanced expression of Th1 t-cell related genes, and increased influx of CD11c+ CD8+ T-cells.

Methods: Beginning on day five post-transplantation of B16F10 melanoma, the vaccine was administered intramuscularly (i.m.) by electroporation. CpG adjuvant was given two days later. 5Aza was given intraperitoneally at 1mg/kg and IFNα therapy intratumorally as noted. Tumor sizes over time were assessed. For immunohistochemistry (IHC), formalin-fixed tumors were processed, embedded, cut into slides, and stained for CD8 by on-site core facility. Stained slides were analyzed by a pathologist in a blinded fashion. Tumor lysate gene expression levels and tumor-infiltrating lymphocytes (TILs) were assessed by qRT-PCR and flow cytometry respectively.

Results: Previous work has shown that the combination of IFNα, 5Aza, and vaccine led to significantly reduced tumor burden and overall increases in mouse survival dependent upon all three components. We have since discovered by IHC that CD8+ cells are more abundant and penetrate further into the tumor with the combination treatment compared to vaccine or therapeutics alone. The tumor immune genetic profile shows broad increases of expression for genes responsible for T-cell activation, efficacy, and trafficking. Of note, the combination therapy doubled the proportion of CD8+ T cells in the tumor microenvironment expressing CD11c (p = 0.027), and the proportions of these cells correlated more strongly to tumor size than do the proportions of CD11c- CD8+ T-cells (r2=0.51; p<0.0001 compared to r2=0.19; p = 0.02).

Conclusions: Efficient targeting of antigen to immature dendritic cells with a chemokine-fusion vaccine offers a potential alternative approach to classic and dendritic cell-based vaccines. Combining this approach with IFNα and 5Aza treatments significantly improved vaccine efficacy. This treatment creates a complex intratumoral network that facilitates T-cell trafficking, Th1-associated gene expression, and an increase of CD11c+CD8+ T-cells, which have recently been shown in the literature to have greater anti-tumor activity than CD11c- T-cells. Further analysis of the pathways engaged by our treatment protocol should provide insights into how to more efficiently activate this recently described, highly effective T cell population.

Citation Format: James T. Gordy, Kaitlyn Comstock, Avinaash K. Sandhu, Yinan Hui, Styliani Karanika, Joel Sunshine, Petros C. Karakousis, Richard B. Markham. The addition of IFNα and 5-Aza-2'deoxycytidine treatments to a dendritic cell-targeting DNA vaccine enhance the expression of Th1-related genes and the infiltration of CD11c+ CD8+ T-cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB531.

Calciphylaxis Cutis Associated With Fibroblast Growth Factor Receptor (FGFR) Inhibitor Therapy: A New Challenge

Specific fibroblast growth factor receptor (FGFR) inhibitors have been developed to treat malignancies harboring fusions or rearrangements in FGFR2 or FGFR3. Here, we report a case of calciphylaxis cutis in association with FGFR inhibitor therapy in a patient with FGFR2 rearranged cholangiocarcinoma. Although calciphylaxis cutis typically arises in the setting of hyperphosphatemia and end-stage renal disease, this patient had preserved renal function, normal serum calcium, and only modestly elevated serum phosphorus levels, which is similar to other recent reports of calciphylaxis in patients receiving FGFR inhibitor therapy. Calciphylaxis cutis is a possible adverse event observed with FGFR inhibitor therapy, and the mechanism of calciphylaxis cutis in association with FGFR inhibitor therapy warrants further investigation.

222 Genetic reprogramming of merkel cell carcinoma and melanoma leads to increased MHC-I expression and antitumor immune activation in vitro and in vivo

Background

Merkel cell carcinoma (MCC) is a rare skin cancer with 46% disease-associated mortality and half of patients unresponsive to immune checkpoint inhibitors.1 2 MCC and melanomas often display decreased MHC class I (MHC-I) expression on the surface of cells, which prevents antigen recognition by T cells (”signal 1”) and hampers immune activation. We therefore sought to genetically reprogram cells to express their own costimulatory molecules (”signal 2”) and immunostimulatory cytokines (”signal 3”) to increase MHC-I expression and drive a targeted immune response.

Methods

We used biodegradable poly(beta-amino ester) nanoparticles (NPs) to co-deliver plasmids encoding a signal 2 molecule (4-1BBL) and two signal 3 molecules (IL-12 and IFNγ) to cancer cells. For in vitro evaluation of NPs we used two patient-derived MCC cell lines with low baseline MHC-I expression; MCC13 and UISO. Co-culture experiments were performed with human PBMCs or primary human natural killer (NK) cells. All in vitro analysis was performed 7 days following PBMC or NK cell addition. For in vivo evaluation, subcutaneous B16F10 mouse melanoma tumors were implanted in C57BL/6J mice and NPs were administered by direct injection into the tumor with and without intraperitoneal injection of αPD1. Tumors were harvested for analysis on day 16.

Results

Transfection with particles delivering the three plasmids to MCC13 and UISO increased MHC-I expression (mean fluorescence intensity) 1.6- and 5.0-fold, respectively, and MHC-II expression increased 1.6- and 6.3-fold, respectively (figure 1). In co-culture with human PBMCs, signal 2/3 particles resulted in increased leukocyte proliferation (4.6- and 6.1-fold increase, respectively) and led to significantly reduced MCC viability (10.6 and 1.6% vs control particles)(figure 2). When MCC13 cells were co-cultured with primary human NK cells, NK cell expansion increased 355-fold with 4-1BBL/IL-12 particles compared to control particles and was accompanied by 2.5% MCC13 cell viability, indicating a potent innate immune response with signal 2/3 NP administration in vitro (figure 3). Following evaluation of NPs in vivo, assessment of MHC-I and MHC-II expression in the melanoma tumors found increased expression with signal 2/3 NPs compared to control NPs (figure 4). When signal 2/3 NPs were administered in combination with αPD1 treatment, 4-1BBL/IL-12 NPs with αPD1 demonstrated improved survival compared to αPD1 treatment with control NPs (p=0.0010) (figure 5).

Abstract 222 Figure 1

Administration of signal 2/3 NPs to MCC13 and UISO cells led to increases in MHC-I and MHC-II expression after 7 days. MHC-I expression in transfected cells (red) and MHC-II expression in transfected cells (blue) compared to untreated control (black)

Abstract 222 Figure 2

Co-culture of transfected MCC cells with human PBMCs led to increases in CD45+ cells and reduced MCC cell viability after 7 days

Abstract 222 Figure 3

Co-culture of 4-1BBL/IL-12 transfected MCC13 cells with isolated CD56+ NK cells demonstrated robust NK-cell expansion and low MCC cell viability after 7 days

Abstract 222 Figure 4

Direct intratumoral injection with signal 2 and 3 NPs led to increases in MHC-I and MHC-II in cancer cells in vivo.

Abstract 222 Figure 5

NPs were administered intratumorally ± intraperitoneal aPD1 on day 9, 11, and 13 following B16F10 melanoma tumor implantation. 4-1BBL/IL12 particles in combination with αPD1 demonstrated a significant improvement in survival compared to control particles (Luc) with αPD1 (p=0.0010)

Conclusions

Together, these results show the ability of signal 2/3 NPs to reprogram MCC and melanoma cells, leading to increased MHC-I expression in vitro and in vivo, eliciting a productive immune response against cancer cells.

References

Hughes MP, Hardee ME, Cornelius LA, Hutchins LF, Becker JC, Gao L. Merkel cell carcinoma: epidemiology, target, and therapy. Curr Dermatol 2014;46–53.

Nghiem PT, Bhatia S, Lipson EJ, Kudchadkar RR, Miller NJ, Annamalai L, Berry S, Chartash EK, Daud A, Fling SP, Friedlander PA, Kluger HM, Kohrt HE, Lundgren L, Margolin K, Mitchell A, Olencki T, Pardoll DM, Reddy SA, Shantha EM, Sharfman WH, Sharon E, Shemanski LR, Shinohara MM, Sunshine JC, Taube JM, Thompson JA, Townson SM, Yearley JH, Topalian SL, Cheever MA. PD-1 blockade with pembrolizumab in advanced merkel-cell carcinoma. N Engl J Med 2016;374:2542–2552.

Anatomical structures, cell types and biomarkers of the Human Reference Atlas

The Human Reference Atlas (HRA) aims to map all of the cells of the human body to advance biomedical research and clinical practice. This Perspective presents collaborative work by members of 16 international consortia on two essential and interlinked parts of the HRA: (1) three-dimensional representations of anatomy that are linked to (2) tables that name and interlink major anatomical structures, cell types, plus biomarkers (ASCT+B). We discuss four examples that demonstrate the practical utility of the HRA.

MR Fingerprinting of Adult Brain Tumors: Initial Experience

BACKGROUND AND PURPOSE

MR fingerprinting allows rapid simultaneous quantification of T1 and T2 relaxation times. This study assessed the utility of MR fingerprinting in differentiating common types of adult intra-axial brain tumors.

MATERIALS AND METHODS

MR fingerprinting acquisition was performed in 31 patients with untreated intra-axial brain tumors: 17 glioblastomas, 6 World Health Organization grade II lower grade gliomas, and 8 metastases. T1, T2 of the solid tumor, immediate peritumoral white matter, and contralateral white matter were summarized within each ROI. Statistical comparisons on mean, SD, skewness, and kurtosis were performed by using the univariate Wilcoxon rank sum test across various tumor types. Bonferroni correction was used to correct for multiple-comparison testing. Multivariable logistic regression analysis was performed for discrimination between glioblastomas and metastases, and area under the receiver operator curve was calculated.

RESULTS

Mean T2 values could differentiate solid tumor regions of lower grade gliomas from metastases (mean, 172 ± 53 ms, and 105 ± 27 ms, respectively; P = .004, significant after Bonferroni correction). The mean T1 of peritumoral white matter surrounding lower grade gliomas differed from peritumoral white matter around glioblastomas (mean, 1066 ± 218 ms, and 1578 ± 331 ms, respectively; P = .004, significant after Bonferroni correction). Logistic regression analysis revealed that the mean T2 of solid tumor offered the best separation between glioblastomas and metastases with an area under the curve of 0.86 (95% CI, 0.69-1.00; P < .0001).

CONCLUSIONS

MR fingerprinting allows rapid simultaneous T1 and T2 measurement in brain tumors and surrounding tissues. MR fingerprinting-based relaxometry can identify quantitative differences between solid tumor regions of lower grade gliomas and metastases and between peritumoral regions of glioblastomas and lower grade gliomas.

PD-1/PD-L1 inhibitors

Tumors may adopt normal physiologic checkpoints for immunomodulation leading to an imbalance between tumor growth and host surveillance. Antibodies targeting the PD-1/PD-L1 checkpoint have shown dynamic and durable tumor regressions, suggesting a rebalancing of the host-tumor interaction. Nivolumab and pembrolizumab are the anti-PD-1 antibodies that are currently the furthest in clinical development, and anti-PD-L1 agents under investigation include MPDL3280A, MEDI4736, and BMS-936559. These agents have been used to treat advanced melanoma, non-small cell lung cancer, renal cell carcinoma, bladder cancer and Hodgkin lymphoma, amongst other tumor types. In this article, we review the updated response results for early clinical trials, note recent FDA actions regarding this class of agents, and summarize results across trials looking at PD-L1 status as a predictor of response to anti-PD-1/PD-L1.

Degradable polymers for gene delivery

Degradable polymers were synthesized that self-assemble with DNA to form particles that are effective for gene delivery. Small changes to polymer synthesis conditions, particle formulation conditions, and polymer structure led to significant changes to efficacy in a cell-type dependent manner. Polymers presented here are more effective than Lipofectamine 2000 or polyethylenimine for gene delivery to cancerous fibroblasts or human primary fibroblasts. These materials may be useful for cancer therapeutics and regenerative medicine.

Small-Molecule End-Groups of Linear Polymer Determine Cell-type Gene-Delivery Efficacy

End-modified polymers are promising for the nonviral delivery of genes to cancer cells, immune cells, and human stem cells and point to polymer end-groups as regulators for cell-type specificity. A library of polymers has been synthesized and, although some polymers are strong transfection agents overall, for each cell type, a particular polymer is most effective.

Gold, poly(beta-amino ester) nanoparticles for small interfering RNA delivery

The safe and effective delivery of RNA therapeutics remains the major barrier to their broad clinical application. Here we develop a new nanoparticulate delivery system based on inorganic particles and biodegradable polycations. First, gold nanoparticles were modified with the hydrophilic polymer poly(ethylene glycol) (PEG), and then small interfering RNA (siRNA) was conjugated to the nanoparticles via biodegradable disulfide linkages, with approximately 30 strands of siRNA per nanoparticle. The particles were then coated with a library of end-modified poly(beta-amino ester)s (PBAEs), previously identified as capable of facilitating intracellular DNA delivery. Nanoparticulate formulations developed here facilitate high levels of in vitro siRNA delivery, facilitating delivery as good or better than the commercially available lipid reagent, Lipofectamine 2000.

Immunoglobulin light chain repertoire in hairy cell leukemia

Of 166 hairy cell leukemia (HCL) patients, 81 had kappa and 80 had lambda expression. IGKV-J and IGLV-J rearrangement structure was analyzed in 21 HCL patients (11 kappa, 10 lambda). For kappa, IGKV1-5 was most frequent, and the KJ2 gene was over-utilized. For lambda HCL, LJ3 was over-utilized compared to normal. This study significantly adds to previous studies of light chain usage in HCL and is the first to report light chain gene usage. In HCL, we confirm the lack of kappa predominance observed in normal lymphocytes and in chronic lymphocytic leukemia, and note over-representation of several light chain genes.

Somatic hypermutation and VH gene usage in hairy cell leukaemia

To examine the usage and mutational status of VH genes in hairy cell leukaemia (HCL), we analysed 24 immunoglobulin heavy chain (IgH) sequences expressed in 23 patients. None had premature stop codons. VH3-23 was the most common gene and a VH6 gene was observed for the first time in HCL. Although the mean mutation frequency was 6.1%, slightly higher than in previous HCL series, four patients had 99.6-100% homology to germline sequences, three of whom had high tumour burdens and poor outcomes. Despite the high mutation frequency, only two of 24 rearrangements had clear statistical evidence of antigen-dependent somatic mutation. Our results increase the database of reported functional HCL rearrangements to 94 in 92 patients. Overall, both gene usage and mutation frequency are very similar to mucosa-associated lymphoid tissue-type marginal zone lymphoma. The data are consistent with HCL originating from post-germinal centre marginal zone B cells, although the heterogeneity observed suggests that HCL may originate differently in some patients, and this could have implications for prognosis and treatment.

Using intake biomarkers to evaluate the extent of dietary misreporting in a large sample of adults: the OPEN study

This paper describes the Observing Protein and Energy Nutrition (OPEN) Study, conducted from September 1999 to March 2000. The purpose of the study was to assess dietary measurement error using two self-reported dietary instruments-the food frequency questionnaire (FFQ) and the 24-hour dietary recall (24HR)-and unbiased biomarkers of energy and protein intakes: doubly labeled water and urinary nitrogen. Participants were 484 men and women aged 40-69 years from Montgomery County, Maryland. Nine percent of men and 7% of women were defined as underreporters of both energy and protein intake on 24HRs; for FFQs, the comparable values were 35% for men and 23% for women. On average, men underreported energy intake compared with total energy expenditure by 12-14% on 24HRs and 31-36% on FFQs and underreported protein intake compared with a protein biomarker by 11-12% on 24HRs and 30-34% on FFQs. Women underreported energy intake on 24HRs by 16-20% and on FFQs by 34-38% and underreported protein intake by 11-15% on 24HRs and 27-32% on FFQs. There was little underreporting of the percentage of energy from protein for men or women. These findings have important implications for nutritional epidemiology and dietary surveillance.

Use trends and geographic variation in neuroimaging: nationwide medicare data for 1993 and 1998

BACKGROUND AND PURPOSE

Powerful tools, including CT and MR imaging, have revolutionized neuroimaging. These are routinely used, but the extent and variation of use has not been studied. Our purposes were to determine the use rates of MR imaging and CT (of spine, brain, or head and neck), myelography, conventional angiography, and MR angiography in diagnosing neurologic disorders; to study trends in use; and to determine regional variations in use.

METHODS

We used the National Part B Medicare Database for 1993 and 1998 to compare rates of use for these procedures in 10 geographic regions.

RESULTS

In 1993 and 1998, respectively, 13,897 and 19,431 (39.8% increase) neuroimaging procedures were performed per 100,000 Medicare beneficiaries nationwide. Use of brain or head and neck CT (30.4%) and MR imaging (43.6%), spinal CT (3.5%) and MR imaging (83.0%), myelography (56.6%), and conventional angiography (24.3%) increased in 1998 versus 1993. Increases in MR angiography were not assessed, because this procedure was not reimbursable in 1993. Regional use of brain or head and neck and spinal CT and MR studies varied considerably; ratios of highest and lowest rates were 1.38-1.56. Use of MR angiography, myelography, and conventional angiography varied three- to fourfold.

CONCLUSION

Use of MR and CT studies of the brain or head and neck and of the spine increased considerably in the Medicare population between 1993 and 1998. Use of conventional invasive procedures such as myelography and angiography increased strikingly, contrary to the expected decline. Regional use varied substantially.

Hiring of diagnostic radiologists in 1998

OBJECTIVE

We sought to determine the 1998 hiring activities of physician practices with respect to diagnostic radiologists.

MATERIALS AND METHODS

A survey was mailed to a sample of 970 radiology practices in the spring through fall of 1999; 73.0% responded. Responses were weighted to represent all practices in the United States providing diagnostic radiology services. Findings were compared with results of similar surveys from previous years.

RESULTS

In 1998, multiradiologist groups sought to hire 2299 (+/-148 [standard error]) diagnostic radiologists, an increase of 20% from 1977. Positions offered in 1998 were split almost equally between expansion positions and replacements for those who had left a practice. Another 422 (+/-58) positions had been vacated that practices did not seek to refill. In 1998, 621 (+/-57) diagnostic radiologists left active practice, which is more than the usual number of approximately 400 annually but less than the approximately 800 of 1996 and 1997. There was no significant association between hiring activity and the self-perceived effect of managed care on a group.

CONCLUSION

The pace of hiring and turnover of diagnostic radiologists increased in 1998. Positions available continue to exceed radiologists available to fill them; the excess was approximately 330 positions, which is not significantly different from the excess reported for 1997, but is higher than the (not statistically significant) net shortfall of 51 positions estimated for 1996.

Changes in the job market for interventional radiology as detected through a help-wanted index of job advertisements

RATIONALE AND OBJECTIVES

The purpose of this study was to study trends in the job market in interventional radiology.

MATERIALS AND METHODS

Each job advertisement for a diagnostic radiologist in the American Journal of Roentgenology and Radiology between January 1991 and December 1999 was coded by practice type (academic vs private), location, and subspecialty. Positions for interventional radiologists were compared with positions for noninterventional radiologists. Data from the first 48 months (January 1991 through December 1994) were compared with data from the second 48 months (January 1995 through December 1998). Data from 1999 were grouped separately.

RESULTS

The nadir for all noninterventional and interventional radiology positions was seen in July 1995, and both areas have experienced great recovery since then. In December 1999, the last month of data collection, the absolute peak number of advertisements for interventional radiologists was reached. In fact, during the last half of the decade, an increasing percentage of jobs advertised for diagnostic radiologists was specifically for interventional radiologists. Statistically significant trends also occurred toward the private sector and toward positions in the Midwest and California.

CONCLUSION

With a help-wanted index, dramatic shifts toward the private sector and toward jobs in the Midwest and California were demonstrated in the interventional radiology job market.

The job market in diagnostic radiology 1999: updated findings from a help wanted index of job advertisements

OBJECTIVE

The purpose of this article is to report 1999 data on the job market in diagnostic radiology detected using a help wanted index of job advertisements and to profile trends in practice type, location, and subspecialty using our previously published data as a basis for comparison.

MATERIALS AND METHODS

Each advertised job for a diagnostic radiologist in the American Journal of Roentgenology and RADIOLOGY: between January 1991 and December 1999 was coded by practice type, location, and subspecialty.

RESULTS

In 1999, 3926 positions were advertised for diagnostic radiologists, representing a 75% increase from 1998. Private practice jobs, which represented 53% of advertisements from 1991 through 1994 and 64% of ads from 1995 through 1998, increased to 66% of ads in 1999. Geographic trends in 1999 were characterized by a relative increase of jobs in the Midwest and California and a decrease in percentage (but increase in total number of ads) in the Northeast and Southwest. The demand for subspecialists continued in 1999, with only 34% of ads placed for general radiologists. A relative increase in demand for neuroradiologists, mammographers, and abdominal imagers was also seen in 1999 in comparison with previously published data from 1995 through 1998.

CONCLUSION

The demand for diagnostic radiologists continues to rise, with more ads placed in 1999 than any other year from 1991 through 1998. Using a help wanted index of job advertisements, we have created an indicator of changes in the diagnostic radiology job market with specific reference to practice type, geographic location, and subspecialty training.

The effect of imaging guidelines on the number and quality of outpatient radiographic examinations

OBJECTIVE

A significant percentage of outpatient diagnostic radiology is performed by nonradiologists. Studies have shown nonradiologists have higher utilization and cost, as well as quality problems. We sought to determine if, in a managed care environment, a set of guidelines limiting imaging privileges of nonradiologist physicians could decrease imaging costs while ensuring that equipment and personnel providing imaging were of the highest quality.

MATERIALS AND METHODS

We determined the number and type of radiographic imaging studies performed the year after these guidelines were set in place (1997) and compared these findings with those of the year before the guidelines were established (1995) and with preguideline trends. We established quality criteria and, based thereon, inspected imaging offices.

RESULTS

The number of radiographic examinations per 1000 enrollees decreased 20-25% from the previous trend. Nonradiologists' share of the total fell from 39% to 15%. No deficiencies were found in the inspection of five radiologists' offices, whereas significant deficiencies of equipment, equipment maintenance, or documentation of the examinations performed were found in 78% of nonradiologists' offices. None of the quality indicators monitored by the health plan showed significant change.

CONCLUSION

Specific guidelines can effect change in the location and number of radiologic examinations performed, with an improvement in the quality of the studies and a decrease in radiation dose and cost. No decline in quality of care appears to result, despite claims by opponents to such changes that widespread serious quality impairment would occur.

Do interventional radiologists pose a significant threat to the practice of vascular surgery?

PURPOSE

Vascular surgeons have become concerned recently about perceived threats to their practices posed by the growth of interventional radiology. The authors studied nationwide 1996 Medicare Part B procedure data to determine the seriousness of these threats.

MATERIALS AND METHODS

The national Health Care Financing Administration (HCFA) Physician/Supplier Procedure Summary Master File for 1996 was searched. Two hundred thirteen distinct Current Procedural Terminology (CPT-4) codes were identified for therapeutic surgical and percutaneous interventional procedures performed to treat noncardiac vascular diseases. For each code, determination was made of total volume, specialty of the physician providers, and Medicare Part B reimbursement dollars paid to the providers as professional fees. In view of the conflicts among various specialties over peripheral vascular interventions, the authors also determined the percentages of these procedures performed by radiologists, surgeons, cardiologists, and other physicians.

RESULTS

A total of 759,548 noncardiac therapeutic vascular procedures (operations or percutaneous interventions) were performed during 1996 in patients receiving Medicare benefits. Radiologists performed 135,103 (17.8%) of these procedures but received only 10.4% of professional reimbursements. By contrast, surgeons performed 510,871 (67.3%) procedures, but received 78.0% of professional reimbursements. Cardiologists performed 4.7% of procedures and other specialists performed the remaining 10.3%. Radiologists performed 75.5% of percutaneous transluminal angioplasties, the majority of thrombolysis procedures, stent placements, and portal decompression procedures, and approximately half of inferior vena cava interruptions. Cardiologists performed 12.6% of percutaneous transluminal angioplasties, surgeons performed 6.3%, and other specialists performed 5.6%.

CONCLUSIONS

In terms of overall physician workload and professional reimbursements paid for invasive treatment of all types of noncardiac vascular disease, surgeons predominate and do not appear to be seriously threatened by interventional radiologists. Radiologists perform three-fourths of noncardiac percutaneous transluminal angioplasties and a majority of other percutaneous interventional therapies for vascular disease, but some inroads have been made by cardiologists and surgeons, particularly the former.

Impact of MR imaging on nationwide health care costs and comparison with other imaging procedures

OBJECTIVE

We wished to determine the extent to which MR imaging contributes to the overall costs of imaging in the United States and to compare MR imaging costs with other imaging techniques.

MATERIALS AND METHODS

All 23 current procedural terminology, version 4 (CPT-4) codes for MR imaging were extracted from the national 1993 Part B Medicare annual data reimbursement file. For each code, we calculated total Medicare physician reimbursements. Aggregate reimbursement for all MR imaging was compared with aggregate reimbursement for all 659 imaging-related current procedural terminology, version 4 codes and also with comparable figures for echocardiography and other categories of cardiovascular imaging.

RESULTS

Within the 23 MR imaging codes, 1,449,911 examinations were performed on Medicare patients in 1993, for which physicians were reimbursed $370 million. Medicare reimbursement of physicians for all 659 imaging-related procedures was $5.3 billion. Thus, MR imaging accounted for only 7% of all imaging costs. By comparison, a group of just 10 imaging codes, which are primarily cardiovascular in nature, accounted for $1.67 billion, or 32% of the entire Part B costs for imaging. Reimbursements for echocardiography alone are more than twice those for MR imaging.

CONCLUSION

From the national perspective, MR imaging does not appear to warrant its reputation as a costly procedure. The costs of echocardiography and other imaging related to the cardiovascular system are considerably higher.

MRI efficacy and effectiveness research: who needs it and who pays for it?

Health care reform has made quality efficacy research in MRI important to an increasing number of audiences. Historically, the deficit of quality outcomes research in MRI was due to difficulties in study design, lack of funding, disincentives for researches and funding sources, and poor coordination. These issues would be best addressed by the formation of an MRI implementation group that would coordinate funding, planning, and dissemination of the outcomes research efforts.

Hiring preferences of diagnostic radiology groups: results of a 1994 survey

RATIONALE AND OBJECTIVES

We surveyed diagnostic radiology group preferences and considerations in hiring radiologists and compared these findings with those of a survey performed in 1990. We sought to identify changes in hiring practices that might have occurred because of socioeconomic changes. We also sought to identify features of job candidates that make them more attractive to hiring groups.

METHODS

One hundred surveys were mailed to a stratified random sample of diagnostic radiology groups identified by the American College of Radiology. We solicited information on the importance of various attributes and the level of experience of a candidate, the fellowship training considered most desirable, and the effect of changes in the health care socioeconomic environment. The responses were weighted by group size and geographic location to estimate what results might have been obtained if we had surveyed all groups in the United States.

RESULTS

Seventy-five groups returned the survey. The two most important factors in choosing a candidate were motivation and radiologic knowledge. The fellowships that groups that were hiring considered to be the most desirable were body imaging, neuroradiology, and angiography/interventional radiology. Groups overwhelmingly preferred recent training over long experience.

CONCLUSION

Fellowship training increases a candidate's marketability, but the two factors that hiring groups consider the most important are motivation and radiologic knowledge.

The job market for radiology residents and fellows graduating in 1994

OBJECTIVE

In response to anecdotal reports of grave deterioration in the job market for graduates of radiology training programs, the American College of Radiology undertook a systematic appraisal of this job market for 1994.

MATERIALS AND METHODS

Between mid-April and mid-May 1994, the American College of Radiology surveyed 40 directors of randomly chosen diagnostic radiology training programs and 20 directors of randomly chosen radiation oncology training programs. We achieved a response rate of 80% or more in both categories. The survey asked, among other questions, the number of graduates, how many had jobs, the number of offers received by graduates this year and last, and how difficult the job market was relative to recent years.

RESULTS

Directors reported that 96% of graduating residents and 86% of graduating diagnostic fellows had commitments for positions. Of those with commitments, 94% of residents and 84% of diagnostic fellows were reported to have jobs that reasonably matched their training and job goals. Program directors estimated that the average graduate received two job offers but, on average, rated the job market as somewhat more difficult than was typical of recent years and reported that 1993 graduates had received more job offers. Plans to change size were reported for one fourth of programs, but the job market situation was not an important reason for these planned changes.

CONCLUSION

Although the overwhelming majority of 1994 graduates obtained jobs, and these overwhelmingly were jobs of interest, program directors reported that the job market was weakening. Given the changes in the socioeconomic environment--managed care, for example--and the changing job market, training programs should give more attention to the job market in planning for changes in size.

Positron emission tomography and breast masses: comparison with clinical, mammographic, and pathological findings

BACKGROUND

Positron emission tomography (PET) is a means of imaging tissue based upon its metabolic activity. Initial studies in the field of oncology suggest that PET may be useful for diagnosis, staging, and treatment of various tumors.

METHODS

Twenty-eight patients with 37 breast lesions were studied with PET using [fluorine-18] 2-deoxy-2-fluoro-D-glucose (FDG) to assess which clinicopathological characteristics relate to FDG accumulation by the primary tumor.

RESULTS

PET-FDG was found to successfully discriminate malignant from benign breast lesions (p = 0.02) and identify axillary lymph node metastases. FDG uptake by the primary tumor was found to be independent of age, menopausal status, race, tumor size, laterality, histologic differentiation, ploidy, DNA index, estrogen or progesterone receptor value, pathologic stage, and serum glucose. Higher tumor nuclear grade and S-phase were associated with more FDG accumulation by the primary tumor compared with normal breast tissue. PET-FDG correctly identified five malignant lesions that were indeterminant for cancer both on clinical breast examination and mammography and identified one occult cancer that was neither palpable nor apparent mammographically. PET-FDG correctly identified clinical occult axillary metastatic cancer in five patients.

CONCLUSIONS

This study shows that PET-FDG imaging can distinguish malignant from benign breast lesions among a diverse group of patients and suggests that PET-FDG may not only allow for preoperative staging of patients but also provide information about prognosis. This study provides impetus for continued research into PET-FDG imaging of breast lesions, which could have a major impact on the treatment of breast cancer.

Basic characteristics of radiology groups in the United States: results of a 1991-1992 census

OBJECTIVE

The American College of Radiology (ACR), the principal professional organization of United States radiologists, receives numerous requests for information on the characteristics of radiology groups. This report describes the basic characteristics of radiology groups in the United States. We defined radiology groups as any practice with two or more radiologists or radiation oncologists, including academic departments, units in multispecialty groups, and staff of government facilities.

MATERIALS AND METHODS

To collect basic information on radiology groups, the ACR conducted a mail census of all identified radiology groups in the United States during late 1991 and early 1992. Follow-up was conducted by mail and telephone. To make the responses accurately representative of all radiology groups, we weighted the approximately 2000 responses to correspond to known control totals for the number of groups of each of seven size categories in each of the four census regions (Northeast, Midwest, South, and West). These control totals were obtained from the ACR's 1990 Manpower Survey, which showed a total of approximately 3200 radiology groups.

RESULTS

Approximately one fourth of all groups have two radiologists, one fourth have three or four radiologists, one fourth have five to seven radiologists, and one fourth have eight or more radiologists. Academic groups were relatively large; almost 50% had 11 or more radiologists. Nonmetropolitan areas had very few large groups, and metropolitan center cities had relatively few small groups. Ninety-two percent of all groups practiced at hospitals, and 73% of all groups practiced at nonhospital offices or centers. The median number of practice sites for all groups was three, including both hospital and nonhospital sites. Eighty-eight percent of all groups provided diagnostic radiology services, 23% provided radiation oncology, 12% offered both, and 11% were oncology-only groups. Relatively many academic groups (25%) were oncology-only groups; very few radiology groups (2%) in multispecialty practices were oncology-only groups. The diagnostic radiology techniques available from the largest percentages of groups were general radiography (plain film), sonography, mammography, and CT. One eighth of academic groups that provided diagnostic services did not report providing mammography, compared with only a few percent of all groups in the United States that provided diagnostic services.

CONCLUSION

Half of all groups have two to four radiologists, and this has not changed since at least 1986. A substantial percentage of groups that perform diagnostic radiology do not provide MR, interventional, or nuclear medicine services. This is particularly true of relatively small groups. These characteristics may become the source of some problems as managed care becomes more prominent and larger groups, offering a full range of services and practicing at several sites, are favored by managed care organizations that seek to contract with one group for all their radiology services.

Radiology practices and their contracts with hospitals, 1989-1990: a representative sample survey

Because of concern about pressures from hospitals for changes in their contracts with radiology practices, the American College of Radiology undertook a stratified sample survey of radiology practices and their contracts with hospitals in late 1989 and early 1990. After three remailings, the survey obtained 904 valid responses for a 64% response rate. It found (weighting data to represent all radiology practices in the nation) that 91% of radiology practices provide services in hospitals. There are contracts at 57% of these hospital sites, and hospitals use tax-exempt bond financing in 54% of the sites with contracts. One year is the most common duration of contracts, and 90 days is the most common cancellation period (89% of contracts can be canceled during the contract's term). Eighty-six percent of contracts are exclusive; 73% are automatically renewable ("evergreen"). Separate billing exists in well over 90% of hospitals with contracts. Two percent of contracts require radiologists to provide equipment; 4% require them to provide support staff. There are fixed-fee arrangements in 9% of contracts and percent compensation arrangements in 3%. Hospitals share in radiologists' fees as a charge for contractual privileges in 5% of contracts. Twenty-seven percent of contracts require hospital approval for radiologists' fee increases; 19% require radiologists to participate with Blue Shield or Medicare. If a contract characteristic is predominant nationally, it is predominant in every region, for solo, small, medium, and large practices, and whether or not hospitals use tax-exempt bond financing. There is, however, some modest variation in frequency of contract provisions. Multivariate analysis shows that most such variation reflects true effects of region and other variables, not statistical artifacts. Region was a statistically significant determinant of 11 of 17 contract characteristics studied. Practice size was a statistically significant determinant of only about half as many characteristics. The survey found some interference in the independence of radiology practices (e.g., required hospital approval of fee increases), questionable clauses (e.g., mandated provision of equipment), and even illegal ones (hospitals charging a fee for contract privileges). Knowledge of the survey findings can make individual radiology practices more effective in negotiations with hospitals and assist the profession in forming a strategy to oppose disadvantageous and illegal provisions.

The neural cell adhesion molecule (NCAM) as a regulator of cell-cell interactions

The neural cell adhesion molecule (NCAM) can influence a number of diverse intercellular events, including junctional communication, the association of axons with pathways and targets, and signals that alter levels of neurotransmitter enzymes. These pleiotropic effects appear to reflect the ability of NCAM to regulate membrane-membrane contact required to initiate specific interactions between other molecules. Such regulation can occur through changes in either NCAM expression or the molecule's content of polysialic acid (PSA). When NCAM with a low PSA content is expressed, adhesion is increased and contact-dependent events are triggered. In contrast, the large excluded volume of NCAM PSA can inhibit cell-cell interactions through hindrance of overall membrane apposition.

Changes in neural cell adhesion molecule (NCAM) structure during vertebrate neural development

Changes in carbohydrate and polypeptide form of the neural cell adhesion molecule (NCAM) have been documented during the development of central nervous system tissue in both chicken and frog. The carbohydrate variations reflect a high and low content of polysialic acid, and for the two vertebrates examined the expression of these forms is similar. At very early stages of neural development NCAM with a low content of polysialic acid is present, during histogenesis of the central nervous system NCAM with a high content of polysialic acid dominates, and there is a gradual return to NCAM with a low content of polysialic acid as the animals approach maturity. In contrast, the order of expression of the major NCAM polypeptide forms is different in the chicken and frog. These findings suggest that changes in sialic acid are a fundamental aspect of the function of NCAM in development, whereas NCAM polypeptide differences may affect events associated with a particular vertebrate. Studies have demonstrated that a decreased sialic acid content enhances the adhesion properties of NCAM. On this basis, we propose that NCAM with a low content of polysialic acid functions both to maintain integrity of neuroepithelium during morphogenesis of the early embryo and to stabilize differentiated structures in the adult, while the decreased adhesive function of NCAM with a high content of polysialic acid provides more plasticity in cell interactions during cell migration, axon outgrowth, and formation of neural circuits.

Neural cell adhesion molecule expression in Xenopus embryos

The spatiotemporal pattern of expression of the neural cell adhesion molecule NCAM was mapped immunohistochemically in embryos of the frog Xenopus, from blastula to early swimming stages, using a polyclonal antibody that recognizes Xenopus NCAM. The neural plate stage was the earliest at which NCAM could be detected. The initial sites of NCAM immunoreactivity were neural ectoderm, somitic mesoderm, and chordamesoderm. During formation of the neural tube, NCAM immunoreactivity became restricted to the neuroectoderm and its derivatives. During closure of the neural tube and for 2-4 hr thereafter, NCAM was expressed in a distinctive radial pattern in coronal sections of the neural tube. NCAM was observed in neural crest cells before migration and after formation of cranial and spinal ganglia. During the period of initial neurite outgrowth, NCAM became concentrated in the developing central nerve fiber pathways. NCAM was seen on peripheral nerves from the time of their initial outgrowth and it was strongly expressed at neuromuscular junctions during the period of their formation. These results show that NCAM is expressed after neural induction and functions during morphogenesis of the neural plate and tube, some neural crest derivatives, development of nerve fiber tracts, and formation of neuromuscular connections.

Expression and function of neural cell adhesion molecule during limb regeneration

The neural cell adhesion molecule (NCAM) has been detected in regenerating limb bud of adult newts in addition to brain and peripheral nerves. In the regenerating tissue, NCAM was found primarily on mesenchymal cells and also in wound epidermis. Infusion of Fab fragments of antibodies to NCAM into limb buds at the early blastema stage delayed the regenerative process. Previous studies have indicated that NCAM serves as a homophilic ligand for adhesion among cells that express this molecule and, in doing so, can influence the interaction of nerves with their environment. The expression of NCAM in regenerating limb and the effects of antibody infusion are therefore consistent with the observation that limb regeneration requires interactions among axons and mesenchymal cells.

Percutaneous abdominal abscess drainage. Portland area experience

After reviewing 21 patients who have had percutaneous abdominal abscess drainage, we believe that the procedure should be considered for those abscesses that are unilocular without septations, with safe access being a key variable dictating the use of percutaneous abdominal abscess drainage rather than surgery. A computerized tomographic scan of the abdomen should be employed at some stage of the percutaneous abdominal abscess drainage procedure to facilitate safe access to the abscess and to distinguish a synchronous abscess where present. In addition, we believe that percutaneous abdominal abscess drainage should be considered for postsurgical abscesses only and not those that are spontaneous in nature or where the original abnormality cannot be accurately surmised. With regard to catheter management, frequent irrigation of the catheter must be carried out at least every 4 to 6 hours, with high levels of antibiotics present in the blood before irrigation. This must be done to obviate the most frequent and potentially lethal complication of the procedure, namely sepsis. Percutaneous abdominal abscess drainage, although safe for the most part, is capable of inducing considerable morbidity. Our data suggest that percutaneous abdominal abscess drainage is not as efficacious as previous reports have suggested. Traditional surgical drainage techniques are best utilized for those abscesses that are multiple, highly viscous, inaccessible, spontaneous, or unresponsive to percutaneous abdominal abscess drainage.