Economic evaluations of radioembolization with yttrium-90 microspheres in liver metastases of colorectal cancer: a systematic review.

BACKGROUND: Transarterial radioembolization with yttrium-90 (Y-90 TARE) microspheres therapy has demonstrated positive clinical benefits for the treatment of liver metastases from colorectal cancer (lmCRC). This study aims to conduct a systematic review of the available economic evaluations of Y-90 TARE for lmCRC. METHODS: English and Spanish publications were identified from PubMed, Embase, Cochrane, MEDES health technology assessment agencies, and scientific congress databases published up to May 2021. The inclusion criteria considered only economic evaluations; thus, other types of studies were excluded. Purchasing-power-parity exchange rates for the year 2020 ($US PPP) were applied for cost harmonisation. RESULTS: From 423 records screened, seven economic evaluations (2 cost-analyses [CA] and 5 cost-utility-analyses [CUA]) were included (6 European and 1 USA). All included studies (n = 7) were evaluated from a payer and the social perspective (n = 1). Included studies evaluated patients with unresectable liver-predominant metastases of CRC, refractory to chemotherapy (n = 6), or chemotherapy-naïve (n = 1). Y-90 TARE was compared to best supportive care (BSC) (n = 4), an association of folinic acid, fluorouracil and oxaliplatin (FOLFOX) (n = 1), and hepatic artery infusion (HAI) (n = 2). Y-90 TARE increased life-years gained (LYG) versus BSC (1.12 and 1.35 LYG) and versus HAI (0.37 LYG). Y-90 TARE increased the quality-adjusted-life-year (QALY) versus BSC (0.81 and 0.83 QALY) and versus HAI (0.35 QALY). When considering a lifetime horizon, Y-90 TARE reported incremental cost compared to BSC (range 19,225 to 25,320 $US PPP) and versus HAI (14,307 $US PPP). Y-90 TARE reported incremental cost-utility ratios (ICURs) between 23,875 $US PPP/QALY to 31,185 $US PPP/QALY. The probability of Y-90 TARE being cost-effective at £ 30,000/QALY threshold was between 56% and 57%. CONCLUSIONS: Our review highlights that Y-90 TARE could be a cost-effective therapy either as a monotherapy or when combined with systemic therapy for treating ImCRC. However, despite the current clinical evidence on Y-90 TARE in the treatment of ImCRC, the global economic evaluation reported for Y-90 TARE in ImCRC is limited (n = 7), therefore, we recommend future economic evaluations on Y-90 TARE versus alternative options in treating ImCRC from the societal perspective.

Experimental Search for Neutron to Mirror Neutron Oscillations as an Explanation of the Neutron Lifetime Anomaly.

An unexplained >4σ discrepancy persists between "beam" and "bottle" measurements of the neutron lifetime. A new model proposed that conversions of neutrons n into mirror neutrons n^{'}, part of a dark mirror sector, can increase the apparent neutron lifetime by 1% via a small mass splitting Δm between n and n^{'} inside the 4.6 T magnetic field of the National Institute of Standards and Technology Beam Lifetime experiment. A search for neutron conversions in a 6.6 T magnetic field was performed at the Spallation Neutron Source which excludes this explanation for the neutron lifetime discrepancy.

Economic evaluations of radioembolization with Itrium-90 microspheres in hepatocellular carcinoma: a systematic review.

BACKGROUND: Transarterial radioembolization (TARE) with yttrium-90 microspheres is a clinically effective therapy for hepatocellular carcinoma (HCC) treatment. This study aimed to perform a systematic review of the available economic evaluations of TARE for the treatment of HCC. METHODS: The Preferred Reported Items for Systematic reviews and Meta-Analyses guidelines was followed by applying a search strategy across six databases. All studies identified as economic evaluations with TARE for HCC treatment in English or Spanish language were considered. Costs were adjusted using the 2020 US dollars based on purchasing-power-parity ($US PPP). RESULTS: Among 423 records screened, 20 studies (6 cost-analyses, 3 budget-impact-analyses, 2 cost-effectiveness-analyses, 8 cost-utility-analyses, and 1 cost-minimization analysis) met the pre-defined criteria for inclusion. Thirteen studies were published from the European perspective, six from the United States, and one from the Canadian perspectives. The assessed populations included early- (n = 4), and intermediate-advanced-stages patients (n = 15). Included studies were evaluated from a payer perspective (n = 20) and included both payer and social perspective (n = 2). TARE was compared with transarterial chemoembolization (TACE) in nine studies or sorafenib (n = 11). The life-years gained (LYG) differed by comparator: TARE versus TACE (range: 1.3 to 3.1), and TARE versus sorafenib (range: 1.1 to 2.53). Of the 20 studies, TARE was associated with lower treatment costs in ten studies. The cost of TARE treatment varied widely according to Barcelona Clinic Liver Cancer (BCLC) staging system and ranged from 1311 $US PPP/month (BCLC-A) to 71,890 $US PPP/5-years time horizon (BCLC-C). The incremental cost-utility ratio for TARE versus TACE resulted in a 17,397 $US PPP/Quality-adjusted-Life-Years (QALY), and for TARE versus sorafenib ranged from dominant (more effectiveness and lower cost) to 3363 $US PPP/QALY. CONCLUSIONS: Economic evaluations of TARE for HCC treatment are heterogeneous. Overall, TARE is a cost-effective short- and long-term therapy for the treatment of intermediate-advanced HCC.

Improved Neutron Lifetime Measurement with UCNτ.

We report an improved measurement of the free neutron lifetime τ_{n} using the UCNτ apparatus at the Los Alamos Neutron Science Center. We count a total of approximately 38×10^{6} surviving ultracold neutrons (UCNs) after storing in UCNτ's magnetogravitational trap over two data acquisition campaigns in 2017 and 2018. We extract τ_{n} from three blinded, independent analyses by both pairing long and short storage time runs to find a set of replicate τ_{n} measurements and by performing a global likelihood fit to all data while self-consistently incorporating the ß-decay lifetime. Both techniques achieve consistent results and find a value τ_{n}=877.75±0.28_{stat}+0.22/-0.16_{syst} s. With this sensitivity, neutron lifetime experiments now directly address the impact of recent refinements in our understanding of the standard model for neutron decay.

A mild case of hemolytic disease of the fetus and newborn due to anti-Sc2.

We report the case of a newborn girl with jaundice due to increased indirect bilirubin with a positive direct antiglobulin test (DAT) and compensated hemolysis. The result of the newborn's DAT was discrepant with the negative result of the mother's indirect antiglobulin test. The multiparous mother had a previous history of fetal hydrops miscarriage, with no known cause, and no record of the cause was found at the hospital where she was treated. After referring samples from the mother and newborn to a reference laboratory, the rare alloanti-Sc2 was identified in the mother's plasma and in the newborn's eluate. HEA BeadChip genotyping of the newborn's DNA sample predicted the SC:1,2 phenotype.We report the case of a newborn girl with jaundice due to increased indirect bilirubin with a positive direct antiglobulin test (DAT) and compensated hemolysis. The result of the newborn's DAT was discrepant with the negative result of the mother's indirect antiglobulin test. The multiparous mother had a previous history of fetal hydrops miscarriage, with no known cause, and no record of the cause was found at the hospital where she was treated. After referring samples from the mother and newborn to a reference laboratory, the rare alloanti-Sc2 was identified in the mother's plasma and in the newborn's eluate. HEA BeadChip genotyping of the newborn's DNA sample predicted the SC:1,2 phenotype.

The Usefulness of International Cooperation in the Repair of Inguinal Hernias in Sub-Saharan Africa.

INTRODUCTION: The burden of disease and mortality associated with inguinal hernia in Africa, especially in sub-Saharan Africa, is very high. The purpose of this study is to show that International Cooperation work in the field of hernia repair is effective; it minimizes the delay in hernia repairs in the targeted population, and can prevent a large number of disability-adjusted life years (DALYs). MATERIALS AND METHODS: As a part of an International Cooperation program, a total of 990 black patients with inguinal hernias were studied, in whom hernioplasty was performed using polypropylene mesh. The type of hernia and surgical technique were studied. Indicators of scientific and technical quality, indicators of efficiency and of effectiveness were analyzed. The results on the usefulness of interventions were calculated as avoided DALYs. RESULTS: Surgery was performed on 926 patients with a total of 1033 hernia repairs. 87.2 % of the repairs were made with mesh. There was no mortality in the series, complications were minor, and 85.7 % of patients remained less than 24 h in the center. There was a 2.8 % of recurrence, with a follow-up 58.7 % of the patients in the first year. 5014 DALYs were avoided, and the average of the avoided DALYs per patient was of 5.41. CONCLUSIONS: Hernia repair with mesh in low development countries is a procedure with low morbidity and high effectiveness that can prevent a large number of DALYs.

Surgical treatment of endemic goiter in a nonhospital setting without general anesthesia in Africa.

BACKGROUND: Endemic goiter remains a serious public health problem and 75 % of people affected live in underdeveloped countries where treatment is difficult for various reasons. The aim of this article is to report our experience in African countries with the management and surgical treatment of endemic goiter, performed in a nonhospital setting and without general anesthesia in the context of a collaborative development project by experienced endocrine surgeons. METHODS: Fifty-six black African patients with a goiter were studied. Those in poor general health, the elderly, patients with either small goiters or clinical hyperthyroidism, and those presenting with an acute episode of malaria were excluded from the study. Cervical epidural anesthesia with spontaneous ventilation was used and a partial thyroidectomy was performed. The technique used, its immediate complications, and early and late follow-up were analyzed. RESULTS: Surgery was performed on 31 patients with grades 3 and 4 goiter without mortality and a morbidity rate of 11.9 %, with 97 % of all complications being minor. There were no instances of dysphonia or symptomatic hypocalcemia and the mean stay was 1.57 days (range 1.25-1.93). Follow-up in the first year was 71 % and no case of severe or recurrent hypothyroidism was detected. CONCLUSIONS: Surgery without general anesthesia performed in a nonhospital setting in underdeveloped countries in patients with goiter is a viable option with good results and low morbidity.

Lipochoristoma of the internal auditory canal.

PROBLEM: Approximately 90% of tumours of cerebellopontine angle and internal auditory canal are vestibular schwannomas (acoustic neuromas) and meningiomas. Lipochoristomas are rare benign masses that represent only 0.15% of cases. METHODOLOGY: We report the case of a 39-year-old man who consulted us for right-sided hearing loss and tinnitus. RESULTS: Tonal audiometry showed a down-sloping right sensorineural hearing loss in frequencies above 2000 Hz. Magnetic resonance imaging (MRI) revealed a heterogeneous lesion in the right internal auditory canal with areas of hyperintensity on noncontrast T1-weighted MRI and suppression of much of the signal of the lesion with persistence of some areas of enhancement on T1-weighted fat-suppressed images. CONCLUSION: Correct imaging diagnosis through MRI (high signal intensity on noncontrast T1-weighted images together with a missing signal in fat suppression sequences) is essential in order to avoid unnecessary surgery or radiation therapy, which are not recommended in the treatment of these lesions.

Point-of-care lung ultrasound predicts in-hospital mortality in acute heart failure.

BACKGROUND: B-lines have been associated with adverse clinical outcomes in patients with heart failure (HF) when found at hospital discharge or during outpatient visits. Whether lung ultrasound (LUS) assessed B-lines may predict in-hospital mortality in patients with acute HF is still undetermined. AIM: To evaluate the association between B-lines on admission and in-hospital mortality among patients admitted with acute HF. METHODS: Hand-held LUS was used to examine patients with acute HF. LUS was performed in eight chest zones with a pocket ultrasound device and analyzed offline. The association between B-lines and in-hospital mortality was assessed using Cox regression models. RESULTS: We included 62 patients with median age 56 years, 69.4% men, and median left ventricle ejection fraction 25%. The sum of B-lines ranged from 0 to 53 (median 6.5). An optimal receiver operating characteristic-determined cut-off of ≥19 B-lines demonstrated a sensitivity of 57% and a specificity of 86% (area under the curve 0.788) for in-hospital mortality. The incremental prognostic value of LUS when compared with lung crackles or peripheral edema by integrated discrimination improvement was 12.96% (95% CI: 7.0-18.8, P = 0.02). Patients with ≥19 B-lines had a 4-fold higher risk of in-hospital mortality (HR 4.38; 95% CI: 1.37-13.95, P < 0.01). CONCLUSION: In patients admitted with acute HF, point-of-care LUS measurements of pulmonary congestion (B-lines) are associated with in-hospital mortality.

Medical management of Ménière's disease: a 10-year case series and review of literature.

Ménière's disease is frequent in our area. It is a disabling pathology that affects the patient's quality of life. Its etiology and pathophysiology remain unclear and there are some therapeutic alternatives with controversial results. We present our series and treatment protocol for Ménière's disease and discuss the current evidence regarding its medical treatment. In the last 10 years, 252 patients were diagnosed with Ménière's disease based on their symptoms, and the results of tonal audiometry, videonystagmography and caloric stimulation tests. All cases received medical treatment according to our management protocol. Ménière's disease is more frequent in women (54.76%); 83.73% of cases are unilateral. Among these, vertigo was observed in 93.7%, hearing loss in 88.1%, tinnitus in 86.1% and pathologic caloric stimulation tests in 71% (88.27% with a reduced vestibular response). A 5-year follow-up was performed in 89.6% of the patients. Subjective improvement as reported by patients was achieved in 94.4% of the cases. There is great controversy about the medical treatment of Ménière's disease. We found no evidence for the most adequate medical treatment among the different alternatives described in literature. The patient's acceptance and understanding of the disease is very important.

Complications of shoulder arthroplasty: added value of SPECT/CT imaging. / Complicaciones de las prótesis de hombro: valor añadido de la imagen SPECT/TC.

The incidence of prosthetic shoulder replacements has increased considerably in recent years, as well as the complications derived from the procedure. The correct diagnosis of each type of complication is essential for therapeutic decision making, which is currently based on the information provided by radiological and nuclear medicine imaging. Nevertheless, both techniques have intrinsic limitations that could be mostly overcome with the advent of the hybrid SPECT/CT imaging, which is set to play a fundamental role in the evaluation of shoulder prostheses.

In vivo antimicrobial activity of silver nanoparticles produced via a green chemistry synthesis using Acacia rigidula as a reducing and capping agent.

INTRODUCTION: One of the main issues in the medical field and clinical practice is the development of novel and effective treatments against infections caused by antibiotic-resistant bacteria. One avenue that has been approached to develop effective antimicrobials is the use of silver nanoparticles (Ag-NPs), since they have been found to exhibit an efficient and wide spectrum of antimicrobial properties. Among the main drawbacks of using Ag-NPs are their potential cytotoxicity against eukaryotic cells and the latent environmental toxicity of their synthesis methods. Therefore, diverse green synthesis methods, which involve the use of environmentally friendly plant extracts as reductive and capping agents, have become attractive to synthesize Ag-NPs that exhibit antimicrobial effects against resistant bacteria at concentrations below toxicity thresholds for eukaryotic cells. PURPOSE: In this study, we report a green one-pot synthesis method that uses Acacia rigidula extract as a reducing and capping agent, to produce Ag-NPs with applications as therapeutic agents to treat infections in vivo. MATERIALS AND METHODS: The Ag-NPs were characterized using transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive spectroscopy, ultraviolet-visible, and Fourier transform infrared. RESULTS: We show that Ag-NPs are spherical with a narrow size distribution. The Ag-NPs show antimicrobial activities in vitro against Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and a clinical multidrug-resistant strain of P. aeruginosa) and Gram-positive (Bacillus subtilis) bacteria. Moreover, antimicrobial effects of the Ag-NPs, against a resistant P. aeruginosa clinical strain, were tested in a murine skin infection model. The results demonstrate that the Ag-NPs reported in this work are capable of eradicating pathogenic resistant bacteria in an infection in vivo. In addition, skin, liver, and kidney damage profiles were monitored in the murine infection model, and the results demonstrate that Ag-NPs can be used safely as therapeutic agents in animal models. CONCLUSION: Together, these results suggest the potential use of Ag-NPs, synthesized by green chemistry methods, as therapeutic agents against infections caused by resistant and nonresistant strains.

Selective dopamine-1 agonist therapy in severe hypertension: effects of intravenous fenoldopam.

To determine the effects of dopamine-1 agonist therapy in severe hypertension, blood pressure, heart rate, catecholamines and left ventricular function were studied in 18 patients (10 with renal disease) with diastolic blood pressure greater than 120 mm Hg (range 124 to 160) after intravenous fenoldopam therapy. Constant infusions of fenoldopam were titrated upward every 10 to 20 min from an initial dose of 0.1 microgram/kg per min to a maximal dose of 0.9 microgram/kg per min. The therapeutic goal of a supine diastolic blood pressure of less than 110 mm Hg was achieved in every patient within 1 h at an average dose of 0.34 +/- 0.22 microgram/kg per min. Blood pressure decreased from 214/134 +/- 33/10 mm Hg at baseline to 170/96 +/- 29/7 mm Hg (p less than 0.0001) at 3 h, whereas heart rate increased from 77 +/- 23 to 88 +/- 21 beats/min (p less than 0.01). Plasma norepinephrine increased during the fenoldopam infusion; epinephrine and dopamine levels did not change. Two indexes of left ventricular function (end-systolic dimension and isovolumic relaxation time) improved during the fenoldopam infusion, but mitral flow velocities during ventricular filling were unchanged. Side effects of intravenous fenoldopam were mild, transient and associated with the marked vasodilatory properties of the drug. Thus, fenoldopam is safe and effective as a parenteral monotherapy in patients with severe essential and renovascular hypertension. Preliminary data suggest that blood pressure reduction with selective dopamine-1 agonist therapy is accompanied by improved left ventricular function.

Renal failure and hyperkalemia associated with ketorolac tromethamine.

Three patients who were treated with ketorolac tromethamine (Toradol), an injectable nonsteroidal anti-inflammatory drug for pain management, developed acute renal failure or hyperkalemia or both. These complications were reversible in two cases after discontinuing the drug. Clinical conditions preexisted in each patient that rendered them susceptible to the renal complications of nonsteroidal anti-inflammatory use. It is well known that caution should be observed while using nonsteroidal anti-inflammatory drugs in patients whose renal function may be preserved through prostaglandin-mediated vasodilatory effects. The same cautions apply to ketorolac. Since its major marketed use is as an analgesic and its potent effect on prostaglandin synthesis may not be well recognized, those cautions must be emphasized.

Intravenous fenoldopam versus sodium nitroprusside in patients with severe hypertension.

In an open-label study, we compared the efficacy and safety of intravenous infusion of fenoldopam mesylate with that of sodium nitroprusside in patients with severe hypertension or in hypertensive crisis. Both antihypertensive medications were infused at a maximal dose increment of 0.2 microgram/kg/min (fenoldopam) and 1 microgram/kg/min (nitroprusside), with a maximal infusion rate of 1.5 micrograms/kg/min fenoldopam mesylate or 8 micrograms/kg/min sodium nitroprusside. Once the desired reduction in diastolic blood pressure was achieved (less than 110 mm Hg if initial diastolic blood pressure was 120-149 mm Hg, or by at least 40 mm Hg if initial diastolic blood pressure was 150-190 mm Hg), the maximal infusion rate used was maintained for at least 1 hour, and then, the infusion was slowed gradually over 2 hours. After the infusion treatment, patients remained in the hospital for 2 days of follow-up. Both antihypertensive agents successfully controlled the blood pressure in all the patients by the end of the maintenance periods. Between the baseline and the end of the maintenance period, analysis of variance showed that the changes in the variables induced by fenoldopam mesylate did not differ significantly from those induced by sodium nitroprusside. The incidence of side effects listed were similar in both groups of patients. The detection of toxic levels of thiocyanate in two patients treated with nitroprusside, however, shows that fenoldopam might be preferable for the control of a hypertensive crisis or severe hypertension in patients with decreased renal function.

Sequential measurement of beta 2-microglobulin levels, p24 antigen levels, and antibody titers following transplantation of a human immunodeficiency virus-infected kidney allograft.

A renal allograft recipient developed symptoms suggestive of AIDS. Serological studies revealed that the donor was positive for human immunodeficiency virus (HIV). Retrospective testing of stored sequential serum samples showed that the recipient was negative for HIV pretransplant; anti-p24 and anti-p41 antibodies appeared 10 and 49 days posttransplant, respectively. The recipient's serum beta 2-microglobulin levels were elevated 14 days posttransplant, with normal renal function, 35 days before the detection of anti-p24 antibody. p24 Antigen was detected for the first time 21 days posttransplant. In addition to p24 antigen, elevated serum beta 2-microglobulins may be a useful marker for HIV infection prior to seroconversion.

Noninvasive radioisotopic diagnosis of acute heart rejection.

In a prospective protocol for noninvasive diagnosis and follow-up of acute heart rejection 162 examinations were performed in 36 patients who underwent heart transplantation. The follow-up period ranged from 15 days to 44 months. The protocol comprised multiple gated acquisition ventriculography with albumin labeled with 99mTc (740 MBq), acquired using a forward/backward by thirds framing mode, 32 frames/cycle, and 10 million total counts. Parameters of left ventricular diastolic function were analyzed. Antimyosin antibody labeled with indium 111 (74 MBq) was injected, and myocardium/lung uptake ratios were obtained at 48 hours in counts per pixel. Endomyocardial biopsy was performed in all patients within 48 hours. The results were evaluated by comparison of mean values of each parameter and global and individual correlation analysis in relation to the presence or absence of rejection and treatable (moderate or severe) or nontreatable (mild or absent) rejection. Antimyosin and diastolic function parameters showed significant differences (p less than 0.001) between patients with and without rejection and between patients with treatable and nontreatable rejection. Global correlation with biopsy existed (p less than 0.05) for antimyosin (r = 0.75), average filling rate (r = 0.61), and peak filling rate (r = 0.56). Individual correlation exhibited significance in all patients only for antimyosin (r = 0.78 to 0.98). In eight patients average filling rate also showed significant correlation (r = 0.65 to 0.88). In conclusion, these results provide a noninvasive diagnosis of cardiac allograft rejection episodes and allow an accurate selection between treatable and nontreatable rejection. Individual patient follow-up is possible with antimyosin. The study of diastolic function is also useful in this setting.

Hypercoagulable states as an evolving risk for spontaneous venous and arterial thrombosis.

This study of 49 patients with spontaneous venous and arterial thrombosis identified 27 with hypercoagulable states: 13 had only venous thrombosis (VT), six had episodes of VT followed by arterial thrombosis (AT) and eight had AT only. All 27 patients were less than 42 years of age; 22 had specific natural anticoagulant or fibrinolytic deficiencies: antithrombin III (nine patients), protein C (eight patients), protein S (three patients), heparin cofactor II (two patients), tissue plasminogen activator release (one patient) and mixed antithrombin III and protein S (one patient). The remaining five patients had recurrent thrombotic events associated with resistance to heparin anticoagulation, but no established laboratory diagnosis. Clotting complications included recurrent VT, pulmonary embolism, multiple failed arterial procedures and lower extremity amputation. The remaining 22 patients (mean age of 53 years, range of 46 to 63 years), 12 with VT and ten with AT, did not have laboratory evidence of hypercoagulability and none had recurrent vascular occlusions. All these patients were successfully treated by conventional therapy without any additional thrombotic events during the follow-up period. Young adults with spontaneous thrombotic events should be screened for possible hypercoagulable states. Additionally, these young patients need further evaluation and treatment of cardiovascular risk factors. Those with premature atherosclerosis have an especially poor prognosis despite surgical intervention and anticoagulant therapy.

Comparison of effects of cyanide and acetylcholine on renal hemodynamics and sodium excretion.

The present study compared the effects of acetylcholine to cyanide under the same experimental conditions of renal clearance in anesthetized dogs. Since cyanide is one of the few drugs for which the mechanism of action is known (cytotoxic hypoxia), some insight may be gained into the renal effects of acetylcholine since both produce direct natriuresis and diuresis. Infusion of 0.2 microgram/kg/min of acetylcholine and 12.0 microgram/kg/min of sodium cyanide into the left renal artery resulted in similar effects, i.e., increased fractional excretion of sodium, potassium, calcium, and magnesium. These effects were immediate and ipsilateral. Both agents increased the renal plasma flow to the same extent. In addition, regression plots of the relation between changes in sodium excretion and changes in renal plasma flow were similar for both agents. The pattern of similar renal functional changes suggested that acetylcholine is not a mere renal vasodilator but that its action is also medicated through alterations on direct transport of ions.

Natural killer cell activity in laryngeal carcinoma.

We studied the relationship of natural killer cell activity from peripheral blood mononuclear cells with the clinical and pathologic stage of disease in 23 male patients with previously untreated carcinoma of the larynx and 22 healthy male control subjects. Levels of natural killer cell activity against K-562 target cells were similar in control subjects and patients, regardless of stage, tumor size, and clinical cervical adenopathies. Natural killer cell activity, however, was significantly decreased in patients with pathologic cervical lymph node involvement. The number of natural killer cells, as estimated by CD16 and CD56 monoclonal antibodies, was similar in all groups of subjects. We conclude that in patients with laryngeal carcinoma, there is a correlation between deficient natural killer cell activity and nodal metastases, which may represent a prognostic indicator in these patients.