CSF-1R inhibition alters macrophage polarization and blocks glioma progression

Glioblastoma multiforme (GBM) comprises several molecular subtypes including proneural GBM. Most therapeutic approaches targeting glioma cells have failed. An alternative strategy is to target cells in the glioma microenvironment, such as tumor-associated macrophages and microglia (TAMs). Macrophages depend upon colony stimulating factor (CSF)-1 for differentiation and survival. A CSF-1R inhibitor was used to target TAMs in a mouse proneural GBM model, which dramatically increased survival, and regressed established tumors. CSF-1R blockade additionally slowed intracranial growth of patient-derived glioma xenografts. Surprisingly, TAMs were not depleted in treated mice. Instead, glioma-secreted factors including GM-CSF and IFN-γ facilitated TAM survival in the context of CSF-1R inhibition. Alternatively activated/ M2 macrophage markers decreased in surviving TAMs, consistent with impaired tumor-promoting functions. These gene signatures were associated with enhanced survival in proneural GBM patients. Our results identify TAMs as a promising therapeutic target for proneural gliomas, and establish the translational potential of CSF-1R inhibition for GBM.

HIV-specific cytotoxic T-cells in HIV-exposed but uninfected Gambian women

A crucial requirement in the rational design of a prophylactic vaccine against the human immunodeficiency virus (HIV) is to establish whether or not protective immunity can occur following natural infection. The immune response to HIV infection is characterized by very vigorous HIV-specific cytotoxic T-lymphocyte (CTL) activity. We have identified four HIV-1 and HIV-2 cross-reactive peptide epitopes, presented to CTL from HIV-infected Gambians by HLA-B35 (the most common Gambian class I HLA molecule). These peptides were used to elicit HIV-specific CTLs from three out of six repeatedly exposed but HIV-seronegative female prostitutes with HLA-B35. These women remain seronegative with no evidence of HIV infection by polymerase chain reaction or viral culture. Their CTL activity may represent protective immunity against HIV infection.

The tumor microenvironment underlies acquired resistance to CSF-1R inhibition in gliomas

Macrophages accumulate with glioblastoma multiforme (GBM) progression and can be targeted via inhibition of colony-stimulating factor-1 receptor (CSF-1R) to regress high-grade tumors in animal models of this cancer. However, whether and how resistance emerges in response to sustained CSF-1R blockade is unknown. We show that although overall survival is significantly prolonged, tumors recur in >50% of mice. Gliomas reestablish sensitivity to CSF-1R inhibition upon transplantation, indicating that resistance is tumor microenvironment-driven. Phosphatidylinositol 3-kinase (PI3K) pathway activity was elevated in recurrent GBM, driven by macrophage-derived insulin-like growth factor-1 (IGF-1) and tumor cell IGF-1 receptor (IGF-1R). Combining IGF-1R or PI3K blockade with CSF-1R inhibition in recurrent tumors significantly prolonged overall survival. Our findings thus reveal a potential therapeutic approach for treating resistance to CSF-1R inhibitors.

Early results of laparoscopic surgery for colorectal cancer. Retrospective analysis of 372 patients treated by Clinical Outcomes of Surgical Therapy (COST) Study Group

This study was undertaken to determine the early experience of the embers of the COST Study Group with colorectal cancer treated by laparoscopic approaches.

METHOD

A retrospective review was performed of all patients with colorectal cancer treated with laparoscopy by the COST Study Group before August 1994. Tumor site, stage, differentiation, procedure completion, presence of recurrence (local, distant, trocar site), and cause of death were analyzed.

RESULTS

A total of 372 patients with adenocarcinoma of the colon and rectum were treated by laparoscopic approach between October 1991 and August 1994 (170 men and 192 women): right colectomy, 170; sigmoid colectomy, 55; low anterior resection, 56; abdominoperineal resection, 44; left colectomy, 22; colostomy, 8; total colectomy, 6; transverse colectomy, 7; exploration, 2. Conversion to an open procedure was required in 15.6 percent of cases. Operative mortality was 2 percent. Tumor characteristics were as follows: TNM state: I, 40 percent; II, 25 percent; III, 18 percent; IV, 17 percent; Differentiation: well-moderate, 88 percent; poor, 12 percent; carcinomatosis, 5 percent. Local (3.6 percent) and distant implantation occurred in four patients (1.1 percent). Only one of these patients died a cancer-related death (Stage III at 36 months). Cancer-related death rates increased with increasing stage of tumor: I, -4 percent; II, 17 percent; III, 31 percent; IV, 70 percent.

CONCLUSION

A laparoscopic approach to colorectal cancer results in early outcome after treatment that is comparable with conventional therapy for colorectal cancer. A randomized trial is needed to compare long-term outcomes of open and laparoscopic approaches with colorectal cancer.

Assessment of the role of alpha2-adrenoceptor subtypes in the antinociceptive, sedative and hypothermic action of dexmedetomidine in transgenic mice

1. The role of alpha2-adrenoceptor (AR) subtypes in the modulation of acute nociception, motor behaviour and body temperature, has been investigated by determining the activity of the alpha2AR selective agonist dexmedetomidine (Dex) in mice devoid of individual alpha2AR subtypes through either a point (alpha2A) or null (alpha2B/alpha2C) mutation ('knock-out'). 2. In a rodent model of acute thermal nociception, the mouse tail immersion test, Dex, in wild type (WT) control animals, produced a dose-dependent increase in the threshold for tail withdrawal from a 52 degrees C water bath with mean ED50 values of 99.9+/-14.5 (alpha2A), 94.6+/-17.8 (alpha2B) and 116.0/-17.1 (alpha2C) microg kg(-1), i.p. 3. In comparison to the WT controls, Dex (100-1000 microg kg(-1), i.p.), was completely ineffective as an antinociceptive agent in the tail immersion test in the alpha2A AR D79N mutant animals. Conversely, in the alpha2B AR and alpha2C AR knock-outs, Dex produced a dose-dependent antinociceptive effect that was not significantly different from that observed in WT controls, with ED50 values of 85.9+/-15.0 (P>0.05 vs WT control) and 226.0+/-62.7 (P>0.05 vs WT control) microg kg(-1) i.p., respectively. 4. Dex (10-300 microg kg(-1), i.p.) produced a dose-dependent reduction in spontaneous locomotor activity in the alpha2A, alpha2B and alpha2C AR WT control animals with ED50 values of 30.1+/-9.0, 23.5+/-7.1 and 32.3+/-4.6 microg kg(-1), i.p., respectively. Again, Dex (100-1000 microg kg(-1), i.p.) was ineffective at modulating motor behaviour in the alpha2A AR D79N mutants. In the alpha2B AR and alpha2C AR knock-out mice, Dex produced a dose-dependent reduction in spontaneous locomotor activity with ED50 values of 29.1+/-6.4 (P>0.05 vs WT control) and 57.5+/-11.3 (P>0.05 vs WT control) microg kg(-1), respectively. 5. Dex was also found to produce a dose-dependent reduction in body temperature in the alpha2A, alpha2B and alpha2C AR WT control mice with ED50 values of 60.6+/-11.0, 16.2+/-2.5 and 47.2+/-9.1 microg kg(-1), i.p., respectively. In the alpha2A AR D79N mutants, Dex had no effect on body temperature at a dose (100 microg kg(-1), i.p.) that produced a significant reduction (-6.2+/-0.5 degrees C; P<0.01 vs vehicle) in temperature in WT controls. However, higher doses of Dex (300 and 1000 microg kg(-1), i.p) produced a small, but statistically significant decrease in temperature corresponding to -1.7+/-0.4 degrees C and -2.4+/-0.3 degrees C (both P<0.01 vs vehicle), respectively. In the alpha2B AR and alpha2C AR knock-out mice, Dex produced a dose-dependent reduction in body temperature with ED50 values of 28.4+/-4.8 (P>0.05 vs WT control) and 54.1+/-8.0 (P>0.05 vs WT control) microg kg(-1), respectively. 6. In conclusion, the data are consistent with the alpha2A AR being the predominant subtype involved in the mediation of the antinociceptive, sedative and hypothermic actions of Dex. This profile would appear to indicate that an alpha2A AR subtype selective analgesic will have a narrow therapeutic window, particularly following systemic administration.

PLAB, a novel placental bone morphogenetic protein

Bone morphogenetic proteins (BMP) constitute a sub-group of the large transforming growth factor-beta (TGF-beta) family. They play important roles in the embryonic development of multiple structures and in adult bone modeling. We have recently isolated a novel member of the BMP family from placenta, termed PLAB. PLAB is expressed highly in placenta, but can be found upon stringent analysis in low levels in most other tissues. At the amino acid level, PLAB is most closely related to BMP-8/OP-2, another member of the BMP family. Like TGF-beta, PLAB inhibits the proliferation of primitive hematopoietic progenitors. The high expression of PLAB by placenta raises the possibility that it may be a mediator of placental control of embryonic development.

A 12-week, placebo-controlled study (6002-US-006) of istradefylline in Parkinson disease

BACKGROUND

The safety and efficacy of istradefylline, a selective adenosine A(2A) receptor antagonist, was evaluated in a 12-week, double-blind study in levodopa-treated Parkinson disease (PD) subjects with motor complications.

METHODS

Levodopa-treated PD subjects (n = 395) received istradefylline 20 mg/day (n = 163), istradefylline 60 mg/day (n = 155), or placebo (n = 77) at 40 sites. The primary efficacy variable was the change in the percentage of time per day spent in the OFF state. Secondary measurements assessed change in ON time, Unified Parkinson's Disease Rating Scale, and Clinical Global Impression. Safety monitoring included clinical laboratory, electrocardiograms, vital signs, physical/neurologic examinations, and adverse events (AEs).

RESULTS

Changes from baseline to endpoint in the percentage OFF time in the active groups compared with placebo were -4.35% (95% CI -8.16 to -0.54; p = 0.026) for istradefylline 20 mg/day and -4.49% (95% CI -8.35 to -0.62; p = 0.024) for 60 mg/day; these changes were significant (analysis of covariance). For total hours, istradefylline demonstrated mean differences from placebo of -0.64 hours (95% CI -1.30 to 0.01) for 20 mg/day and -0.77 hours (95% CI -1.44 to -0.11) for 60 mg/day (p = 0.065; overall treatment effect). Clinical response occurred by the second week and was maintained throughout the study. Istradefylline was well tolerated. The common AEs were dyskinesia, nausea, dizziness, and hallucinations.

CONCLUSIONS

Istradefylline demonstrated a significant reduction in the percentage of awake time per day spent in the OFF state, which resulted in a clinically meaningful reduction in OFF time, without an increase in ON time with troublesome dyskinesia, and was well tolerated as adjunctive treatment to levodopa in Parkinson disease.

Genesis, a winged helix transcriptional repressor with expression restricted to embryonic stem cells

A novel member of the winged helix (formerly HNF-3/Forkhead) transcriptional regulatory family, termed Genesis, was isolated and characterized. Putative translation of the complete cDNA revealed the winged helix DNA binding domain to be centrally located within the protein, with regions on either side that contain known transcriptional regulatory motifs. Extensive Northern analysis of Genesis found that the message was exclusively expressed in embryonic stem cells or their malignant equivalent, embryonal carcinoma cells. The Genesis transcript was down-regulated when these cells were stimulated to differentiate. DNA sequences that Genesis protein would interact with were characterized and were found to contain a consensus similar to that found in an embryonic stem cell enhancer sequence. Co-transfection experiments revealed that Genesis is a transcriptional repressor. Genesis mapped to mouse chromosome 4 in a region syntenic with human chromosome 1p31, a site of nonrandom abnormalities in germ cell neoplasia, neuroblastoma, and acute lymphoblastic leukemia. Genesis is a candidate for regulating the phenotype of normal or malignant embryonic stem cells.

Pallidotomy increases activity of motor association cortex in Parkinson's disease: a positron emission tomographic study

Stereotactic posteroventral pallidotomy can improve motor performance in Parkinson's disease. Interruption of inhibitory pallidal projections to ventrolateral thalamus, components of a cortical-basal ganglia motor loop allows for this clinical benefit. We hypothesized that pallidotomy would lead to increased movement related activity in motor cortical areas receiving projections from ventrolateral thalamus. This was tested in 6 Parkinson's disease patients who underwent stereotactic posteroventral pallidotomy. Each patient was imaged with positron emission tomography (PET) measures of regional cerebral blood flow (rCBF) during performance of a simple prehension task and at rest. Scans were acquired before and 17 weeks after surgery. After pallidotomy, movement-related changes of rCBF increased significantly in both the supplementary motor area (SMA) and premotor cortex but not in primary motor cortex. The results demonstrate the importance of pallidothalamic circuitry for regulating volitional movements and confirm that disruption of inhibitory input to the ventrolateral thalamus can augment movement-related activity in motor association areas.

Comparison of right ventricular outflow tract and apical lead permanent pacing on cardiac output

Cardiac output was measured in 89 patients using transthoracic continuous-wave echo Doppler comparing right ventricular outflow tract pacing with the right ventricular apex at the time of permanent pacemaker implantation. Overall, cardiac output improved 18.8% (p <0.0001) and cardiac index 21.0% (p <0.0001) with outflow tract placement; patients with a lower baseline cardiac index had a greater percent improvement with outflow tract placement.

Compensatory induction of MYC expression by sustained CDK9 inhibition via a BRD4-dependent mechanism

CDK9 is the kinase subunit of positive transcription elongation factor b (P-TEFb) that enables RNA polymerase (Pol) II's transition from promoter-proximal pausing to productive elongation. Although considerable interest exists in CDK9 as a therapeutic target, little progress has been made due to lack of highly selective inhibitors. Here, we describe the development of i-CDK9 as such an inhibitor that potently suppresses CDK9 phosphorylation of substrates and causes genome-wide Pol II pausing. While most genes experience reduced expression, MYC and other primary response genes increase expression upon sustained i-CDK9 treatment. Essential for this increase, the bromodomain protein BRD4 captures P-TEFb from 7SK snRNP to deliver to target genes and also enhances CDK9's activity and resistance to inhibition. Because the i-CDK9-induced MYC expression and binding to P-TEFb compensate for P-TEFb's loss of activity, only simultaneously inhibiting CDK9 and MYC/BRD4 can efficiently induce growth arrest and apoptosis of cancer cells, suggesting the potential of a combinatorial treatment strategy.

Growth hormone in exercise: comparison of physiological and pharmacological stimuli

This study was designed to compare the serum growth hormone (GH) response with quantified exercise to that obtained with other stimuli. In eight normal males, aged 21-24 yr, we studied the serum GH response to 20 min cycle ergometer exercise at 300, 600, and 900 kpm/min on three separate occasions and compared the results with those found during sleep, insulin hypoglycemia, arginine infusion, and L-DOPA. Exercise at 900 kpm/min and insulin hypoglycemia resulted in the greatest elevations in serum GH which were significantly greater than those found with sleep, arginine or L-DOPA. The 20-min exercise at 900 kpm/min represented 75-90% of the subjects' maximal oxygen uptake and is a suitable provocative test for GH secretion. As a screening test for pituitary GH reserve, exercise compares favorably with insulin hypoglycemia and is superior to sleep, arginine, and L-DOPA.

Discovery and Evaluation of Clinical Candidate IDH305, a Brain Penetrant Mutant IDH1 Inhibitor

Inhibition of mutant IDH1 is being evaluated clinically as a promising treatment option for various cancers with hotspot mutation at Arg¹³². Having identified an allosteric, induced pocket of IDH1^R132H, we have explored 3-pyrimidin-4-yl-oxazolidin-2-ones as mutant IDH1 inhibitors for in vivo modulation of 2-HG production and potential brain penetration. We report here optimization efforts toward the identification of clinical candidate IDH305 (13), a potent and selective mutant IDH1 inhibitor that has demonstrated brain exposure in rodents. Preclinical characterization of this compound exhibited in vivo correlation of 2-HG reduction and efficacy in a patient-derived IDH1 mutant xenograft tumor model. IDH305 (13) has progressed into human clinical trials for the treatment of cancers with IDH1 mutation.

The role of opioid peptides in the hormonal responses to acute exercise in man

Opioid involvement in the physiological and hormonal responses to acute exercise was investigated in six normal male subjects. Each was exercised to 40% (mild exercise) and 80% (severe exercise) of his previously determined maximal oxygen consumption on two occasions, with and without an infusion of high-dose naloxone. The exercise task was a bicycle ergometer; mild and severe exercise were performed for 20 min each, followed by a recovery period. Exercise produced the expected increases in heart rate, blood pressure, ventilation, tidal volume, respiratory rate, oxygen consumption and carbon dioxide production. After severe exercise, naloxone infusion increased ventilation from 94.8 +/- 4.9 litres/min to 105.7 +/- 5.0 litres/min (P less than 0.05), but had no effect on any of the other physiological variables. Exercise-induced changes in several hormones and metabolites were noted, including elevations in circulating lactate, growth hormone (GH), prolactin, cortisol, luteinizing hormone (LH), follicle stimulating hormone (FSH), adrenaline noradrenaline, plasma renin activity (PRA) and aldosterone. There was no change in plasma met-enkephalin. Naloxone infusion produced the expected increases in LH and cortisol, but also significantly enhanced the elevations in prolactin, adrenaline, noradrenaline, plasma renin activity and aldosterone (P less than 0.05). Psychological questionnaires revealed minor mood changes after exercise, but no evidence was found for the suggested 'high' or euphoria of exercise. Effort was perceived as greater during the naloxone infusion than the saline infusion in every subject.(ABSTRACT TRUNCATED AT 250 WORDS)

A sequence pattern for peptides presented to cytotoxic T lymphocytes by HLA B8 revealed by analysis of epitopes and eluted peptides

HLA B8-restricted cytotoxic T lymphocytes (CTL) specific for influenza A virus were generated and shown to recognize the nucleoprotein (NP). The dominant epitope was mapped using recombinant vaccinia viruses that expressed fragments of the NP and then synthetic peptides based on the NP amino acid sequence. The peptide 380-393 was first identified and further refined; it was shown that the glutamic acid at position 380 was essential for recognition by CTL and that the nonamer 380-388 was the optimum peptide. Six HLA B8-positive influenza immune donors that we have tested respond to this peptide as part of their influenza-specific CTL response. The amino acid sequence of the peptide epitope was compared to six other known virus peptides known to be restricted by HLA B8 and a sequence homology was identified, which predicted nonamer and octamer epitope sequences. Probable anchor residues were identified at peptide residues 3 (lysine/arginine), 5 (lysine/arginine) and 9 (leucine/isoleucine). Support for this pattern came from sequencing peptides eluted from purified HLA B8 molecules, where lysines were predominant at positions 3 and 5. One of the predicted epitope peptides was made and shown to be recognized by specific CTL. These and the two others were shown to compete with NP 380-388 for binding to HLA B8. A model was made of the HLA B8 molecule and negatively charged pockets predicted, which could accommodate the positively charged side chains of the peptide anchor residues.

Social competition in school: relationships with bullying, Machiavellianism and personality

BACKGROUND

Bullying is investigated as part of the individual's general framework of attitudes towards interpersonal relationships, social competition and motivation in school.

AIMS

It was hypothesised that bullying behaviour and pro-bullying attitudes would be associated with socially competitive attitudes in the classroom, Machiavellianism, and the personality constructs of Psychoticism and Extraversion.

SAMPLES

198 9- to 12-year-old children from two Glasgow primary schools.

METHODS

Children completed several measures: a newly developed questionnaire assessing motivations behind social competition and effort in class, the Kiddie-Mach scale, the Pro-Victim scale, items from the Olweus Bullying Questionnaire, and the Junior Eysenck Personality Questionnaire.

RESULTS

A 'Desire for social success' factor (incorporating a deliberate lack of effort) was negatively correlated with support for victims of bullying, even after partialling out Machiavellianism, Psychoticism, and social desirability. Pro-victim attitudes were in turn negatively correlated with Machiavellianism and Psychoticism, and positively correlated with Lie score. Finally, children categorised as bullies scored significantly higher than controls on Machiavellianism, and significantly lower in terms of pro-victim attitudes.

CONCLUSIONS

Results are discussed in terms of further study and implications for classroom practice and anti-bullying policy.

Operation Everest II: muscle energetics during maximal exhaustive exercise

To investigate the metabolic basis for the reduction in peak blood lactate concentration that occurs with maximal exercise after acclimatization to altitude, eight male subjects [maximal O2 uptake of 51.2 +/- 3.0 (SE) ml.kg-1.min-1] were acclimated to progressive hypobaria over a 40-day period. Before decompression (SL-1), at 380 and 282 Torr, and on return to sea level (SL-2) the subjects performed progressive cycle exercise to exhaustion. Analysis of muscle samples obtained from the vastus lateralis before exercise and at exhaustion indicated a pronounced reduction (P less than 0.05) in muscle lactate concentration (mmol/kg dry wt) at 282 Torr (39.2 +/- 11) compared with SL-1 (113 +/- 9.7), 380 Torr (94.6 +/- 18), and SL-2 (92.7 +/- 22). For the other glycolytic intermediates studied (glucose 1-phosphate, glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-bisphosphate, and pyruvate) only the increase in glucose 1-phosphate, glucose 6-phosphate, and fructose 6-phosphate were blunted (P less than 0.05) at 282 Torr. The reduction in muscle glycogen concentration during exercise was similar (P less than 0.05) for all environmental conditions. Although exercise resulted in reductions (P less than 0.05) in ATP and creatine phosphate averaging 30 and 51%, respectively, the magnitude of the change was not dependent on the degree of hypobaria. Inosine monophosphate was elevated (P less than 0.05) approximately 11-fold with exercise at both SL-1 and SL-2. These findings support the hypothesis that the lower lactate concentration observed at 282 Torr after exhaustive exercise is due to a reduction in anaerobic glycolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Type I Interferon Receptor Signaling of Neurons and Astrocytes Regulates Microglia Activation during Viral Encephalitis

In sterile neuroinflammation, a pathological role is proposed for microglia, whereas in viral encephalitis, their function is not entirely clear. Many viruses exploit the odorant system and enter the CNS via the olfactory bulb (OB). Upon intranasal vesicular stomatitis virus instillation, we show an accumulation of activated microglia and monocytes in the OB. Depletion of microglia during encephalitis results in enhanced virus spread and increased lethality. Activation, proliferation, and accumulation of microglia are regulated by type I IFN receptor signaling of neurons and astrocytes, but not of microglia. Morphological analysis of myeloid cells shows that type I IFN receptor signaling of neurons has a stronger impact on the activation of myeloid cells than of astrocytes. Thus, in the infected CNS, the cross talk among neurons, astrocytes, and microglia is critical for full microglia activation and protection from lethal encephalitis.

Solid-phase synthesis and SAR of 4-carboxy-2-azetidinone mechanism-based tryptase inhibitors

A series of nonguanidine N1-activated C4-carboxy azetidinone tryptase inhibitors was prepared by solid-phase methodology to quickly assess the SAR associated with distal functionality on the N1-activating group. From these studies, potent inhibitors with improved specificity were discovered.

Synthesis and SAR of 4-carboxy-2-azetidinone mechanism-based tryptase inhibitors

A series of N1-activated C4-carboxy azetidinones was prepared and tested as inhibitors of human tryptase. The key stereochemical and functional features required for potency, serine protease specificity and aqueous stability were determined. From these studies compound 2, BMS-262084, was identified as a potent and selective tryptase inhibitor which, when dosed intratracheally in ovalbumin-sensitized guinea pigs, reduced allergen-induced bronchoconstriction and inflammatory cell infiltration into the lung.

Genetic modulation of antigen presentation by HLA-B27 molecules

In studies of antigenic peptide presentation, we have found a healthy volunteer whose lymphoblastoid cells were unable to present three different virus-derived epitopes to cytotoxic T lymphocytes (CTL) despite expressing the correct restricting HLA-B27 molecules on the cell surface. B cell lines were established from other members of the donor's family, including individuals suffering from ankylosing spondylitis and related diseases, and were tested for their ability to function as target cells in the same assay. None of the eight B cell lines that expressed HLA-B27 presented a known peptide epitope to CTL. However, cells from a family member that expressed HLA-B8 could present an epitope peptide restricted by that molecule. The B27 molecule in this family proved to be the B2702 subtype on isoelectric focusing gels, appearing in exactly the same position as B2702 from other cell lines that did present the peptide. To exclude mutations resulting in noncharged amino acid substitutions, cDNA coding for B2702 was cloned from the proband's cell line and sequenced. No coding changes were found. The cloned cDNA was transfected into HLA-A- and B-negative HMy/C1R cells, and the B2702 molecules generated in this environment rendered these cells, after incubation with peptide, susceptible to lysis by peptide-specific CTL. These data are compatible with the presence of a factor(s), possibly HLA linked, interfering with antigen presentation by otherwise normal B2702 molecules in this family.

Decision analysis for best management of mildly dyskaryotic smear

Should a woman with a mildly dyskaryotic cervical smear be referred for colposcopy or should the smear be repeated? One way to answer this question is to use decision analysis and compare the expected mortality and cost of each policy. Data for each component of the question were obtained from published work worldwide and were supplemented with an audit of mildly dyskaryotic smears in West Yorkshire, UK. 2 out of 1000 women with an initial mildly dyskaryotic smear will develop cancer if a conservative repeat smear policy is adopted in association with five-yearly cervical screening. This number can be reduced to 1.6 per 1000 if cervical screening is offered every three years. A policy of immediate referral for colposcopy is also associated with a subsequent cancer rate of 1.6 per 1000. Therefore, repeating the smear is almost as effective as an immediate referral to a colposcopy unit. Even if a five-yearly cervical screening programme is adopted, 2500 women with a mildly dyskaryotic smear will need to be referred for immediate colposcopy to save 1 additional cancer. A conservative policy is not financially cheaper: an average of six additional smears is required to save each colposcopy referral. Sensitivity analysis shows that the excess cost of the conservative policy increases exponentially as the risk of a subsequent cytological abnormality exceeds 60%. Local cytopathology laboratories should audit their recurrent dyskaryosis rate associated with borderline, mild, and moderate dyskaryosis before accepting the U-turn in the national recommendations.