Predictive accuracy of risk prediction models for recurrence, metastasis and survival for early-stage cutaneous melanoma: a systematic review

OBJECTIVES

To identify prognostic models for melanoma survival, recurrence and metastasis among American Joint Committee on Cancer stage I and II patients postsurgery; and evaluate model performance, including overall survival (OS) prediction.

DESIGN

Systematic review and narrative synthesis.

DATA SOURCES

Searched MEDLINE, Embase, CINAHL, Cochrane Library, Science Citation Index and grey literature sources including cancer and guideline websites from 2000 to September 2021.

ELIGIBILITY CRITERIA

Included studies on risk prediction models for stage I and II melanoma in adults ≥18 years. Outcomes included OS, recurrence, metastases and model performance. No language or country of publication restrictions were applied.

DATA EXTRACTION AND SYNTHESIS

Two pairs of reviewers independently screened studies, extracted data and assessed the risk of bias using the CHecklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies checklist and the Prediction study Risk of Bias Assessment Tool. Heterogeneous predictors prevented statistical synthesis.

RESULTS

From 28 967 records, 15 studies reporting 20 models were included; 8 (stage I), 2 (stage II), 7 (stages I-II) and 7 (stages not reported), but were clearly applicable to early stages. Clinicopathological predictors per model ranged from 3-10. The most common were: ulceration, Breslow thickness/depth, sociodemographic status and site. Where reported, discriminatory values were ≥0.7. Calibration measures showed good matches between predicted and observed rates. None of the studies assessed clinical usefulness of the models. Risk of bias was high in eight models, unclear in nine and low in three. Seven models were internally and externally cross-validated, six models were externally validated and eight models were internally validated.

CONCLUSIONS

All models are effective in their predictive performance, however the low quality of the evidence raises concern as to whether current follow-up recommendations following surgical treatment is adequate. Future models should incorporate biomarkers for improved accuracy.

PROSPERO REGISTRATION NUMBER

CRD42018086784.

Optimal surveillance strategies for patients with stage 1 cutaneous melanoma post primary tumour excision: three systematic reviews and an economic model

BACKGROUND

Malignant melanoma is the fifth most common cancer in the UK, with rates continuing to rise, resulting in considerable burden to patients and the NHS.

OBJECTIVES

The objectives were to evaluate the effectiveness and cost-effectiveness of current and alternative follow-up strategies for stage IA and IB melanoma.

REVIEW METHODS

Three systematic reviews were conducted. (1) The effectiveness of surveillance strategies. Outcomes were detection of new primaries, recurrences, metastases and survival. Risk of bias was assessed using the Cochrane Collaboration's Risk-of-Bias 2.0 tool. (2) Prediction models to stratify by risk of recurrence, metastases and survival. Model performance was assessed by study-reported measures of discrimination (e.g. D-statistic, Harrel's c-statistic), calibration (e.g. the Hosmer-Lemeshow 'goodness-of-fit' test) or overall performance (e.g. Brier score, R ²). Risk of bias was assessed using the Prediction model Risk Of Bias ASsessment Tool (PROBAST). (3) Diagnostic test accuracy of fine-needle biopsy and ultrasonography. Outcomes were detection of new primaries, recurrences, metastases and overall survival. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Review data and data from elsewhere were used to model the cost-effectiveness of alternative surveillance strategies and the value of further research.

RESULTS

(1) The surveillance review included one randomised controlled trial. There was no evidence of a difference in new primary or recurrence detected (risk ratio 0.75, 95% confidence interval 0.43 to 1.31). Risk of bias was considered to be of some concern. Certainty of the evidence was low. (2) Eleven risk prediction models were identified. Discrimination measures were reported for six models, with the area under the operating curve ranging from 0.59 to 0.88. Three models reported calibration measures, with coefficients of ≥ 0.88. Overall performance was reported by two models. In one, the Brier score was slightly better than the American Joint Committee on Cancer scheme score. The other reported an R ² of 0.47 (95% confidence interval 0.45 to 0.49). All studies were judged to have a high risk of bias. (3) The diagnostic test accuracy review identified two studies. One study considered fine-needle biopsy and the other considered ultrasonography. The sensitivity and specificity for fine-needle biopsy were 0.94 (95% confidence interval 0.90 to 0.97) and 0.95 (95% confidence interval 0.90 to 0.97), respectively. For ultrasonography, sensitivity and specificity were 1.00 (95% confidence interval 0.03 to 1.00) and 0.99 (95% confidence interval 0.96 to 0.99), respectively. For the reference standards and flow and timing domains, the risk of bias was rated as being high for both studies. The cost-effectiveness results suggest that, over a lifetime, less intensive surveillance than recommended by the National Institute for Health and Care Excellence might be worthwhile. There was considerable uncertainty. Improving the diagnostic performance of cancer nurse specialists and introducing a risk prediction tool could be promising. Further research on transition probabilities between different stages of melanoma and on improving diagnostic accuracy would be of most value.

LIMITATIONS

Overall, few data of limited quality were available, and these related to earlier versions of the American Joint Committee on Cancer staging. Consequently, there was considerable uncertainty in the economic evaluation.

CONCLUSIONS

Despite adoption of rigorous methods, too few data are available to justify changes to the National Institute for Health and Care Excellence recommendations on surveillance. However, alternative strategies warrant further research, specifically on improving estimates of incidence, progression of recurrent disease; diagnostic accuracy and health-related quality of life; developing and evaluating risk stratification tools; and understanding patient preferences.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018086784.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol 25, No. 64. See the NIHR Journals Library website for further project information.

Axillary treatment for operable primary breast cancer

BACKGROUND

Axillary surgery is an established part of the management of primary breast cancer. It provides staging information to guide adjuvant therapy and potentially local control of axillary disease. Several alternative approaches to axillary surgery are available, most of which aim to spare a proportion of women the morbidity of complete axillary dissection.

OBJECTIVES

To assess the benefits and harms of alternative approaches to axillary surgery (including omitting such surgery altogether) in terms of overall survival; local, regional and distant recurrences; and adverse events.

SEARCH METHODS

We searched the Cochrane Breast Cancer Group Specialised Register, MEDLINE, Pre-MEDLINE, Embase, CENTRAL, the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov on 12 March 2015 without language restrictions. We also contacted study authors and checked reference lists.

SELECTION CRITERIA

Randomised controlled trials (RCTs) including women with clinically defined operable primary breast cancer conducted to compare axillary lymph node dissection (ALND) with no axillary surgery, axillary sampling or sentinel lymph node biopsy (SLNB); RCTs comparing axillary sampling with SLNB or no axillary surgery; RCTs comparing SLNB with no axillary surgery; and RCTs comparing ALND with or without radiotherapy (RT) versus RT alone.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed each potentially relevant trial for inclusion. We independently extracted outcome data, risk of bias information and study characteristics from all included trials. We pooled data according to trial interventions, and we used hazard ratios (HRs) for time-to-event outcomes and odds ratios (OR) for binary outcomes.

MAIN RESULTS

We included 26 RCTs in this review. Studies were at low or unclear risk of selection bias. Blinding was not done, but this was only considered a source of bias for outcomes with potential for subjectivity in measurements. We found no RCTs of axillary sampling versus SLNB, axillary sampling versus no axillary surgery or SLNB versus no axillary surgery. No axillary surgery versus ALND Ten trials involving 3849 participants compared no axillary surgery versus ALND. Moderate quality evidence showed no important differences between overall survival of women in the two groups (HR 1.06, 95% confidence interval (CI) 0.96 to 1.17; 3849 participants; 10 studies) although no axillary surgery increased the risk of locoregional recurrence (HR ranging from 1.10 to 3.06; 20,863 person-years of follow-up; four studies). It was uncertain whether no surgery increased the risk of distant metastasis compared with ALND (HR 1.06, 95% CI 0.87 to 1.30; 946 participants; two studies). Low-quality evidence indicated no axillary surgery decreased the risk of lymphoedema compared with ALND (OR 0.31, 95% CI 0.23 to 0.43; 1714 participants; four studies). Axillary sampling versus ALND Six trials involving 1559 participants compared axillary sampling versus ALND. Low-quality evidence indicated similar effectiveness of axillary sampling compared with ALND in terms of overall survival (HR 0.94, 95% CI 0.73 to 1.21; 967 participants; three studies) but it was unclear whether axillary sampling led to increased risk of local recurrence compared with ALND (HR 1.41, 95% CI 0.94 to 2.12; 1404 participants; three studies). The relative effectiveness of axillary sampling and ALND for locoregional recurrence (HR 0.74, 95% CI 0.46 to 1.20; 406 participants; one study) and distant metastasis was uncertain (HR 1.05, 95% CI 0.74 to 1.49; 406 participants; one study). Lymphoedema was less likely after axillary sampling than after ALND (OR 0.32, 95% CI 0.13 to 0.81; 80 participants; one study). SLNB versus ALND Seven trials involving 9426 participants compared SLNB with ALND. Moderate-quality evidence showed similar overall survival following SLNB compared with ALND (HR 1.05, 95% CI 0.89 to 1.25; 6352 participants; three studies; moderate-quality evidence). Differences in local recurrence (HR 0.94, 95% CI 0.24 to 3.77; 516 participants; one study), locoregional recurrence (HR 0.96, 95% CI 0.74 to 1.24; 5611 participants; one study) and distant metastasis (HR 0.80, 95% CI 0.42 to 1.53; 516 participants; one study) were uncertain. However, studies showed little absolute difference in the aforementioned outcomes. Lymphoedema was less likely after SLNB than ALND (OR ranged from 0.04 to 0.60; three studies; 1965 participants; low-quality evidence). Three studies including 1755 participants reported quality of life: Investigators in two studies found quality of life better after SLNB than ALND, and in the other study observed no difference. RT versus ALND Four trials involving 2585 participants compared RT alone with ALND (with or without RT). High-quality evidence indicated that overall survival was reduced among women treated with radiotherapy alone compared with those treated with ALND (HR 1.10, 95% CI 1.00 to 1.21; 2469 participants; four studies), and local recurrence was less likely in women treated with radiotherapy than in those treated with ALND (HR 0.80, 95% CI 0.64 to 0.99; 22,256 person-years of follow-up; four studies). Risk of distant metastasis was similar for radiotherapy alone as for ALND (HR 1.07, 95% CI 0.93 to 1.25; 1313 participants; one study), and whether lymphoedema was less likely after RT alone than ALND remained uncertain (OR 0.47, 95% CI 0.16 to 1.44; 200 participants; one study). Less surgery versus ALND When combining results from all trials, treatment involving less surgery was associated with reduced overall survival compared with ALND (HR 1.08, 95% CI 1.01 to 1.17; 6478 participants; 18 studies). Whether local recurrence was reduced with less axillary surgery when compared with ALND was uncertain (HR 0.90, 95% CI 0.75 to 1.09; 24,176 participant-years of follow up; eight studies). Locoregional recurrence was more likely with less surgery than with ALND (HR 1.53, 95% CI 1.31 to 1.78; 26,880 participant-years of follow-up; seven studies). Whether risk of distant metastasis was increased after less axillary surgery compared with ALND was uncertain (HR 1.07, 95% CI 0.95 to 1.20; 2665 participants; five studies). Lymphoedema was less likely after less axillary surgery than with ALND (OR 0.37, 95% CI 0.29 to 0.46; 3964 participants; nine studies).No studies reported on disease control in the axilla.

AUTHORS' CONCLUSIONS

This review confirms the benefit of SLNB and axillary sampling as alternatives to ALND for axillary staging, supporting the view that ALND of the clinically and radiologically uninvolved axilla is no longer acceptable practice in people with breast cancer.

Is MRI better than CT for detecting a vascular component to dementia? A systematic review and meta-analysis

BACKGROUND

Identification of causes of dementia soon after symptom onset is important, because appropriate treatment of some causes of dementia can slow or halt its progression or enable symptomatic treatment where appropriate. The accuracy of MRI and CT, and whether MRI is superior to CT, in detecting a vascular component to dementia in autopsy confirmed and clinical cohorts of patients with VaD, combined AD and VaD ("mixed dementia"), and AD remain unclear. We conducted a systematic review and meta-analysis to investigate this question.

METHODS

We searched eight databases and screened reference lists to identify studies addressing the review question. We assessed study quality using QUADAS. We estimated summary diagnostic accuracy according to imaging finding, and ratios of diagnostic odds ratios (RDORs) for MRI versus CT and high versus low risk of bias.

RESULTS

We included 7 autopsy and 31 non-autopsy studies. There was little evidence that selective patient enrolment and risk of incorporation bias impacted on diagnostic accuracy (p = 0.12 to 0.95). The most widely reported imaging finding was white matter hyperintensities. For CT (11 studies) summary sensitivity and specificity were 71% (95% CI 53%-85%) and 55% (44%-66%). Corresponding figures for MRI (6 studies) were 95% (87%-98%) and 26% (12%-50%). General infarcts was the most specific imaging finding on MRI (96%; 95% CI 94%-97%) and CT (96%; 93%-98%). However, sensitivity was low for both MRI (53%; 36%-70%) and CT (52%; 22% to 80%). No imaging finding had consistently high sensitivity. Based on non-autopsy studies, MRI was more accurate than CT for six of seven imaging findings, but confidence intervals were wide.

CONCLUSION

There is insufficient evidence to suggest that MRI is superior to CT with respect to identifying cerebrovascular changes in autopsy-confirmed and clinical cohorts of VaD, AD, and 'mixed dementia'.

The effectiveness of emergency obstetric referral interventions in developing country settings: a systematic review

BACKGROUND

Pregnancy complications can be unpredictable and many women in developing countries cannot access health facilities where life-saving care is available. This study assesses the effects of referral interventions that enable pregnant women to reach health facilities during an emergency, after the decision to seek care is made.

METHODS AND FINDINGS

Selected bibliographic databases were searched with no date or language restrictions. Randomised controlled trials and quasi experimental study designs with a comparison group were included. Outcomes of interest included maternal and neonatal mortality and other intermediate measures such as service utilisation. Two reviewers independently selected, appraised, and extracted articles using predefined fields. Forest plots, tables, and qualitative summaries of study quality, size, and direction of effect were used for analysis. Nineteen studies were included. In South Asian settings, four studies of organisational interventions in communities that generated funds for transport reduced neonatal deaths, with the largest effect seen in India (odds ratio 0·48 95% CI 0·34-0·68). Three quasi experimental studies from sub-Saharan Africa reported reductions in stillbirths with maternity waiting home interventions, with one statistically significant result (OR 0.56 95% CI 0.32-0.96). Effects of interventions on maternal mortality were unclear. Referral interventions usually improved utilisation of health services but the opposite effect was also documented. The effects of multiple interventions in the studies could not be disentangled. Explanatory mechanisms through which the interventions worked could not be ascertained.

CONCLUSIONS

Community mobilisation interventions may reduce neonatal mortality but the contribution of referral components cannot be ascertained. The reduction in stillbirth rates resulting from maternity waiting homes needs further study. Referral interventions can have unexpected adverse effects. To inform the implementation of effective referral interventions, improved monitoring and evaluation practices are necessary, along with studies that develop better understanding of how interventions work.

WITHDRAWN: Home-based support for disadvantaged teenage mothers

BACKGROUND

Babies born to socio-economically disadvantaged mothers are at higher risk of injury, abuse or neglect and health problems than babies born to more affluent mothers; disadvantaged teenage mothers are at particular risk of adverse outcomes. Home-visiting programs are thought to improve outcomes for both mothers and children, largely through advice and support.

OBJECTIVES

To assess the effectiveness of home-visiting programmes for women who have recently given birth and who are socially or economically disadvantaged.

SEARCH STRATEGY

The following electronic databases were searched: CENTRAL (2006, Issue 3); MEDLINE (1966 to March 2006); EMBASE (1980 to week 12 2006); CINAHL (1982 to March week 4 2006); PsycINFO (1872 to March week 4 2006); ASSIA (1987 to March 2006); LILACS (1982 to March 2006); and Sociological Abstracts (1963 to March 2006). Grey literature was also be searched using ZETOC (1993 to March 2006); Dissertation Abstracts International (late 1960s to 2006); and SIGLE (1980 to March 2006). Communication with published authors about ongoing or unpublished research was also undertaken.

SELECTION CRITERIA

Included studies were randomised controlled trials investigating the efficacy of home visiting directed at teenage mothers.

DATA COLLECTION AND ANALYSIS

Titles and abstracts identified in the search were independently assessed for eligibility by two review authors (EC and JP or CB). Data were extracted and entered into RevMan (EC, JP and CB), synthesised and presented in both written and graphical form (forest plots). Outcomes included in this review were established at the protocol stage by an international steering group. The review did not report on all outcomes reported in included studies.

MAIN RESULTS

Five studies with 1838 participants were included in this review. Data from single studies provided support for the effectiveness of home visiting on some outcomes, but the evidence overall provided only limited support for the effectiveness of home visiting as a means of improving the range of maternal and child outcomes considered in this review.

AUTHORS' CONCLUSIONS

This review suggests there is only limited evidence that home-visiting programmes of the kind described in this review can impact positively on the quality of parenting of teenage mothers or on child development outcomes for their offspring. For reasons discussed in the review, this does not amount to a conclusion that home-visiting programmes are ineffective but indicates a need to think carefully about the problems that home visiting might influence and about improvements in the conduct and reporting of outcome studies in this area.

Home-based support for disadvantaged adult mothers

BACKGROUND

Babies born to socio-economically disadvantaged mothers are at higher risk of a range of problems in infancy. Home visiting programs are thought to improve outcomes, both for mothers and children, largely through advice and support.

OBJECTIVES

To assess the effectiveness of home visiting programmes for women who have recently given birth and who are socially or economically disadvantaged.

SEARCH STRATEGY

We searched the following electronic databases: The Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 3, 2006); MEDLINE (1966 to March 2006); EMBASE (1980 to 2006 week 12); CINAHL (1982 to March week 4 2006); PsycINFO (1872 to March week 4 2006); ASSIA (1987 to March 2006); LILACS (1982 to March 2006); and Sociological Abstracts(1963 to March 2006). We searched grey literature using ZETOC (1993 to March 2006); Dissertation Abstracts International (late 1960s to 2006); and SIGLE (1980 to March 2006). We also undertook communication with published authors about ongoing or unpublished research.

SELECTION CRITERIA

Included studies were randomised controlled trials investigating the efficacy of home visiting directed at disadvantaged adult mothers.

DATA COLLECTION AND ANALYSIS

Two reviewers (EC and JP or CB) independently assessed titles and abstracts identified in the search for eligibility. Data were extracted and entered into RevMan (EC, JP and CB), synthesised and presented in both written and graphical form (forest plots). Outcomes included in this review were established at the protocol stage by an international steering group. The review does not report on all outcomes reported in included studies.

MAIN RESULTS

We included 11 studies with 4751 participants in this review. Data show no statistically significant differences for those receiving home visiting, either for maternal outcomes (maternal depression, anxiety, the stress associated with parenting, parenting skills, child abuse risk or potential or breastfeeding) or child outcomes (preventive health care visits, psychosocial health, language development, behaviour problems or accidental injuries. Evidence about uptake of immunisations is mixed, and the data on child maltreatment difficult to interpret.

AUTHORS' CONCLUSIONS

This review suggests that for disadvantaged adult women and their children, there is currently no evidence to support the adoption of home visiting as a means of improving maternal psychosocial health, parenting or outcomes for children. For reasons discussed in the review, this does not amount to a conclusion that home visiting programmes are ineffective, but indicates a need to think carefully about the problems that home visiting might influence, and improvements in the conduct of outcome studies in this area.

Home-based support for disadvantaged teenage mothers

BACKGROUND

Babies born to socio-economically disadvantaged mothers are at higher risk of injury, abuse or neglect and health problems than babies born to more affluent mothers; disadvantaged teenage mothers are at particular risk of adverse outcomes. Home-visiting programs are thought to improve outcomes for both mothers and children, largely through advice and support.

OBJECTIVES

To assess the effectiveness of home-visiting programmes for women who have recently given birth and who are socially or economically disadvantaged.

SEARCH STRATEGY

The following electronic databases were searched: CENTRAL (2006, Issue 3); MEDLINE (1966 to March 2006); EMBASE (1980 to week 12 2006); CINAHL (1982 to March week 4 2006); PsycINFO (1872 to March week 4 2006); ASSIA (1987 to March 2006); LILACS (1982 to March 2006); and Sociological Abstracts (1963 to March 2006). Grey literature was also be searched using ZETOC (1993 to March 2006); Dissertation Abstracts International (late 1960s to 2006); and SIGLE (1980 to March 2006). Communication with published authors about ongoing or unpublished research was also undertaken.

SELECTION CRITERIA

Included studies were randomised controlled trials investigating the efficacy of home visiting directed at teenage mothers.

DATA COLLECTION AND ANALYSIS

Titles and abstracts identified in the search were independently assessed for eligibility by two review authors (EC and JP or CB). Data were extracted and entered into RevMan (EC, JP and CB), synthesised and presented in both written and graphical form (forest plots). Outcomes included in this review were established at the protocol stage by an international steering group. The review did not report on all outcomes reported in included studies.

MAIN RESULTS

Five studies with 1838 participants were included in this review. Data from single studies provided support for the effectiveness of home visiting on some outcomes, but the evidence overall provided only limited support for the effectiveness of home visiting as a means of improving the range of maternal and child outcomes considered in this review.

AUTHORS' CONCLUSIONS

This review suggests there is only limited evidence that home-visiting programmes of the kind described in this review can impact positively on the quality of parenting of teenage mothers or on child development outcomes for their offspring. For reasons discussed in the review, this does not amount to a conclusion that home-visiting programmes are ineffective but indicates a need to think carefully about the problems that home visiting might influence and about improvements in the conduct and reporting of outcome studies in this area.

Factors associated with teenage pregnancy in the European Union countries: a systematic review

BACKGROUND

As part of the REPROSTAT2 project, this systematic review aimed to identify factors associated with teenage pregnancy in 25 European Union countries.

METHODS

The search strategy included electronic bibliographic databases (1995 to May 2005), bibliographies of selected articles and requests to all country representatives of the research team for relevant reports and publications. Primary outcome measure was conception. Inclusion criteria were quantitative studies of individual-level factors associated with teenage (13-19 years) pregnancy in EU countries.

RESULTS

Of 4444 studies identified and screened, 20 met the inclusion criteria. Most of the included studies took place in UK and Nordic countries. The well-recognized factors of socioeconomic disadvantage, disrupted family structure and low educational level and aspiration appear consistently associated with teenage pregnancy. However, evidence that access to services in itself is a protective factor remains inconsistent. Although further associations with diverse risk-taking behaviours and lifestyle, sexual health knowledge, attitudes and behaviour are reported, the independent effects of these factors too remain unclear.

CONCLUSIONS

Included studies varied widely in terms of methods and definitions used. This heterogeneity within the studies leaves two outstanding issues. First, we cannot synthesize or generalize key findings as to how all these factors interact with one another and which factors are the most significant. Second, it is not possible to examine potential variation between countries. Future research ensuring comparability and generalizability of results related to teenage sexual health outcomes will help gain insight into the international variation in observed pregnancy rates and better inform interventions.

Altered neuroendocrine response and gastric dysmotility in the Flinders Sensitive Line rat

In the search for animal models that can replicate some features of functional dyspepsia (FD) patients, we turned our interest to the Flinders Sensitive Line (FSL) rat. Gastric motility disturbances prevalent in FD patients as well as urine corticosterone and plasma prolactin were measured following buspirone challenge. Flinders Resistant Line (FRL) rat was used as control. The results show that the FSL rats have a disturbed gastric motility, reflected as both an increased gastric accommodation rate and gastric volume during gastric distension as well as a delayed gastric emptying, the latter possibly as a consequence of the former. Lipid administration resulted in a significant increase in maximal gastric volume only in the FRL rats. Both the corticosterone response to buspirone and the 24-h urinary output of corticosterone were normal in FSL rats. Similar to FD patients, the FSL rat showed supersensitivity to buspirone in the increase in prolactin release. Although FSL rats show some features similar to a subset of FD patients, the increased gastric accommodation contrasts to the reduced accommodation often seen in FD patients. Further studies are warranted to determine the relevance of this rat strain as a model for FD.

Microvascular effects of selective prostaglandin analogues in the eye with special reference to latanoprost and glaucoma treatment

Prostaglandin F(2alpha) analogues have recently been introduced on the market for glaucoma treatment. While these drugs have a well-documented intraocular pressure reducing effect only a limited number of studies have been published regarding their effects on the microvasculature in the eye. Since many naturally occurring prostaglandins have marked effects on the cardiovascular system it is conceivable that synthetic prostaglandins used as glaucoma drugs may exert microvascular effects in the eye, even if they exhibit receptor selectivity. Latanoprost, the active principle of Xalatan((R)) eye drops, is a selective FP prostanoid receptor agonist, and much of the paper is focused on the microvascular effects of latanoprost and some closely related prostaglandin analogues. The purpose of the paper is to review the literature on the microvascular effects of prostaglandins in the eye, and to present some unpublished data on the effects of selective prostaglandin analogues. Most of the prostaglandin analogues studied exhibit selectivity for the FP prostanoid receptor. Results from studies with the following prostaglandin analogues are presented in the paper: PGF(2alpha)-isopropyl ester (PGF(2alpha)-IE), 17-phenyl-18,19,20-trinor-PGF(2alpha)-isopropyl ester (17-phenyl-PGF(2a)-IE), 15-keto-17-phenyl-18,19, 20-trinor-PGF(2alpha)-isopropyl ester (15-keto-17-phenyl-PGF(2a)-IE), 13,14-dihydro-17-phenyl-18,19,20-trinor-PGF(2alpha)-isopropy l ester (latanoprost), 13,14-dihydro-15R,S-17-phenyl-18,19, 20-trinor-PGF(2alpha)-isopropyl ester (PhXA34), 17-phenyl-18,19, 20-trinor-PGE(2)-isopropyl ester (17-phenyl-PGE(2)-IE), and 19R-hydroxy-PGE(2) (19R-OH-PGE(2)). The regional blood flow has been determined with radioactively labelled microspheres, the blood volume with (51)Cr labelled erythrocytes and the capillary permeability to albumin with (125)I and (131)I labelled albumin. PGF(2alpha)-IE has been shown to exert marked microvascular effects in the rabbit anterior segment including vasodilatation, increased capillary permeability, and a breakdown of the blood-aqueous barrier. 17-phenyl-PGF(2alpha)-IE, 15-keto-17-phenyl-PGF(2alpha)-IE, and PhXA34/latanoprost exerted significantly less vasodilatory effect, and little effect on capillary permeability was seen with the FP receptor agonists when studied with Evans blue. Intravenous administration of PhXA34 at a dose range of 1-100 microg/kg b.w. had no consistent effect on the regional blood flow in the eye indicating that FP receptors in the ocular blood vessels are not expressed in the rabbit, or alternatively are not functionally coupled to regulation of vascular tone. In cats topical application of PGF(2alpha)-IE had no significant effect the on the regional blood flow in cannulated eyes. No blood flow experiments were performed in intact eyes with PGF(2alpha)-IE. 17-phenyl-PGF(2alpha)-IE and latanoprost caused some vasodilation in the anterior segment. None of the analogues had any significant effect on the blood volume in the ocular tissues, but an increase in capillary permeability to albumin was seen in several tissues of the eye. However, in the eyelid, nictitating membrane and conjunctiva exposed to high concentrations of the prostaglandins no or only little leakage of albumin was detected. It appears that the intraocular microvasculature in the cat exhibits some sensitivity to FP prostanoid receptor agonists. (ABSTRACT TRUNCATED)

Effect of latanoprost on regional blood flow and capillary permeability in the monkey eye

OBJECTIVE

To evaluate the effects of latanoprost on regional blood flow and capillary permeability in the monkey eye.

METHODS

Anesthetized cynomolgus monkeys were unilaterally treated with a single dose containing 6 pg of latanoprost; or 10 microg of PhXA34 (13,14-dihydro-15R, S-17-phenyl-18,19,20-trinor-prostaglandin F2alpha [PGF2alpha]-isopropyl ester), which contains about 50% latanoprost. Regional blood flow in the eye was measured with radioactively labeled microspheres; capillary permeability was measured by determining the extravascular plasma-equivalent albumin space using 125I-albumin, 131I-albumin, and 51Cr-labeled erythrocytes.

RESULTS

Latanoprost or PhXA34 had no or only a slight effect on the regional blood flow when measured 1, 2 1/2, 3, 4 1/2, and 6 hours after dose administration, with the exception of the anterior sclera, in which a moderate increase in blood flow was detected. No effect on capillary permeability to albumin was detected when studied 30 minutes to 2 1/2 hours and 5 to 6 hours after dose administration.

CONCLUSION

Latanoprost, a selective prostaglandin F receptor agonist, exerted no or only slight vascular effects for up to 6 hours after dose administration in the monkey eye, with the exception of the anterior sclera, in which a moderate increase in blood flow was detected.

CLINICAL RELEVANCE

Naturally occurring prostaglandins may cause marked microcirculatory changes in the eye that could be of clinical concern. Latanoprost, a selective prostaglandin F receptor agonist, seems to be devoid of such effects.

Effects of prostaglandin E2, F2alpha, and latanoprost acid on isolated ocular blood vessels in vitro

The vascular effects of PGE2, PGF2alpha and latanoprost acid on isolated bovine long posterior ciliary arteries and episcleral veins have been investigated using a small vessel myograph. PGE2 caused vasorelaxation both in the ciliary artery and episcleral vein (EC50: 7.9x10(-9) M and 2.1x10(-8) M respectively). Blockade of thromboxane receptors with GR 32191B, a TP receptor antagonist, shifted the concentration-response curves to the left in both preparations, probably indicating a slight co-stimulation of TP receptors in these vessels. Blockade of tachykinin NK-1 receptors had no effect on the PGE2 concentration-response curve. PGF2alpha caused a concentration dependent contraction in half of the ciliary arteries examined and relaxation in the other half. In the presence of the thromboxane receptor antagonist (GR 3211B) PGF2alpha always induced relaxation of the ciliary artery (EC50:1.3x10[-5] M). At higher concentrations PGF2alpha tended to slightly constrict the episcleral veins, but in the presence of the TP receptor antagonist (GR 32191B) only relaxation was observed. Latanoprost acid contracted the ciliary artery at concentrations above 10(-6) M. This effect was completely abolished by the TP receptor antagonist (GR 32191B). In the episcleral vein latanoprost acid induced a slight relaxation but in the presence of the TP receptor antagonist (GR 32191B) no effect was observed. These results indicate that PGE2 invariably induces vasorelaxation of bovine ciliary arteries and episcleral veins, whereas both PGF2alpha and latanoprost acid at high concentrations can cause vasoconstriction probably by stimulating TP receptors. PGF2alpha causes marked relaxation of both ciliary arteries and episcleral veins in the presence of the TP blocker which seems unlikely to be mediated by FP receptors.

Mechanism of prostaglandin E2-, F2alpha- and latanoprost acid-induced relaxation of submental veins

The mechanism of prostaglandin E2-, prostaglandin F2alpha- and latanoprost acid (13,14-dihydro-17-phenyl-18,19,20-trinor-prostaglandin F2alpha)-induced relaxation of the rabbit submental vein was studied. Prostaglandin E2 caused maximum relaxation of endothelin-1 precontracted vessels (EC50: 1.8 x 10(-8) M). Much of the relaxation could be abolished by denuding the endothelium with the nitric oxide synthase inhibitor, L-NAME (N(G)-Nitro-L-arginine methylester). CGRP-(8-37) (calcitonin gene-related peptide fragment (8-37)), a calcitonin gene-related peptide receptor antagonist, exhibited a partial blocking effect, whereas the tachykinin NK1 receptor blocker, GR 82334 ([D-Pro9[Spiro-gamma-Lactam]Leu10,Trp11]physalaemin (1-11)), markedly attenuated the response. Both prostaglandin F2alpha and the relatively selective FP receptor agonist, latanoprost acid, caused relaxation of the veins to about 50% of the precontracted state in the presence of GR 32191B ([1R-[1alpha(Z),2beta,3beta,5alpha]]-(+)-7-[5-([1,1'-b iphenyl]-4-ylmethoxy)-3-hydroxy-2-(1-piperidinyl)cyclopentyl]-4-he ptenoic acid), a thromboxane receptor antagonist (EC50: for prostaglandin F2alpha 7.9 x 10(-9) M, and for latanoprost acid 4.9 x 10(-9) M). L-NAME, as well as denuding the endothelium, completely abolished the effect. In addition, most or at least a large part of the relaxation was also blocked by CGRP-(8-37) as well as GR 82334. These results indicate that the FP receptor-mediated relaxation of veins is based on release of nitric oxide in addition to involvement of calcitonin gene-related peptide and substance P, or some other tachykinin, probably released from perivascular sensory nerves. The more pronounced relaxation induced by prostaglandin E2 could be due to vasodilator EP receptors in the smooth muscle layer of the veins.

Mediation of prostaglandin f2 alpha-induced ocular surface hyperemia by sensory nerves in rabbits

PURPOSE

Prostaglandin F2 alpha (PGF2 alpha) and several other prostaglandins cause surface hyperemia of the eye when applied topically. The purpose of the present study was to investigate the role of sensory nerves in prostaglandin-induced ocular hyperemia.

METHODS

The ophthalmic branch of the trigeminal nerve was unilaterally electrocoagulated in rabbits using a stereotaxic technique. Two weeks later the animals received bilaterally one drop of PGF2 alpha-isopropyl ester (PGF2 alpha-IE) at a dose of 1 microgram/ eye. The blood flow to the different parts of the eye was measured with the radioactively labeled microsphere technique before, 30 and 60 min after treatment with PGF2 alpha-IE.

RESULTS

In the control eyes with intact sensory innervation, PGF2 alpha-IE caused a marked increase in blood flow to the surface structures of the eye (conjunctiva, anterior sclera, eyelids and nictitating membrane) and the iris, and a moderate increase in the blood flow to the ciliary processes, but no increase in the choroidal blood flow. In the denervated eyes the increase in blood flow to the surface structures was almost completely abolished, and there was also a tendency toward less increase in blood flow in the anterior uvea.

CONCLUSIONS

These results indicate that PGF2 alpha-induced ocular surface hyperemia, at least at the early stage, is mediated to a large extent by sensory nerves.

Analysis of variance of microspheres blood flow measurements in rabbits

As part of a larger study on the interpretation of angiographically derived hemodynamic parameters, blood flow in several ocular tissues was measured using the radioactively labelled microspheres technique. As an unexpected secondary results, it was found that the microspheres data gave quantitative information on hyperaemic effects in the eye. This is the subject of the present paper. The measurements were made in 13 anaesthetized pigmented rabbits. In each animal, three blood flow measurements were performed at three different ocular perfusion pressures (60-15 mmHg). The perfusion pressures of the experimental eye were varied by changing the intra-ocular pressure. The contra-lateral eye served as a control. Labelled microspheres were used as a non-recirculating blood flow indicator, enabling the estimation of regional blood flows, in this case for the iris, ciliary body, peripheral choroid and peripapillary choroid separately. Using analysis of variance with perfusion pressure as covariate and taking into account the blood flow of the control eye, hyperaemia could be quantified in the experimental eye. Apart from a difference amongst animals, hyperaemia depended on tissue type. The amount of hyperaemia proved to be more pronounced in the anterior part of the eye, iris and ciliary body, and to decrease towards the posterior pole. With regard to the causes of this hyperaemia one could speculate about the invasive handling (anterior eye needles) topical administration of tropicamide, in combination with the general anaesthesia.

Fluorescein angiographic evaluation of the effect of latanoprost treatment on blood-retinal barrier integrity: a review of studies conducted on pseudophakic glaucoma patients and on phakic and aphakic monkeys

Endogenous prostaglandins (PGs) have been claimed to play a role in the development of cystoid macular edema (CME). Two fluorescein angiographic studies evaluating the effect of latanoprost, a new ocular hypotensive PG analogue, on blood-retinal barrier integrity are, therefore, reviewed here. In the first study, six of eight unilaterally aphakic cynomolgus monkeys were treated bilaterally once daily for six months with 0.035% latanoprost (seven times the clinically used oculohypotensive concentration). Two of the animals served as controls. Fluorescein angiography of the fundus after one, three and six months of treatment revealed no leakage of fluorescein in any of the 16 eyes. In another study, pseudophakic eyes of 16 glaucoma patients who received twice-daily treatment with 0.006% latanoprost for four weeks were compared to eight patients treated with placebo. Biomicroscopic examination did not reveal any signs of CME and only one placebo-treated eye revealed a slight perifoveal leakage of fluorescein. These studies suggest that topically-applied latanoprost does not have a fluorescein angiographically detectable direct effect on the integrity of the blood-retinal barrier system in phakic or aphakic monkey eyes or in pseudophakic human eyes. This does not rule out the occurrence of CME in eyes more susceptible to CME, due to vitreous loss, posterior capsulotomy, or other postoperative situations. Especially in those eyes a study with latanoprost is proposed. Since, fluorescein angiography is a rather crude method of detecting abnormalities of the blood-retinal barriers, vitreous fluorometry in addition is suggested.

Study of choroidal blood flow by comparison of SLO fluorescein angiography and microspheres

Choroidal hemodynamics estimated with parameters describing the dye build-up curves obtained with video fluorescein angiography, were compared with a classical regional blood flow measurement: radioactively labelled microspheres. Video fluorescein angiograms (Rodenstock's SLO 101) and microspheres blood flow measurements were made in 13 anaesthetized pigmented rabbits. Ocular perfusion pressures were varied from 60 to 15 mmHg by changing the intraocular pressure. The angiographically derived dye build-up curves were described by means of an exponential model. One of the model parameters is the time constant tau theoretically reflecting local blood refreshment time. Labelled microspheres act as a non-recirculating blood flow indicator, enabling the estimation of regional blood flows. The relation between choroidal blood flow and perfusion pressure is nearly linear, suggesting the passive nature of choroidal vasculature. There is a significant correlation between tau and microspheres flow (R = 0.67, P < 0.01). According to the rheological model the product of blood flow and tau corresponds to the relevant blood volume. Hence, a function for the volume of the choriocapillaris as a function of perfusion pressure was established. The model parameter tau can be interpreted as the local blood refreshment time. Since the parameter tau, unlike microspheres, can be used clinically, tau may be used to retrieve information on choroidal hemodynamics in clinical practice. Information on the spatial distribution of choroidal hemodynamics is also obtained.

The prevalence of pain in a disabled population

An estimated 1.7 million disabled adults (95% CI +/- 74,000), living in private households in Great Britain, reported pain symptoms which severely affected their daily activities. That is, the pain they experienced is so severe, unrelieved and recurring as to limit or prevent their ability to perform ordinary, everyday, activities. They represent 30% of disabled adults suggesting that pain is a substantial cause of disability and a major public health problem. The prevalence of severely limiting pain increased with age declining beyond age 55 though younger disabled adults, and women generally, reported more severe pain symptoms. Pain was associated with disabilities which commonly have a physical origin and directly affect bodily movement, compounding the problems of daily living for this population. Three-quarters of those whose lives were limited by pain said the worst bouts of pain occurred at least once a week; half took analgesic medicine every day. More than nine out of ten disabled people suffering pain had recent contact with primary and community health or hospital services.

Role of nitric oxide in PGF2 alpha-induced ocular hyperemia

The effect of nitric oxide synthase inhibition on prostaglandin F2 alpha (PGF2 alpha)-induced ocular hyperemia in the rabbit has been studied. PGF2 alpha was administered topically as the isopropyl ester (PGF2 alpha-IE) unilaterally, with the other eye serving as a control. The regional blood flow in the eye was determined with radioactively-labelled microspheres in conscious animals. Synthesis of nitric oxide (NO) was blocked by L-NMMA (200 mg kg-1 b.w., i.v.). PGF2 alpha-IE induced marked hyperemia of the surface structures of the eye (conjunctiva, eye lids, nictitating membrane, anterior sclera), as well as increased blood flow of the anterior uvea. L-NMMA blocked the hyperemia of the surface structures but not completely the increase in blood flow of the anterior uvea. PhXA41 (13,14-dihydro-17-phenyl-18,19,20-trinor-PGF2 alpha-isopropyl ester), a selective prostaglandin FP-receptor agonist, had no significant effect on the ocular blood flow. These results indicate that PGF2 alpha causes surface hyperemia of the eye by activating nitric oxide synthase, but this mechanism seems to be only partly involved in the increase in blood flow of the ciliary processes and the iris. The PGF2 alpha-induced ocular hyperemia is unlikely to be mediated by FP receptors.

Phenyl-substituted prostaglandins: potent and selective antiglaucoma agents

A series of phenyl-substituted analogues of prostaglandin F2 alpha (PGF2 alpha) were prepared and evaluated for ocular hypotensive effect and side effects in different animal models. In addition, the activity of the analogues on FP receptors was studied in vitro. The results were compared with those of PGF2 alpha and its isopropyl ester. The phenyl-substituted PGF2 alpha analogues exhibited good intraocular pressure reducing effect, were more selective, and exhibited a much higher therapeutic index in the eye than PGF2 alpha or its isopropyl ester. The analogues exhibited high activity on FP receptors in a stereoselective manner for the 15 alpha-hydroxyl group.

Argon laser therapy of endometriosis: a review of 92 consecutive patients

The conception rate, relief of pain, and safety of argon laser photocoagulation of endometriosis were evaluated in 92 patients. All patients were treated at the time of diagnosis with the argon laser delivered through a flexible quartz fiber passed through the operating channel of a standard and unmodified laparoscope. The uncorrected pregnancy rate was 34% (19 of 56), with 64% of the pregnancies occurring within 6 months of therapy. The conception rate was slightly greater in women with infertility of 24 months or less and in women without other fertility factors. Ninety-two percent of 50 women with pelvic pain reported a reduction of their pain after treatment. The argon laser is an effective, simple, and safe alternative for the treatment of mild or moderate endometriosis.