Cancer screening programs in South-east Asia and Western Pacific

BACKGROUND

The burden of cancer can be altered by screening. The field of cancer screening is constantly evolving; from the initiation of program for new cancer types as well as exploring innovative screening strategies (e.g. new screening tests). The aim of this study was to perform a landscape analysis of existing cancer screening programs in South-East Asia and the Western Pacific.

METHODS

We conducted an overview of cancer screening in the region with the goal of summarizing current designs of cancer screening programs. First, a selective narrative literature review was used as an exploration to identify countries with organized screening programs. Second, representatives of each country with an organized program were approached and asked to provide relevant information on the organizations of their national or regional cancer screening program.

RESULTS

There was wide variation in the screening strategies offered in the considered region with only eight programs identified as having an organized design. The majority of these programs did not meet all the essential criteria for being organized screening. The greatest variation was observed in the starting and stopping ages.

CONCLUSIONS

Essential criteria of organized screening are missed. Improving organization is crucial to ensure that the beneficial effects of screening are achieved in the long-term. It is strongly recommended to consider a regional cancer screening network.

Correction: Chua et al. Cost-Effectiveness Analysis of HPV Extended versus Partial Genotyping for Cervical Cancer Screening in Singapore. Cancers 2023, 15, 1812

The authors wish to revise two words in Table 1 row 3, and the first paragraph of Section 2 [...].

Budget Impact Analysis of Adopting a One-Step Nucleic Acid Amplification Testing (NAAT) Alone Diagnostic Pathway for Clostridioides difficile in Japan Compared to a Two-Step Algorithm with Glutamate Dehydrogenase/Toxin Followed by NAAT

Clostridioides difficile infection (CDI) is a major healthcare-associated infection that leads to a significant health economic burden in Japan. Using a decision tree model, we evaluated the budget impact of adopting a one-step nucleic acid amplification test (NAAT) alone pathway compared to a two-step diagnostic algorithm with glutamate dehydrogenase (GDH) and toxin antigen, followed by NAAT. The analysis was conducted from the government payer's perspective for 100,000 symptomatic, hospitalized adults requiring a CDI diagnostic test. One-way sensitivity analysis was conducted for all data inputs. The NAAT alone strategy costed JPY 225,886,360 (USD 2,424,714) more, but was more effective, resulting in 1749 more patients accurately diagnosed and 91 fewer deaths compared to the two-step algorithm. Additionally, the NAAT alone pathway costed JPY 26,146 (USD 281) less per true positive CDI diagnosed. The total budget impact, and cost per CDI diagnosed was most sensitive to GDH sensitivity in one-way sensitivity analysis, where a lower GDH sensitivity resulted in greater cost savings with the NAAT alone pathway. Findings from this budget impact analysis can guide the adoption of a NAAT alone pathway for CDI diagnosis in Japan.

Cost-Effectiveness Analysis of HPV Extended versus Partial Genotyping for Cervical Cancer Screening in Singapore

Human papillomavirus (HPV) partial genotyping (PGT) identifies HPV16 and HPV18 individually, alongside 12 other high-risk HPV genotypes (hrHPV) collectively. HPV extended genotyping (XGT) identifies four additional hrHPV individually (HPV31, 45, 51, and 52), and reports the remaining eight in three groups (HPV33|58; 56|59|66; 35|39|68). Quality-adjusted life years (QALY), health care resource use, and costs of XGT were compared to PGT for cervical cancer screening in Singapore using DICE simulation. Women with one of the three hrHPV identified by XGT (HPV35|39|68; 56|59|66; 51), and atypical squamous cells of undetermined significance (ASCUS) on cytology, are recalled for a repeat screening in one year, instead of undergoing an immediate colposcopy with PGT. At the repeat screening, the colposcopy is performed only for persistent same-genotype infections in XGT, while with PGT, all the women with persistent HPV have a colposcopy. Screening 500,122 women, aged 30-69, with XGT, provided an incremental cost-effectiveness ratio (ICER) versus PGT of SGD 16,370/QALY, with 7130 (19.4%) fewer colposcopies, 6027 (7.0%) fewer cytology tests, 9787 (1.6%) fewer clinic consultations, yet 2446 (0.5%) more HPV tests. The XGT ICER remains well below SGD 100,000 in sensitivity analyses, (-SGD 17,736/QALY to SGD 50,474/QALY). XGT is cost-effective compared to PGT, utilizes fewer resources, and provides a risk-based approach as the primary cervical cancer screening method.

Determining tolerance levels for quality assurance of 3D printed bolus for modulated arc radiotherapy of the nose

Given the existing literature on the subject, there is obviously a need for specific advice on quality assurance (QA) tolerances for departments using or implementing 3D printed bolus for radiotherapy treatments. With a view to providing initial suggested QA tolerances for 3D printed bolus, this study evaluated the dosimetric effects of changes in bolus geometry and density, for a particularly common and challenging clinical situation: specifically, volumetric modulated arc therapy (VMAT) treatment of the nose. Film-based dose verification measurements demonstrated that both the AAA and the AXB algorithms used by the Varian Eclipse treatment planning system (Varian Medical Systems, Palo Alto, USA) were capable of providing sufficiently accurate dose calculations to allow this planning system to be used to evaluate the effects of bolus errors on dose distributions from VMAT treatments of the nose. Thereafter, the AAA and AXB algorithms were used to calculate the dosimetric effects of applying a range of simulated errors to the design of a virtual bolus, to identify QA tolerances that could be used to avoid clinically significant effects from common printing errors. Results were generally consistent, whether the treatment target was superficial and treated with counter-rotating coplanar arcs or more-penetrating and treated with noncoplanar arcs, and whether the dose was calculated using the AAA algorithm or the AXB algorithm. The results of this study suggest the following QA tolerances are advisable, when 3D printed bolus is fabricated for use in photon VMAT treatments of the nose: bolus relative electron density variation within [Formula: see text] (although an action level at [Formula: see text] may be permissible); bolus thickness variation within [Formula: see text] mm (or 0.5 mm variation on opposite sides); and air gap between bolus and skin [Formula: see text] mm. These tolerances should be investigated for validity with respect to other treatment modalities and anatomical sites. This study provides a set of baselines for future comparisons and a useful method for identifying additional or alternative 3D printed bolus QA tolerances.

148 Acute Renal Infarcts from Spontaneous Intra-Renal Dissection

Spontaneous renal artery dissection and acute renal infarcts are rare occurrences and often misdiagnosed in clinical practice. We present four male patients, between 30-50 years of age, who have no underlying cardiac conditions, hypertension, or diabetes mellitus. They presented with abdominal/loin/flank pain due to spontaneous renal artery dissection and were all treated with endovascular stenting. Two patients had renal artery fibromuscular dysplasia, confirmed by CT angiogram, a rare pathology which is reported in literature to mostly affect women. All four patients recovered fully from the operation, with no post-operative complications noted. These patients were post-operatively managed medically with anti-platelet therapy for two years and did not experience any post-procedural complications at their 24-month follow up. Classically visceral artery dissection can be managed by anti-platelet therapy alone, however fibromuscular dysplasia can cause spontaneous dissection with renal infarcts and this requires urgent treatment with endovascular stents. Further research is needed on the post-procedural medical management guidelines.

Barriers to and Facilitators of Cervical Cancer Screening among Women in Southeast Asia: A Systematic Review

In Southeast Asia, cervical cancer is the second most common cancer in women. Low coverage for cervical cancer screening (CCS) becomes a roadblock to disease detection and treatment. Existing reviews on CCS have limited insights into the barriers and facilitators for SEA. Hence, this study aims to identify key barriers and facilitators among women living in SEA. A systematic literature review was conducted on Pubmed, Embase, PsycINFO, CINAHL, and SCOPUS. Primary qualitative and quantitative studies published in English that reported barriers and facilitators to CCS were included. The Mix Methods Appraisal Tool was used for the quality assessment of the included studies. Among the 93 included studies, pap smears (73.1%) were the most common screening modality. A majority of the studies were from Malaysia (35.5%). No studies were from Timor-Leste and the Philippines. The most common barriers were embarrassment (number of articles, n = 33), time constraints (n = 27), and poor knowledge of screening (n = 27). The most common facilitators were related to age (n = 21), receiving advice from healthcare workers (n = 17), and education status (n = 11). Findings from this review may inform health policy makers in developing effective cervical cancer screening programs in SEA countries.

The utility of postoperative radiotherapy in intermediate-risk oral squamous cell carcinoma

The effectiveness of postoperative radiotherapy (PORT) in improving outcomes remains debatable for oral squamous cell carcinoma (OSCC) patients with pathological intermediate-risk factors (IRFs) after surgery. A retrospective analysis was conducted on 432 intermediate-risk OSCC patients defined by histological reporting of close margin (<5mm), early nodal disease (pN1), depth of invasion/tumour thickness ≥5mm, perineural invasion, and/or lymphovascular invasion. Outcomes measured were disease-free survival (DFS), disease-specific survival (DSS), and overall survival (OS). PORT was associated with an improvement in 5-year DFS on univariable analysis (80% vs 71%; P=0.044), but this did not remain significant on multivariable analysis. PORT was not associated with differences in DSS or OS. The surgical salvage rate was similar in the PORT and surgery-only groups (41% vs 47%; P=0.972). Perineural invasion was found to be an independent predictor of inferior DSS (hazard ratio (HR) 2.19), DFS (HR 1.89), and OS (HR 1.97). Significantly worse outcomes were observed for patients with ≥4 concurrent IRFs. The application of PORT was associated with lower rates of recurrence, but the benefit was less apparent on mortality. Patients with perineural invasion and multiple concurrent IRFs were found to be at greatest risk, representing a subset of intermediate-risk OSCC patients who may benefit from PORT.

Refill Adherence Measures and Its Association with Economic, Clinical, and Humanistic Outcomes Among Pediatric Patients: A Systematic Review

Although refill adherence measures (RAMs) are widely reviewed on their use among adult patients, existing reviews on adherence among children have only focused on self-report measures and electronic monitoring. Hence, this systematic review aims to examine the use of RAMs and their association with economic, clinical, and humanistic outcomes (ECHO) among pediatric patients. A literature search was conducted in Pubmed, Embase, CINAHL, and PsycINFO. Studies published in English involving subjects aged ≤18 years were included if RAMs were analyzed with ECHO. Of the 35 included studies, the majority (n = 33) were conducted in high-income countries. Asthma was the most common condition (n = 9) studied. Overall, 60.6% of 33 clinical outcomes reported among 22 studies was positive (improved clinical outcomes with improved adherence), while 21.9% of 32 economic outcomes reported among 16 studies was positive (reduced healthcare utilization or cost outcomes with improved adherence). Only four studies evaluated the relationship of adherence with 11 humanistic outcomes, where the majority (72.7%) were considered unclear. RAMs are associated with ECHO and can be considered for use in the pediatric population. Future studies could explore the use of RAMs in low-income countries, and the association of RAMs with quality of life.

Characterization of a hepatitis C virus-like particle vaccine produced in a human hepatocyte-derived cell line

An effective immune response against hepatitis C virus (HCV) requires the early development of multi-specific class 1 CD8+ and class II CD4+ T-cells together with broad neutralizing antibody responses. We have produced mammalian-cell-derived HCV virus-like particles (VLPs) incorporating core, E1 and E2 of HCV genotype 1a to produce such immune responses. Here we describe the biochemical and morphological characterization of the HCV VLPs and study HCV core-specific T-cell responses to the particles. The E1 and E2 glycoproteins in HCV VLPs formed non-covalent heterodimers and together with core protein assembled into VLPs with a buoyant density of 1.22 to 1.28 g cm-3. The HCV VLPs could be immunoprecipited with anti-ApoE and anti-ApoC. On electron microscopy, the VLPs had a heterogeneous morphology and ranged in size from 40 to 80 nm. The HCV VLPs demonstrated dose-dependent binding to murine-derived dendritic cells and the entry of HCV VLPs into Huh7 cells was blocked by anti-CD81 antibody. Vaccination of BALB/c mice with HCV VLPs purified from iodixanol gradients resulted in the production of neutralizing antibody responses while vaccination of humanized MHC class I transgenic mice resulted in the prodution of HCV core-specific CD8+ T-cell responses. Furthermore, IgG purified from the sera of patients chronically infected with HCV genotypes 1a and 3a blocked the binding and entry of the HCV VLPs into Huh7 cells. These results show that our mammalian-cell-derived HCV VLPs induce humoral and HCV-specific CD8+ T-cell responses and will have important implications for the development of a preventative vaccine for HCV.

The roller coaster flight strategy of bar-headed geese conserves energy during Himalayan migrations

The physiological and biomechanical requirements of flight at high altitude have been the subject of much interest. Here, we uncover a steep relation between heart rate and wingbeat frequency (raised to the exponent 3.5) and estimated metabolic power and wingbeat frequency (exponent 7) of migratory bar-headed geese. Flight costs increase more rapidly than anticipated as air density declines, which overturns prevailing expectations that this species should maintain high-altitude flight when traversing the Himalayas. Instead, a "roller coaster" strategy, of tracking the underlying terrain and discarding large altitude gains only to recoup them later in the flight with occasional benefits from orographic lift, is shown to be energetically advantageous for flights over the Himalayas.

The effect of carbon dioxide flow rate on the euthanasia of laboratory mice

Laboratory rodents are commonly euthanized by exposure to gradually increasing concentrations of carbon dioxide (CO2). Current recommended flow rates range between 10 and 30% chamber vol/min and result in insensibility before exposure to painful concentrations (<40%). However, this method causes dyspnea, indicated by deep, rapid breathing. In humans dyspnea is associated with a negative affective experience. Sensations of dyspnea may explain why rodents find CO2 concentrations >3% aversive. This study aimed to assess the effect of CO2 flow rates on time between the onset of dyspnea and various measures of insensibility (recumbency, loss of the righting reflex and loss of the pedal withdrawal reflex) to identify flow rates that minimize the potential experience of dyspnea. The results of this study indicate that a flow rate of 50% chamber vol/min, while holding the CO2 cage concentration just below 40%, minimizes the interval between the onset of labored breathing and recumbency. Using a 50% flow rate this interval averaged (± SE) 30.3 ± 2.9 s versus 49.7 ± 2.9 s at 20% chamber vol/min (F3,22 = 7.83, P = 0.0013). Similarly, the interval between the onset of labored breathing and loss of the righting reflex averaged 38.2 ± 2.4 s at a flow rate of 50% versus 59.2 ± 2.4 s at 20% chamber vol/min of CO2 (F3,22 = 13.62, P < 0.0001). We conclude that higher flow rates reduce the duration of dyspnea, but even at the highest flow rate mice experience more than 30 s between the onset of dyspnea and the most conservative estimate of insensibility.

The paradox of extreme high-altitude migration in bar-headed geese Anser indicus

Bar-headed geese are renowned for migratory flights at extremely high altitudes over the world's tallest mountains, the Himalayas, where partial pressure of oxygen is dramatically reduced while flight costs, in terms of rate of oxygen consumption, are greatly increased. Such a mismatch is paradoxical, and it is not clear why geese might fly higher than is absolutely necessary. In addition, direct empirical measurements of high-altitude flight are lacking. We test whether migrating bar-headed geese actually minimize flight altitude and make use of favourable winds to reduce flight costs. By tracking 91 geese, we show that these birds typically travel through the valleys of the Himalayas and not over the summits. We report maximum flight altitudes of 7290 m and 6540 m for southbound and northbound geese, respectively, but with 95 per cent of locations received from less than 5489 m. Geese travelled along a route that was 112 km longer than the great circle (shortest distance) route, with transit ground speeds suggesting that they rarely profited from tailwinds. Bar-headed geese from these eastern populations generally travel only as high as the terrain beneath them dictates and rarely in profitable winds. Nevertheless, their migration represents an enormous challenge in conditions where humans and other mammals are only able to operate at levels well below their sea-level maxima.

NCIC-CTG MA.20: An intergroup trial of regional nodal irradiation in early breast cancer

LBA1003

Background: Randomized trials have demonstrated that locoregional radiation after mastectomy reduces locoregional recurrence and improves overall survival (OS) in women with node positive breast cancer treated with adjuvant systemic therapy. MA.20 evaluated the addition of regional nodal irradiation (RNI) to whole breast irradiation (WBI) following breast conserving surgery (BCS). Methods: Women with high risk node-negative or node-positive breast cancer treated with BCS and adjuvant chemotherapy and/or endocrine therapy were stratified by positive nodes, axillary nodes removed, chemo- and endocrine therapy and randomized to WBI (50Gy in 25 fractions +/- boost irradiation) or WBI plus RNI (45Gy in 25 fractions) to the internal mammary, supraclavicular, and high axillary lymph nodes. The primary outcome was OS. The Data Safety Monitoring Committee approved the analysis plan for the protocol specified interim analysis of relapse patterns, survival and toxicity at 5 years. Upon review of the data, they recommended release of the results. Results: Between March 2000 to March 2007, 1,832 women were randomly assigned to WBI+RNI (916) or WBI (916). Median follow-up was 62 months. Characteristics of the study population were: mean age, 53.3 years; node negative, 10%; 1-3 positive nodes, 85%; > 4 positive nodes, 5%; adjuvant chemotherapy, 91%; and adjuvant endocrine therapy, 71%. WBI+RNI in comparison to WBI alone was associated with an improvement in isolated locoregional disease free survival (DFS; HR=.59, p=.02, 5 year risk: 96.8% and 94.5% respectively), distant DFS (HR=.64, p=.002, 5 year risk: 92.4% and 87.0% respectively), DFS (HR=.68, p=.003, 5 year risk: 89.7% and 84.0% respectively) and OS (HR=.76, p=.07, 5 year risk: 92.3% and 90.7% respectively). WBI+RNI in comparison to WBI was associated with an increase in grade 2 or greater pneumonitis (1.3% and 0.2% respectively, p=.01), and lymphedema (7.3% and 4.1% respectively, p=.004). Conclusions: The majority of women with node positive breast cancer are now managed by BCS followed by WBI and adjuvant systemic therapy. Results from MA.20 demonstrate that additional RNI reduces the risk of locoregional and distant recurrence, and improves DFS with a trend in improved OS.

Bioactive Hydroxyapatite-Polysulfone Composite for Tissue Replacement

A new composite material consisting of hydroxyapatite (HA) and polysulfone (PSU) was produced and evaluated for potential medical applications. The HA/PSU composite containing up to 40vol% of particulate HA was manufactured via a standardised procedure which included drying, compounding, and injection or compression moulding. Defect-free composite samples (bars, discs and dumbbell specimens) could be obtained by injection moulding. Thick composite plates suitable for making fatigue specimens were compression moulded. Both compounded materials and moulded parts were assessed using various techniques. It was found that HA particles were well dispersed in the PSU matrix. Thermogravimetric analysis verified the amount of HA in the composite. Density close to the theoretical value could be achieved for the composite, indicating a void-free structure. Differential scanning calorimetry results indicated that the glass transition temperature of the polymer matrix was not significantly affected by the incorporation of HA. Rheological analysis revealed that PSU and the composite exhibited pseudoplastic flow behaviour at processing temperatures. It was shown that the hardness and modulus of the composite were increased with an increase in HA volume percentage.

Associations between CMS's Clinical Performance Measures project benchmarks, profit structure, and mortality in dialysis units

Prior studies observing greater mortality in for-profit dialysis units have not captured information about benchmarks of care. This study was undertaken to examine the association between profit status and mortality while achieving benchmarks. Utilizing data from the US Renal Data System and the Centers for Medicare & Medicaid Services' end-stage renal disease (ESRD) Clinical Performance Measures project, hemodialysis units were categorized as for-profit or not-for-profit. Associations with mortality at 1 year were estimated using Cox regression. Two thousand six hundred and eighty-five dialysis units (31,515 patients) were designated as for-profit and 1018 (15,085 patients) as not-for-profit. Patients in for-profit facilities were more likely to be older, black, female, diabetic, and have higher urea reduction ratio (URR), hematocrit, serum albumin, and transferrin saturation. Patients (19.4 and 18.6%) in for-profit and not-for-profit units died, respectively. In unadjusted analyses, profit status was not associated with mortality (hazard ratio (HR)=1.04, P=0.09). When added to models with profit status, the following resulted in a significant association between profit status (for-profit vs not-for-profit) and increasing mortality risk: URR, hematocrit, albumin, and ESRD Network. In adjusted models, patients in for-profit facilities had a greater death risk (HR 1.09, P=0.004). More patients in for-profit units met clinical benchmarks. Survival among patients in for-profit units was similar to not-for-profit units. This suggests that in the contemporary era, interventions in for-profit dialysis units have not impaired their ability to deliver performance benchmarks and do not affect survival.

A risk index for early node-negative breast cancer

BACKGROUND

This study compared the application of the St Gallen 2001 classification with a risk index developed at the New South Wales Breast Cancer Institute (BCI Index) for women with node-negative breast cancer treated without adjuvant systemic therapy.

METHODS

The BCI risk categories were constructed by identifying combinations of prognostic indicators that produced homogeneous low-, intermediate- and high-risk groups using the same variables as in the St Gallen classification.

RESULTS

The BCI low-risk category consisted of women aged 35 years or more with a grade 1 oestrogen receptor (ER)-positive tumour 20 mm or less in diameter, or with a grade 2 ER-positive tumour of 15 mm or less. This category constituted 40.1 per cent of patients, with a 10-year distant relapse-free survival (DRFS) rate of 97.2 per cent. The BCI intermediate-risk category included women aged 35 years or more with a grade 2 ER-positive tumour of diameter 16-20 mm, or a grade 1 or 2 ER-negative tumour measuring 15 mm or less, and comprised 12.1 per cent of the women, with a 10-year DRFS rate of 88 per cent. The high-risk category comprised 47.7 per cent of women, with a 10-year DRFS rate of 68.4 per cent.

CONCLUSION

If confirmed in other data sets, the BCI Index may be used to identify women at low risk of distant relapse (2.8 per cent at 10 years) who are unlikely to benefit from adjuvant systemic therapy, and women at intermediate risk of distant relapse (12 per cent at 10 years) in whom the benefit of adjuvant systemic therapy is small.

Temporal changes in the control of blood pressure in an older Australian population

Trends in blood pressure prevalence and control have important public health implications. We aim to document trends in hypertension prevalence, awareness and control in the older Australian population, a group at greatest risk of blood pressure related diseases. The Blue Mountains Eye Study (BMES) is a population-based study of residents aged 49 years or older, in two postcode areas of the Blue Mountains, Australia. The first cross-section (BMES I, 1992-1994) included 3654 participants (82.4% of eligible). The second cross-section (BMES II, 1997-2000) included 3509 participants, 2335 (75.1% of BMES I survivors) and 1174 (85.2% of newly eligible residents who qualified because of age or moved into the area). Detailed history and examinations were conducted. The prevalence of hypertension increased significantly from 45.4% (95% confidence interval, CI 43.7-47.0%) to 52.2% (CI 50.6-53.9%) from 1992-1994 to 1997-2000, paralleled by an increase in the population mean body mass index (BMI) from 26.1 kg/m2 (CI 26.0-26.3 kg/m2) to 27.7 kg/m2 (CI 27.5-27.9 kg/m2). Hypertension awareness decreased significantly from 79.8 to 73.0%, while treatment and control rates decreased from 71.1 to 67.3% and 56.3 to 46.5%, respectively (P<0.0001). Our results showed that elevated BMI (P<0.0001), lack of exercise (P<0.002) and serum triglyceride >2 mmol/l (P<0.0001) were significantly associated with prevalence of hypertension. We found that the prevalence of hypertension in the older Australian population was increasing while awareness, treatment and control rates decreased. Programmes to improve community awareness of hypertension, and its association with BMI may lead to further reductions in blood pressure and the burden of cardiovascular disease.

Consequences of amblyopia on education, occupation, and long term vision loss

AIMS

To describe the effect of amblyopia on education, occupation, and 5 year incident vision loss.

METHODS

3654 participants aged 49 years or older participated in the Blue Mountains Eye Study (BMES I, 1992-4) and 2335 (75.1% of survivors) were re-examined (BMES II, 1997-9). All participants underwent detailed eye examination. Amblyopia, defined as best corrected visual acuity of less than or equal to 6/9 and not attributable directly to any underlying structural abnormality of the eye or the visual pathway, was identified in 118 participants (3.2%) in BMES I, of whom 73 were re-examined in BMES II. Occupation and educational classifications used definitions of the Australian Bureau of Statistics.

RESULTS

The mean age of people with amblyopia seen at baseline was 67.0 years. Amblyopia did not affect lifetime occupational class (p = 0.5), but fewer people completed higher university degrees (p = 0.05). In people with amblyopia, there was an increased risk of 5 year incident visual impairment in the better seeing eye worse than 6/12, relative risk (RR) 2.7, 95% confidence interval (CI) 1.6 to 4.6. One of 11 (9.1%) people with amblyopia showed significant improvement in visual acuity in the poorer seeing eye after a two line (10 logMAR letter) vision loss in the better seeing eye.

CONCLUSION

This study further documents the longitudinal history of amblyopia using population based data.

Use of the St Gallen classification for patients with node-negative breast cancer may lead to overuse of adjuvant chemotherapy

BACKGROUND

The 1998 St Gallen classification was devised to guide clinicians in the use of adjuvant systemic therapy for women with early breast cancer. In this study, the classification was applied to a historical group of patients with node-negative breast cancer who were treated without adjuvant therapy.

METHODS

The St Gallen classification was applied to 421 women with breast cancer treated with conservative surgery and radiotherapy alone between 1979 and 1994. Primary tumour characteristics were reviewed centrally.

RESULTS

When the most stringent version of the St Gallen classification was applied (grade 2 or 3 tumours classified as "high risk"), only 10 per cent of patients were "low risk", with a 10-year distant relapse-free survival (DRFS) rate of 100 per cent, and 15 per cent were at "intermediate risk" (10-year DRFS rate of 94 per cent). The high-risk group (75 per cent of women) had a 10-year DRFS rate of 77 per cent (P < 0.01). If the St Gallen classification had been applied to all patients in this series who were aged less than 70 years, up to 91 per cent would have been recommended to have chemotherapy.

CONCLUSION

The St Gallen classification is an inaccurate measure of prognosis for patients with node-negative breast cancer and should be used with caution.

Effects of pair versus individual housing on the behavior and performance of dairy calves

This study compared the health, performance, and behavior of individually and pair-housed calves fed milk ad libitum by artificial teats. Calves were separated from their dams within 24 h of birth and assigned to housing in either a single pen (10 calves) or a group pen (10 pairs of pair-housed calves). Calves were gradually weaned at approximately 5 wk of age and remained on the experiment until wk 8. Behavior was video recorded during wk 2 to 8. Before and after weaning, calves gained weight steadily with no differences between treatments. During the week of weaning, pair-housed calves continued to gain weight normally, but the individually housed calves experienced a growth check. There were no differences between groups in the amounts of milk, starter, or hay consumed, or in the incidence of scouring. There were also no differences in the amount of time spent self-grooming, sucking on the teat, or lying down. However, pair-housed calves spent more time standing inactive, more time moving, and less time with their head out of the pen than individually housed animals. Paired calves spent approximately 2% of the day in social contact, and the incidences of agonistic behavior and cross-sucking were very low. These results indicate that housing dairy calves in pairs allows benefits such as increased space for movement and social opportunities with no disadvantages in health and weight gains.

Frequency and predictors of axillary lymph node metastases in invasive breast cancer

BACKGROUND

The objectives of the present study were to evaluate the incidence and predictors of axillary lymph node metastases (ALNM) in patients with breast cancer, and to identify if axillary surgery could be safely omitted in selected patients.

METHODS

Between January 1996 and May 2000, 492 patients underwent 501 axillary lymph node dissections (ALND). The incidence of ALNM was correlated with clinical and pathological characteristics by univariate and multivariate analyses.

RESULTS

Axillary lymph node metastases were found in 41% (207/501) of cases. Univariate analysis showed that palpability of primary and axillary lymph node (ALN), pathological tumour size, grade, lymphovascular invasion (LVI) and multifocality or multicentricity were significant predictors of ALNM. By multivariate analysis, palpability of ALN, pathological tumour size, LVI and multifocality or multicentricity remained as independent predictors. Among the 431 cases without palpable ALN, no ALNM were found if the tumour was < or = 5 mm, non-multifocal or multicentric, and without LVI, or the tumour was a tubular or mucinous carcinoma < or = 15 mm (n = 21). The frequency of ALNM in the absence of the other risk factors was 11% (7/64) if the tumour size was > 5-10 mm, and 17% (19/113) if the tumour was > 10-20 mm. However, the incidence of ALNM was 72% for the 32 clinically node-negative cases with multifocal or multicentric tumour > or = 10 mm and LVI. Those patients with palpable ALN (n = 66) had a greater than 50% risk of ALNM.

CONCLUSIONS

Routine ALND could be omitted in clinically node-negative patients with either a < or = 5-mm, LVI-negative tumour, or a < or = 15-mm tubular or mucinous carcinoma. Axillary lymph node dissection is still useful for determining pathological nodal status in all other cases, and in most cases with palpable ALN, as a therapeutic manoeuvre.

Treatment of the axilla in early breast cancer: past, present and future

BACKGROUND

The optimal treatment of the axilla in early breast cancer is controversial. The present study reviews the pattern and predictors of regional recurrence (RR) and prognosis after RR in patients with early breast cancer treated by conservative surgery and radiotherapy (CS + RT). Implications of the results on current practice and future directions are explored.

METHODS

Between 1979 and 1994, 1158 patients with stage I or II breast cancer were treated with CS + RT at Westmead Hospital. Two groups of patients were compared: 782 patients who underwent axillary dissection (axillary surgery group) and 229 patients who received radiotherapy (axillary RT group) as the only axillary treatment. At least 10 lymph nodes were dissected in 82% of the axillary surgery group. Of the women in the RT group, 90% received RT to the axilla and supraclavicular fossa (SCF) only and 10% also received RT to the internal mammary chain (IMC).

RESULTS

With a median follow-up period of 79 months for the axillary surgery group and 111 months for the axillary RT group, 27 patients developed a RR (2.8% and 2.2%, respectively). Seven patients (0.9%) in the axillary surgery group and three patients (1.3%) in the axillary RT group developed a RR in the axilla (P, not significant). Of the patients with SCF recurrences, 14 (1.8%) were in the axillary surgery group and one (0.4%) in the axillary RT group (P, not significant). One patient in the axillary surgery group developed concurrent axillary and SCF recurrences, while a patient in the axillary RT group developed an IMC recurrence. Twenty (74%) of the 27 patients with a RR developed a concurrent or subsequent distant relapse (30% and 44%, respectively). In the pathologically node-positive patients, the axillary recurrence rate was higher in those who had less than five nodes removed (17%) than those who had 10 or more nodes removed (0%; P = 0.01). The SCF recurrence rate was higher in patients with four or more positive axillary nodes (9.5%) than in those with 0-3 positive nodes (1.5%; P = 0.003).

CONCLUSION

Adequate treatment of the axilla by surgery or RT alone is associated with a low rate of RR. The incidence of distant relapse was substantial in patients who developed a RR, which gives emphasis to the importance of optimizing local-regional control.

Estimating the benefits of adjuvant systemic therapy for women with early breast cancer

BACKGROUND

Prognostic factors are commonly used to help identify women with node-negative breast cancer at high risk of recurrence. Although many are available, knowing which risk factor or combination of factors to use to estimate prognosis for an individual woman is often difficult. This study documented the baseline prognoses for a group of women with node-negative breast cancers, and estimated the potential benefits of adjuvant systemic therapy.

METHODS

Ten-year, actuarial, cause-specific survival based on tumour size and histological grade using data from the Swedish Two-County Trial of mammographic screening was calculated for 1200 women with node-negative cancers of less than 30 mm diameter. The benefits of adjuvant systemic therapy for these women were then estimated using the published odds reductions in death from adjuvant systemic therapy from the Early Breast Cancer Trialists' Collaborative Group overview.

RESULTS

The absolute 10-year survival benefits for subgroups of women based on tumour size and histological grade were estimated for women aged under 50 years by the addition of chemotherapy, and over 50 years by the addition of tamoxifen and/or chemotherapy.

CONCLUSION

Decisions about adjuvant systemic therapy in women with node-negative breast cancer need to be individualized, taking into account treatment efficacy and toxicity. The quantitative methods presented in this paper facilitate such decisions.

Treatment implications of a positive sentinel lymph node biopsy for patients with early-stage breast carcinoma

BACKGROUND

Sentinel lymph node (SLN) mapping and biopsy is emerging as an alternative to axillary lymph node dissection (ALND) in determining the lymph node status of patients with early-stage breast carcinoma. The hypothesis of the technique is that the SLN is the first lymph node in the regional lymphatic basin that drains the primary tumor. Non-SLN (NSLN) metastasis in the axilla is unlikely if the axillary SLN shows no tumor involvement, and, thus, further axillary interference may be avoided. However, the optimal treatment of the axilla in which an SLN metastasis is found requires ongoing evaluation. The objectives of this study were to evaluate the predictors for NSLN metastasis in the presence of a tumor-involved axillary SLN and to examine the treatment implications for patients with early-stage breast carcinoma.

METHODS

Between June 1998 and May 2000, 167 patients participated in the pilot study of SLN mapping and biopsy at Westmead Hospital. SLNs were identified successfully and biopsied in 140 axillae. All study patients also underwent ALND. The incidence of NSLN metastasis in the 51 patients with a SLN metastasis was correlated with clinical and pathologic characteristics.

RESULTS

Of 51 patients with a positive SLN, 24 patients (47%) had NSLN metastases. The primary tumor size was the only significant predictor for NSLN involvement. NSLN metastasis occurred in 25% of patients (95% confidence interval [95%CI], 10-47%) with a primary tumor size </= 20 mm and in 67% of patients (95%CI, 46-83%) with a primary tumor size > 20 mm (P = 0.005). The size of the SLN metastasis was not associated significantly with NSLN involvement. Three of 7 patients (43%) with an SLN micrometastasis (< 1 mm) had NSLN involvement compared with 38 of 44 patients (48%) with an SLN macrometastasis (> or = 1 mm).

CONCLUSIONS

The current study did not identify a subgroup of SLN positive patients in whom the incidence of NSLN involvement was low enough to warrant no further axillary interference. At present, a full axillary dissection should be performed in patients with a positive SLN.

Production and evaluation of hydroxyapatite reinforced polysulfone for tissue replacement

A variety of bioactive composites have been developed for tissue replacement over the last two decades. In this investigation, a new material consisting of hydroxyapatite (HA) and polysulfone (PSU) was produced and evaluated for potential medical applications. The HA/PSU composite containing up to 20 vol % of HA was studied at the initial stage. It was manufactured via a standardized procedure which included drying, blending, compounding and injection/compression molding. Defect-free composite samples (rectangular bars, discs and dumbbell specimens) could be obtained by injection molding. Thick composite plates could be made by compression molding. Both compounded materials and molded parts were assessed using a variety of techniques. It was found through scanning electron microscopy (SEM) that HA particles were well dispersed in the PSU matrix. Thermogravimetric analysis (TGA) verified the amount of HA in the composite. Differential scanning calorimetry (DSC) results indicated that the glass transition temperature (Tg) of the polymer matrix was not affected by the incorporation of HA. Rheological analysis revealed that PSU and the composite exhibited pseudoplastic behavior. For unfilled PSU, its viscosity decreased with an increase in temperature. The viscosity of HA/PSU composite increased with an increase in the HA volume fraction. It was shown through dynamic mechanical analysis (DMA) that the storage modulus of the composite was increased with an increase in HA volume percentage below Tg of the polymer, while tan delta was maintained at nearly the same level. It was established that water uptake reached an equilibrium after 7 days' immersion in distilled water for PSU and HA/PSU composite. After 7 days' immersion in distilled water, the storage modulus of the composite was decreased less than that of PSU.

Reabsorption of lung liquid produced by 2,4-dinitrophenol in in vitro lungs from fetal guinea pigs

Lungs from near-term fetal guinea pigs (62 +/- 2 days of gestation) were supported in vitro for 3 h, and lung liquid production was measured by a dye dilution technique. Twelve untreated preparations produced fluid at 1.54 +/- 0.29 mL.kg-1 body weight.h-1 during the 1st h, with no significant changes in later hours. Twelve preparations treated with 2 x 10(-4) M 2,4-dinitrophenol (DNP) showed strong reabsorptions (significant, ANOVA and regression analysis); total loss of lactate from the preparations doubled (significant, same tests). In 12 additional preparations, increasing DNP fivefold did not abolish reabsorption; results resembled those at the lower concentration. Amiloride at 10(-6) M abolished reabsorptions after 2 x 10(-4) M DNP, although fluid production still halted (n = 6; reductions significant, same tests). Amiloride alone had no effect (n = 6); untreated controls showed no change (n = 6). Similarly, 10(-4) M sodium iodoacetate virtually abolished reabsorptions after 2 x 10(-4) M DNP, although fluid production still stopped (n = 6; reductions significant, same tests). Iodoacetate alone only reduced fluid production (n = 6; significant, same tests); untreated controls showed no change (n = 6). The results suggest that reabsorptions seen after inhibition of oxidative processes depend on amiloride-sensitive Na+ channels and glycolytic metabolism.

Effects of cardiac work and leucine on protein turnover

The purpose of these experiments was to assess effects of cardiac work and leucine in hearts supplied only glucose or substrate and hormone mixtures that simulated plasma. Rates of protein degradation greatly exceeded protein synthesis in Langendorff preparations supplied glucose. This severely negative nitrogen balance was brought closer to zero by provision of more complete substrate mixtures. Cardiac work further improved the nitrogen balance by stimulating protein synthesis in hearts supplied glucose (mixture 1), glucose-insulin-glucagon-lactate-beta-hydroxybutyrate (mixture 2), or palmitate-beta-hydroxybutyrate-glucose (mixture 3) and inhibiting protein degradation in hearts supplied glucose. Cardiac work did not affect the rates of either protein synthesis or degradation in hearts provided insulin-lactate-glucose (mixture 4). The increase in protein synthesis was associated with increased rates of peptide chain initiation. Addition of 1 mM leucine had an additional effect to restore nitrogen balance to zero or to achieve positive balance in working hearts supplied substrate and hormone mixture 2.

Effect of leucine and metabolites of branched chain amino acids on protein turnover in heart

Leucine, but not isoleucine or valine, inhibited protein degradation and accelerated protein synthesis in hearts perfused with buffer that contained glucose (15 mM) and normal plasma levels of other amino acids, except for the branched chain compounds. Products of leucine, isoleucine, and valine metabolism also inhibited protein degradation and stimulated protein synthesis. These compounds included the transamination and decarboxylation products, as well as acetate, acetoacetate, and propionate. In some, but not all instances, inhibition of degradation and acceleration of synthesis were accompanied by an increase in intracellular leucine. When insulin was added to the perfusate, the rate of degradation was reduced by 40%, but addition of leucine was ineffective in the presence of the hormone. Insulin, leucine (2 mM) and a mixture of branched chain amino acids at normal plasma levels increased latency of cathepsin D in hearts that were perfused with buffer containing glucose. A combination of leucine and insulin increased latency more than either substance alone. These studies indicate that leucine as well as a variety of substrates that are oxidized in the citric acid cycle are involved in regulation of protein turnover in heart muscle.

Effects of experimental diabetes and food intake on rat intestine and serum alkaline phosphatase

Alkaline phosphatase activity of rat serum was reduced 50% by fasting the animal for 24 hours. Diabetes, induced by alloxan or streptozotocin, increased serum alkaline phosphatase 3- to 5-fold in fed rats and the elevated activity was reduced by insulin administration. In the absence of insulin, fasting alone was able to reduce the serum alkaline phosphatase of diabetic rats to control values. The elevated serum isozyme was found to be of intestinal origin by the use of appropriate inhibitors and electrophoretic mobility following neuraminidase treatment. It is concluded that food intake, particularly the hyperphagia of diabetes, plays a major role in regulating the concentration of intestine and serum alkaline phosphatase in the rat.