New tools suggest a middle Jurassic origin for mammalian endothermy: Advances in state-of-the-art techniques uncover new insights on the evolutionary patterns of mammalian endothermy through time: Advances in state-of-the-art techniques uncover new insights on the evolutionary patterns of mammalian endothermy through time

We suggest that mammalian endothermy was established amongst Middle Jurassic crown mammals, through reviewing state-of-the-art fossil and living mammal studies. This is considerably later than the prevailing paradigm, and has important ramifications for the causes, pattern, and pace of physiological evolution amongst synapsids. Most hypotheses argue that selection for either enhanced aerobic activity, or thermoregulation was the primary driver for synapsid physiological evolution, based on a range of fossil characters that have been linked to endothermy. We argue that, rather than either alternative being the primary selective force for the entirety of endothermic evolution, these characters evolved quite independently through time, and across the mammal family tree, principally as a response to shifting environmental pressures and ecological opportunities. Our interpretations can be tested using closely linked proxies for both factors, derived from study of fossils of a range of Jurassic and Cretaceous mammaliaforms and early mammals.

A robust, semi-automated approach for counting cementum increments imaged with synchrotron X-ray computed tomography

Cementum, the tissue attaching mammal tooth roots to the periodontal ligament, grows appositionally throughout life, displaying a series of circum-annual incremental features. These have been studied for decades as a direct record of chronological lifespan. The majority of previous studies on cementum have used traditional thin-section histological methods to image and analyse increments. However, several caveats have been raised in terms of studying cementum increments in thin-sections. Firstly, the limited number of thin-sections and the two-dimensional perspective they impart provide an incomplete interpretation of cementum structure, and studies often struggle or fail to overcome complications in increment patterns that complicate or inhibit increment counting. Increments have been repeatedly shown to both split and coalesce, creating accessory increments that can bias increment counts. Secondly, identification and counting of cementum increments using human vision is subjective, and it has led to inaccurate readings in several experiments studying individuals of known age. Here, we have attempted to optimise a recently introduced imaging modality for cementum imaging; X-ray propagation-based phase-contrast imaging (PPCI). X-ray PPCI was performed for a sample of rhesus macaque (Macaca mulatta) lower first molars (n = 10) from a laboratory population of known age. PPCI allowed the qualitative identification of primary/annual versus intermittent secondary increments formed by splitting/coalescence. A new method for semi-automatic increment counting was then integrated into a purpose-built software package for studying cementum increments, to count increments in regions with minimal complications. Qualitative comparison with data from conventional cementochronology, based on histological examination of tissue thin-sections, confirmed that X-ray PPCI reliably and non-destructively records cementum increments (given the appropriate preparation of specimens prior to X-ray imaging). Validation of the increment counting algorithm suggests that it is robust and provides accurate estimates of increment counts. In summary, we show that our new increment counting method has the potential to overcome caveats of conventional cementochronology approaches, when used to analyse three-dimensional images provided by X-ray PPCI.

Synchrotron radiation-based X-ray tomography reveals life history in primate cementum incrementation

Cementum is a mineralized dental tissue common to mammals that grows throughout life, following a seasonally appositional rhythm. Each year, one thick translucent increment and one thin opaque increment is deposited, offering a near-complete record of an animal's life history. Male and female mammals exhibit significant differences in oral health, due to the contrasting effects of female versus male sex hormones. Oestrogen and progesterone have a range of negative effects on oral health that extends to the periodontium and cementum growth interface. Here, we use synchrotron radiation-based X-ray tomography to image the cementum of a sample of rhesus macaque (Macaca mulatta) teeth from individuals of known life history. We found that increased breeding history in females corresponds with increased increment tortuosity and less organized cementum structure, when compared to male and juvenile cementum. We quantified structural differences by measuring the greyscale 'texture' of cementum and comparing results using principal components analysis. Adult females and males occupy discrete regions of texture space with no overlap. Females with known pregnancy records also have significantly different cementum when compared with non-breeding and juvenile females. We conclude that several aspects of cementum structure and texture may reflect differences in sexual life history in primates.

Reptile-like physiology in Early Jurassic stem-mammals

Despite considerable advances in knowledge of the anatomy, ecology and evolution of early mammals, far less is known about their physiology. Evidence is contradictory concerning the timing and fossil groups in which mammalian endothermy arose. To determine the state of metabolic evolution in two of the earliest stem-mammals, the Early Jurassic Morganucodon and Kuehneotherium, we use separate proxies for basal and maximum metabolic rate. Here we report, using synchrotron X-ray tomographic imaging of incremental tooth cementum, that they had maximum lifespans considerably longer than comparably sized living mammals, but similar to those of reptiles, and so they likely had reptilian-level basal metabolic rates. Measurements of femoral nutrient foramina show Morganucodon had blood flow rates intermediate between living mammals and reptiles, suggesting maximum metabolic rates increased evolutionarily before basal metabolic rates. Stem mammals lacked the elevated endothermic metabolism of living mammals, highlighting the mosaic nature of mammalian physiological evolution.

The use of extruded finite-element models as a novel alternative to tomography-based models: a case study using early mammal jaws

Finite-element (FE) analysis has been used in palaeobiology to assess the mechanical performance of the jaw. It uses two types of models: tomography-based three-dimensional (3D) models (very accurate, not always accessible) and two-dimensional (2D) models (quick and easy to build, good for broad-scale studies, cannot obtain absolute stress and strain values). Here, we introduce extruded FE models, which provide fairly accurate mechanical performance results, while remaining low-cost, quick and easy to build. These are simplified 3D models built from lateral outlines of a relatively flat jaw and extruded to its average width. There are two types: extruded (flat mediolaterally) and enhanced extruded (accounts for width differences in the ascending ramus). Here, we compare mechanical performance values resulting from four types of FE models (i.e. tomography-based 3D, extruded, enhanced extruded and 2D) in Morganucodon and Kuehneotherium. In terms of absolute values, both types of extruded model perform well in comparison to the tomography-based 3D models, but enhanced extruded models perform better. In terms of overall patterns, all models produce similar results. Extruded FE models constitute a viable alternative to the use of tomography-based 3D models, particularly in relatively flat bones.

The role of miniaturization in the evolution of the mammalian jaw and middle ear

The evolution of the mammalian jaw is one of the most important innovations in vertebrate history, and underpins the exceptional radiation and diversification of mammals over the last 220 million years^1,2. In particular, the transformation of the mandible into a single tooth-bearing bone and the emergence of a novel jaw joint-while incorporating some of the ancestral jaw bones into the mammalian middle ear-is often cited as a classic example of the repurposing of morphological structures^3,4. Although it is remarkably well-documented in the fossil record, the evolution of the mammalian jaw still poses the paradox of how the bones of the ancestral jaw joint could function both as a joint hinge for powerful load-bearing mastication and as a mandibular middle ear that was delicate enough for hearing. Here we use digital reconstructions, computational modelling and biomechanical analyses to demonstrate that the miniaturization of the early mammalian jaw was the primary driver for the transformation of the jaw joint. We show that there is no evidence for a concurrent reduction in jaw-joint stress and increase in bite force in key non-mammaliaform taxa in the cynodont-mammaliaform transition, as previously thought^5-8. Although a shift in the recruitment of the jaw musculature occurred during the evolution of modern mammals, the optimization of mandibular function to increase bite force while reducing joint loads did not occur until after the emergence of the neomorphic mammalian jaw joint. This suggests that miniaturization provided a selective regime for the evolution of the mammalian jaw joint, followed by the integration of the postdentary bones into the mammalian middle ear.

Observation versus late reintroduction of letrozole as adjuvant endocrine therapy for hormone receptor-positive breast cancer (ANZ0501 LATER): an open-label randomised, controlled trial

BACKGROUND

Despite the effectiveness of adjuvant endocrine therapy in preventing breast cancer recurrence, breast cancer events continue at a high rate for at least 10 years after completion of therapy.

PATIENTS AND METHODS

This randomised open label phase III trial recruited postmenopausal women from 29 Australian and New Zealand sites, with hormone receptor-positive early breast cancer, who had completed ≥4 years of endocrine therapy [aromatase inhibitor (AI), tamoxifen, ovarian suppression, or sequential combination] ≥1 year prior, to oral letrozole 2.5 mg daily for 5 years, or observation. Treatment allocation was by central computerised randomisation, stratified by institution, axillary node status and prior endocrine therapy. The primary outcome was invasive breast cancer events (new invasive primary, local, regional or distant recurrence, or contralateral breast cancer), analysed by intention to treat. The secondary outcomes were disease-free survival (DFS), overall survival, and safety.

RESULTS

Between 16 May 2007 and 14 March 2012, 181 patients were randomised to letrozole and 179 to observation (median age 64.3 years). Endocrine therapy was completed at a median of 2.6 years before randomisation, and 47.5% had tumours of >2 cm and/or node positive. At 3.9 years median follow-up (interquartile range 3.1-4.8), 2 patients assigned letrozole (1.1%) and 17 patients assigned observation (9.5%) had experienced an invasive breast cancer event (difference 8.4%, 95% confidence interval 3.8% to 13.0%, log-rank test P = 0.0004). Twenty-four patients (13.4%) in the observation and 14 (7.7%) in the letrozole arm experienced a DFS event (log-rank P = 0.067). Adverse events linked to oestrogen depletion, but not serious adverse events, were more common with letrozole.

CONCLUSION

These results should be considered exploratory, but lend weight to emerging data supporting longer duration endocrine therapy for hormone receptor-positive breast cancer, and offer insight into reintroduction of AI therapy.

CLINICAL TRIALS NUMBER

Australian New Zealand Clinical Trials Registry (www.anzctr.org.au), ACTRN12607000137493.

Within-guild dietary discrimination from 3-D textural analysis of tooth microwear in insectivorous mammals

Resource exploitation and competition for food are important selective pressures in animal evolution. A number of recent investigations have focused on linkages between diversification, trophic morphology and diet in bats, partly because their roosting habits mean that for many bat species diet can be quantified relatively easily through faecal analysis. Dietary analysis in mammals is otherwise invasive, complicated, time consuming and expensive. Here we present evidence from insectivorous bats that analysis of three-dimensional (3-D) textures of tooth microwear using International Organization for Standardization (ISO) roughness parameters derived from sub-micron surface data provides an additional, powerful tool for investigation of trophic resource exploitation in mammals. Our approach, like scale-sensitive fractal analysis, offers considerable advantages over two-dimensional (2-D) methods of microwear analysis, including improvements in robustness, repeatability and comparability of studies. Our results constitute the first analysis of microwear textures in carnivorous mammals based on ISO roughness parameters. They demonstrate that the method is capable of dietary discrimination, even between cryptic species with subtly different diets within trophic guilds, and even when sample sizes are small. We find significant differences in microwear textures between insectivore species whose diet contains different proportions of 'hard' prey (such as beetles) and 'soft' prey (such as moths), and multivariate analyses are able to distinguish between species with different diets based solely on their tooth microwear textures. Our results show that, compared with previous 2-D analyses of microwear in bats, ISO roughness parameters provide a much more sophisticated characterization of the nature of microwear surfaces and can yield more robust and subtle dietary discrimination. ISO-based textural analysis of tooth microwear thus has a useful role to play, complementing existing approaches, in trophic analysis of mammals, both extant and extinct.

Independent predictors of breast malignancy in screen-detected microcalcifications: biopsy results in 2545 cases

Background:

Mammographic microcalcifications are associated with many benign lesions, ductal carcinoma in situ (DCIS) and invasive cancer. Careful assessment criteria are required to minimise benign biopsies while optimising cancer diagnosis. We wished to evaluate the assessment outcomes of microcalcifications biopsied in the setting of population-based breast cancer screening.

Methods:

Between January 1992 and December 2007, cases biopsied in which microcalcifications were the only imaging abnormality were included. Patient demographics, imaging features and final histology were subjected to statistical analysis to determine independent predictors of malignancy.

Results:

In all, 2545 lesions, with a mean diameter of 21.8 mm (s.d. 23.8 mm) and observed in patients with a mean age of 57.7 years (s.d. 8.4 years), were included. Using the grading system adopted by the RANZCR, the grade was 3 in 47.7% 4 in 28.3% and 5 in 24.0%. After assessment, 1220 lesions (47.9%) were malignant (809 DCIS only, 411 DCIS with invasive cancer) and 1325 (52.1%) were non-malignant, including 122 (4.8%) premalignant lesions (lobular carcinoma in situ, atypical lobular hyperplasia and atypical ductal hyperplasia). Only 30.9% of the DCIS was of low grade.

Mammographic extent of microcalcifications >15 mm, imaging grade, their pattern of distribution, presence of a palpable mass and detection after the first screening episode showed significant univariate associations with malignancy. On multivariate modeling imaging grade, mammographic extent of microcalcifications >15 mm, palpable mass and screening episode were retained as independent predictors of malignancy. Radiological grade had the largest effect with lesions of grade 4 and 5 being 2.2 and 3.3 times more likely to be malignant, respectively, than grade 3 lesions.

Conclusion:

The radiological grading scheme used throughout Australia and parts of Europe is validated as a useful system of stratifying microcalcifications into groups with significantly different risks of malignancy. Biopsy assessment of appropriately selected microcalcifications is an effective method of detecting invasive breast cancer and DCIS, particularly of non-low-grade subtypes.

Models in palaeontological functional analysis

Models are a principal tool of modern science. By definition, and in practice, models are not literal representations of reality but provide simplifications or substitutes of the events, scenarios or behaviours that are being studied or predicted. All models make assumptions, and palaeontological models in particular require additional assumptions to study unobservable events in deep time. In the case of functional analysis, the degree of missing data associated with reconstructing musculoskeletal anatomy and neuronal control in extinct organisms has, in the eyes of some scientists, rendered detailed functional analysis of fossils intractable. Such a prognosis may indeed be realized if palaeontologists attempt to recreate elaborate biomechanical models based on missing data and loosely justified assumptions. Yet multiple enabling methodologies and techniques now exist: tools for bracketing boundaries of reality; more rigorous consideration of soft tissues and missing data and methods drawing on physical principles that all organisms must adhere to. As with many aspects of science, the utility of such biomechanical models depends on the questions they seek to address, and the accuracy and validity of the models themselves.

Modeling the effects of cingula structure on strain patterns and potential fracture in tooth enamel

The mammalian cingulum is a shelf of enamel, which rings the base of the molar crown (fully or partially). Certain nonmammalian cynodonts show precursors of this structure, indicating that it may be an important dental character in the origins of mammals. However, there is little consensus as to what drove the initial evolution of the cingulum. Recent work on physical modeling of fracture mechanics has shown that structures which approximate mammalian dentition (hard enamel shell surrounding a softer/tougher dentine interior) undergo specific fracture patterns dependent on the material properties of the food items. Soft materials result in fractures occurring at the base of the stiff shell away from the contact point due to heightened tensile strains. These tensile strains occur around the margin in the region where cingula develop. In this article, we test whether the presence of a cingulum structure will reduce the tensile strains seen in enamel using basic finite element models of bilayered cones. Finite element models of generic cone shaped "teeth" were created both with and without cingula of various shapes and sizes. Various forces were applied to the models to examine the relative magnitudes and directions of average maximum principal strain in the enamel. The addition of a cingulum greatly reduces tensile strains in the enamel caused by "soft-food" forces. The relative shape and size of the cingulum has a strong effect on strain magnitudes as well. Scaling issues between shapes are explored and show that the effectiveness of a given cingulum to reducing tensile strains is dependent on how the cingulum is created. Partial cingula, which only surround a portion of the tooth, are shown to be especially effective at reducing strain caused by asymmetrical loads, and shed new light on the potential early function and evolution of mammalian dentitions.

Clinical and pathological factors predictive of lymph node status in women with screen-detected breast cancer

Two thousand one hundred and thirty five asymptomatic invasive breast cancers detected through screening mammography were analysed to identify predictors of lymph node involvement. Multivariable analysis indicated that predictors included larger tumour diameter, an infiltrating ductal or lobular histological type, multifocal disease, a palpable lesion, and a younger age at diagnosis. An association also was found between nodal involvement and the presence of an extensive in situ component (EIC). Grade was associated with nodal involvement as a univariate predictor. It would be more accurate for screening assessment clinics to use models for predicting nodal status that were customised to their own experience rather than generic models developed in other settings that related predominantly to symptomatic cancer. These models could assist clinical decision-making on axillary node dissection and give guidance to pathologists on numbers of tissue sections to examine.

Detection by screening mammography is a powerful independent predictor of survival in women diagnosed with breast cancer

Four hundred and sixteen invasive breast cancers, detected initially by mammography, were compared with 929 presenting symptomatically, all treated at a South Australian teaching hospital. Predictable differences included lower stages and grades, less vascular invasion and proliferative activity, and more hormone-receptor expression among the mammographically detected. Unpredicted differences included significantly higher survivals for mammographically detected cases throughout the 9 year follow-up period after adjusting for stage and the Nottingham Prognostic Index. In a multivariable analysis, differences in stage, grade, and hormone receptor expression accounted for only about half the survival advantage of mammographically detected tumours. Accounting for additional person and tumour characteristics had only a marginal effect on this result. This suggests that detection by mammography has independent favourable prognostic significance beyond that explained by conventional indicators. If confirmed, this finding would have important implications for the prognostic advice given to women and may merit further investigation into its underlying biological mechanisms.

Tumour location and prognostic characteristics as determinants of survival of women with invasive breast cancer: South Australian hospital-based cancer registries, 1987-1998

Survivals from breast cancer varied by location of lesion (P<0.001), with 10-year survivals of 61% applying for central (n=772), 73% for medial (n=350), and 72% for lateral (n=966) lesions. Univariate analyses of determinants of central locations indicated that the following were predictive: a more advanced TNM stage (P<0.001); a larger tumour diameter (P=0.002); a higher grade (P=0.032); a negative oestrogen receptor status (P=0.004); a negative progesterone receptor status (P=0.004); and histological type (P=0.011), with more of the lobular lesions being located centrally. Cox proportional hazards regression indicated that the relative risk (95% confidence limits) of case fatality for central, as opposed to other, lesions reduced from 1.46 (1.20, 1.78) to 1.16 (0.95, 1.41) when stage was added to the model, with no other factor having an additional conditioning effect. It is concluded that central lesions have worse outcomes, mostly due to their more advanced stages. Means of finding these tumours earlier should be investigated.

Removal of two sentinel nodes accurately stages the axilla in breast cancer

Background

Assessment of lymph node status in breast cancer is still necessary for staging. Sentinel lymph node biopsy (SNB) may provide accurate staging with less morbidity than axillary clearance. The aim of this study was to assess the effect of the number of sentinel nodes removed on the false-negative rate.

Methods

Data were collected prospectively from 395 women undergoing SNB for breast cancer, between June 1995 and December 2001. All nodes that were hot and/or blue were removed and analysed.

Results

During this interval 136 patients who had SNB were lymph node positive. The median number of sentinel nodes removed was two (range one to five). The overall false-negative rate of SNB in these women was 7·1 per cent. If only one sentinel node had been removed, the false-negative rate would have been 16·5 per cent. The removal of more than two nodes had no effect on axillary staging in all but two women.

Conclusion

In early breast cancer, when there were multiple sentinel nodes, removal of two sentinel nodes significantly reduced the false-negative rate compared with removal of one node. Removing more than two sentinel nodes did not significantly reduce the false-negative rate further.

Clinical impact of false-negative sentinel node biopsy in primary breast cancer

BACKGROUND

The aim was to assess the false-negative sentinel node biopsy rate in women with early breast cancer and its implications in patient treatment.

METHODS

Between January 1995 and March 2001, 328 consecutive patients with clinically lymph node-negative primary operable breast cancer underwent lymphatic mapping and sentinel node biopsy using a combination of preoperative lymphoscintigraphy and/or blue dye. All underwent immediate axillary dissection. The intraoperative success rate in sentinel node identification, false-negative rate, predictive value of negative sentinel node status and overall accuracy were assessed. The clinical features and primary tumour characteristics for each false-negative case were reviewed.

RESULTS

The sentinel node was identified in 285 (86.9 per cent) of 328 women. The false-negative rate was 7.9 per cent (eight of 101). Most members of the breast multidisciplinary team would have instituted adjuvant systemic therapy for six false-negative cases based on clinical features and primary tumour histology. In all, only two (0.7 per cent) of 285 women who had sentinel node biopsy may have had their management and survival prospects potentially jeopardized owing to a false-negative sentinel node.

CONCLUSION

The results of this study suggest that the clinical impact of a false-negative sentinel node is low.

Quality assurance in a multidisciplinary symptomatic breast assessment clinic

BACKGROUND

Although quality assurance guidelines for surgeons have been issued and adopted for use in population-based breast screening programs in Australia, similar guidelines are unavailable for women referred with symptomatic breast problems.

METHODS

Six hundred and ninety-six women who attended the Royal Adelaide Hospital Women's Health Centre between February and November 1998 for investigation and management of a new breast-related complaint were prospectively evaluated. Investigation strategies and outcomes of the initial consultation were determined and the results compared with the performance quality standards for symptomatic breast disease according to the British Association of Surgical Oncology (BASO) Breast Surgeons' Group.

RESULTS

A breast lump was the presenting symptom in 45%, while breast pain was present in 26%. Ninety per cent of women referred with breast symptoms were given a definitive benign or malignant diagnosis at the initial clinic visit. Although the median time delay between the date of general practitioner referral and breast clinic appointments for all patients was < or =7 days, the time delay for 'urgent' cases was not met according to BASO performance indicators. All other Royal Adelaide Hospital Breast Clinic audit data were within the range suggested by BASO performance indicators for new consultations in a symptomatic breast assessment clinic.

CONCLUSIONS

A multidisciplinary breast clinic in a public hospital setting is able to provide clinical services to symptomatic women, with the majority of patients obtaining a confident diagnosis at the first presentation. Performance indicators for symptomatic breast disease are useful in identifying inadequacies at the clerical or clinical level which, following the implementation of subsequent changes, may lead to improvement in patient outcomes.

Computer simulations of lymph node metastasis for optimizing the pathologic examination of sentinel lymph nodes in patients with breast carcinoma

BACKGROUND

Many empiric protocols are used to detect metastases in sentinel lymph nodes (SLNs), but comparison of the efficacy of these methods is impractical because tissue is lost in processing, making reassessment with another policy difficult. Consequently, performance indicators of this test are largely unknown.

DESIGN

The authors retrospectively examined 112 SLNs removed from 89 patients with breast carcinoma treated at the authors' institution and used the histologic data to devise a mathematic model of a SLN with Matlab modeling software. The authors simulated examination of this computer-generated (virtual) lymph node according to several macroscopic and histologic sampling protocols and for each protocol assessed the probability of detecting micrometastases of specified sizes. The authors used published costing figures to estimate the cost of the policies.

RESULTS

Direct comparison of 6 sectioning strategies currently in use by pathology laboratories showed the chances of detecting a 500-microm metastasis ranged from 20% to 75%. Four of the 6 protocols had a less than 30% chance of detecting metastases of this size. The detection rate of smaller metastases was poorer. Cost was not a good discriminator because some policies were more efficient than others.

CONCLUSIONS

The detection of metastases is highly dependent on the methods used to look for them. The authors' simulations suggest that commonly used methods of examining lymph nodes have high false-negative rates, particularly for small metastases. There is an urgent need for pathologists and clinicians to agree on the minimum size of SLN metastases that will be sought by histology and set standard methods for examining these lymph nodes.

Clinical and histological factors associated with sentinel node identification in breast cancer

BACKGROUND

Although sentinel lymph node biopsy is likely to be offered as a method of assessing nodal status in primary breast cancer, the inability to identify the sentinel node at the time of surgery will limit the number of patients who may benefit from the procedure. The purpose of the present study was to identify factors that are associated with intraoperative identification of the sentinel node(s).

METHODS

Between September 1995 and May 1999, lymphatic mapping using a combination of preoperative lymphoscintigraphy and/or blue dye was performed on 169 consecutive patients with clinically lymph node-negative primary operable breast cancer. Clinical and histological factors were assessed using univariate and multivariate analysis to determine those that were associated with intraoperative identification of the sentinel node.

RESULTS

The sentinel node was identified at the time of surgery in 142 cases (84%). Of the clinical factors assessed, preoperative identification of the sentinel node on lymphoscintigraphy (P < 0.0001), use of blue dye in combination with isotope (P = 0.001), symptomatic palpable tumours (P < 0.05) and the experience of the surgeon (P = 0.03) were significant in identifying the sentinel node at operation. No histological factor was associated with intraoperative identification of the sentinel node. Using multivariate analysis, positive identification of the sentinel node on lymphoscintigram, the experience of the surgeon and the use of both blue dye and isotope for sentinel node mapping were independent factors associated with intraoperative sentinel node identification. The lymphoscintigram result was the strongest independent factor according to its beta value, a measure of the weight of significance.

CONCLUSION

Patients undergoing sentinel lymph node mapping and biopsy should be warned of the possibility of failure of sentinel node identification at operation. Our results suggest that the best predictor of intraoperative sentinel node identification is the visualization of the sentinel node on preoperative lymphoscintigraphy. The result of the lymhoscintigram may allow for additional preoperative counselling of the patient regarding the success or failure of sentinel node biopsy. Technical factors such as the experience and diligence of the surgeon, as well as the sentinel node mapping technique, are also important in determining the success of the procedure.

Sentinel node biopsy in breast cancer: recommendations for surgeons, pathologists, nuclear physicians and radiologists in Australia and New Zealand

BACKGROUND

Assessment of axillary lymph node status is necessary for patients with invasive breast cancer. Sentinel node biopsy is a new minimally invasive technique that may provide accurate assessment of regional lymph node status while limiting the morbidity associated with axillary clearance.

METHODS

A workshop conducted in Adelaide in November 1998 aimed to assess current sentinel node mapping and biopsy techniques, and make recommendations regarding its application in the surgical management of early breast cancer in Australia and New Zealand.

RESULTS

At the conclusion of the workshop, a consensus was reached regarding indications, exclusions, sentinel node mapping/biopsy technique, nuclear medicine requirements, pathology and safety of sentinel node biopsy in breast cancer. It was agreed that a feasibility study according to an agreed prospective protocol was necessary to validate the technique by breast surgeons. Surgeons that satisfied validation criteria for the feasibility study could then consider a prospective randomized study comparing sentinel node biopsy with standard axillary dissection.

CONCLUSIONS

Sentinel node biopsy in breast cancer involves close cooperation between members of a multidisciplinary team including surgeons, nuclear physicians, pathologists and radiologists. Although the technique has the potential to reduce morbidity associated with axillary surgery, surgical performance in this area will need to be closely monitored to ensure that the technique does not fall into disrepute by adversely affecting breast cancer prognosis.

Reliability of sentinel node status in predicting axillary lymph node involvement in breast cancer

OBJECTIVES

To assess the reliability of determining sentinel node status in staging regional lymph nodes in breast cancer.

DESIGN AND SETTING

Prospective validation study in a major public teaching hospital, comparing histological sentinel node status with that of remaining axillary nodes.

PATIENTS

117 women who underwent sentinel node biopsy and axillary dissection for primary breast cancer between 1995 and 1998.

MAIN OUTCOME MEASURES

Intraoperative success rate in sentinel node identification; false negative rate; predictive value of negative sentinel node status; overall accuracy of sentinel node status.

RESULTS

The sentinel node was identified at operation in 95 patients (81.2%). Tumour involvement of the sentinel node was demonstrated in 29 of 31 women (93.5%; 95% CI, 79%-99%). Sixty-four of the 66 women in whom the sentinel node was negative for tumour showed no further involvement of remaining axillary nodes (standard haematoxylin-eosin histological assessment), giving a predictive value of negative sentinel node status of 97% (95% CI, 89%-100%). The overall accuracy in 95 women in whom sentinel node status was compared with axillary node status was 97.9%.

CONCLUSIONS

Histopathological examination of the sentinel node is an accurate method of assessing axillary lymph node status in primary breast cancer and is likely to be incorporated into future surgical management of women with primary breast cancer.

Lymphoid cell infiltration during breast cancer growth: a syngeneic rat model

The systematic study of potential alterations in lymphoid infiltrates during tumour growth is extremely limited in humans. Therefore, development of a model utilizing a spontaneously arising mammary adenocarcinoma in Dark Agouti rats was adopted for the study of the dynamics of lymphoid cell infiltration during tumour development. Syngeneic rats were inoculated with tumour cell suspensions and the tumours were resected from 5 to 15 days. Serial sections were immunohistochemically stained using a panel of monoclonal antibodies. Irrespective of tumour age, ED2 (macrophages) and W3/25 (CD4)-positive cells were the most prominent cell infiltrates in tumours. There were no significant differences in cell counts for any marker between 8-day and 15-day tumours. However, in 5-day tumours there were significantly fewer macrophages, OX19+ T cells, W3/25+ cells, OX8+ (CD8) cells and OX62+ dendritic cells. Interleukin-2 receptor alpha chain expression was low at all examined stages of tumour growth, indicating a lack of tumour infiltrating lymphocyte (TIL) activation and/or possible TIL anergy. B cell staining was absent in all tumours, negating the possibility of these cells mediating coregulatory signals for TIL activation in the micro-environment of established tumours. The results parallel previous immunohistochemical findings in humans, suggesting that a dysfunctional local immune response in breast cancer may be determined very early during tumour development.

The utility of the proliferative index in pretreatment biopsy specimens of esophageal squamous cell carcinoma

The proliferative index detected immunohistochemically by monoclonal antibody MIB-1 from pre-treatment biopsy tissues of 33 patients with esophageal squamous cell carcinoma who underwent preoperative concurrent chemoradiotherapy was evaluated in relation to clinicopathologic features and chemoradiotherapeutic responses. The response to chemoradiotherapy was assessed both endoscopically and pathologically and classified as complete or partial response. Higher MIB-1 LI was significantly associated with lymph node metastases, suggesting that detection of MIB-1 LI from biopsy tissues may contribute to pre-treatment staging of tumors and prediction of persistence of lymph node involvement after chemoradiotherapy, which would permit the optimization of systemic treatment for individual patients. Statistically, significant correlation existed between higher MIB 1-LI and poor overall survival, implicating the prognostic significance of the MIB-1 LI in patients undergoing multimodality treatment. No significant relationship was found between the MIB-1 LI and either endoscopic or pathologic responses, although a trend for tumors with lower MIB-1 LI to have better responses was observed.

Clinical and radiological predictors of complete excision in breast-conserving surgery for primary breast cancer

BACKGROUND

Local recurrence after conservative surgery for breast cancer usually results from growth of residual cancer adjacent to the excised primary tumour or from multicentric disease. Complete local excision (CLE) confirmed histologically is essential to ensure that the risk of local recurrence is minimal. This study was undertaken to determine that clinical or radiological factors may assist the surgeon at the time of surgery to achieve this aim.

METHODS

A retrospective review of 101 cases treated by conservative surgery identified 70 cases of CLE and 31 of incomplete local excision (ILE). Clinical, surgical and histopathological data were taken from hospital records. Mammographic features and those of specimen X-rays were evaluated without knowledge of the histopathological outcome of surgery.

RESULTS

Complete excision was significantly associated with type of operation (lumpectomy vs wide local excision/quadrantectomy, P < 0.003), absence of calcification (P < 0.03) and the presence of a mass on mammography (P = 0.05). Tumour size (> 2.5 cm) and the presence of extensive ductal carcinoma in situ (DCIS) were associated with incomplete excision (P = 0.0005). No relationship was demonstrated with patient age, breast size, breast density, tumour grade, receptor status, axillary nodal status or spicules on X-ray and completeness of excision. Specimen X-ray had a positive predictive value of 94% with CLE.

CONCLUSIONS

Clinical and pre-operative mammographic parameters are important for predicting CLE for breast cancers treated by breast-conserving surgery. Specimen radiology for palpable lesions can confirm excision of the cancer and permit re-excision of breast tissue at the time of initial surgery. Its role in determining CLE should be further evaluated.

Medroxyprogesterone acetate addition or substitution for tamoxifen in advanced tamoxifen-resistant breast cancer: a phase III randomized trial. Australian-New Zealand Breast Cancer Trials Group

PURPOSE

To determine whether a strategy of adding medroxyprogesterone acetate (MPA) to tamoxifen (TAM) is superior to the substitution of MPA for TAM among women with advanced breast cancer and disease progressing on TAM. To assess the patterns or response and subsequent progression in sites and tissues according to prior involvement and treatment.

PATIENTS AND METHODS

Two-hundred-fifteen postmenopausal women with advanced breast cancer progressing on TAM after receiving TAM for at least six months were randomized: 109 to add MPA 500 mg/day orally (TAM + MPA), and 106 to stop TAM and to substitute MPA.

RESULTS

There were no significant differences between the groups with respect to complete plus partial response rates: TAM + MPA 10%, MPA 9%, median time to progression TAM + MPA 3.0 months, MPA 4.5 months, or median overall survival, TAM + MPA 17.2 months, MPA 18.4 months. In a multivariate model, prognostic factors significant for a shorter time to disease progression were worse for performance status, involvement of more than one tissue, prior radiotherapy, and shorter time from recurrence after primary therapy to randomization. Adjusting for these factors, treatment with TAM + MPA was associated with a higher relative risk for disease progression, with a hazards ratio of 1.31, but this was not significant (95% confidence interval, 0.98 to 1.74; P = .067). However, in an exploratory analysis, the time to disease progression, among patients with progesterone receptor positive (PR+) tumors, was 6.3 months with MPA versus 2.9 months with TAM + MPA, with a hazards ratio of 1.92 (95% confidence interval, 1.12 to 3.32; P = .02). There was a significant interaction, P = .04, between PR status and treatment, indicating an advantage to treatment substitution for those who have PR+ tumors. Tumor response occurred in 14% of assessed metastatic sites. Subsequent progression occurred in a new tissue alone in 13% of patients, in both new and previously involved (old) tissues in 76%, and in old tissues only in 11%. In 23% of patients, progression occurred only at a new site, in 50% at both old and new sites, and in 27% only at old sites. No significant differences in the patterns of response or progression were seen in the different treatment groups.

CONCLUSION

Among women with breast cancer whose disease is progressing after at least six months of treatment with TAM, there is no advantage to maintaining TAM when MPA is to be given. An overall effect of treatment on the pattern of failure at old sites or at new sites or tissues cannot be discerned.

A combined modality approach to the management of oesophageal cancer

This study aims to update the experience of multimodality approaches in the management of oesophageal cancer that have been adopted in several Australian and New Zealand hospitals. Between 1984 and 1985, 92 patients received pre-operative radiotherapy (30-36 Gy over 3 weeks) and one of two chemotherapy regimes (one or two courses of i.v. cisplatin 80 mg/m2 plus a 4-5 day continuous i.v. of fluorouracil 5-800 mg/m2/day) concurrently prior to surgery. Eighty-two patients (89%) underwent resection as planned. Operative specimens were microscopically free of residual tumour in 18 patients. Eight patients (9%) had treatment-related deaths: seven from surgery and one due to pre-operative chemoradiation. The Kaplan-Meier 5-year cause-specific survival estimates were 32.9 +/- 7.8% for the 58 patients with squamous cancer and 0% for the 32 with adenocarcinoma. Complete pathological response to the pre-operative regime was more common in females and was associated with a survival advantage. Five-year cause-specific survival expectation in patients who experienced a complete pathological response was 71.5 +/- 12.4%, whereas it was only 15.9 +/- 5.6% in patients who had residual cancer in their surgical specimens. Although less toxic the pre-operative regime utilizing only one cycle of chemotherapy was no less efficacious either in producing a complete pathological response or in terms of survival expectation. This uncontrolled pilot study has produced encouraging long-term results, especially for patients with squamous carcinoma that experienced a complete response to pre-operative synchronous chemoradiotherapy. A randomized controlled study comparing surgery alone with (one cycle) chemoradiation followed by surgery is now underway.

Laparoscopic versus open splenectomy for immune thrombocytopenic purpura

BACKGROUND

We sought to determine whether laparoscopic techniques can reduce the operative morbidity of surgery in patients undergoing splenectomy for immune thrombocytopenic purpura (ITP).

METHODS

All patients (60) undergoing splenectomy for ITP at the Royal Adelaide Hospital from January 1985 to November 1995 were reviewed. Results of patients undergoing open operation were obtained by means of retrospective case note review, whereas details of all patients undergoing laparoscopic splenectomy were collected prospectively and maintained on a computerized database.

RESULTS

Forty-seven patients underwent splenectomy with an open technique and 13 with a laparoscopic technique. Patient groups were demographically similar. All laparoscopic procedures were completed with the laparoscopic technique. An accessory spleen was also removed at laparoscopic operation from two (15%) patients and at open operation from three patients (6%). Two more accessory spleens were missed at the original procedure, one at open operation and one at laparoscopic operation. These required later removal by using open and laparoscopic techniques, respectively. Blood and platelet transfusion requirements were reduced by the laparoscopic approach. Although mean operating times were similar (87 versus 88 minutes), laparoscopic splenectomy was associated with a greatly reduced postoperative hospital stay (10 versus 2 days, median; p < 0.0001) and no major morbidity. Long-term normalization of platelet counts was similar for the two techniques. The laparoscopic approach resulted in a reduction in hospital treatment costs from $4224 to $2238 per case (cost savings of $1986 per case).

CONCLUSIONS

Laparoscopic splenectomy results in improved clinical outcomes and reduced costs for patients undergoing elective splenectomy for ITP.

Prolonged survival follows resection of oesophageal SCC downstaged by prior chemoradiotherapy

BACKGROUND

The poor survival rate of surgically treated patients with oesophageal cancer has not improved substantially over the last 25 years, but combined modality therapy has shown early promising results.

METHODS

A prospective study was undertaken to determine the effect of pre-operative synchronous chemoradiotherapy followed by oesophagectomy in 53 patients with squamous cell carcinoma (SCC) of the oesophagus. The patient group was unselected, other than by fitness for surgery.

RESULTS

In 25% of patients, complete pathological regression of the tumour was achieved. All but one of the patients in this subgroup had T2 tumours on pre-operative clinical staging and two had evidence of lymph node involvement, but postoperative pathological examination revealed that pre-operative chemoradiotherapy had downstaged their disease to T0N0. There was no hospital mortality in this subgroup and the actuarial 7 year survival was 69%.

CONCLUSIONS

For squamous oesophageal tumours deep to the submucosa this is an extremely good survival. For the present, this form of therapy for SCC of the oesophagus appears capable of achieving results comparable to, or better than, those reported for 3-field lymphadenectomy.

Combined modality therapy for esophageal carcinoma: preliminary results from a large Australasian multicenter study

PURPOSE

This report updates local control and survival experience and focuses on treatment toxicity in 294 patients with esophageal cancer who have been treated at six Australasian centers using three prospective unrandomized protocols that used concurrent radiation, cisplatin, and modest dose infusional fluorouracil.

METHODS AND MATERIALS

Protocol 1--"definitive" chemoradiation. One hundred and thirty-seven patients have been treated with "definitive" radiation to 60 Gy in 6 weeks plus two courses of cisplatin (80 mg/m2) and infusional fluorouracil (800 mg/m2/day over 4 days) during the first and fourth weeks of radiation. Protocol 2--"preoperative" chemoradiation and surgery. Seventy-eight patients received chemoradiation using the same chemotherapy, but 30-35 Gy in 3-4 weeks prior to surgery. Protocol 3--"palliative" chemoradiation. Seventy-nine patients deemed incurable were treated "palliatively" with the same chemoradiation protocol without surgery. Follow-up ranges from 6 months to 7 years (mean 22 months) in live patients.

RESULTS

Durable palliation of dysphagia in all three treatment groups has been reflected by encouraging 3-year survival expectations of 43.2 +/- 5% in definitively treated patients, 40.3 +/- 7.65% in surgically treated patients, and 8.5% +/- 3.9% in the palliatively treated patients. There are early indications that female patients have fared better than males. Toxicity levels were modest in all three groups. Following definitive treatment, severe myelotoxicity (World Health Organization grades 3 and 4) occurred in 19%, severe esophagitis (World Health Organization grade 3) in 11%, and moderate or severe benign stricture in 17%, depending upon age and sex of the patient (being worse in female patients).

CONCLUSIONS

These studies demonstrate that the concurrent addition of modest dose cisplatin and infusional dose fluorouracil to radiation in the definitive, preoperative, and palliative settings contribute to high rates of durable dysphagia-free survival, with overall survival comparable to (and possibly better than) the chemoradiation arm of the recently reported Intergroup Study, but at the cost of less morbidity.

Soft-tissue sarcoma of the extremity. Experience with limb-sparing surgery

OBJECTIVES

To assess the degree to which limb-sparing surgery is implemented in patients with soft-tissue sarcoma, and its outcome.

DESIGN AND SETTING

A detailed review of 40 patients who were all tertiary referrals to one surgeon, and general review of all 215 patients with sarcoma treated in South Australia between 1986 and 1992.

INTERVENTIONS

Conservation of the limb by wide resection or marginal resection of soft tissue, combined when necessary with radiotherapy. Amputation was used when limb conservation failed or was not possible.

MAIN OUTCOME MEASURES

Median survival time after treatment.

RESULTS

Limb-sparing treatment was successful in 37 of the group of 40 patients. Thirty-two patients received adjuvant radiotherapy, and 19 received chemotherapy. Median survival time was 35 months. Review of all 215 patients with sarcoma revealed a higher initial amputation rate and a lower use of combined treatment methods than in our series. Twenty-six patients (65%) were initially incorrectly diagnosed before referral, resulting in a median delay in treatment of 16 weeks.

CONCLUSIONS

The concept of limb-sparing surgery is well established, but is not yet as widely practised for limb sarcomas as it could be. Delay in diagnosis is a significant problem.

Randomized comparison of the effects of tamoxifen, megestrol acetate, or tamoxifen plus megestrol acetate on treatment response and survival in patients with metastatic breast cancer

BACKGROUND

The antioestrogen tamoxifen and progestins act via different receptors and may therefore have complementary effects against human breast cancer. This possibility was tested in a randomized study which compared the effects of tamoxifen, standard-dose megestrol acetate, and these two agents in combination, in patients with metastatic breast cancer.

PATIENTS AND METHODS

184 post-menopausal patients with metastatic breast cancer were randomized to initial treatment with either tamoxifen (TAM) 40 mg daily, megestrol acetate (MA) 160 mgm daily, or the combination of the two administered simultaneously. Patients crossed over to the alternative single agent on relapse or disease progression. Patients were evaluated for response, time to initial and ultimate treatment failure, and survival.

RESULTS

There were no significant differences between the three groups with respect to response rates, nor the other parameters. Patient survival was significantly associated with age > 60 years, ER positive status, and the absence of visceral metastases.

CONCLUSIONS

TAM and MA are both equally effective in response induction as initial treatments and the combination has no advantage. Sequential treatment is still optimal, TAM being the preferred initial agent in view of the reported side effects with MA.

Estrogen and progesterone regulate secretion of insulin-like growth factor binding proteins by human breast cancer cells

We examined the effects of estradiol and progesterone agonist, promegestone (R5020), on secretion of insulin-like growth factors (IGF) and binding proteins (IGFBPs) by T-47D human breast cancer cells cultured in a serum-free defined medium. Estrogen, IGF-I and IGF-II promoted and R5020 inhibited growth under these conditions. Cells secreted IGFs and four IGFBPs. The amounts of all IGFBPs in cell-conditioned media were increased by estradiol and reduced by R5020, which also abolished the stimulatory effect of estradiol on IGFBPs without inducing an IGFBP protease. Therefore estrogen and progesterone may alter growth of breast cancers by regulating tumour secretion of IGFBPs and hence change carcinoma responsiveness to IGFs.

Surgical bypass for palliation of malignant oesophageal obstruction

It is possible to achieve satisfactory palliation for most patients with malignant oesophageal obstruction by endoscopic means, surgical resection or radiotherapy. Despite these options, a small group of patients remains for whom another alternative should be considered. Fifteen patients presenting with extensive tumour, a non-dilatable stricture, or a tracheo-oesophageal fistula, not suitable for any of the standard methods of palliation, underwent palliative surgical bypass using stomach or colon. The hospital mortality was 33% and the median survival 6 months. Anastomotic leakage occurred in six patients and the median postoperative stay was 28 days (range 20-42 days). All patients who survived surgery, except one, achieved satisfactory palliation. The nature of these patients is such that whatever is done, mortality will almost inevitably be high. The authors believe that all patients in this series were better off than they would have been if left untreated, and oesophageal bypass should be considered for patients with distressing dysphagia due to disease not amenable to standard palliative methods.

Interferon-alpha 2a does not improve response or survival when combined with dacarbazine in metastatic malignant melanoma: results of a multi-institutional Australian randomized trial

Following extensive phase II trials of the combination of dacarbazine and interferon-alpha 2a we performed a prospective, randomized, controlled trial of this combination versus dacarbazine alone as systemic therapy for symptomatic, measurable metastatic malignant melanoma. The two treatment arms were well matched for age, sex, performance, status, relapse-free survival, prior therapy and sites of disease. Therapy consisted of dacarbazine given in combination in escalating doses of 200 mg/m2, 400 mg/m2 and 800 mg/m2 i.v. every 3 weeks, or alone at 800 mg/m2 i.v. every 3 weeks. Interferon was administered subcutaneously starting at 3 mU daily on days 1-3, 9 mU daily on days 4-70, then 9 mU three times per week. Therapy was continued for at least 6 months unless overt progressive disease was observed. Eighty seven patients were randomized to the combination and 83 patients to dacarbazine alone. Response rates were respectively, complete 7% and 2%, and partial 14% and 15%, for a total response rate of 21% (95% confidence limits 13-31%) and 17% (95% confidence limits 10-27%). Median duration of response was 258 and 286 days, and survival of the whole groups 229 and 269 days respectively. Toxicity was worse in the combination arm, with more patients experiencing fatigue, nausea and anorexia, flu-like symptoms and neutropenia. However quality of life was not significantly different in either group, except that fatigue, as measured at week 12 by LASA scales, and activity, as measured by the functional living index, were both improved in the combination.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic value of quality of life scores in a trial of chemotherapy with or without interferon in patients with metastatic malignant melanoma

In a multi-centre randomised clinical trial comparing dacarbazine (DTIC) plus recombinant interferon-alfa2a (IFN) versus DTIC alone for patients with metastatic malignant melanoma, aspects of quality of life (QL) were measured prospectively by patients using linear analogue self assessment (LASA) scales including the GLQ-8 and by doctors using Spitzer's QL Index. QL scores and performance status at the time of randomisation were available for 152 of 170 eligible patients. These scores carried significant prognostic information. In univariate analyses, Spitzer QL Index assessed by the doctor and LASA scores for physical wellbeing (PWB), mood, pain, appetite, nausea and vomiting, GLQ-8 total and overall QL were significant (P < 0.01) predictors of subsequent survival. QL Index and LASA scales for mood, appetite, and overall QL remained independently significant (all P < 0.05) in multivariate models allowing for significant prognostic factors other than QL (liver metastases and performance status). These findings closely parallel those in patients with metastatic breast cancer. They add further validity to the QL Index and LASA scores, provide the first evidence of the prognostic significance of the GLQ-8, and argue strongly for the routine assessment of QL in future therapy trials.

Non-haematological toxicity limiting the application of sequential high dose chemotherapy in patients with advanced breast cancer

A programme of repeated high dose chemotherapy for advanced breast cancer was developed using (1) cyclophosphamide 4 g/m2 followed by autologous peripheral blood stem cell (PBSC) collection; (2) three cycles of conventional dose chemotherapy; (3) high dose cyclophosphamide, cisplatin, and carmustine with PBSC rescue; and (4) high dose etoposide and melphalan with PBSC rescue. Fifteen eligible patients had advanced poor prognosis breast cancer either at initial diagnosis (one patient) or at relapse (14 patients). During the course of the protocol, there were three treatment related deaths, two patient withdrawals due to debilitating toxicity, five patient withdrawals due to disease progression, and one patient withdrawal due to inadequate collection of PBSC. The remaining four patients did not complete the planned protocol as the programme was terminated because of the unacceptable morbidity and mortality. They were treated with an alternative high dose chemotherapy protocol which was well tolerated. This study highlights the significant problems associated with a complex sequential high dose chemotherapy regimen. Cyclophosphamide mobilized PBSC infused following high dose chemotherapy enables rapid haematological recovery. However the non-haematological toxicity following high dose chemotherapy regimens is often severe and may limit the application of certain sequential high dose chemotherapy combinations in patients with breast cancer.

Patterns of treatment failure and prognostic factors associated with the treatment of esophageal carcinoma with chemotherapy and radiotherapy either as sole treatment or followed by surgery

PURPOSE

The records of patients with esophageal cancer who were treated with a combined modality therapy were reviewed to determine the effects of simultaneously administered chemotherapy and radiotherapy (RT) at sites of recurrence and the relationship between treatment outcome and clinicopathologic variables.

PATIENTS AND METHODS

One hundred seventeen patients were treated with fluorouracil (800 mg/m2) [corrected] and cisplatin (80 mg/m2) combined with either 36 Gy (36 patients) or 54 to 60 Gy (35 patients) of RT as sole therapy. Forty-six patients underwent surgery after they had received chemotherapy and 36 Gy of RT as initial treatment. Patients with either squamous cell cancer (SCC) or adenocarcinoma were included.

RESULTS

Complete endoscopic regression after an initial 36 Gy of RT and chemotherapy occurred in more than 50% of patients and in both tumor types. Relief of dysphagia accompanied tumor regression. Forty-two tumors were resected, and 11 showed a complete histologic response. Significant associations were demonstrated between enhanced survival and a diagnosis of SCC, a complete endoscopic response to initial chemotherapy and RT, and a tumor length of less than 5 cm. Multivariate analyses suggested that tumor length and complete endoscopic response were independent prognostic variables. The survival rate of patients treated by resection or radical-dosage RT was not significantly different.

CONCLUSIONS

The relief of dysphagia demonstrates the palliative value of chemotherapy and RT in both tumor types. The similar survival rates of patients with SCC or adenocarcinoma treated either surgically or with high-dose combined therapy (54 to 60 Gy) emphasize the need to evaluate the role of surgery and combined treatment in randomized studies.

The pre-operative treatment of oesophageal carcinoma with synchronously administered chemotherapy and radiotherapy

Forty-six patients with either squamous cell cancer of the oesophagus or adenocarcinoma involving the lower oesophagus have been treated with synchronously administered radiotherapy and chemotherapy (5FU & Cisplatin) prior to resection of the oesophagus. Endoscopically, complete regression of tumour occurred in 21 patients (46%) and when the oesophagus was resected in these patients, it was found that 11 of the resected specimens contained residual tumour deep to the mucosa. Thus, the actual complete regression rate in the 46 patients was 22%. The postoperative mortality rate was 13% (22% in the first half of the series and 4% in the second half). The median survival rate was 36 months in the 24 patients operated on for squamous cancer of the oesophagus, and 14.5 months in 18 patients operated on for adenocarcinoma of the cardia. Eight patients are alive and disease free at more than three years from surgery, and all of these patients had a squamous cell carcinoma, and all had a complete histological response from their preoperative radiotherapy and chemotherapy.

Inhibition of T47D human breast cancer cell growth by the synthetic progestin R5020: effects of serum, estradiol, insulin, and EGF

The mechanism of the antiproliferative effects of progestins on human breast cancer cells is not known. In view of the ability of estrogen to stimulate human breast cancer cell production of peptide growth factors, and since previous studies have suggested that the inhibitory action of progestins is dependent on estrogen-stimulated growth, the present study examined the interaction of growth factors and the synthetic progestin R5020 on the proliferation of T47D human breast cancer cells. In this study, the concentrations of estradiol, insulin, and EGF for optimal stimulation of T47D cell growth in 3% dextran-charcoal treated fetal bovine serum (DCC-FBS) were determined to be 1 nM, 100 nM, and 1 nM, respectively. Furthermore, incubation with these optimal concentrations of estradiol, insulin, and EGF in various combinations produced additive effects on T47D cell proliferation, suggesting that these agents act, at least in part, by different mechanisms. In contrast, in a chemically defined medium (DM), both estradiol and EGF were unable to stimulate T47D cell proliferation. In the case of estradiol, the inability to demonstrate stimulation of T47D cell growth in DM was not due to down-regulation of the estrogen receptor. R5020 inhibited the growth of T47D cells, although its effect was more marked in the presence of 3% DCC-FBS than in DM. Stimulation of T47D cell growth by either estradiol or insulin in 3% DCC-FBS was effectively inhibited by R5020. In contrast, growth of T47D cells stimulated by EGF in the absence of estradiol was not markedly inhibited by R5020, the growth being comparable to that of untreated control cells. These findings suggest that the inhibitory effect of R5020 on T47D cell proliferation is dominant over the action of some, but not all, breast cancer mitogens.

Treatment of adenocarcinoma of the cardia with synchronous chemotherapy and radiotherapy

Twenty-nine evaluable patients with adenocarcinoma of the cardia were treated with synchronously administered chemotherapy (two cycles of 5-fluouracil and cisplatin and 30-36 Gy of radiation to determine whether these tumours are responsive to such treatment. Complete regression of tumour was observed endoscopically in 19 patients, and partial regression in four. Fourteen patients had their tumours resected and in six no microscopic tumour was found in the specimen. Nine patients received additional radiotherapy to a total dose of 54-60 Gy instead of surgery. Tumour response was associated with rapid reversal of dysphagia. Only one patient required subsequent intervention for relief of dysphagia due to fibrous stricture. Enhanced survival was associated with a complete endoscopic response to initial chemotherapy and radiotherapy, and a tumour of less than 5 cm in length. The median survival of responding patients was 15 months. Synchronous chemotherapy and radiotherapy was of major palliative benefit in this series and merits further evaluation.