Abstract S2-03: Does BRCA status affect outcome in young breast cancer patients? Results from the prospective study of outcomes in sporadic and hereditary breast cancer (POSH)

Background

Germline mutations in BRCA1/2 account for ∼3% of breast cancer cases but >10% of young patients who present with triple negative (TN) breast cancer. Young age at diagnosis is also associated with an increased risk of recurrence and inferior survival compared to older patients. Numerous publications describe an increased incidence of adverse biological features in tumours from young breast cancer patients; however it is unclear whether these fully explain the poor outcome.

The effect of carrying a BRCA1/2 mutation on the prognosis of breast cancer remains controversial with retrospective studies reporting better, similar and worse outcomes for mutation carriers compared to patients with sporadic tumours. BRCA carriers could feasibly have enhanced or reduced sensitivity to certain chemotherapeutics; however retrospective studies are problematic due to missing data and biased ascertainment. POSH is multicentre prospective observational cohort study designed to investigate factors which affect prognosis in young breast cancer patients (Copson et al, JNCI, 2013). Here we report the pathology, treatment and outcome of patients with TN tumours as a preliminary analysis to determine the impact of a germline BRCA1 mutation on survival. The whole cohort analysis including BRCA1 and BRCA2 is in progress.

Methods

2956 patients aged ≤40 at breast cancer diagnosis were recruited from 127 UK oncology centres between 2000 and 2008. Patient characteristics, family history, risk factors, tumour pathology and treatment information, and blood DNA were collected at recruitment. Follow-up data were collected at 6 and 12 months, then annually. Summary statistics were used to describe patients by BRCA1 status. Kaplan-Meier estimates were used to describe univariate survival data.

Results

BRCA1 status is currently available for 542 patients with TN tumours. Pathogenic BRCA1 mutations were identified in 122 patients (BRCA1+); 420 had no BRCA1 mutation (BRCA1-). BRCA1+ were younger than BRCA1- (median age 34 vs 36 years, p<0.001) and more likely to have a positive family history (p<0.001). There were no significant differences between BRCA1+ vs BRCA1- for: median tumour size (20.8mm vs 23.0mm); tumour grade distribution (95.8% grade 3 vs 93.6%); nodal involvement (35.2% node positive vs 39.9%); or presence of metastases at diagnosis (0.0% vs 1.0%).

Median follow-up was 7.3 years. Overall survival of patients with stage 1-3 disease treated with anthracycline +/- taxane neoadjuvant chemotherapy (n=538; 151 deaths) was better for BRCA1+ vs BRCA1- (79.1% vs 73.6% at 5-yrs; HR[95%CI]=0.84[0.57,1.25],p=0.388). Distant disease-free survival (DDFS) was also higher for BRCA1+ (5-yr DDFS 76.1% vs 71.5%; HR[CI]=0.92[0.63,1.35], p=0.682). Moreover, survival after first distant relapse was better for BRCA1+ patients (41.9% vs 36.8% at 1-yr; HR[CI]=0.78[0.51,1.18], p=0.233).

Conclusions

Our prospective data show better survival in young BRCA1+ patients with early TN breast cancer treated with anthracycline/-taxane chemotherapy than BRCA1- patients. However, the difference between the groups was not significant in this partial sample. Results for the whole cohort will be available by the time of the meeting.

Citation Format: Eccles DM, Copson ER, Maishman T, Tapper W, Cutress R, Gerty S, Stanton L, Altman DG, Durcan L, Simmonds P, Decker B, Allen J, Luccarini C, Easton D, Dunning A, POSH Steering Group and Collaborators. Does BRCA status affect outcome in young breast cancer patients? Results from the prospective study of outcomes in sporadic and hereditary breast cancer (POSH) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr S2-03.

Propensity score-based analysis of outcomes of laparoscopic versus open liver resection for colorectal metastases

BACKGROUND

There is a need for high-level evidence regarding the added value of laparoscopic (LLR) compared with open (OLR) liver resection. The aim of this study was to compare the surgical and oncological outcomes of patients with colorectal liver metastases (CRLM) undergoing LLR and OLR using propensity score matching to minimize bias.

METHODS

This was a single-centre retrospective study using a prospective database of patients undergoing liver resection for CRLM between August 2004 and April 2015. Co-variates selected for matching included: number and size of lesions, tumour location, extent and number of resections, phase of surgical experience, location and lymph node status of primary tumour, perioperative chemotherapy, unilobar or bilobar disease, synchronous or metachronous disease. Prematching and postmatching analyses were compared. Surgical and oncological outcomes were analysed.

RESULTS

Some 176 patients undergoing LLR and 191 having OLR were enrolled. After matching, 133 patients from each group were compared. At prematching analysis, patients in the LLR group showed a longer overall survival (OS) and higher R0 rate than those in the OLR group (P = 0·047 and P = 0·030 respectively). Postmatching analyses failed to confirm these results, showing similar OS and R0 rate between the LLR and OLR group (median OS: 55·2 versus 65·3 months respectively, hazard ratio 0·70 (95 per cent c.i. 0·42 to 1·05; P = 0·082); R0 rate: 92·5 versus 86·5 per cent, P = 0·186). The 5-year OS rate was 62·5 (95 per cent c.i. 45·5 to 71·5) per cent) for OLR and 64·3 (48·2 to 69·5) per cent for LLR. Longer duration of surgery, lower blood loss and morbidity, and shorter postoperative stay were found for LLR on postmatching analysis.

CONCLUSION

Propensity score matching showed that LLR for CRLM may provide R0 resection rates and long-term OS comparable to those for OLR, with lower blood loss and morbidity, and shorter postoperative hospital stay.

Family history and outcome of young patients with breast cancer in the UK (POSH study)

BACKGROUND

Young patients presenting to surgical clinics with breast cancer are usually aware of their family history and frequently believe that a positive family history may adversely affect their prognosis. Tumour pathology and outcomes were compared in young British patients with breast cancer with and without a family history of breast cancer.

METHODS

Prospective Outcomes in Sporadic versus Hereditary breast cancer (POSH) is a large prospective cohort study of women aged less than 41 years with breast cancer diagnosed and treated in the UK using modern oncological management. Personal characteristics, tumour pathology, treatment and family history of breast/ovarian cancer were recorded. Follow-up data were collected annually.

RESULTS

Family history data were available for 2850 patients. No family history was reported by 65·9 per cent, and 34·1 per cent reported breast/ovarian cancer in at least one first- or second-degree relative. Patients with a family history were more likely to have grade 3 tumours (63·3 versus 58·9 per cent) and less likely to have human epidermal growth factor receptor 2-positive tumours (24·7 versus 28·8 per cent) than those with no family history. In multivariable analyses, there were no significant differences in distant disease-free intervals for patients with versus those without a family history, either for the whole cohort (hazard ratio (HR) 0·89, 95 per cent c.i. 0·76 to 1·03; P = 0·120) or when stratified by oestrogen receptor (ER) status (ER-negative: HR 0·80, 0·62 to 1·04, P = 0·101; ER-positive: HR 0·95, 0·78 to 1·15, P = 0·589).

CONCLUSION

Young British patients presenting to breast surgical clinics with a positive family history can be reassured that this is not a significant independent risk factor for breast cancer outcome.

An evaluation of the prognostic model PREDICT using the POSH cohort of women aged ⩽40 years at breast cancer diagnosis

BACKGROUND

Breast cancer is the most common cancer in younger women (aged ⩽40 years) in the United Kingdom. PREDICT (http://www.predict.nhs.uk) is an online prognostic tool developed to help determine the best available treatment and outcome for early breast cancer. This study was conducted to establish how well PREDICT performs in estimating survival in a large cohort of younger women recruited to the UK POSH study.

METHODS

The POSH cohort includes data from 3000 women aged ⩽40 years at breast cancer diagnosis. Study end points were overall and breast cancer-specific survival at 5, 8, and 10 years. Evaluation of PREDICT included model discrimination and comparison of the number of predicted versus observed events.

RESULTS

PREDICT provided accurate long-term (8- and 10-year) survival estimates for younger women. Five-year estimates were less accurate, with the tool overestimating survival by 25% overall, and by 56% for patients with oestrogen receptor (ER)-positive tumours. PREDICT underestimated survival at 5 years among patients with ER-negative tumours.

CONCLUSIONS

PREDICT is a useful tool for providing reliable long-term (10-year) survival estimates for younger patients. However, for more accurate short-term estimates, the model requires further calibration using more data from young onset cases. Short-term prediction may be most relevant for the increasing number of women considering risk-reducing bilateral mastectomy.

Obesity and the outcome of young breast cancer patients in the UK: the POSH study

BACKGROUND

Obese breast cancer patients have a poorer prognosis than non-obese patients. We examined data from a large prospective cohort study to explore the associations of obesity with tumour pathology, treatment and outcome in young British breast cancer patients receiving modern oncological treatments.

PATIENTS AND METHODS

A total of 2956 patients aged ≤40 at breast cancer diagnosis were recruited from 126 UK hospitals from 2001 to 2007. Height and weight were measured at registration. Tumour pathology and treatment details were collected. Follow-up data were collected at 6, 12 months, and annually.

RESULTS

A total of 2843 eligible patients (96.2%) had a body mass index (BMI) recorded: 1526 (53.7%) were under/healthy-weight (U/H, BMI <25 kg/m(2)), 784 (27.6%) were overweight (ov, BMI ≥25 to <30), and 533 (18.7%) were obese (ob, BMI ≥30). The median tumour size was significantly higher in obese and overweight patients than U/H patients (Ob 26 mm versus U/H 20 mm, P < 0.001; Ov 24 mm versus U/H 20 mm, P < 0.001). Obese and overweight patients had significantly more grade 3 tumours (63.9% versus 59.0%, P = 0.048; Ov 63.6% versus U/H 59.0% P = 0.034) and node-positive tumours (Ob 54.6% versus U/H 49.0%, P = 0.027; Ov 54.2% versus U/H 49%, P = 0.019) than U/H patients. Obese patients had more ER/PR/HER2-negative tumours than healthy-weight patients (25.0% versus 18.3%, P = 0.001). Eight-year overall survival (OS) and distant disease-free interval (DDFI) were significantly lower in obese patients than healthy-weight patients [OS: hazard ratio (HR) 1.65, P < 0.001; DDFI: HR 1.44, P < 0.001]. Multivariable analyses adjusting for tumour grade, size, nodal, and HER2 status indicated that obesity was a significant independent predictor of OS and DDFI in patients with ER-positive disease.

CONCLUSIONS

Young obese breast cancer patients present with adverse tumour characteristics. Despite adjustment for this, obesity still independently predicts DDFI and OS.

Ethnicity and outcome of young breast cancer patients in the United Kingdom: the POSH study

BACKGROUND

Black ethnic groups have a higher breast cancer mortality than Whites. American studies have identified variations in tumour biology and unequal health-care access as causative factors. We compared tumour pathology, treatment and outcomes in three ethnic groups in young breast cancer patients treated in the United Kingdom.

METHODS

Women aged ≤ 40 years at breast cancer diagnosis were recruited to the POSH national cohort study (MREC: 00/06/69). Personal characteristics, tumour pathology and treatment data were collected at diagnosis. Follow-up data were collected annually. Overall survival (OS) and distant relapse-free survival (DRFS) were assessed using Kaplan-Meier curves, and multivariate analyses were performed using Cox regression.

RESULTS

Ethnicity data were available for 2915 patients including 2690 (91.0%) Whites, 118 (4.0%) Blacks and 87 (2.9%) Asians. Median tumour diameter at presentation was greater in Blacks than Whites (26.0 mm vs 22.0 mm, P=0.0103), and multifocal tumours were more frequent in both Blacks (43.4%) and Asians (37.0%) than Whites (28.9%). ER/PR/HER2-negative tumours were significantly more frequent in Blacks (26.1%) than Whites (18.6%, P=0.043). Use of chemotherapy was similarly high in all ethnic groups (89% B vs 88.6% W vs 89.7% A). A 5-year DRFS was significantly lower in Blacks than Asians (62.8% B vs 77.0% A, P=0.0473) or Whites (62.8 B% vs 77.0% W, P=0.0053) and a 5-year OS for Black patients, 71.1% (95% CI: 61.0-79.1%), was significantly lower than that of Whites (82.4%, 95% CI: 80.8-83.9%, W vs B: P=0.0160). In multivariate analysis, Black ethnicity had an effect on DRFS in oestrogen receptor (ER)-positive patients that is independent of body mass index, tumour size, grade or nodal status, HR: 1.60 (95% CI: 1.03-2.47, P=0.035).

CONCLUSION

Despite equal access to health care, young Black women in the United Kingdom have a significantly poorer outcome than White patients. Black ethnicity is an independent risk factor for reduced DRFS particularly in ER-positive patients.

Abstract P6-06-06: Family history and young breast cancer patients in the UK: The POSH study

Background

Approximately 4% of breast cancer cases occur in women under 40 years. Young age at diagnosis is associated with inferior survival compared to older patients. It is unclear whether an increased incidence of adverse biological features fully explains this. An underlying genetic pre-disposition to breast cancer is characterised by young age of disease onset, yet even at a very young age of diagnosis most individuals do not have an identifiable mutation in a known high risk breast cancer gene. Genome wide association studies have identified low penetrance genetic variants which may account for unexplained family histories of breast cancer. The effect of a BRCA 1/2 mutation on breast cancer prognosis remains controversial with retrospective studies reporting inconsistent outcomes for mutation carriers compared to sporadic tumours. The prognostic effect of low penetrance breast cancer susceptibility genes is under investigation.

POSH is a prospective observational cohort study designed to investigate prognostic factors in young breast cancer patients. Here we report pathology, treatment and outcome of these patients according to their family history of breast cancer.

Methods

2956 patients aged ≤40 at breast cancer diagnosis were recruited from 126 UK hospitals between 2001 and 2007. Details of personal characteristics, tumour pathology and treatment were collected. Family history details were collected using a questionnaire completed by participants at recruitment. BRCA mutation testing is in progress. Follow-up data were collected at 6 and 12 months and then annually.

Results

Family history data were available for 2850 patients. 1878 (65.9%) reported no family history of breast/ ovarian malignancies and 972 (34.1%) reported breast/ ovarian cancer in one or more 1st or 2nd degree relative. Patients with a positive family history were significantly more likely to have a surveillance detected breast cancer than those without a family history (3.0% vs. 0.1% p&lt;0.001) and patients with an affected 1st degree relative had a higher incidence of surveillance detected tumours than those with an affected 2nd degree relative (6.0% vs. 0.7% p&lt;0.001). Patients with a positive family history were significantly more likely to have a grade 3 tumour than patients with a negative family history (63.3% vs. 58.9% p = 0.04). There were no significant differences in median tumour diameter, incidence of nodal involvement or presence of metastases between the positive and negative family history groups. The frequency of ER and PR overexpressing tumours did not vary significantly between family history groups. Patients with a negative family history were significantly more likely to have a HER2 positive tumour than those with a positive family history (28.8% vs.24.7% p = 0.031). There were no significant differences in tumour grade, size, nodal status, and ER, PR or HER2 status between patients with 1st degree or 2nd degree affected relatives.

Conclusions

Our data indicates that having a first or second degree relative with a breast/ ovarian cancer is associated with an increased frequency of grade 3 and HER2 negative breast tumours but not with other pathological features. Further analyses will investigate the independent effect of family history on breast cancer survival and recurrence rates.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-06.

Abstract P2-12-01: BRCA1 and BRCA2 in multifocal cancers: Results from the POSH study

Background:

Multifocal (MF) breast cancers are more common in pre and perimenopausal women and in estrogen receptor (ER) positive disease. Young onset breast cancer and a positive family history of breast/ovarian cancer are characteristic of BRCA1 and BRCA2 carriers, but tumour receptor status and other pathological features may also be helpful in identifying BRCA gene carriers, particularly where family history is negative or unknown. Multifocal cancer may either be clonal in origin or unrelated multiple primaries (multicentric) and in a patient with a strong genetic predisposition the latter might be expected due to a field change effect. There are few data on whether multifocality is a predictor of an underlying BRCA 1 or BRCA2 mutation. A mutation frequency of 18% (combined BRCA1 and 2) in 61 multifocal cancers has been previously reported.

We sought evidence of an association between multifocality and BRCA carrier status in young women both with and without a relevant cancer family history.

Methods:

POSH, the UK population based cohort study recruited breast cancer patients aged ≤40 at diagnosis. Family history data were collected by patient questionnaire (positive family history defined as any number of first or second degree relatives diagnosed with breast or ovarian cancer). Genetic testing occurred either as part of clinical breast cancer management or the research study.

Results:

MF cancer was present in 797 of 2956 patients (27.0%) of the whole POSH cohort, more frequent in ER positive (34.9%) than ER negative (19.9%) cancers (p&lt;0.001). Genetic testing results are available for 760 patients of whom 196 had MF disease; the majority of those tested had a positive family history (57.4%). For those with genetic testing results there was no significant difference in ER, Her2, PR, high grade or multifocal tumours between patients with or without a family history. In total 214/760 patients had a pathogenic BRCA mutation (136 BRCA1, 78 BRCA2). In patients with MF disease a BRCA2 mutation was more likely than a BRCA 1 mutation (68.8% vs 36.2%, p&lt;0.001).

Type of BRCA mutation with distribution of breast cancer by ER status Localised n = 150Multifocal n = 47Missing n = 17Total n = 214BRCA1110 (73.3%)17 (36.2%)9136 (63.6%)ER pos23 (20.9%)6 (35.3%)029 (21.3%)ER neg87 (79.1%)11 (64.7%)9107 (78.7%)BRCA240 (26.7%)30 (68.8%)878 (36.4%)ER pos33 (82.5%)27 (90.0%)666 (84.6%)ER neg7 (17.5%)3 (10.0%)212 (15.4%)

Conclusions:

Multifocal disease is associated with an increased probability of BRCA2 mutations in our data and may be an indicator of BRCA2 genetic status. The ratio of multifocal to unifocal disease in BRCA1, BRCA2 carriers and non BRCA1/2 cases was highest in BRCA2 cases for both ER positive and ER negative tumours. With the caveat of small numbers and incomplete testing of the cohort, there is some evidence pointing to BRCA2 causing a field effect rather than just as a function of predominantly ER positive cancers, and this characteristic may be useful in an algorithm to predict BRCA2 status incorporating further adjustment for other potential confounders. We plan to conduct further genetic testing across the whole cohort to refine the algorithm and to confirm the observed multifocal/BRCA2 association.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-12-01.

Polygalacturonase-inhibiting proteins can function as activators of polygalacturonase

The interaction between fungal endopolygalacturonases (EPGs) and polygalacturonase-inhibiting proteins (PGIPs) found in plant cell walls has been well established. The typical EPG/PGIP interaction is characterized by high affinity, reversibility, and a 1:1 stoichiometry that results in lowering the catalytic rate of a particular endopolygalacturonase by up to 99.7%. Various EPG and PGIP isoforms and glycoforms have been isolated and characterized, and combinations of EPGs and PGIPs demonstrate a range of enzyme inhibition. EPG/PGIP interactions have prompted many researchers to suspect the involvement of these proteins in the production of specific signals (oligosaccharins) during plant pathogenesis. We have recently reported on initial studies in our laboratory indicating that, for certain EPG/PGIP combinations, the specific activity of EPG is increased beyond that characteristic of the enzyme alone. In this paper, we present a detailed analysis of the product of the interaction of native Phaseolus vulgaris PGIP-2 with five EPGs from Aspergillus niger, namely PGI, PGII, PGA, PGB, and PGC in the presence of homogalacturonan. We demonstrate that for PGA and PGC, the interaction with PGIP-2 may result in either inhibition or activation in a manner that is pH dependent. This data suggests the need for a reevaluation of the conventional description applied to PGIPs; suggestions include polygalacturonase-binding protein and polygalacturonase-modulating protein.

Tuberculosis meningitis and attention deficit hyperactivity disorder in children

The purpose of this study was to investigate the prevalence of attention deficit hyperactivity disorder (ADHD) in children who recovered from tuberculous meningitis (TBM) as part of an ongoing TBM research project. During this study, each TBM group subject underwent a thorough clinical-neurological examination, and a test battery which included the child behaviour check list (CBCL) Teacher's Report Form and Conners Rating Scale. The parents and teachers of each of the 21 TBM group and 21 control group subjects completed the above-mentioned questionnaires. All 21 TBM group subjects displayed symptoms of ADHD. The TBM group was significantly more hyperactive and unable to sustain attention than the control group. Furthermore, TBM group subjects were perceived as being significantly more unpopular, obsessive, compulsive and aggressive than the control group subjects. With regard to the frequency of externalizing behaviour, the TBM group subjects displayed significantly more externalizing behaviours as well as symptoms of attention deficit and hyperactivity. No significant differences between parents' and teachers' ratings were found. We conclude that ADHD is a common long-term complication of TBM.

A peptide derived from neutrophil inhibitory factor (NIF) blocks neutrophil adherence to endothelial cells

OBJECTIVE AND DESIGN

Peptides derived from neutrophil inhibitory factor (NIF), a known antagonist of Mac-1, were evaluated as inhibitors of neutrophil adherence.

MATERIAL

In vitro assays of adherence employed: 1) human polymorphonuclear cells (PMN), 2) human umbilical vein endothelial cells (HUVEC), and 3) CHO cells expressing ICAM-1 (CHO-ICAM cells).

TREATMENT

Cells, pretreated with NIF-derived peptides (0.1-100 microM) for 10 minutes, were permitted to adhere for 20 min in the continued presence of peptide.

METHODS

Cell-based assays: 1) PMN adherence to HUVEC, 2) PMN adhesion to immobilized human serum proteins, and 3) adherence of CHO-ICAM cells to immobilized Mac-1.

RESULTS

A NIF-derived peptide of 29 amino acids blocked PMN adherence to HUVEC, but behaved somewhat differently than the parent NIF protein. NIF specifically antagonized Mac-1 dependent adherence, but the peptide blocked neutrophil adherence that was dependent upon both Mac-1 and LFA-1 integrins. CHO-ICAM adherence to Mac-1 was blocked by NIF, but not by the peptide. Binding studies with NIF and the peptide indicate that the molecules bind to different sites.

CONCLUSIONS

A peptide derived from NIF blocks PMN adherence but, unlike NIF, the mechanism of action is not mediated by direct antagonism Mac-1.

Urokinase thrombolysis as initial therapy for acute and non-acute ischemic extremities

Limb ischemia, both acute and chronic, presents a risk to life and limb with mortality rates from 3% to 37% and amputation rates of the same range. Our experience with urokinase thrombolysis as the initial therapy for acute and non-acute ischemic extremities over 57 consecutive cases of native arterial occlusion by either thrombus or embolus has resulted in no mortality and only 3.5% requiring amputation (2 of 57). In 74% of cases initial thrombolytic therapy was followed by either balloon angioplasty (35 patients) or surgery (7 patients) to relieve the underlying cause of obstruction (i.e., stenosis, occlusion or aneurysm). Thrombolysis alone was sufficient and effective treatment in the remaining 26% (15 patients).

The predictive value of biophysical profiles and Doppler velocimetry for fetal acidosis in a low risk population

Antenatal fetal monitoring is the principal means of distinguishing the fetus requiring imminent delivery from that which is coping well in utero. The ability to detect fetal compromise, defined by fetal acidosis, in a low-risk population was evaluated in a prospective study of 50 women undergoing a Caesarean section in the absence of labour. The sensitivity and positive predictive value of a modified biophysical profile (BPP) or Doppler velocimetry to detect a fetus subsequently born with an umbilical artery pH of less than 7.20 was poor. The incidence of fetal acidosis in the population under study was 8%. Interpretation of antenatal fetal assessments must be tempered by the clinical features of each case. Decisions to deliver should take into account the low sensitivity of these tests in the absence of other complicating factors.

Quality assurance breast phantoms for screen-film mammography: design and use

Used properly, well-designed breast phantoms are a very useful part of the mammography QA program. However, they should be designed specifically for the purpose. The principles involved are discussed and illustrated by the design of the unit shown in figure 1. QA phantoms also must be applied appropriately. Procedures are described for checking the consistency of film density, evaluating image quality, and checking phototimer operation. The simple film density measurement test (table 2) also provides a useful check on the constancy of patient dose levels. However, errors may result when QA phantoms are used for dosimetry, primarily because their composition differs from that of the mixture BR12, which is usually taken as the standard for dosimetry measurement. Procedures are described for computing average glandular dose, as well as measuring the two required quantities: the beam HVL and the exposure in air required for proper film density.

Screen-film mammographic technique for breast cancer screening

The values of dose and signal-to-noise ratio (SNR) for many techniques and breast thicknesses were computed and compared with a reference technique and breast thickness to provide a valid basis upon which to select a screening technique for screen-film mammography. The reference consisted of a Min-R/OM1 combination (or its equivalent) exposed through a 4.5-cm thick breast via 28 kV and a molybdenum target-beryllium window tube with a 0.03-mm Mo filter. Radiographs of an improved breast phantom were used to relate computed relative SNR values of techniques to diameters of the smallest calcific and soft-tissue objects demonstrated in mammograms. Without use of a grid, four Mo target/filtration combinations yielded similar computed dose and SNR levels, as did a tungsten target tube operated at 23 kV without a filter. Operation of the latter tube at 27.5 kV with a 0.051-mm rhodium filter should reduce dose by half but also SNR by 22%. However, such operation with a grid should greatly improve imaging moderate to large breasts without increasing dose over reference values.

Human proto-oncogene N-myc encodes nuclear proteins that bind DNA

N-myc is a gene whose amplification has been implicated in the genesis of several malignant human tumors. We have identified two proteins with molecular weights of 65,000 and 67,000 encoded by N-myc. The abundance of these proteins in tumor cells was consonant with the extent of amplification of N-myc. The two proteins apparently arose from the same mRNA, were phosphorylated, were exceptionally unstable, were located in the nucleus of cells, and bound to both single- and double-stranded DNA. These properties suggest that the products of N-myc and of the related proto-oncogene c-myc may have similar biochemical functions and that N-myc may be a regulatory gene. Our findings sustain the view that inordinate expression of N-myc may contribute to the genesis of several different human tumors.

Dosage evaluation in mammography

Estimates of breast dose per view are needed for selection of mammographic techniques and verification of their proper use. However, accurate dosimetry requires standardization of both the methodology and the assumed breast composition. Because several different methods have been reported, the authors developed a simple and reproducible method using a reference "average breast" composition of 50/50% water/fat by weight. Working curves were derived for average glandular and whole-breast dose per unit of exposure in air vs. HVL and thickness. When these curves are combined with on-site measurements of exposure per view, one obtains values of dose per view for each technique. Factors were also computed to correct dosage from the reference composition to other breast compositions.

Breast radiography: phantom, equipment performance, and radiation dosage comparisons for twenty-eight major mammography centers in the midwest. Work in progress

This preliminary report discusses mammography tests that were conducted at 28 midwest medical centers. Equipment-parameter measurements were made, and images that were obtained with the Stanton Mark IIR Mammography Phantom were studied to compare image quality. These tests indicate that variations in equipment parameters and techniques can result in differences in the imaging of various sized phantom fibril and speck groups.

Measurements of diagnostic x-ray backscatter by a novel ion chamber method

There is a major gap in backscatter information for diagnostic x-ray beams. Such information is increasingly needed for dose measurements and calculations, as well as for designing devices and techniques. We have therefore carried out measurements on both low Z materials and metals, using an ion chamber method designed specifically for the purpose. Lucite and two D.R. White tissue substitutes were studied extensively (BR 12 "average breast" and MS 11 "water"). Measured percent backscatter (BS) was greatest for Lucite and least for MS 11, with BR 12 in between. Backscatter buildup is rapid: 50% of full backscatter is achieved with 6 mm thickness for all three materials using mammographic beams and with about 12 mm using general diagnostic beams. A simple relationship between BS and field area permits close estimates of BS values for fields for which measured data is not available. Among metals tested, copper exhibited greatest backscatter (39% BS maximum), aluminum least, and lead in between--information of potential importance in cassette design and similar applications.

Comparison of ion chamber and TLD dosimetry in mammography

An ionization chamber method has been developed to measure exposure vs depth in a uniform BR 12 "average breast" phantom. It employs a Memorial mammography chamber for exit exposure measurements; resulting data is then corrected for backscatter as well as for the exceptionally thin window of this chamber. A careful comparison has then been made with relative exposure vs depth curves obtained using TLD at several mammography beam qualities, for identical exposure factors and SSD values. Use of a correction for residual and background TL signals significantly improved agreement between TLD and ion chamber curves in the 28 to 35 kVp/0.03 mm Mo range of beam quality. Agreement was within +/- 5% for the Mo target tube, but TLD readings were 4%--8% higher than ion chamber values for the W/Mo target tube. At Xeromammography energies (45 kVp/1.6 mm Al), corrected TLD curve readings were 6% higher at depth than ion chamber curve values. TLD meaurements with 28 to 35 kVp/0.03 mm Mo beams tend to underestimate dosage to the midbreast parenchyma. For example, in a 5 cm "average breast", the underestimation ranges from 2%--10% for corrected, 10%--16% for uncorrected TLD readings.

A study of mammographic exposure and detail visibility using three systems: Xerox 125, Min-R, and Xonics XERG

A breast phantom of novel design has been used to measure visibility of simulated calcific and soft-tissue fibrillar details in mammography, as well as to determine the roentgen exposure vs. depth. Exposure data were combined with a model of the breast as compressed during mammography to compute the mean exposure to the ductal parenchyma (MDE). Three different imaging systems were compared over a wide range of x-ray beam energies and breast characteristics. "Dosage" criteria other than the MDE are discussed.

Auditory evoked potentials and auditory behavior following prenatal and perinatal asphyxia in rhesus monkeys

Two types of asphyxia were studied in monkeys, total asphyxia during mid-pregnancy (94--98 days gestation) and combined partial and total axphyxia at term (165 days gestation). Auditory evoked potentials and the acquisition of 2 auditory discrimination tasks were studied in asphyxiated animals as well as in group of controls. The brains of all asphyxiates were examined histologically. No auditory discrimination deficit was found in the asphyxiated animals; however, the auditory evoked potentials differentiated between control and asphyxiated animals, especially those with verified inferior colliculus damage.

Rapid computation of diagnostic X-ray bremsstrahlung spectra

A method is described for rapid and accurate computation of diagnostic x-ray spectra. Accuracy limitations of Kramers' equation are overcome by providing intensity correction factors derived from published measured data. Use of a parameter based on the energy of the Kramers spectrum intensity peak permits deriving master factor curves which are remarkably independent of kVp, waveform and filtration. Computed and measured spectra generally agree to better than +/- 1 keV for beams generated at 100 kVp and below. Possible application of the method to higher energy diagnostic beams is discussed.

A breast phantom method for evaluating mammography technique

A new breast phantom has been designed for use in evaluating mammographic system performance. This phantom incorporates simulated calcifications and fibrillar objects in fat, of graded size, to permit measurements of detail visibility. A special methodology has been developed for measuring visible object size to achieve reproducible and clinically relevant results. Materials and construction of the phantom also permit carrying out dosimetry with an appropriate ionization chamber. Dosage and detail visibility measurements are reported for the Xerox 125, Min-R and Xonics systems. In addition to providing information regarding technique and image receptors, these results demonstrate the usefulness of the basic phantom design, and suggest possible improvements.

Image characteristics of liquid developed electron radiographs

This paper presents electron radiograph studies using the new Xonics liquid development system described only briefly previously. Results indicate: (a) higher contrast images with reduced but useful edge enhancement; (b) adjustable contrast; (c) reduced exposure vs. aerosol development; (d) sharp, low artifact images to densities greater than 2.5; and (e) possibility of nongrid scatter control in some situations.

Clinical evaluation of electron radiography. Current status

Details of a 4-phase evaluation of electron radiography are reported. The experimental equipment now uses liquid toners which result in less edge contrast and latitude than in powder-cloud exposures. Use of a bias technique during development prevents deposition except to areas where voltage exceeds the bias voltage. Quality radiographs with decreased doses and expense result.

Racial differences in color vision: do they exist?

The present experiment investigated the possibility that variation in fundus pigmentation among individuals may be related to differential color sensitivity. Fifty black and white observers representing a wide range of skin (and fundus) pigmentation made direct heterochromatic brightness matches for a white standard field against each of five chromatic comparison fields. Results indicated that pigment (i.e., racial) differences in color vision do not exist, as measured by the two psychophysical methods used. The data showed that the heterochromatic matches were less reliable for the more saturated colors, violet and red, and also that the psychophysical methods used to obtain the matching data differentially influenced the results for the more saturated colors.

Edge sharpness and enhancement of electron radiographs (ERGs) produced with powder cloud development

Much renewed interest has developed in electrostatic imaging systems. This is partly because of their use of relatively inexpensive materials and their potential for improved diagnostic accuracy--a novel combination of image latitude with great detail contrast. All such systems can exhibit these image characteristics when developed by the generally used "powder cloud" technique or some similar partial development system. We have measured edge sharpness and enhancement of electron radiographs (ERGs) produced with the powder cloud technique. Edge sharpness can be excellent at low image-density levels, but deteriorates with increasing density. Edge enhancement is also appreciable; it appears to decrease somewhat with increasing image density, but no simple relationship has yet been shown.