Sarah Pinder

Changes in glycosylation are common in malignancy, and as almost all surface proteins are glycosylated, this can dramatically affect the behavior of tumor cells. In breast carcinomas, the O-linked glycans are frequently truncated, often as a result of premature sialylation. The sialyltransferase ST3Gal-I adds sialic acid to the galactose residue of core 1 (Galbeta1,3GalNAc) O-glycans and this enzyme is over-expressed in breast cancer resulting in the expression of sialylated core 1 glycans. In order to study the role of ST3Gal-I in mammary tumor development, we developed transgenic mice that over-express the sialyltransferase under the control of the human membrane-bound mucin 1 promoter. These mice were then crossed with PyMT mice that spontaneously develop mammary tumors. As expected, ST3Gal-I transgenic mice showed increased activity and expression of the enzyme in the pregnant and lactating mammary glands, the stomach, lungs and intestine. Although no obvious defects were observed in the fully developed mammary gland, when these mice were crossed with PyMT mice, a highly significant decrease in tumor latency was observed compared to the PyMT mice on an identical background. These results indicate that ST3Gal-I is acting as a tumor promoter in this model of breast cancer. This, we believe, is the first demonstration that over-expression of a glycosyltransferase involved in mucin-type O-linked glycosylation can promote tumorigenesis.

It has been shown that the tumour microenvironment plays a crucial role in regulating tumour progression by a number of different mechanisms, including the remodeling of collagen fibres in tumour-associated stroma. It is still unclear, however, if these stromal changes are of benefit to the host or the tumour. We hypothesise that stromal maturity is an important reflection of tumour biology, and thus can be used to predict prognosis. The aim of this study is to develop a texture analysis methodology which will automatically classify stromal regions from images of hematoxylin and eosin-stained (H and E) sections into two categories: mature and immature. Subsequently we will investigate whether stromal maturity could be used as a predictor of survival and also as a means to better understand the relationship between the radiological imaging signal and the underlying tissue microstructure. We present initial results for 118 regions-of-interest from a dataset of 39 patients diagnosed with invasive breast cancer.

Introduction Mammographic screening identifies many women with small breast cancers with favourable biological features, which have an excellent prognosis. Some of these may never have become clinically apparent without screening and are commonly described as ‘overdiagnosed’ cancers. Despite this, all patients with screen-detected cancers are currently treated with surgical excision and sentinel lymph node biopsy, although this may represent overtreatment. There is, therefore, a need for less invasive approaches to reduce treatment burden for patients while maintaining current excellent oncological outcomes. Vacuum-assisted excision (VAE) may represent such an alternative treatment approach, and the SMALL ( Open Surgery versus Minimally invasive-vacuum Assisted excision for smaLL screen-detected breast cancer ) trial aims to investigate the use of VAE for the safe de-escalation of surgical treatment for such excellent prognosis invasive breast cancers. Methods SMALL is a prospective, multicentre, randomised phase III trial of VAE versus surgery in patients with small, biologically favourable screen-detected invasive breast cancer. SMALL has an innovative hybrid design with coprimary endpoints. These include a randomised non-inferiority comparison of surgical re-excision rates following initial treatment, and a single-arm analysis of local recurrence at 5 years following VAE. Secondary outcomes include complication rates, overall survival, quality of life and a health economic analysis. The trial includes a QuinteT Recruitment Intervention to support recruitment. Ethics and dissemination Ethical approval was obtained from the Office for Research Ethics (Northern Ireland) for all UK sites. Results will be submitted for publication in a peer-reviewed journal, presented, shared with patient partners and with relevant professional organisations to inform future guideline development for the management of screen-detected breast cancer. Trial registration number ISRCTN12240119 .

Background Annual surveillance mammograms for an unspecified period, after treatment for early breast cancer, are widely practised in the United States of America and Europe. Current UK guidelines recommend annual mammograms for 5 years, then reverts to 3-yearly screening. The aim of this trial was to evaluate whether less than annual mammography was non-inferior in terms of breast cancer-specific survival and cost-effectiveness in women aged 50 years or older at diagnosis and 3 years post curative surgery. Methods We conducted a multicentre, randomised phase III trial of annual mammography versus less-frequent mammography (2-yearly after conservation surgery or 3-yearly after mastectomy). Women were eligible if aged ≥ 50 years at initial diagnosis of breast cancer (invasive or ductal carcinoma in situ) and recurrence-free 3 years post curative surgery. The trial was conducted at 114 NHS hospitals in the UK. Participants were randomly assigned (1 : 1) to annual or less-frequent mammograms; followed up for 6 years. Coprimary outcomes were breast cancer-specific-survival and cost-effectiveness; secondary outcomes included recurrence-free interval and overall survival. Analyses were by intention to treat, with a pre-planned per-protocol analysis. Planned sample size was 5000. Clinical results are now reported. Results Five thousand two hundred and thirty-five women were randomised between April 2014 and September 2018. With a median of 5.7-year follow-up, 343 women have died, of whom 116 died of breast cancer (61 on annual arm; 55 on less-frequent arm). Breast cancer-specific-survival at 5 years was 98% on both arms with a hazard ratio of 0.92 (95% confidence interval 0.64 to 1.32), which demonstrated non-inferiority of less-frequent mammograms at the 3% margin (non-inferiority p < 0.0001) and the 1% margin (non-inferiority p = 0.003). Non-inferiority was demonstrated at the 2% level for both recurrence-free interval [hazard ratio 1.00 (95% confidence interval 0.83 to 1.28); non-inferiority p = 0.0024] and overall survival [hazard ratio 1.07 (95% confidence interval 0.87 to 1.33); non-inferiority p = 0.008]. Less-frequent mammograms were associated with a significant cost saving (mean difference £544, 95% confidence interval −£1116 to £26), heavily driven by mammogram costs. Incorporating societal costs resulted in a larger cost-saving (£1543 per person, 95% confidence interval −£2416 to −£669), increasing cost-effectiveness. There was no impact of less-frequent mammograms on patients’ quality of life. Conclusion For patients aged ≥ 50 years and 3 years post diagnosis, less-frequent mammograms were non-inferior and cost-effective compared with annual mammograms, with no detriment to patients’ quality of life. Mammo-50 provides evidence to inform guideline development. Limitations Adherence to the mammographic schedules was 76%, though the per-protocol analysis showed no difference compared to the intention to treat results. The majority of the participants had small lower-grade oestrogen receptor-positive tumours and were from a White ethnic group. Future work More research is needed for women with ductal carcinoma in situ; women aged under 50 years old at diagnosis and different ethnic groups, especially those women of Black ethnicity who tend to present younger. Funding This synopsis presents independent research funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme as award number 11/25/03.