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Low dose Molecular Breast Imaging for improved cancer detection in dense breast tissue.

Periodic Reporting for period 1 - LDMBI (Low dose Molecular Breast Imaging for improved cancer detection in dense breast tissue.)

Reporting period: 2016-03-01 to 2016-08-31

Breast cancer screening programmes exist in most major advanced countries to detect breast cancer earlier, in order to treat the disease more effectively, leading to better clinical outcomes and reduced mortality. Mammography is currently used as the primary screening tool, in which X-rays are shone through the breast, and the absorbent tumours show as dark sections in the image.
In dense breasts, that is those with a high proportion of fibroglandular tissue as opposed to adipose, the tumours are difficult to identify as the fibroglandular tissue is also absorbent and shows as a dark region in the image. This leads to poor detection rates, with less than 50% of tumours detected in dense breasts. With 30-50% of women in the western world having dense breast tissue, this leads to a large number of cancers being missed. As a consequence, the tumours are not detected until they are detected symptomatically (usually when the woman has discovered a lump), when the tumours are more advanced. Larger tumours will require a greater treatment, and are more likely to metastasise and cause death.
Molecular Breast Imaging (MBI) is a functional imaging technique which has been demonstrated to detect around 90% of tumours. The radioactive isotope technicium-99m is combined with the tracer sestamibi, which is preferentially taken up by sites with high blood flow, such as tumours. By detecting the gamma rays emitted by the radiotracer, MBI is able to image the breast and identify tumours.
MBI is a technique which has been developed at the Mayo Clinic, USA, to whom Kromek is a detector supplier. The technique is being offered to patients by Mayo and their affiliates as a secondary screening technique, but it has not yet gained widespread use. It is not currently offered within the EU.
The objective of the Phase 1 project is to assess the validity of introducing the technique into breast cancer screening processes within the EU, replacing mammography as the primary screening technique for women with dense breasts. This includes a health economic assessment for the introduction of the technology, along with primary target markets and the regulatory pathway. The main output of the project is a business plan for the introduction of the technology.

The main conclusions of the study are:
The primary barrier to adoption of MBI as a screening technique is a lack of awareness of its benefits in the clinical and commissioning communities.
The optimum path to adoption and regulatory change is via initial clinician-led trials, proving dissemination and building momentum.
The current radiation dose of MBI is higher than mammography, and is likely to cause resistance to adoption. Developing a low dose version of MBI, lower than mammography, will create positive reasons for adoption.
The cost per cancer detected will fall by replacing mammography with MBI for women with dense breast tissue, but the total screening costs will increase.
The first section of this project was concerned with investigating the barriers that are preventing, in particular the currently higher dose of MBI than mammography, and regulatory requirements and other inertia in the healthcare systems. This involved visits and discussions with players in the field: the original developers of MBI (the Mayo clinic in the USA), potential users (clinicians etc.), commissioners (care commissioning groups, NHS England, NICE) and other interested parties (advocates of screening, opponents, researchers).
The conclusion from these studies was that mammography is so engrained in the screening pathway, and secondary techniques such as MRI and ultrasound readily available, that clinicians were not actively seeking new technologies, despite the inherent problems with mammography. Although it is preferable to achieve a dose as close as possible to mammography (it is currently about double), dose is likely to play a significant role in adoption further down the line. Several sources indicated the most promising route to adoption is to initially target individual clinicians, probably through a clinical trial, and build up momentum through clinician-led change.

The second section of the project was to carry out a Health Economic Assessment. After an information gathering exercise, we commissioned JB Medical, a health economics company, to assess the economic impact of the introduction of MBI as a primary screening tool for women with dense breasts. The study found that in Europe the cost per cancer detected by MBI is 15-20% lower for strategies using MBI than mammography, mainly due to the extra number of cancers detected. Once the cost consequences of delayed cancer diagnosis are taken into account, the incremental cost benefit of MBI versus mammography falls in the range €4,000 – €10,000 per additional cancer detected. In the USA, the corresponding figure is €43,000, which, given the different market conditions, is likely to make the USA an even more likely adopter.

The project concluded with the creation of a business plan, which will form the basis of the Phase 2 application.
This project has been to assess the feasibility for the introduction of a new technique with much better performance in breast cancer screening that the incumbent screening technology. This Phase 1 project did not look to take the technology further, but provide the basis for further developments required to ensure widespread adoption as a primary screening technology.
If and when the technology is adopted for primary screening of breast cancer for women with dense breasts we predict 147,000 extra cancers detected every year across Europe. This earlier detection will cut treatment costs for these women (we have estimated from a range of statistics that cancers detected by screening cost 20% less to treat than those diagnoses symptomatically), with less disruption to the life of the woman, thereby increasing economic productivity. We have not been able to find reliable predictions for the link between early detection and likelihood of death, therefore we can’t put a figure on lives saves, but there is likely to be some decrease in mortality and increase in life expectancy.
Example of mammogram (left) and MBI image (right) of tumour in dense breast