A fine eye for detail with new breast cancer screening
Breast screening with x-ray mammography has made a vital contribution to reducing deaths from breast cancer. Dr José Maria Benlloch of CSIC (Spanish National Research Council) and his partners in the MAMMI project (Mammography with Molecular Imaging) recognised this, but they were driven to push science and engineering further to develop machines dedicated exclusively to breast scanning. Now it is possible to radically improve the quality of imaging, detect cancer cells at a much earlier stage and monitor the effectiveness of the treatment more accurately.
In this project, science and engineering worked together to respond to a set of needs and desires of those on the front line of cancer treatment. Many women, especially older women, complain that traditional scanning procedures that compress the breast are very uncomfortable and also rather undignified. At the end of it all, the results are still limited and in at least 10 % of cases they could produce a false positive, where patients are told they have cancer when in fact they don’t.
Equally, false negatives, where women are wrongly reassured they don’t have cancer, are also an issue.
At the other end of the age spectrum, young women with denser breast tissue can be even harder to screen accurately, causing more uncertainty with diagnosis and treatment.
At the moment, whole-body scanners tend to be used, but these new PET (positron emission tomography) scanners are specific to the breast and so are smaller and portable. Women can be examined lying down, which is much more comfortable, and this equipment also allows a clearer view of the pectoral wall, where the breast joins the chest. It is here that cancer cells start to form but cannot be detected by mammograms until a lesion of around 5 mm has formed; so getting clearer results and at very early stages of tumours developing are big assets for the new scanners.
PET scans are based on gamma ray imaging with radioactive isotopes, which creates a whole new dimension in identifying tumours. They give a much more sensitive response to the presence of cancer cells, improving the initial diagnosis and the level of detailed information about the tumour. Tumours accumulate more glucose to feed the growth of the cancer cells and radioactive tracers can target and cling to these sugar-fuelled hotspots and reveal much clearer results on the scan.
Diagnosis is a vital first step and this technology is giving doctors fuller and more accurate information before treatment begins. The level of detail is transforming the speed of intervention and the specific type of treatment recommended. This may be surgery, radiotherapy or a combination of the two, plus lengthy drug treatments.
Scarring following treatment is the next hurdle to overcome. Scar tissue reduces the effectiveness of normal mammography, but molecular imaging through PET scanning can see through it better. The improvements don’t stop there however, because the MAMMI prototype also gives much quicker follow-up information to monitor how treatment is going. Instead of waiting for months before doctors can assess the effectiveness of their treatment choices, this type of imaging is giving detailed feedback within weeks. This fast response means drugs can be changed and fine-tuned much sooner, giving a better and more efficient service to patients and the health system.
Dr Benlloch has generally been really encouraged by the momentum of the project. It has been an opportunity to see excellent doctors working with engineers to deliver a novel piece of equipment.
Their enthusiasm has kept up motivation and demonstrated the powerful combination of science, engineering and commercial need.
As a reality check however, management and logistical problems cropped up early on because the number of partners and the range of clinical aspects included were too big. Everyone needed to simplify and scale down, which was hard but essential if they were to produce useable results.
Biting this bullet meant that a pilot project with 60 patients was completed on time and within budget, paving the way for future developments.
The next step should be based on a clinical validation study with 5 000 patients. In other words, results from the pilot project need now to be subjected to testing on a much bigger scale, but the small, complex beginnings of the MAMMI study may lead on to reliable real-world outcomes.