The SEGMENT Study
Metastatic (stage 4) breast cancer is incurable, but a new study suggests that genomic profiling could lead to better treatment options for patients.
The SEGMENT study examined the feasibility of characterising genomic alterations using gene sequencing on tumour specimens from patients with breast cancer.
The study found that genomic sequencing for the management of metastatic breast cancer is both feasible and has implications for clinical practice, particularly for patients who are able to participate in clinical trials of newer treatments.
The project, which was spearheaded by Professor Sherene Loi at the Peter MacCallum Cancer Centre, received funding from Breast Cancer Trials.
“Patients with metastatic breast cancer are looking for anything that can give them hope,” says medical oncologist Dr Peter Savas, Dr Loi’s colleague at the Peter MacCallum Cancer Centre. “SEGMENT was about trying to use what was at the time quite a new technology, and bring it into the clinic to see if we could use that to give patients more options.”
The development of Herceptin – a drug that targets overactivity of the HER-2 gene in one of the more aggressive types of breast cancer – in the 1990s, opened the door to better-targeted therapies.
“Now, the prognosis of that cancer is significantly better,” Dr Savas says. “That’s a really good example of the proof of principle that tailoring treatments to specific features in the cancer can be very fruitful. The next logical question is, can we take that approach and make it more broadly applicable to patients with metastatic breast cancer?”
Meanwhile, sequencing technologies – relatively rare when SEGMENT began in 2013 – have become cheaper and more accurate, making profiling of metastatic breast cancer more available.
One barrier to that, Dr Savas says, is a lack of awareness among oncologists and patients. “But that’s improving over time, and the pairing of genomic findings with treatments will become more widespread.”
Launched in 2019, the drug alpelisib is one example of this. It specifically targets the PIK3CA mutation, which is common in many patients with hormone receptor positive breast cancer, Dr Savas says. “Following that, there’s a long tail of rarer alterations,” he adds.
“SEGMENT is a big study, but it doesn’t have enough patients to understand the importance of rarer alterations. But by putting it together with other datasets, we can get a better idea of the changes and their significance.”
Clinical implications of prospective genomic profiling of metastatic breast cancer patients.
van Geelen CT, Savas P, Teo ZL, Luen SJ, Weng C-F, Ko Y-A, Kuykhoven KS, Caramia F, Salgado R, Francis PA, Dawson S-J, Fox SB, Fellowes A, Loi S. Breast Cancer Research. 2020; 22:91:https://doi.org/10.1186/s13058-020-01328-0.
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