Unselected multigene testing supported for all patients with breast cancer

By Michael Woodhead

22 Oct 2019

Multigene testing should be offered to all women with breast cancer, rather than be offered on the basis of family history or clinical characteristics, a new study suggests.

Testing of all unselected patients with breast cancer for BRCA1/BRCA2/PALB2  would identify many more gene carriers and potentially prevent many cases of breast cancer and ovarian cancer, according to a UK/Australian modelling analysis published in JAMA Oncology.

The simulation study based on data from 11 836 women found that unselected BRCA1/BRCA2/PALB2 testing at breast cancer diagnosis would be extremely cost-effective compared with BRCA1/BRCA2 testing based on clinical criteria or family history.

The strategy was associated with an additional 419-day increase in life expectancy for UK and 298 days for US BRCA1/BRCA2/PALB2 pathogenic variant carriers.

One year’s unselected panel genetic testing could therefore potentially prevent 2101 cases of breast or ovarian cancer and 633 deaths in the UK and 9733 cases and 2406 deaths in the US, the researchers estimated.

In terms of incremental cost-effectiveness ratio (ICER) the study showed that QALY-based health outcomes would justify the cost differences between an unselected strategy and the current approach, said researchers led by a groups from the London School of Hygiene & Tropical Medicine.

“These findings support changing current policy to expand genetic testing to all women with breast cancer,” they concluded.

They said the current family history- or clinical criteria–based policy misses a large proportion of pathogenic variant carriers who fall below the current clinical threshold.

“Moving toward unselected breast cancer testing may give an impetus for prevention in unaffected family members along with clinical implications for the patient with breast cancer.”

“Pathogenic variant carriers with newly diagnosed breast cancer can opt for bilateral mastectomy rather than breast conservation at initial breast cancer surgery.

“Bilateral mastectomy reduces contralateral breast cancer risk, may provide better options for breast reconstruction, and may obviate the need for adjuvant radiotherapy. The patients also become eligible for therapeutic options, such as PARP inhibitors.”

The modelling assumed that affected BRCA/PALB2 carriers could undertake contralateral preventive mastectomy; BRCA carriers could choose risk-reducing salpingo-oophorectomy (RRSO), and relatives of mutation carriers would udergo cascade testing.

Unaffected relative carriers could undergo magnetic resonance imaging or mammography screening, chemoprevention, or risk-reducing mastectomy for BC risk and RRSO for ovarian cancer (OC) risk.

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