ATM: Options for Cancer Treatment

Cancer Treatment for People with Inherited ATM Mutations

Testing positive for an inherited ATM mutation may affect your treatment options or eligibility for clinical trials studying which treatments work best. The following are examples of situations where an ATM mutation may play a part in treatment decision-making. 

Radiation therapy in people with a mutation in both copies of their ATM gene 

People with an inherited mutation in both copies of the ATM gene (people with Ataxia-Telangiectasia) are very sensitive to radiation damage. However, according to experts, people with a single ATM mutation can safely undergo radiation therapy to treat their cancer as recommended by their oncologist. 

Breast cancer surgical decisions 

It is believed that the risk for a second breast cancer diagnosis in women with an ATM mutation is slightly higher than women without a mutation. For this reason, some women with ATM mutations who are diagnosed with breast cancer may choose  bilateral mastectomy rather than lumpectomy and radiation. Mutation carriers who undergo mastectomy are less likely to develop a second breast cancer. These decisions should be made after discussion of the benefits and risks of each option with your healthcare providers.

Targeted therapies for advanced cancers

PARP inhibitors 

PARP inhibitors are a type of targeted therapy that work by blocking a protein used to repair DNA damage. These drugs were initially developed to treat cancers in people with BRCA1 or BRCA2 mutations. More recently they have been studied for treating advanced cancers in people with other mutations.

ATM-deficient tumors may be sensitive to PARP inhibitors, but responses are less consistent than those seen in BRCA1- or BRCA2-associated cancers. Researchers are continuing to study which ATM-altered tumors are most likely to benefit. 

Currently, the PARP inhibitors, Lynparza (olaparib) and Talzenna (talazoparib) have received FDA-approval to treat metastatic, castration-resistant prostate cancer (mCRPC), with a mutation in ATM or another gene linked to a certain type of DNA damage repair.

ATR inhibitors 

Some cancers that develop in people with an inherited ATM mutation develop a second mutation that completely inactivates both copies of the ATM gene. These tumors can be tested for loss of ATM function. Not all cancers in people with inherited ATM mutations have this loss. When cancer cells lose their ATM function, they rely more heavily on other DNA repair systems to survive. Researchers are studying treatments that target these backup repair systems, which may be especially effective against tumors with ATM loss. Clinical trials are currently evaluating new drugs, called ATR inhibitors, that may be particularly effective against cancers with ATM loss.

To learn more about treatment options for specific types of cancer, visit our section on cancer treatment by cancer type. 

Options for people with advanced cancers with no other treatments available

If you have an ATM mutation and advanced cancer that no longer responds to standard therapy, you may want to talk with your doctor about additional biomarker testing or whether you might benefit from treatment with a PARP inhibitor or participation in a clinical trial. 

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