Stage IIIA Right Breast Cancer Followed by a Late Radiation Nerve Injury

What happened, in summary

At age 50, a woman was diagnosed in 1998 with a second primary breast cancer in the right breast, classified as Stage IIIA. Four axillary lymph nodes were positive. She underwent bilateral mastectomy with tissue expanders, followed by 6 months of cyclophosphamide, epirubicin, and 5-fluorouracil. She then received 5 weeks of daily radiation to the right chest wall, supraclavicular area, and axilla. Hormone therapy continued for 10 years, with 5 years of tamoxifen followed by 5 years of letrozole.

In May 2018, 20 years after treatment, she suddenly noticed weakness in her right thumb. Over the following months, spasms, finger movements, numbness, and worsening weakness made writing difficult. Imaging in January 2019 found no cancer recurrence. Nerve testing supported radiation-induced brachial plexopathy.

The weakness substantially reduced her grip, pinch strength, and dexterity. She could no longer write legibly or play tennis as before. Hand therapy, splints, pencil grips, and a larger racket grip provided some practical improvement. Forty hyperbaric oxygen treatments did not improve the nerve injury.