That publication is from 1989 when older techniques of x-ray diagnoses were used prior to that study; persons were exposed to much more radiation then. In that study the average duration of x-ray monitoring was 8+ years. That is a long time.
Something to think about is that less radiation is used now days. Also, breast shields are used now unless the curve is so bad that the spine lies under the breast---me pre-op.
I haven't looked up more recent studies, however, physicians urged menopausal women with scoliosis to use HRT which itself could be implicated in breast cancer.
Just food for thought
Original scoliosis surgery 1956 T-4 to L-2 ~100 degree thoracic (triple)curves at age 14. NO hardware-lost correction.
Anterior/posterior revision T-4 to Sacrum in 2002, age 60, by Dr. Boachie-Adjei @Hospital for Special Surgery, NY = 50% correction