Long-term impact of young age at diagnosis on treatment outcome and patterns of failure in patients with ductal carcinoma in situ treated with breast-conserving therapy.

We reviewed our institution's long-term experience treating patients diagnosed with ductal carcinoma in situ (DCIS) of the breast with breast-conserving therapy (BCT) to determine the impact of patient age on outcome over time. All DCIS cases receiving BCT between 1980 and 1993 were reviewed. Patient demographics (including age <45) and pathologic factors were analyzed for effect on outcomes including ipsilateral breast tumor recurrence (IBTR) and survival. BCT included limited surgery (excisional biopsy or lumpectomy) followed by radiotherapy to the whole breast (median whole-breast dose: 50 Gy, median tumor bed dose: 60.4 Gy). One hundred and forty-five cases were evaluated; the median follow-up was 19.3 years. Twenty-five patients developed an IBTR, for 5-, 10-, 15-, and 20-year actuarial rates of 9.9%, 12.2%, 13.7%, and 17.5%, respectively. The 10-year ipsilateral rate of recurrence was 23.3% (<45 years) versus 9.1% (≥ 45 years) (p = 0.05). Younger patients more frequently developed invasive recurrences (20-year actuarial rates: 20.4% versus 12.8%, p = 0.22) and true recurrences/marginal misses of the index lesion (23.3% versus 9.7%, p = 0.04) with lower rates of contralateral breast cancer (0.0% and 0.0% versus 12.0% and 20.5%, p = < 0.01, at 10 and 20 years, respectively). Young women under the age of 45 diagnosed with DCIS have a greater risk of local recurrence with different patterns of failure following BCT, which is most notable within 10 years of diagnosis.