Long-term risk of second malignancies in women after breast conservation therapy for ductal carcinoma in situ or early-stage breast cancer

• Published in: Breast cancer research and treatment Vol. 170; no. 1; pp. 45 - 53
• Main Authors: Kushner, Carolyn J., Hwang, Wei-Ting, Wang, Shiyu, Solin, Lawrence J., Vapiwala, Neha
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-07-2018; Springer; Springer Nature B.V
• Subjects: Adult; Age Factors; Aged; Aged, 80 and over; Antineoplastic agents; Breast cancer; Breast carcinoma; Breast Neoplasms - epidemiology; Breast Neoplasms - pathology; Breast Neoplasms - surgery; Cancer research; Cancer therapies; Carcinoma, Intraductal, Noninfiltrating - epidemiology; Carcinoma, Intraductal, Noninfiltrating - pathology; Carcinoma, Intraductal, Noninfiltrating - surgery; Care and treatment; Chemotherapy; Clinical Trial; Combined Modality Therapy; Ductal carcinoma in situ; Epidemiology; Female; Health risk assessment; Humans; Lumpectomy; Malignancy; Mammography; Mastectomy, Segmental - adverse effects; Mastectomy, Segmental - methods; Medical research; Medical schools; Medicine; Medicine & Public Health; Melanoma; Middle Aged; Neoplasm Staging; Neoplasms, Second Primary - epidemiology; Neoplasms, Second Primary - pathology; Oncology; Population studies; Prognosis; Radiation therapy; Risk; Risk Assessment; SEER Program; Surgery; Women; Breast carcinoma; Ductal carcinoma in situ; Secondary malignancy; Breast conservation treatment; Radiation treatment; DCIS
• ISSN: 0167-6806; 1573-7217
• DOI: 10.1007/s10549-018-4729-7

Purpose
Women with ductal carcinoma in situ (DCIS) or early-stage breast cancer have an excellent prognosis, but their risk of developing second malignant neoplasms (SMNs) is not well established. We analyzed SMNs in a large cohort with long follow-up after breast conservation therapy.
Methods
The study population comprised 755 women with DCIS (
n
 = 135) or stage I-II breast carcinoma (
n
 = 620). Subjects were aged 25-89 (median 55) years when they underwent breast-conserving surgery followed by radiotherapy to the entire breast (60-68Gray) between 1992 and 2001. Additional treatment included hormonal therapy and/or chemotherapy based on clinical characteristics. SMNs were grouped by site. The rate of SMNs over time was determined using the Kaplan–Meier method. To compare the probability of developing SMNs overall and for specific organs or sites, probability estimates were obtained for a 55-year-old female from the Surveillance, Epidemiology, and End Results Program (SEER).
Results
Median follow-up from radiotherapy was 13.8 years. The 15-year age-adjusted probability of developing any SMN was 12.0%, close to the SEER rate of 12.1% for a non-breast malignancy. Systemic therapy and higher-dose radiotherapy (> 63 Gray) were not associated with significantly increased risks of SMNs. Compared to SEER, significantly increased risk was noted for gynecologic cancers and melanoma.
Conclusions
Most SMNs were unrelated to treatment, and the 15-year incidence was similar to that of cancer in the SEER control group—findings that should be reassuring to patients. Further risk reduction is expected from prophylactic gynecologic surgery. Continued investigations into genetic links with melanoma are warranted.