A possible association between breast cancer, bronchiectasis and nontuberculous mycobacterial (NTM) lung disease

Background Nontuberculous mycobacterial (NTM) lung infections in the U.S. occur predominantly in women with bronchiectasis and a characteristic phenotype that includes thin body habitus, scoliosis and mitral valve prolapse. The explanation(s) for this association is unclear, but may be related to hormone regulation. We hypothesized that women with bronchiectasis and NTM lung infection are also predisposed to hormonally mediated tumors such as breast cancer. Methods We identified age appropriate women from our outpatient clinic who were diagnosed with bronchiectasis and asked them to respond by telephone questions focused on hormone regulation and hormone associated malignancies such as breast cancer. Results A total of 113 surveys were completed. NTM lung disease was present in 110/113 (97.3%) of respondents. 21/113 (18.6%) of respondents had a history of breast cancer. (Women have a 12.4% lifetime risk of developing breast cancer in the U.S.) 30/113 (26.5%) had a first degree relative with breast cancer. The average age of breast cancer diagnosis was 59.9 +/- 4 yrs. Osteoporosis was present in 9/21 (42.9%) and in 42/92 (45.7%) of respondents with and without breast cancer respectively. 13/21 (62%) of respondents with breast cancer vs 60/92 (65%) of respondents without breast cancer had at least a partial hysterectomy. The average age at menopause was 47 +/- 4.8 yrs vs 46 +/- 5 yrs in the breast cancer and non-breast cancer groups respectively. Conclusions Women with bronchiectasis and NTM lung disease may also be at increased risk for the development of breast cancer. Corroboration of this observation and investigation of common pathophysiologic links requires more study.