Pathological confirmation of primary lung cancer following breast cancer.
OBJECTIVE
Studies have shown that women who survive breast cancer have an increased risk of a future primary lung cancer, though many are based only on data recorded in tumor registries and none have conducted pathological confirmation. Previous studies and future use of large registries may be affected by misdiagnosis.


METHODS
Pathological analysis was conducted on tumors from 110 women with breast cancer followed by lung cancer using morphology, Estrogen Receptor-alpha (ER), and Thyroid Transcription Factor-1 (TTF1). We developed an algorithm to classify lung tumors as unlikely lung cancer (score=1) to likely lung cancer (score=5).


RESULTS
Mean time to diagnosis of lung cancer after breast cancer was 13 years. 76% of breast tumors and 20% of lung tumors were positive for ER and 51% of lung tumors were positive for TTF-1. 86% of the lung tumors were probable primaries, 7% were probable metastases from the breast, and 7% were of undetermined status. 70% of probable metastases had a latency of longer than 10 years.


CONCLUSIONS
Prior studies identifying the association of breast cancer and breast cancer treatments with lung cancer are likely to reflect true associations not confounded by misdiagnosis, as evidenced by the low rate of misclassification detected in this study. Analysis of the years of diagnosis suggests that latency may not be an accurate criterion for assignment of primary status, which could be significant in a clinical setting. These data may also benefit future retrospective studies using large registries.
Tennis
M
M
Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA. Meredith.tennis@ucdenver.edu
Singh
B
B
Hjerpe
A
A
Prochazka
M
M
Czene
K
K
Hall
P
P
Shields
P G
PG
D000230:Adenocarcinoma / Q000145:classification / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D000368:Aged; D000465:Algorithms; D001943:Breast Neoplasms / Q000145:classification / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D047628:Estrogen Receptor alpha / Q000276:immunology / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D008875:Middle Aged; D009362:Neoplasm Metastasis; D016609:Neoplasms, Second Primary / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D009687:Nuclear Proteins / Q000276:immunology / Q000378:metabolism; D011379:Prognosis; D012042:Registries; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000276:immunology / Q000378:metabolism
D047628:Estrogen Receptor alpha; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors