Usual interstitial pneumonia with lung cancer: clinicopathological analysis of 43 cases.

Background: Previous studies have suggested an association between usual interstitial pneumonia (UIP) and lung cancer (Ca). However, clinical and histological information is not enough to determine such an association, due to the low incidence and short survival time of patients with both conditions.

Methods: We retrospectively reviewed the clinical and histological records of Ca patients with UIP between January 1999 and August 2013 at the Samsung Medical Center, Seoul, Korea. We found 43 patients who had Ca with UIP (UIP-Ca). Previously reported data of eighty-four patients with UIP-only were included as a comparison group.

Results: Smoking is related to poor prognosis in patients with UIP-Ca, and the number of patients with a high smoking index of more than 30 pack-years significantly increased in UIP-Ca patients compared with UIP-only patients. There is no significant prognostic differentiation between UIP-Ca patients and UIP-only patients. Microscopically, UIP-Ca patients showed characteristically heterogeneous histological patterns and degrees of differentiation. There were many foci of squamous metaplasia or dysplasia at the peripheral area of squamous cell carcinomas.

Conclusions: We report 43 cases of UIP-Ca. Our results suggest that smoking is related to cancer occurrence in UIP patients and poor prognosis in UIP-Ca patients.