In contrast,
adenoid cystic carcinoma, the second most common histologic
type in our study, is a relatively rare, slow growing,
though proliferating tumor. Liu et al. found that 36 patients
who had undergone resection of pulmonary metastases of
adenoid cystic carcinomas had an estimated five-year survival
rate of 84%, though no patient survived beyond 14 years.10 In
an attempt to determine whether the prognosis depended on
the histologic type of the tumor, we included SCC, adenoid
cystic carcinoma, and other types of cancers in our study.
However, our multiple variable analyses did not reveal the
existence of correlations between specific histologic diagnosis
and prognosis.