Background: Increased incidence of a second primary aero-digestive malignancy after an index head and neck cancer (HNC) is well-documented. Furthermore, a clear set of surveillance strategies for second primary aero-digestive cancers in these patients exists.
Methods: The goal of this article is to review the published literature on risk of second primary malignancies (SPMs) (including aero-digestive malignancies) after a treated index HNC as well as its associated predictors, prognosis and surveillance. Most relevant publications were identified through searching the PubMed database for articles published up to July 2012; epidemiologic evidence was synthesized and thoroughly analyzed.
Findings: Data from randomized controlled trials, meta-analyses, population-based and cohort group studies, prior reviews, and case reports indicate an increased incidence of various SPMs after occurrence of a HNC. These cancers are not limited to upper aero-digestive sites. Common risk factors including environmental, genetic and immune factors may explain the increased incidence of second cancers in this patient population. In addition, site of the index HNC may predict the site of a future SPM.
Conclusions: As a general rule, oral cavity and oropharyngeal squamous cell cancers are associated more with head and neck region SPM, while laryngeal and hypopharyngeal cancers - with that of the lung. As these cancers confer dismal prognosis and shorter survival in patients with HNCs, several literature sources recommend close surveillance for and an aggressive therapy of SPM. Notwithstanding, their optimal management and follow-up schedule remains to be established.