The significance of associated pre-invasive lesions in patients resected for primary lung neoplasms.

Objective: To evaluate the prevalence and clinico/prognostic significance of the presence of pre-invasive lesions in patients resected for primary lung neoplasm.

Methods: From 1993 to 2002, 1090 patients received resection for primary lung carcinomas. Of these, 73 presented an associated pre-invasive lesion in the surgical specimen distant from the primary tumour. Classification of pre-invasive lesions included Atypical Adenomatous Hyperplasia (AAH); Carcinoma In Situ (CIS) either diffuse or at the bronchial resection margin; Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH). Correlation between the presence of pre-invasive lesion and the following variables were calculated by logistic regression analysis: sex, age, median tumour size, histology, histologic differentiation, histologic evidence of invasiveness (vascular and perineural invasion), peritumoural lymphocytic infiltrate, pTNM, lobe location, history of previous malignancy. Survival rates were computed using Kaplan-Meier method and survival differences with the total patient population of resected lung carcinomas were tested using the log-rank method.

Results: There were 28 AAH, 42 CIS (5 at the bronchial resection margin) and 3 DIPNECH. Histology of the primary tumor included bronchioloalveolar carcinoma (9 patients), adenocarcinoma (19), squamous cell carcinoma (39), typical carcinoid tumour (3) and adenosquamous carcinoma (3). Overall prevalence of pre-invasive lesion was 6.7%. A strong correlation was found between the presence of AAH and the co-existence of either adenocarcinoma, bronchioloalveolar carcinoma or mixed adenocarcinoma-containing tumours (P = 0.00002) between CIS and squamous cell carcinoma (P = 0.009) and between DIPNECH and carcinoid tumours (P = 0.001). No significant correlation was found between the presence of any type of pre-invasive lesion and sex, age, median tumour size, histologic differentiation, histologic evidence of invasiveness, pTNM, lobe location and history of previous malignancy or the probability to develop a second primary lung carcinoma in the remaining lobe(s) after resection. Survival rates in the patients with AAH and CIS were not significantly different from those of patients without pre-invasive lesion (P = 0.3 and P = 0.1).

Conclusions: Associated pre-invasive lesions in patients resected for primary lung neoplasms are not infrequent. AAH is associated with adenocarcinoma, CIS with squamous cell carcinoma, DIPNECH with typical carcinoid tumours. Our experience indicates that in these patients histology, stage distribution and survival do not differ from the total population of resected patients with lung tumors.