Host defense and survival in patients with lung carcinoma

Numerous studies have investigated locoregional immune responses and long term survival in patients with various types of cancer; few have focused on patients with lung carcinoma. The current study was designed to assess the prognostic value of immunomorphologic changes in locoregional lymph nodes and lymphocytic infiltration of primary tumor (LI) in patients who undergo resection for bronchogenic carcinoma.

In a retrospective analysis, immune responses in locoregional lymph nodes and at primary tumor sites were studied histologically in 172 selected patients. Lymph node morphology was studied according to the system of Cottier et al. Sinus histiocytosis and paracortical lymphoid cell hyperplasia were considered to be cellular immune responses, and follicular hyperplasia of the cortical area was considered to be a humoral reaction. LI was classified with Black's method. The survival rate was estimated by using the Kaplan-Meier product-limit method. The log rank test and the Cox proportional-hazards model were used to determine statistical significance in univariate and multivariate survival analyses.

Among the 172 patients, 35.5% had no evident response in regional lymph nodes, 19.8% had a marked cellular response, 11% had a marked humoral response, and 33.7% had a mixed cellular and humoral response. LI was intense in 36.6% of patients and was absent or scarcely evident in 63.4%. A lymph node cellular response and marked LI improved long term survival rates even in patients with regional lymph node metastases. Multivariate analysis identified two independent variables that had high prognostic value: lymph node immunoreactivity and LI.

Lymph node immunoreactivity and LI significantly influence long term survival after curative surgery for patients with carcinoma of the lung and may be useful in stratifying patients for prospective trials of adjuvant treatment, including immunotherapy.