Lung cancer invading the pericardium: quantum of lymph nodes

Lung cancer may invade the pericardium (T3) and the intrapericardial pulmonary veins and left atrium (T4). Our purpose was to analyze the characteristics of this invading process in search of the reasons explaining its poor prognosis.

The clinical records of 4,668 patients who underwent surgery for lung cancer between January 1983 and December 2006 in two thoracic surgery centers were retrospectively reviewed. The epidemiology, pathology, and prognostic characteristics of the tumors invading the pericardium alone (T3) or with pulmonary veins and atrium (T4) were analyzed and compared with all other tumors.

There were 75 male and 16 female patients, with 85 pneumonectomies and 6 lobectomies that proved R0 in 59.3% of patients, and contained 69 squamous cell cancers, 11 adenocarcinomas, and 13 miscellaneous tumors; 12 were N0 (13.2%), 31 were N1 (34.1%), and 48 were N2 (52.8%). Pericardium alone was invaded in 32 patients (35.2%), and with pulmonary vein and atrium in 34 (37.3%) and 25 (27.5%), respectively. Patient characteristics were similar in each group. Five-year and 10-year survival rates were 15.1% and 10.4%, respectively. Frequency of pneumonectomy, R1-2 resection, and N1-2 involvement were significantly more important compared with noninvading tumors (p < 10(-6)).

Reports on T3 and T4 cancer with pericardial involvement are few, but also stress that pulmonary vein and left atrium invasion does not worsen the prognosis more than pericardial invasion alone. The rich pericardial lymph drainage might enhance the spread of tumor cells, explaining excessively high N1-N2 rates and pericardial invasion-related poor prognosis.