Carcinoma of the middle lobe

Is the rate of pneumonectomy higher in right middle lobe lung cancer than in other right-sided locations?

BACKGROUND

Historically, right middle lobe (RML) non-small cell lung cancer (NSCLC) has been reported to be associated with a higher rate of pneumonectomy than other right-sided locations. Because this would discourage minimally invasive approaches in RML-NSCLC, we sought to update this assertion through the study of a large surgical series.

METHODS

Clinical records of patients who underwent operations for right-sided NSCLC in 2 French surgical centers were prospectively entered and retrospectively reviewed. Demographic and pathologic characteristics of RML NSCLC were compared with other right-sided NSCLC.

RESULTS

This study included 3,234 right-sided and 211 RML (6.5%) NSCLC patients. After exclusion of 14 patients who underwent exploratory thoracotomy, patients were a mean age of 61.5 years, most RML resections occurred in men (134 [72.8%]), and most were lobectomies (wedge, n=4; lobectomy, n=102; bilobectomy, n=22; pneumonectomy, n=56). Pathologic analysis revealed adenocarcinoma in 88 patients (47.8%) and squamous cell carcinoma in 80 (43.5%). pStaging was stage I in 86 patients (46.7%), II in 42 (22.8%), III in 47 (25.5%), and IV in 9 (4.9%). Superior and inferior mediastinal N2 were found in 45.4% and 54.6% of patients, respectively, when 1 station was involved. When compared with other right-sided NSCLC, RML was characterized by higher T status and higher rates of bilobectomy (10.9% vs 5.6%, p=0.0017) and pneumonectomy (30.3% vs 22.3%, p=0.0071) but similar 5-year survival (47.4%).

CONCLUSIONS

Compared with other right-sided NSCLC, RML location is associated with a higher albeit limited rate of pneumonectomy.

Middle lobe syndrome

A review of the major literature dealing with the middle lobe syndrome shows that benign inflammatory disease is the most common etiological factor (62%), with bronchiectasis responsible for at least a quarter of the patients in these series. Early workers indicated that carcinoma rarely originates in the right middle lobe; however, 22% of patients reviewed had malignant tumors as a cause of the syndrome. The original view that bronchial compression was the pathophysiological abnormality leading to development of the syndrome has been rejected by more recent authors. The focus has now turned to the relative isolation of the middle lobe, especially when a complete minor fissure is present. This isolation prevents the aerating effects of collateral ventilation of the upper lobe from reaching the middle lobe and thus impairs the clearing of secretions from the middle lobe bronchus. Bronchoscopy and bronchography are vital in the rational approach to this syndrome. Severe stenosis of the bronchus or tumor can be seen endoscopically in about 40% of patients, and bronchography will demonstrate an anatomical abnormality more than 70% of the time. Both the surgical and the medical approaches to therapy have been endorsed strongly by various authors in the 30 years since the syndrome was described. It now appears that bronchoscopy and, if need be, bronchography should be undertaken to rule out an endobronchial lesion. Timing of these studies will depend on the patient's age, with early examination advocated for the older patient at high risk for lung cancer. If there is reasonable evidence that the process is benign, medical management should be attempted. Lobectomy is performed if malignancy is suspected or if medical therapy fails.