Right Upper Lobectomy Twenty Years After Left Pneumonectomy: DISCUSSION

Patients who survive more than five years following resection of lung cancer are considered cured. However, they have a 10 percent or greater chance of a second primary lung carcinoma. Although reoperation for lung carcinoma was once considered contraindicated, it is now being done more frequently with good results. Patients with synchro­nous primary lung carcinomas appear to do uniformly poorly and probably are not helped by aggressive surgery. How­ever, carefully selected patients with metachronous primary malignancies have better survival rates. Computerized re­view of the medical literature (1966 to present) revealed four previous cases of patients having lobectomy after contralateral pneumonectomy. One patient died post­operatively, while the other three had long-term survival. One of these patients had only the right upper lobe remaining and another had only the right lower lobe remaining.

Multiple techniques have been employed in the past to evaluate resectability. Since the risk of lung cancer rises in direct proportion to the degree of obstructive lung disease (COPD), most of these studies have focused on resection in patients with COPD rather than in restrictive lung disease (as occurs following previous lung resection). Boysen et al developed a simple technique for estimating postoperative lung function (FEVj) by coupling quantitative perfusion lung scanning and spirometry. Other investigators have confirmed this method to be highly predictive of postoperative FEVj. An arbitrary cutoff of a predicted FEV1 >0.80 L has been used to determine operability in these patients, most of whom had chronic obstructive pulmonary disease. However, these studies were performed on patients who had not undergone previous lung resection. We applied the tech­nique of whole lung scanning to predict postoperative lobar function in our patient, who had restrictive changes on preoperative pulmonary function testing. The measured postoperative FEV, was approximately 20 percent less than predicted two months after surgery, but improved to 10 percent greater than predicted 21 months later. This may have reflected improvement of chest wall mechanics.
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In patients such as ours, pulmonary arterial pressure may well be the limiting factor in determining the “physiologic” capacity to survive extensive pulmonary resection. Adams et al and Williams and co-authors showed that dogs survive 68 to 80 percent lung resection, but that they invariably have pulmonary hypertension. Early reports documented the frequent development of pulmonary hy­pertension at rest and particularly with exercise in patients after prior pneumonectomy. In 1951, Carlens and coworkers developed the technique of temporary unilateral balloon occlusion of a pulmonary artery as a method of assessing operability. Laros and Swierenga,® among others, have shown the value of such studies. Our patient underwent cardiac catheterization using essentially this same protocol except that occlusion of the lobar artery was performed rather than the main pulmonary artery. Exercise tests such as stair climbing now have a logical refinement in formal cardiopulmonary exercise testing; measurement of maximal oxygen consumption was recently shown to have predictive value in assessing operability. Testing during exercise, like right heart catheterization, assesses not only ventilatory reserve, but also combined cardiopulmonary reserve. It represents a noninvasive method for evaluating borderline patients for resection.

This case illustrates that sequential pulmonary resection exceeding pneumonectomy may be tolerated in patients without COPD. A careful work-up to exclude disseminated disease should be done first, followed by quantitative perfusion lung scanning and spirometry. If these assessments suggest operability, temporary pulmonary arterial occlusion should be carried out to further confirm “physiologic re­sectability.”

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Tags: Pneumonectomy

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