Risk of death from intercurrent disease is not excessively increased by modern postoperative radiotherapy for high-risk resected non-small-cell lung carcinoma

PURPOSE

Some studies report a high risk of death from intercurrent disease (DID) after postoperative radiotherapy (XRT) for non-small-cell lung cancer (NSCLC). This study determines the risk of DID after modern-technique postoperative XRT.

PATIENTS AND METHODS

A total of 202 patients were treated with surgery and postoperative XRT for NSCLC. Most patients (97%) had pathologic stage II or III disease. Many patients (41%) had positive/close/uncertain resection margins. The median XRT dose was 55 Gy with fraction size of 1.8 to 2 Gy. The risk of DID was calculated actuarially and included patients who died of unknown/uncertain causes. Median follow-up was 24 months for all patients and 62 months for survivors.

RESULTS

A total of 25 patients (12.5%) died from intercurrent disease, 16 from confirmed noncancer causes and nine from unknown causes. The 4-year actuarial rate of DID was 13.5%. This is minimally increased compared with the expected rate for a matched population (approximately 10% at 4 years). On multivariate analysis, age and radiotherapy dose were borderline significant factors associated with a higher risk of DID (P =.06). The crude risk of DID for patients receiving less than 54 Gy was 2% (4-year actuarial risk 0%) versus 17% for XRT dose > or = 54 Gy. The 4-year actuarial overall survival was 34%; local control was 84%; and freedom from distant metastases was 37%.

CONCLUSION

Modern postoperative XRT for NSCLC does not excessively increase the risk of intercurrent deaths. Further study of postoperative XRT, particularly when using more sophisticated treatment planning and reasonable total doses, for carefully selected high-risk resected NSCLC is warranted.

Expanded indications for transcervical thymectomy in the management of anterior mediastinal masses

BACKGROUND

Transcervical thymectomy (TCT) is an accepted though controversial approach for thymectomy in myasthenia gravis (MG). The suggestion of thymoma on computed tomography (CT) has been considered a contraindication to TCT. We sought to determine whether the indications for TCT could be safely expanded to include selected patients with thymomas as well as other types of anterior mediastinal masses.

METHODS

Between January 1992 and September 1999, we performed 121 TCTs: 98 in patients with MG and 23 in patients without MG. The patients' records were retrospectively reviewed.

RESULTS

Among the 98 MG patients, 28 had CT scans suspicious for thymoma. Of these, 14 had a thymoma pathologically. These were classified as stage I (5), stage II (8), and stage III (1). Five patients required extension of the incision for completion of the procedure. There have been no thymoma recurrences to date with a mean follow-up of 48 months (range 3 to 96 months). In the 23 patients without MG, 12 had new anterior mediastinal masses, 4 had a history of treated lymphoma, 1 had a history of treated germ cell tumor, and 6 had suspected mediastinal parathyroid adenoma. Diagnostic tissue was obtained in all patients undergoing the procedure for diagnosis, and in 4 of 6 patients, a parathyroid adenoma was successfully resected.

CONCLUSIONS

Transcervical exploration and thymectomy offers a less invasive approach to the diagnosis and/or definitive treatment of selected anterior mediastinal masses. We suggest that it is appropriate to expand its use to several clinical scenarios beyond the typical indication of thymectomy in MG patients without thymoma.

Bronchial anastomotic stricutre caused by ossification of an intercostal muscle flap

We report a case of heterotopic ossification of a pedicled intercostal muscle flap that had been wrapped circumferentially around a bronchial sleeve anastomosis. This ossification caused severe bronchial stenosis and recurrent pneumonias. Stent insertion failed, and the patient ultimately required completion pneumonectomy. We recommended that caution be used when wrapping intercostal muscle around any important lumen.

Lung volume reduction surgery restores the normal diaphragmatic length-tension relationship in emphysematous rats

OBJECTIVE

Improved respiratory muscle function is a major effect of a lung volume reduction surgery. We studied length adaptation in rat diaphragmatic muscle in an attempt to elucidate the mechanism by which diaphragmatic function improves after this controversial operation.

METHODS

We developed a model of elastase-induced emphysema and bilateral volume reduction through median sternotomy in rats. Five months after emphysema induction, maximum exchangeable lung volume was determined in intubated and anesthetized control animals and animals with emphysema. Costal diaphragmatic length was measured in vivo, and the length at which maximal twitch force is generated was determined on muscle strips in vitro. Also 5 months after elastase administration, another cohort underwent volume reduction or sham sternotomy. Five months after the operation, these animals were similarly studied.

RESULTS

Lung volume was increased in emphysematous rats versus control rats (50.9 +/- 1.7 vs 45.4 +/- 1.3 mL, P =.001). Lung volume was decreased in emphysematous animals that had undergone volume reduction versus sham sternotomy (44.7 +/- 0.60 vs 49.4 +/- 1.0 mL, P =.001). In situ diaphragm length (1.99 +/- 0.04 vs 2.24 +/- 0.07 cm, P =.001) and the length at which maximal twitch force is generated (2.25 +/- 0.06 vs 2.48 +/- 0.09 cm, P =.038) were shorter in emphysematous than control animals. After volume reduction, in situ diaphragm length (2.13 +/- 0.06 vs 1.83 +/- 0.02 cm, P <.001) and the length at which maximal twitch force is generated (2.50 +/- 0.08 vs 2.27 +/- 0.06 cm, P =.013) were longer than in animals undergoing sham sternotomy.

CONCLUSIONS

In this experimental model of emphysema and lung volume reduction surgery, emphysema shortens the length at which maximal twitch force is generated and shifts the diaphragmatic length-tension curve to lower lengths; volume reduction returns the length at which maximal twitch force is generated toward normal and shifts the diaphragmatic length-tension curve back to longer lengths. This restoration toward normal physiology may enable the improvement in diaphragmatic function seen after lung volume reduction surgery. The mechanism by which these length adaptations occur merits further investigation.

Lobectomy with tangential pulmonary artery resection without regard to pulmonary function

BACKGROUND

Non-small cell carcinoma of the lung invading the pulmonary artery (PA) has traditionally been treated by pneumonectomy. Although PA resection and reconstruction (PAR) has begun to gain acceptance, previous series of PAR by the simplest technique of tangential excision and primary repair have been unfavorable. We have maintained a policy of performing PAR preferentially whenever anatomically feasible, and usually this has been possible by tangential excision and primary repair. This study sought to determine if this approach is sound.

METHODS

Retrospective clinical and pathologic review.

RESULTS

Thirty-three PARs were performed from 1992 to 1999. The patients, followed 6 to 65 months (mean 25), were aged 36 to 80 years (mean 61), and their tumors were pathologic stage IB (n = 7), IIB (n = 13), IIIA (n = 9), and IIIB (n = 4). The mean preoperative forced expiratory volume in 1 second was 70% predicted. The procedures included 14 bronchial sleeve lobectomies with PAR and 19 simple lobectomies with PAR. The PARs were performed without heparinization and included 19 tangential excisions with primary closure, 11 larger tangential excisions with pericardial patch closure, and 3 sleeve resections. There were no operative deaths and 2 (6.1%) early major complications, all unrelated to the PAR. Thirteen patients (39%) had early minor complications. Four-year Kaplan-Meier survival was 48.3% for stages I/II and 45% for stage III. Ipsilateral, central, intrathoracic recurrence occurred in 3 patients (9.1%).

CONCLUSIONS

These data are not dramatically different from those reported for standard resections. Although the numbers are small, the results suggest that lobectomy with PAR by tangential excision is an acceptable alternative to pneumonectomy whenever anatomically possible.

Human skeletal myosin heavy chain genes are tightly linked in the order embryonic-IIa-IId/x-ILb-perinatal-extraocular

Myosin heavy chain (MyHC) is the major contractile protein of muscle. We report the first complete cosmid cloning and definitive physical map of the tandemly linked human skeletal MyHC genes at 17p13.1. The map provides new information on the order, size, and relative spacing of the genes. and it resolves uncertainties about the two fastest twitch isoforms. The physical order of the genes is demonstrated to contrast with the temporal order of their developmental expression. Furthermore, nucleotide sequence comparisons allow an approximation of the relative timing of five ancestral duplications that created distinct genes for the six isoforms. A firm foundation is provided for molecular analysis in patients with suspected primary skeletal myosinopathies and for detailed modelling of the hypervariable surface loops which dictate myosin's kinetic properties.

Thoracoscopic lung biopsy. Five commonly asked questions about video-assisted thoracic surgery

VATS has proved to be an extremely useful diagnostic tool. Perhaps its most frequent application has been in lung biopsy to diagnose indeterminate solitary pulmonary nodules and interstitial infiltrates. In many institutions, VATS procedures have largely replaced previous methods of attempting to establish the nature of a solitary pulmonary nodule. In ambulatory patients with indeterminate infiltrates, VATS techniques have prompted earlier referral to establish a tissue diagnosis, with apparently decreased morbidity. VATS has clearly found a place in the modern practice of thoracic surgery and is likely to play an ever-increasing role in the management of diseases of the chest.

Bronchopulmonary carcinoid tumors associated with Cushing's syndrome: a more aggressive variant of typical carcinoid

OBJECTIVES

Our objectives were to delineate the clinicopathologic characteristics of adrenocorticotropin-secreting bronchopulmonary carcinoid tumors causing Cushing's syndrome and to derive from these findings a rational approach to diagnosis and surgical management of this unusual condition.

METHODS

We conducted a retrospective, chart-review analysis of seven consecutive patients treated at the Massachusetts General Hospital over a 16-year period.

RESULTS

The patients uniformly had symptoms of marked hypercortisolism, and the underlying lung lesions remained clinically occult for a mean of 24 months. Standard endocrine testing was misleading in 83% of patients, reinforcing the need for an alternative diagnostic strategy based on petrosal sinus catheterization and computed tomography of the chest. Although 72% of the tumors were typical carcinoids by standard criteria, 57% demonstrated microscopic evidence of local invasiveness, and 43% were associated with mediastinal lymph node metastases. Eighty-six percent of patients have been cured by pulmonary resection a mean of 59 months after the operation, but 50% of these required a second operation for resection of involved lymph nodes after an initial relapse.

CONCLUSIONS

These data suggest that adrenocorticotropin-secreting bronchopulmonary carcinoid tumors represent a distinct, more aggressive subtype of the usual, typical carcinoid. The high rate of lymphatic and local spread demands a surgical approach consisting of anatomic resection and routine mediastinal lymph node dissection.

Treatment of refractory, nonmalignant hydrothorax with a pleurovenous shunt

We present a case of long-term successful application of pleurovenous shunting for the management of pleural effusion. Intractable symptomatic hydrothorax developed as a result of transdiaphragmatic migration of hepatic ascites. After failure of traditional treatment by mechanical pleurodesis, a pleurovenous shunt was inserted. After 1 year of follow-up, the effusion is well controlled, and the shunt remains patent.

Video-assisted thoracic surgery: the current state of the art

Surgical thoracoscopy (or pleuroscopy) has historically been underused in the diagnosis and therapy of diseases of the chest. The rapid developments in laparoscopy in recent years caused thoracic surgeons to reconsider the use of endoscopic techniques in surgery of the chest. Advances in video camera technology and the use of digital processing technology so expanded the potential of thoracoscopy that an entirely new set of procedures, called video-assisted thoracic surgery, has emerged. This article reviews situations in which video-assisted procedures have proven useful, the techniques by which these procedures are performed, and the rationale behind using the video-assisted in lieu of the open approach. Video-assisted surgery often allows one to accomplish the same goal as the comparable open procedure but with less morbidity and a shorter hospital stay. With continued development of instrumentation, increasingly complex procedures continue to be accomplished. It is important for radiologists to be aware of these new developments in minimally invasive surgery, as the techniques have major implications for the practice of chest medicine and surgery as a whole. The evolution of the management of the solitary pulmonary nodule is but one example of the way video-assisted thoracic surgery has called into question the traditional approach to diseases of the chest.

Villous adenoma of the main pancreatic duct: a clue to the pathogenesis of pancreatic malignancy

We describe the case of a 78 year old woman with a severely dysplastic villous adenoma of the duct of Wirsung presenting with abdominal pain, emesis, weight loss, and hyperamylasemia. Abdominal ultrasound, computed tomography, and endoscopic retrograde cholangiopancreatography suggested an intraductal lesion in the head of the pancreas with a dilated distal duct. The patient underwent uncomplicated pancreaticoduodenectomy and has done well. A review of the literature on benign and malignant neoplasms of the main pancreatic duct allows formulation of the typical clinical syndrome, appropriate diagnostic work-up, treatment, and prognosis of patients with these rare lesions. The pancreatic ductal epithelium can present the full spectrum of lesions along the pathogenetic route to malignancy. This is evidence for the presence of an adenoma-to-carcinoma sequence in the pancreas analogous to that which exists in the colon.

The Vineberg procedure: the immediate forerunner of coronary artery bypass grafting

Promulgated by the Canadian surgeon Arthur Vineberg, internal mammary artery implantation received fairly widespread clinical application during the 1960s, only to be abandoned upon the introduction of coronary artery bypass grafting toward the end of the decade. By 1978, Hurst and Logue's The Heart (4th ed. New York: McGraw-Hill, page 1291) mentioned the procedure only to relate that "indirect myocardial revascularization using the internal thoracic artery is now seldom used." Between the introduction of the operation in 1945 and the mid-1960s, a remarkably hard-fought debate raged over the value of internal mammary artery implantation. Despite the fact that coronary arteriography ultimately demonstrated the viability of Vineberg's concept, for a variety of reasons the operation could not compete with coronary artery bypass grafting, and therefore rapidly fell into disuse. The central role the Vineberg procedure has played in the evolution of coronary revascularization surgery highlights the importance of reviewing the history of its development, application, and eventual abandonment. The Vineberg procedure was, after all, the first intervention documented to increase myocardial perfusion. Recent reports of long-term graft patency and clear patient benefit with internal mammary artery implants reinforce the belief that Vineberg should be given more credit for his work than he has generally received, and that internal mammary artery implantation should not be relegated to the status of a historical curiosity.

Adaptations in myosin heavy chain expression and contractile function in dystrophic mouse diaphragm

The X chromosome-linked muscular dystrophic (mdx) mouse lacks the subsarcolemmal protein dystrophin and thus represents a genetic homologue of human Duchenne muscular dystrophy. The present study examined alterations in diaphragm contractile properties and myosin heavy chain (MHC) expression in young (3-4 mo) and old (22-24 mo) control and mdx mice. In young mdx mice, maximum isometric tension (Po) was reduced to 50% of control values. An increase in fibers coexpressing types I (slow) and IIa MHC as well as regenerating fibers expressing embryonic MHC occurred, whereas IIx/b fibers were decreased. In the old mdx group, Po underwent a further reduction to 25% of control, and there was a slowing of twitch kinetics along with markedly increased diaphragm endurance. These changes were associated with an approximate sevenfold increase in type I MHC fibers and virtual elimination of the IIx/b fiber population; there was no detectable embryonic MHC expression. We conclude that the mdx diaphragm responds to progressive muscle degeneration with transition to a slower phenotype associated with reduced power output and augmented muscle endurance. In the setting of progressive muscle fiber destruction, these changes may help preserve contractile function and promote greater survival of remaining muscle fibers by decreasing cellular energy requirements.

Dystrophin protects the sarcolemma from stresses developed during muscle contraction

The protein dystrophin, normally found on the cytoplasmic surface of skeletal muscle cell membranes, is absent in patients with Duchenne muscular dystrophy as well as mdx (X-linked muscular dystrophy) mice. Although its primary structure has been determined, the precise functional role of dystrophin remains the subject of speculation. In the present study, we demonstrate that dystrophin-deficient muscle fibers of the mdx mouse exhibit an increased susceptibility to contraction-induced sarcolemmal rupture. The level of sarcolemmal damage is directly correlated with the magnitude of mechanical stress placed upon the membrane during contraction rather than the number of activations of the muscle. These findings strongly support the proposition that the primary function of dystrophin is to provide mechanical reinforcement to the sarcolemma and thereby protect it from the membrane stresses developed during muscle contraction. Furthermore, the methodology used in this study should prove useful in assessing the efficacy of dystrophin gene therapy in the mdx mouse.

A PCR-based assay for the wild-type dystrophin gene transferred into mdx mouse

Myoblast transfer has emerged as a promising treatment for inherited myopathies such as Duchenne muscular dystrophy (DMD). Further development of the technique's therapeutic potential requires an experimental system in which issues of graft rejection can be clearly discriminated from those related to myoblast biology. Here we report the development and initial application of a quantitative assay for myogenic cells bearing a wild-type dystrophin gene following transfer into the mdx mouse. The technique relies upon the ability of a mutagenizing polymerase chain reaction (PCR) primer to create a new restriction site in the amplification production of the wild-type, but not the mdx dystrophin gene. The ratio of host to donor cells can be determined from muscle biopsies as small as 1 mg, regardless of donor H-2 background. This simple technique should allow a number of basic questions related to myoblast and direct gene transfer to be addressed using the mdx mouse model.

The mdx mouse diaphragm reproduces the degenerative changes of Duchenne muscular dystrophy

Although murine X-linked muscular dystrophy (mdx) and Duchenne muscular dystrophy (DMD) are genetically homologous and both characterized by a complete absence of dystrophin, the limb muscles of adult mdx mice suffer neither the detectable weakness nor the progressive degeneration that are features of DMD. Here we show that the mdx mouse diaphragm exhibits a pattern of degeneration, fibrosis and severe functional deficit comparable to that of DMD limb muscle, although adult mice show no overt respiratory impairment. Progressive functional changes include reductions in strength (to 13.5% of control by two years of age), elasticity, twitch speed and fibre length. The collagen density rises to at least seven times that of control diaphragm and ten times that of mdx hind-limb muscle. By 1.5 years of age, similar but less severe histological changes emerge in the accessory muscles of respiration. On the basis of these findings, we propose that dystrophin deficiency alters the threshold for work-induced injury. Our data provide a quantitative framework for studying the pathogenesis of dystrophy and extend the application of the mdx mouse as an animal model.