Cerebral imaging in the asymptomatic preoperative bronchogenic carcinoma patient: is it worthwhile?

Diagnostic Yield of Staging Brain MRI in Patients with Newly Diagnosed Non-Small Cell Lung Cancer

Background Existing guidelines are inconsistent regarding the indications for staging brain MRI in patients with newly diagnosed, early-stage non-small cell lung cancer (NSCLC). Purpose To evaluate the diagnostic yield of staging brain MRI in the initial evaluation of lung cancer. Materials and Methods This retrospective, observational, single-institution study included patients with newly diagnosed NSCLC who underwent staging chest CT and staging brain MRI from November 2017 to October 2018. Diagnostic yield was defined as the proportion of patients with brain metastases among all patients. Yield was stratified into clinical stage groups per the eighth edition of the American Joint Committee on Cancer staging guidelines, based on staging chest CT and in adenocarcinoma with epidermal growth factor receptor (EGFR) gene mutation and anaplastic lymphoma kinase (ALK) gene rearrangement. Subgroup analyses were performed on the basis of cell types and molecular markers. The χ² test was performed to compare the diagnostic yields, and Bonferroni correction was used to account for multiple testing between stage groups. Results A total of 1712 patients (mean age, 64 years ± 10 [standard deviation]; 1035 men) were included. The diagnostic yield of staging brain MRI in newly diagnosed NSCLC was 11.9% (203 of 1712; 95% confidence interval [CI]: 10.4%, 13.5%). In clinical stage IA, IB, and II disease, the diagnostic yields were 0.3% (two of 615; 95% CI: 0.0%, 1.2%), 3.8% (seven of 186; 95% CI: 1.5%, 7.6%), and 4.7% (eight of 171; 95% CI: 2.0%, 9.0%), respectively. The diagnostic yield was higher in patients with adenocarcinoma (13.6%; 176 of 1297; 95% CI: 11.8%, 15.6%) than squamous cell carcinoma (5.9%; 21 of 354; 95% CI: 3.7%, 8.9%) and in patients with EGFR mutation-positive adenocarcinoma (17.5%; 85 of 487; 95% CI: 14.2%, 21.1%) than with EGFR mutation-negative adenocarcinoma (10.6%; 68 of 639; 95% CI: 8.4%, 13.3%) (P < .001 for both). Conclusion The diagnostic yield of staging brain MRI in clinical stage IA non-small cell lung cancer was low, but staging brain MRI had a higher diagnostic yield in clinical stage IB and epidermal growth factor receptor mutation-positive adenocarcinoma. © RSNA, 2020 Online supplemental material is available for this article.

Impact of neuroimaging in the pretreatment evaluation of early stage non-small cell lung cancer

Background

There are limited data and conflicting guideline recommendations regarding the role of neuroimaging in the pretreatment evaluation of non-small cell lung cancer (NSCLC).

Methods

We performed a retrospective, pragmatic cohort study of patients with NSCLC diagnosed between January 1 and December 31, 2015. Eligible patients were identified from an institutional tumor registry. We collected all records of pretreatment neuroimaging within 12 weeks of diagnosis, including CT head (CT) and MRI brain (MRI). We abstracted the indication for neuroimaging, presence of central neurologic symptoms and cancer stage (with and without neuroimaging findings) from the tumor registry and the electronic health record.

Results

We identified 216 evaluable patients with newly diagnosed NSCLC. 157 of 216 patients (72.7%) underwent neuroimaging as part of initial staging, and 41 (26%) were found to have brain metastases. Of 43 patients with central neurologic symptoms at the time of neuroimaging, 28 (67%) had brain metastasis. In patients without central neurologic symptoms, brain metastases were discovered in 0 of 33 patients with clinical stage I or II, 4 of 36 (11%) with clinical stage III and 9 of 45 (20%) with clinical stage IV disease.

Conclusions

In patients with early stage NSCLC (i.e. clinical stage I and II) without central neurologic symptoms, brain metastases are unlikely. The continued use of neuroimaging in the pretreatment evaluation of clinical stage I patients without central neurologic symptoms is not needed.

Incidence of brain metastasis in lung adenocarcinoma at initial diagnosis on the basis of stage and genetic alterations

OBJECTIVE

Patients with lung adenocarcinoma (ADC) are at higher risk of the development of brain metastasis (BM), and genetic alterations are associated with BM.

PATIENTS AND METHODS

A total of 598 patients with lung ADC in our institution between January 2014 and December 2014 were reviewed retrospectively. We evaluated the incidence of BM by stage and genetic alterations.

RESULTS

Of the 598 patients, 97 (16.2%) had BM, which occurred across all stages. The incidence of BM showed a tendency to increase as the stage increased (p < 0.001, trend test). Although patients with EGFR mutations had BM across all stages, those with ALK or K- mutations had BM only in stage III and IV diseases. Regardless of types of mutations, the incidence of BM showed a tendency to increase as the T or N staging increased (p < 0.001 for each of EGFR, ALK, and K-RAS mutations, trend test). Whereas BM incidence showed a tendency to increase as the M staging increased in patients with EGFR-mutant lung ADC (p < 0.001, trend test), there was no linear trend between M staging and ALK (p = 0.469, trend test) or K-RAS mutations (p = 0.066, trend test). After adjusting covariables, EGFR mutations were associated with BM in never-smokers (adjusted OR = 2.07, 95% CI = 1.02-4.34) and K-RAS mutations were risk factors for BM in males (adjusted OR = 3.86, 95% CI = 1.01-14.43).

CONCLUSIONS

BM occurred in approximately 16% of lung ADC patients, including 3% with stage I diseases. Whereas EGFR-mutant lung ADC had BM across all stages, ALK- or K-RAS-mutant lung ADC had BM only in advanced stages. EGFR mutations were risk factors for BM among never-smokers and K-RAS mutations were risk factors among males.

Early stage non-small cell lung cancer patients need brain imaging regardless of symptoms

BACKGROUND

Japanese Lung Cancer Society and ESMO guideline recommends screening for brain metastasis in all patients with non-small cell lung cancer (NSCLC), while NCCN/ACCP guidelines do not recommend screening patients who are asymptomatic and with clinical stage I NSCLC. However, brain metastasis sometimes occurs in early stage NSCLC patients without any neurological symptoms.

METHODS

We retrospectively reviewed medical records of 124 patients admitted to the University of Tokyo Hospital with stage IV NSCLC from January 2012 to April 2016. We analyzed clinical stage, the presence of the central nervous system manifestations and the number of brain metastases.

RESULTS

Forty-six out of 124 cases had brain metastasis at presentation. The brain metastasis group had larger number of female, never smokers and patients with EGFR mutation compared with extracranial metastasis group. Twenty-one of 35 adenocarcinoma cases with brain metastasis had EGFR mutations. Out of 46 brain metastasis patients, 29 patients (63%) were asymptomatic and patients with EGFR mutations were significantly less likely to have neurological symptoms (4/21 vs. 7/14, p = 0.049). Six out of 46 cases with brain metastasis (13%) were clinical T1-2aN0. In clinical T1-2aN0 cases, only one patient had neurological symptoms at presentation.

CONCLUSION

In clinical T1-2aN0 lung cancer patients with brain metastasis, almost all patients were asymptomatic. Patients with EGFR mutations and brain metastasis were likely to be asymptomatic. Regardless of central nervous system symptoms, routine brain imaging seems warranted in all NSCLC patients, especially in areas where patients have a higher frequency of EGFR mutations.

[Impact of routine brain imaging in the initial management of lung cancer]

INTRODUCTION

Brain metastases are a common complication of bronchial carcinoma (BC). There is no consensus as to the need to undertake a systematic search for these lesions during the initial assessment. The aim of this study was to evaluate the contribution of brain imaging in the initial evaluation of patients with CB.

METHODS

We undertook a retrospective analysis of patients treated in the Thoracic Oncology Clinic at the Institute Jules-Bordet between 01/09/2008 and 31/08/2013, who were treatment-naïve and were having a full diagnostic work-up including brain imaging.

RESULTS

Four hundred and sixty-three patients consecutively diagnosed with BC were included. Brain magnetic resonance imaging and/or CT-scan showed brain metastases in 101 patients (21.8%), of whom 67 had no symptoms suggestive of brain metastatic disease. The addition of a brain imaging into the work-up procedure resulted in a stage migration for 30 patients (6.5%), mainly otherwise staged IIIA (n=10) or IIIB (n=14) without brain imaging.

CONCLUSION

The addition of brain imaging in the initial assessment of bronchial carcinoma allows the identification of brain metastases in one case among 5, of which 2/3 are asymptomatic. This leads to a change in staging, primarily for disease otherwise considered to be stage III.

S100B and S100B autoantibody as biomarkers for early detection of brain metastases in lung cancer

BACKGROUND

S100B is an astrocytic protein that enters the blood stream when there is disruption of the blood-brain barrier (BBB). Over time, antibodies against S100B develop in the sera of patients who experience persistent or repeated BBB disruptions. We explored the use of serum S100B protein and S100B autoantibodies for the detection of brain metastasis in patients with lung cancer.

METHODS

One hundred and twenty eight untreated patients with lung cancer who had brain imaging performed as part of their routine evaluation, participated. Serum S100B protein levels were measured by direct ELISA and S100B autoantibody levels by reverse ELISA. These levels in patients with brain metastases were compared alone and in combination to those without brain metastases.

RESULTS

Eighteen (14%) patients had brain metastasis at the time of lung cancer diagnosis. An S100B cutoff of 0.058 ng/mL had a sensitivity of 89% and specificity of 43% for brain metastasis. When an autoantibody threshold of <2.00 absorbance units was used in conjunction with S100B, the sensitivity remained at 89%, and the specificity increased to 58%. The overall accuracy was 51% with S100B alone, improving to 62.5% when combined with autoantibodies.

CONCLUSIONS

Serum S100B and S100B autoantibody levels may help to identify which lung cancer patients have brain metastases.

Appropriateness of imaging for lung cancer staging in a national cohort

PURPOSE

Optimizing evidence-based care to improve quality is a critical priority in the United States. We sought to examine adherence to imaging guideline recommendations for staging in patients with locally advanced lung cancer in a national cohort.

METHODS

We identified 3,808 patients with stage IIB, IIIA, or IIIB lung cancer by using the national Department of Veterans Affairs (VA) Central Cancer Registry (2004-2007) and linked these patients to VA and Medicare databases to examine receipt of guideline-recommended imaging based on National Comprehensive Cancer Network and American College of Radiology Appropriateness Criteria. Our primary outcomes were receipt of guideline-recommended brain imaging and positron emission tomography (PET) imaging. We also examined rates of overuse defined as combined use of bone scintigraphy (BS) and PET, which current guidelines recommend against. All imaging was assessed during the period 180 days before and 180 days after diagnosis.

RESULTS

Nearly 75% of patients received recommended brain imaging, and 60% received recommended PET imaging. Overuse of BS and PET occurred in 25% of patients. More advanced clinical stage and later year of diagnosis were the only clinical or demographic factors associated with higher rates of guideline-recommended imaging after adjusting for covariates. We observed considerable regional variation in recommended PET imaging and overuse of combined BS and PET.

CONCLUSION

Receipt of guideline-recommended imaging is not universal. PET appears to be underused overall, whereas BS demonstrates continued overuse. Wide regional variation suggests that these findings could be the result of local practice patterns, which may be amenable to provider education efforts such as Choosing Wisely.

Methods for staging non-small cell lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

Correctly staging lung cancer is important because the treatment options and prognosis differ significantly by stage. Several noninvasive imaging studies and invasive tests are available. Understanding the accuracy, advantages, and disadvantages of the available methods for staging non-small cell lung cancer is critical to decision-making.

METHODS

Test accuracies for the available staging studies were updated from the second iteration of the American College of Chest Physicians Lung Cancer Guidelines. Systematic searches of the MEDLINE database were performed up to June 2012 with the inclusion of selected meta-analyses, practice guidelines, and reviews. Study designs and results are summarized in evidence tables.

RESULTS

The sensitivity and specificity of CT scanning for identifying mediastinal lymph node metastasis were approximately 55% and 81%, respectively, confirming that CT scanning has limited ability either to rule in or exclude mediastinal metastasis. For PET scanning, estimates of sensitivity and specificity for identifying mediastinal metastasis were approximately 77% and 86%, respectively. These findings demonstrate that PET scanning is more accurate than CT scanning, but tissue biopsy is still required to confirm PET scan findings. The needle techniques endobronchial ultrasound-needle aspiration, endoscopic ultrasound-needle aspiration, and combined endobronchial ultrasound/endoscopic ultrasound-needle aspiration have sensitivities of approximately 89%, 89%, and 91%, respectively. In direct comparison with surgical staging, needle techniques have emerged as the best first diagnostic tools to obtain tissue. Based on randomized controlled trials, PET or PET-CT scanning is recommended for staging and to detect unsuspected metastatic disease and avoid noncurative resections.

CONCLUSIONS

Since the last iteration of the staging guidelines, PET scanning has assumed a more prominent role both in its use prior to surgery and when evaluating for metastatic disease. Minimally invasive needle techniques to stage the mediastinum have become increasingly accepted and are the tests of first choice to confirm mediastinal disease in accessible lymph node stations. If negative, these needle techniques should be followed by surgical biopsy. All abnormal scans should be confirmed by tissue biopsy (by whatever method is available) to ensure accurate staging. Evidence suggests that more complete staging improves patient outcomes.

Noninvasive staging of non-small cell lung cancer: ACCP evidenced-based clinical practice guidelines (2nd edition)

BACKGROUND

Correctly staging lung cancer is important because the treatment options and the prognosis differ significantly by stage. Several noninvasive imaging studies including chest CT scanning and positron emission tomography (PET) scanning are available. Understanding the test characteristics of these noninvasive staging studies is critical to decision making.

METHODS

Test characteristics for the noninvasive staging studies were updated from the first iteration of the lung cancer guidelines using systematic searches of the MEDLINE, HealthStar, and Cochrane Library databases up to May 2006, including selected metaanalyses, practice guidelines, and reviews. Study designs and results are summarized in evidence tables.

RESULTS

The pooled sensitivity and specificity of CT scanning for identifying mediastinal lymph node metastasis were 51% (95% confidence interval [CI], 47 to 54%) and 85% (95% CI, 84 to 88%), respectively, confirming that CT scanning has limited ability either to rule in or exclude mediastinal metastasis. For PET scanning, the pooled estimates of sensitivity and specificity for identifying mediastinal metastasis were 74% (95% CI, 69 to 79%) and 85% (95% CI, 82 to 88%), respectively. These findings demonstrate that PET scanning is more accurate than CT scanning. If the clinical evaluation in search of metastatic disease is negative, the likelihood of finding metastasis is low.

CONCLUSIONS

CT scanning of the chest is useful in providing anatomic detail, but the accuracy of chest CT scanning in differentiating benign from malignant lymph nodes in the mediastinum is poor. PET scanning has much better sensitivity and specificity than chest CT scanning for staging lung cancer in the mediastinum, and distant metastatic disease can be detected by PET scanning. With either test, abnormal findings must be confirmed by tissue biopsy to ensure accurate staging.

Imaging to optimally stage lung cancer: conventional modalities and PET/CT

Accurately staging patients with lung cancer is important in determining treatment options and prognoses. Staging allows the distinction of patients who are candidates for surgical resection from those with inoperable disease who may be treated with chemotherapy and/or radiation therapy. Conventional imaging plays an essential role in the noninvasive and invasive methods of the evaluation and staging of patients with non-small-cell lung cancer (NSCLC). Imaging modalities used for staging include chest radiography, chest computed tomography (CT), abdominal CT, brain CT or magnetic resonance imaging, bone scans, and (18)F-2-deoxy-d-glucose positron emission tomography (PET). Recently, PET/CT, the integration of the functional data of PET with the anatomic data of CT, has emerged as a modality to potentially change the way patients are evaluated. This article reviews current recommendations regarding the staging of patients with NSCLC and addresses the role of PET/CT.

Does initial staging or tumor histology better identify asymptomatic brain metastases in patients with non-small cell lung cancer?

BACKGROUND

To determine whether the distribution, staging features, or tumor histology of non-small cell lung cancer (NSCLC) distinguishes neurologically symptomatic from asymptomatic patients initially diagnosed with lung cancer, and to determine whether these factors may predict the presence of brain metastasis.

METHODS

We performed a retrospective review of 809 patients with NSCLC and brain metastases who were treated in our institution between January 1996 and March 2003. Patients who had brain metastasis on initial staging were included. Thoracic computed tomographic scans were reviewed for lung tumor features and staging. Neurological computed tomographic or magnetic resonance image scans were assessed for distribution of brain metastases. Medical records were reviewed for comprehensive staging, tumor histology, and neurological symptoms. Fisher's exact test was used to determine any differences among tumor histology, staging, and imaging features among patients with or without neurological symptoms.

RESULTS

Of the 809 patients, 181 had brain metastasis at initial staging. Among these 181 patients, 120 (66%) presented with neurological symptoms (group 1); 61 (34%) patients were asymptomatic (group 2). Patients with adenocarcinoma and large-cell carcinoma had greater odds of brain metastases than patients with squamous cell carcinoma (p = 0.001). There were 106 (58.6%) patients with adenocarcinoma, 32 (17.7%) with large cell carcinoma, and 18 (9.9%) with squamous cell carcinoma. In both groups, most lung cancers were in the right lung with upper lobe dominance. No significant difference in tumor histology or T stage was found between groups, although group 2 was more likely to have a higher N stage. Of the 181 patients with brain metastasis, 60 (33.1%) had N0 disease, 51 (28.2%) had T1 disease, and 23 (19.2%) had no other metastasis. There was no correlation between number/distribution of brain metastases and tumor histology, although patients with disease in the cerebellum or temporal lobes had a greater likelihood of neurological symptoms (odds ratio 3.7).

CONCLUSION

There was no significant difference in tumor histology, staging, or distribution between symptomatic or asymptomatic patients with NSCLC with brain metastases. The odds of brain metastases were greater in those with adenocarcinoma or large-cell carcinoma.

Comparative study of vascular enhancement on post-contrast CT using three dosages of iodinated contrast media for the aim of detecting brain metastasis in patients with lung cancer

OBJECTIVE

A prospective double-blind randomized study was performed to compare the contrast of vascular enhancement using three dosages of iodinated contrast media for a possible metastatic lesion in the brain.

MATERIALS AND METHODS

Sixty-six patients with lung cancer received brain computed tomography (CT) with intravenous administration of iodinated contrast medium (CM). The patients were randomly assigned to receive one of the three types of CM: 30 g iodine, 24 g iodine, and 15 g iodine. Three radiologists judged the degree of vascular contrast enhancement and diagnosed the presence of brain metastasis. The CT numbers in major arteries were also measured.

RESULTS

The subjective average scores with standard deviation were 2.06+/-0.48, 1.97+/-048, and 1.44+/-0.43, and the measured average CT numbers with standard deviation (SD) were 168.5+/-39.6, 166.1+/-28.6, and 146.1+/-27.0 HU with 30 g, 24 g, and 15 g iodine, respectively. The scores and the CT numbers in 15 g iodine were less than those with 30 g and 24 g iodine. Brain metastasis was detected in one patient each in groups A and C, and one false-positive case was found in group B.

CONCLUSION

CT study with a dose of 24 g iodine showed equivalent quality on vascular enhancement in comparison with a 30 g iodine dose.

Screening of brain metastasis with limited magnetic resonance imaging (MRI): clinical implications of using limited brain MRI during initial staging for non-small cell lung cancer patients

The purpose of this prospective study was to determine whether using magnetic resonance imaging (MRI) for early screening for brain metastases (BM) can improve quality of life, survival in patients with non-small cell lung cancer (NSCLC). The study group comprised 183 patients newly diagnosed with NSCLC. All patients underwent limited brain MRI and routine workups. The control group comprised 131 patients with NSCLC who underwent limited brain MRI only if they had neurologic symptoms. The incidence of BM was 20.8% (38/183) in the study group and 4.6% (6/131) in the control group. The rate of upstaging based on the MRI data was 13.5% (15/111) overall and 15.9% (11/69) in patients that had been considered initially to be resectable surgically. There was no significant difference in survival outcome between the groups. Patients who had BM alone had a greater overall survival time (49 weeks) than those who had multiple systemic metastases (27 weeks; p=0.0307). In conclusions, limited brain MRI appears to be a useful, cost-effective method to screen for BM at the time of initial staging. And it may facilitate timely treatment of patients with NSCLC and improve their survival and quality of life.

The value of performing head CT in screening for cerebral metastases in patients with potentially resectable non-small cell lung cancer: experience from a UK cardiothoracic centre

AIM

To evaluate the whether screening for cerebral metastases in neurologically intact patients with potentially resectable non-small cell lung cancer patients is both worthwhile and cost-effective.

METHODS

We prospectively performed computed tomography (CT) of the head in 105 consecutive patients with potentially resectable lung cancer over an 18-month period. None of these patients had neurological symptoms or signs.

RESULTS

Five patients (4.8%) with cerebral metastases were identified using CT. At our institution the financial saving of avoiding five thoracotomies was pound sterling 45,000, whilst the cost of performing 105 head CTs was pound sterling 16,000. This represented a substantial saving for the healthcare provider and preserved the quality of life in five patients.

CONCLUSIONS

We conclude that screening for cerebral metastases in neurologically intact patients with potentially resectable non small cell lung cancer patients is both worthwhile and cost effective.

Noninvasive staging of non-small cell lung cancer: a review of the current evidence

STUDY OBJECTIVES

To determine the test performance characteristics of CT scanning, positron emission tomography (PET) scanning, MRI, and endoscopic ultrasound (EUS) for staging the mediastinum, and to evaluate the accuracy of the clinical evaluation (ie, symptoms, physical findings, or routine blood test results) for predicting metastatic disease in patients in whom non-small cell lung cancer or small cell lung cancer is diagnosed.

DESIGN, SETTING, AND PARTICIPANTS

Systematic searches of MEDLINE, HealthStar, and Cochrane Library databases to July 2001, and of print bibliographies. Studies evaluating the staging results of CT scanning, PET scanning, MRI, or EUS, with either tissue histologic confirmation or long-term clinical follow-up, were included. The performance of the clinical evaluation was compared against the results of brain and abdominal CT scans and radionuclide bone scans.

MEASUREMENT AND RESULTS

Pooled sensitivities and specificities for staging the mediastinum were as follows: for CT scanning: sensitivity, 0.57 (95% confidence interval [CI], 0.49 to 0.66); specificity, 0.82 (95% CI, 0.77 to 0.86); for PET scanning: sensitivity, 0.84 (95% CI, 0.78 to 0.89); specificity, 0.89 (95% CI, 0.83 to 0.93); and for EUS: sensitivity, 0.78 (95% CI, 0.61 to 0.89); specificity, 0.71 (95% CI, 0.56 to 0.82). For the evaluation of brain metastases, the summary estimate of the negative predictive value (NPV) of the clinical neurologic evaluation was 0.94 (95% CI, 0.91 to 0.96). For detecting adrenal and/or liver metastases, the summary NPV of the clinical evaluation was 0.95 (95% CI, 0.93 to 0.96), and for detecting bone metastases, it was 0.90 (95% CI, 0.86 to 0.93).

CONCLUSIONS

PET scanning is more accurate than CT scanning or EUS for detecting mediastinal metastases. The NPVs of the clinical evaluations for brain, abdominal, and bone metastases are > or = 90%, suggesting that routinely imaging asymptomatic lung cancer patients may not be necessary. However, more definitive prospective studies that better define the patient population and improved reference standards are necessary to more accurately assess the true NPV of the clinical evaluation.

The noninvasive staging of non-small cell lung cancer: the guidelines

Correctly staging lung cancer is extremely important because the treatment options and the prognosis differ significantly by stage. Several noninvasive imaging studies are available to aid in identifying disease both within and outside of the chest. Chest CT scanning is useful in providing anatomic detail that better identifies the location of the tumor, its proximity to local structures, and whether or not lymph nodes in the mediastinum are enlarged. Unfortunately, the accuracy of chest CT scanning in differentiating benign from malignant lymph nodes in the mediastinum is unacceptably low. Whole-body positron emission tomography (PET) scanning provides functional information on tissue activity and has much better sensitivity and specificity than chest CT scanning for staging lung cancer in the mediastinum. In addition, metastatic disease can be detected by PET scan. Still, positive findings of PET scans can occur from nonmalignant etiologies (eg, infections), so that tissue sampling to confirm the suspected malignancy must be performed. The clinical evaluation tool, which is composed of a thorough history and physical examination, remains the best predictor of metastatic disease. If the findings from the clinical evaluation are negative, then imaging studies such as a CT scan of the head, a bone scan, or an abdominal CT scan are unnecessary, and the search for metastatic disease is complete. If signs, symptoms, or findings from the physical examination suggest the presence of malignancy, then sequential imaging, starting with the most appropriate study based on the clues obtained by the clinical evaluation, should be performed. Abnormalities detected by all of the aforementioned imaging studies are not always cancer. Unless overwhelming evidence of metastatic disease is present on an imaging study, in situations in which it will make a difference in treatment, all abnormal scan findings require tissue confirmation of malignancy so that patients are not precluded from having potentially curative surgery.

Clinical and surgical staging of non-small cell lung cancer

The necessity for a compulsive attitude toward preoperative assessment of lung cancer is to be emphasized, since rational treatment and prognosis depend largely on the stage of disease at the time of diagnosis. In the preoperative setting, the techniques used should be sequential, logical, and help to identify patients suitable for treatment with curative intent. With regard to the primary tumor (T status), the accuracy of CT or MRI to predict the need for extended resections is limited. Similarly, all noninvasive methods to determine the nodal status (N) are valuable, but mediastinoscopy has a greater sensitivity and specificity than either CT or MRI. The role of routine organ screening for the detection of distant occult metastasis in the asymptomatic patient is still controversial. Ultimately, the prognosis of the resected patient with lung cancer is based on complete intraoperative staging, which can be done by either systematic node sampling or complete lymphadenectomy. At present, neither of these techniques has been shown to improve the quality of staging or survival.

Detection of brain metastasis in potentially operable non-small cell lung cancer: a comparison of CT and MRI

STUDY OBJECTIVE

To compare the usefulness of MRI and CT in the detection of brain metastases during preoperative evaluation and postoperative follow-up.

DESIGN

A prospective and sequential comparison.

PATIENTS AND METHODS

Of 332 patients with potentially operable non-small cell lung cancer who were free of neurologic signs and symptoms, brain CT was performed preoperatively on 155 patients (CT group) and brain MRI on 177 patients (MRI group). Patient characteristics in both groups were comparable. In 279 patients with complete resection of the primary lung tumor, intensive follow-up with CT and MRI was performed in the respective groups. The preoperative detection of brain metastases, postoperative intracranial recurrence rates, and characteristics of detected brain tumors were compared between the two groups. The survival of patients with brain metastases was also compared.

RESULTS

From the first evaluation to 12 months after surgery for primary lung cancer, brain metastases were observed in 11 patients (7.1%) from the CT group and 12 patients (6.8%) from the MRI group. MRI detected brain metastases preoperatively in 6 of the 12 patients (3.4% of the total MRI group), whereas CT detected brain metastases preoperatively in 1 of the 11 patients (0.6% of the total CT group). MRI showed a tendency toward a higher preoperative detection rate of brain metastases than CT (p = 0.069). Furthermore, the mean (+/- SD) maximal diameter of the brain metastases was significantly smaller in the MRI group (12.8+/-9.1 mm) than in the CT group (20.3+/-7.0 mm) (p = 0.041). However, the median survival time and 2-year survival rate after treatment of detected brain metastases, respectively, were 10 months and 27% in the CT group and 17 months and 28% in the MRI group. There was no significant difference between the groups in survival time.

CONCLUSIONS

Preoperative evaluation and intensive follow-up with MRI could facilitate early detection of brain metastases in patients with potentially operable lung cancer. However, further studies on detection and treatment of the metastatic tumors are considered necessary.