A comparison of computed tomography and radionuclide scanning for detection of brain metastases in small cell lung cancer

Outcome of small cell lung cancer (SCLC) patients with brain metastases in a routine clinical setting

BACKGROUND

Small cell lung cancer (SCLC) represents approximately 13 to 18% of all lung cancers. It is the most aggressive among lung cancers, mostly presented at an advanced stage, with median survival rates of 10 to12 months in patients treated with standard chemotherapy and radiotherapy. In approximately 15-20% of patients brain metastases are present already at the time of primary diagnosis; however, it is unclear how much it influences the outcome of disease according the other metastatic localisation. The objective of this analysis was to evaluate the median survival of SCLC patients treated by specific therapy (chemotherapy and/or radiotherapy) with regard to the presence or absence of brain metastases at the time of diagnosis.

PATIENTS AND METHODS

All SCLC patients have been treated in a routine clinical practice and followed up at the University Clinic Golnik in Slovenia. In the retrospective study the medical files from 2002 to 2007 were review. All patients with cytological or histological confirmed disease and eligible for specific oncological treatment were included in the study. They have been treated according to the guidelines valid at the time. Chemotherapy and regular followed-up were carried out at the University Clinic Golnik and radiotherapy at the Institute of Oncology Ljubljana.

RESULTS

We found 251 patients eligible for the study. The median age of them was 65 years, majority were male (67%), smokers or ex-smokers (98%), with performance status 0 to 1 (83%). At the time of diagnosis no metastases were found in 64 patients (25.5%) and metastases outside the brain were presented in 153 (61.0%). Brain metastases, confirmed by a CT scan, were present in 34 patients (13.5%), most of them had also metastases at other localisations. All patients received chemotherapy and all patients with confirmed brain metastases received whole brain irradiation (WBRT). The radiotherapy with radical dose at primary tumour was delivered to 27 patients with limited disease and they got 4-6 cycles of chemotherapy. Median overall survival (OS) of 34 patients with brain metastases was 9 months (95% CI 6-12) while OS of 153 patients with metastases in other locations was 11 months (95% CI 10-12); the difference did not reach the level of significance (p = 0.62). As expected, the OS of patients without metastases at the time of primary diagnosis turned out to be significantly better compared to the survival of patients with either brain or other location metastases at the primary diagnosis (15 months vs 9 and 11 months, respectively, p < 0.001).

CONCLUSIONS

In our investigated population, the prognosis of patients with extensive SCLS with brain metastases at the primary diagnosis treated with chemotherapy and WBRT was not significantly worse compared to the prognosis of patients with extensive SCLC and metastases outside the brain. In extensive SCLC brain metastases were not a negative prognostic factor per se if the patients were able to be treated appropriately. However, the survival rates of extensive SCLC with or without brain metastases remained poor and novel treatment approaches are needed. The major strength of this study is that it has been done on a population of patients treated in a routine clinical setting.

Tc-99m glucoheptonate is poor man's fluorodeoxyglucose

While fluoro-deoxy-glucose (FDG) has emerged as an important radiotracer for imaging tumors, myocardial viability and infection, the role of other glucose analogues should also be explored. Tc-99m Glucoheptonate (GHA) has been used for imaging brain tumors and lung tumors. The uptake mechanism may be linked to GLUT-1 (Glucose transporter) and GLUT-4 expression similar to FDG. GHA is easily available and cheap. With the availability of single photon emission computed tomography/computed tomography (SPECT/CT), GHA imaging should be re-explored as a tumor agent and also for imaging myocardial viability.

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.

Detecting extrathoracic metastases in patients with non-small cell lung cancer: Is routine scanning necessary?

There is controversy over whether to scan extrathoracic sites for metastases in patients with non-small cell lung cancer (NSCLC). We tested the efficiency of clinical factors to determine whether metastasis has occurred, and whether routine scanning for NSCLC is required. Nine hundred and forty five patients scanned for extrathoracic metasates were included. Clinical factors indicating metastasis were determined using multivariate analysis. Of the 945 cases, 377 (39.9%) had metastasis. Bone metastases were determined by focal skeleton pains, elevated serum alkaline phosphatase levels, adenocarcinoma, KPS</=70, sensitivity of 90.6, specificity of 12.7, PPV of 16.3, NPV of 87.8, and silent metastases rate (SMR) of 9.4%. Brain metastases were determined by neurological symptoms, adenocarcinoma, hematocrite <40 for men and <35 for women, KPS</=70, sensitivity of 89.9, specificity of 7.9, PPV of 9.2, NPV of 88.3, and SMR of 10.1%. Abdominal metastases were determined by abdominal pain/tension, hepatomegaly, elevated GGT levels, serum LDH levels >500 IU, a N2 or N3 case, KPS</=70, sensitivity of 95.9, specificity of 7.1, PPV of 13.3, NPV of 92.1 and SMR of 4.1%. Of the 224 patients with stage I and II disease, 73 had metastasis with a rate of 10.9% silent metastasis. We concluded that routine scanning of NSCLC for staging is necessary.

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.

Asymptomatic brain metastases (BM) in small cell lung cancer (SCLC): MR-imaging is useful at initial diagnosis

PURPOSE

In this study we evaluated the usefulness of MR-imaging in the detection of asymptomatic brain metastases (BM) at the initial diagnosis in patients with small cell lung cancer (SCLC) and studied the follow-up of these patients.

PATIENTS AND METHODS

One-hundred and twenty-five patients with SCLC were investigated with MR-imaging.

RESULTS

In 112 patients with normal neurological findings, MR-imaging of the brain demonstrated BM in 17 patients (15%). Six of these 17 patients were therefore upgraded to extensive disease (ED). Two of these 17 patients died during chemotherapy because of progressive disease and 3 patients became neurologic symptomatic with progressive disease on MR-imaging of the brain. After completion of chemotherapy a repeated MR-imaging of the brain in the remaining 12 patients showed 1 complete remission, 4 partial remission and 7 progressive disease of the BM.

CONCLUSION

This study showed that at presentation an unexpectedly high percentage of SCLC patients had asymptomatic BM on MR-imaging. We propose that MR-imaging of the brain should be included in the staging of SCLC patients as well for staging, prognosis and therapy.

Factors influencing the distribution of metastases and survival in extensive disease small cell lung cancer

This study was conducted to investigate the distribution of metastatic lesions and their influence on survival, as well as other prognostic factors previously shown to have an impact on the outcome of patients with extensive small cell lung cancer (SCLC). Of the 207 patients were included and retrospectively analyzed; 124 patients had extended disease at initial presentation and the remaining 83 developed metastatic disease during follow-up. Patients who relapsed presented most frequently with distant metastases. The brain was the most frequent organ targeted for metastatic disease following the completion of chemotherapy (p<0.05). Serum LDH levels correlated significantly with the presence of liver metastasis (p<0.001). The site of involvement did not seem to have an impact on survival. Nevertheless, patients with multiple metastatic sites had a significantly poor survival rate (p = 0.001). Weight loss, performance status, gender, clinical stage, serum LDH and albumin levels were all shown to correlate with survival (p<0.05). Response to chemotherapy was determined to be the most important prognostic factor.

Survival of patients with extensive small-cell lung cancer who have only brain metastases at initial diagnosis

To study the therapeutic outcome of patients with extensive small-cell lung cancer (SCLC) with the brain as the single site of metastases at initial diagnosis, we retrospectively reviewed the outcome of 30 such patients (23 men and seven women; median age, 59 years; range, 36-74 years). Medical histories were taken, and physical examination, complete blood cell count, chemistry profile, chest radiography, radionuclide bone scan, computed tomography (CT) scan of the abdomen or radionuclide liver scan, and CT scan of the head were performed as the staging workup for each patient. Bone marrow biopsies were performed in 19 patients. All patients initially received cisplatin-based chemotherapy and concomitant whole-brain radiation therapy consisting of 3,600-4,800 cGy. Subsequently, 22 patients also received thoracic radiation therapy (17 patients as part of the protocol treatment and five patients at the time of disease progression). Thirteen patients had a complete response, 11 had a partial response, three had regression, and three had stable disease. Median survival of the entire group was 14 months (range, 1.4-70.7 months). Twenty-four patients eventually had progression of disease, with a median time to progression of 10 months (range, 2.3-48.5 months). Only one patient had disease progression in the brain (12.6 months after diagnosis). Twenty-two patients eventually died of the disease. The results of our study suggest that the therapeutic outcome in SCLC with the brain as the single site of metastases at initial diagnosis is similar to that of limited-stage SCLC.

Cost-effectiveness of head CT in patients with lung cancer without clinical evidence of metastases

OBJECTIVE

To estimate the cost-effectiveness of CT for detecting brain lesions in patients with lung cancer without clinical evidence of metastases.

DESIGN

Decision analysis model comparing two different strategies for detecting brain metastases: brain CT routinely (CT-first) or brain CT only when patients develop neurologic signs and/or symptoms (CT-deferred).

PATIENTS

Hypothetical cohort of patients with lung cancer with an unremarkable screening clinical evaluation for metastases.

MEASUREMENTS

Net costs are calculated as the difference in costs between the two limbs of the decision tree. Net benefits are expressed as the difference in calculated years of life expectancy between the two strategies. Net costs are divided by net benefits, yielding the marginal cost per quality adjusted year of added life expectancy (C/QALY) for the CT-first strategy.

RESULTS

In the baseline analysis, the C/QALY for the CT-first strategy is about $70,000. Improving the clinical evaluation as a screen for detecting brain metastases markedly increases the C/QALY. Increasing the cost of brain CT magnifies this effect. More effective treatment for asymptomatic brain metastases and better accuracy of CT for identifying resectable and unresectable brain metastases lower C/QALY.

CONCLUSIONS

Although a threshold cost-effectiveness has not been defined for identifying "cost-effective" diagnostic procedures, the marginal C/QALY of the CT-first strategy is substantially higher than many accepted medical interventions. At current costs, the routine use of brain CT is not warranted in patients with lung cancer who have normal findings on a standardized clinical evaluation for metastases.

The value of computed tomographic (CT) scan surveillance in the detection and management of brain metastases in patients with small cell lung cancer

One hundred and twenty-seven consecutive patients presenting with small cell lung cancer were entered into a whole-brain CT scan surveillance study, starting at presentation and repeating at 3-monthly intervals for 2 years as an alternative to prophylactic cranial irradiation (PCI). The aim of the study was to detect CNS metastases at an early asymptomatic stage in the hope that prompt CNS radiotherapy could achieve long-term control; at the same time unnecessary PCI with its potential long-term morbidity could be avoided. CNS metastases were found in 56 patients (44%) including 16 (13%) at diagnosis and 40 at a median of 4 months (range 1-27 months) after completing chemotherapy. No patient developed CNS disease while on chemotherapy. Thirty-six patients were asymptomatic at diagnosis (group A) but 20 developed clinical CNS relapse between scans (group B) (interval relapse). Despite prompt radiotherapy 56% of patients in group A and 60% of patients in group B died with active CNS disease. Likewise, there was no survival difference between patients in group A, group B or those who never developed CNS disease. Regular 3-month CT scan surveillance is therefore not an effective substitute for PCI.

Results of therapeutic cranial irradiation in small cell lung cancer

A large proportion of patients with small cell lung cancer develop intracranial metastases which are often severely disabling. The optimal radiotherapeutic program for treating these metastases is unknown. We therefore evaluated objective response rates, response duration, and survival after therapeutic cranial irradiation in 59 patients with proven brain metastases from small cell lung cancer. Objective responses to a variety of doses and schedules were observed in 37 (63%) patients. However, progression of intracranial disease after radiotherapy was common, with 24 responding patients having relapsed in the brain prior to death. The actuarial likelihood of remaining free of progressive brain tumor at 1 year was only 37% in complete and 0% in partial responders. Patients who received radiation doses of more than 40 Gy had longer response durations than those given lower doses, although patient selection could well explain this observation. Brain metastases presenting after initiation of systemic chemotherapy or occurring in conjunction with other sites of extrathoracic disease were associated with a poor prognosis. In patients who present with brain metastases as the sole site of metastatic disease, higher doses of cranial irradiation should be considered, in view of the high intracranial relapse rate associated with currently accepted dose and fractionation schedules.

Small cell lung cancer: a problem of tumor heterogeneity

Small cell undifferentiated carcinoma represents a subtype of lung cancer that possesses biologic and clinical characteristics that make it significantly distinct from other forms. A major impact on the natural history of this disease has been accomplished during the past 15 years, including the potential for cure by non-surgical treatment modalities. Further progress in the management of this disorder has been impaired by a number of factors that appear to be inherent to the biology of the tumor and its clinical features. Analysis of initial clinical trials and more detailed examination of this tumor in vitro have permitted the elucidation of many barriers to curative outcome presently being evaluated at the laboratory and clinical levels. These include clear biologic and morphologic heterogeneity; problems with chemotherapy responsiveness including drug resistance; the potential for combining chemotherapy and radiation modalities; the re-examination of the role of surgical intervention in selected patients; and the need to deal with central nervous system dissemination of tumor cells. Further advances in this disease will be dependent on the successful integration of laboratory and clinical disciplines.