Assessment of factors influencing the result of sputum cytology in bronchial carcinoma

Sputum analysis by flow cytometry; an effective platform to analyze the lung environment

Low dose computed tomography (LDCT) is the standard of care for lung cancer screening in the United States (US). LDCT has a sensitivity of 93.8% but its specificity of 73.4% leads to potentially harmful follow-up procedures in patients without lung cancer. Thus, there is a need for additional assays with high accuracy that can be used as an adjunct to LDCT to diagnose lung cancer. Sputum is a biological fluid that can be obtained non-invasively and can be dissociated to release its cellular contents, providing a snapshot of the lung environment. We obtained sputum from current and former smokers with a 30+ pack-year smoking history and who were either confirmed to have lung cancer or at high risk of developing the disease. Dissociated sputum cells were counted, viability determined, and labeled with a panel of markers to separate leukocytes from non-leukocytes. After excluding debris and dead cells, including squamous epithelial cells, we identified reproducible population signatures and confirmed the samples’ lung origin. In addition to leukocyte and epithelial-specific fluorescent antibodies, we used the highly fluorescent meso-tetra(4-carboxyphenyl) porphyrin (TCPP), known to preferentially stain cancer (associated) cells. We looked for differences in cell characteristics, population size and fluorescence intensity that could be useful in distinguishing cancer samples from high-risk samples. We present our data demonstrating the feasibility of a flow cytometry platform to analyze sputum in a high-throughput and standardized matter for the diagnosis of lung cancer.

Role of I-scan technique in screening for lung cancer in smokers with positive sputum cytology

Background

Lung cancer has a very poor prognosis and high mortality. Positive sputum for malignant and/or atypical cells warrants the need for fibreoptic bronchoscopy. White light bronchoscopy (WLB) is usually unable to detect preinvasive lesions; therefore, autofluorescence bronchoscopy (AFB) was introduced as a gold standard for detecting such lesions. The aim of this work was to investigate the role of I-scan as a screening tool for cancer in smoker patients showing positive sputum cytology.

Results

New suspicious findings under I-scan occurred in 11 patients (36.7%). The overall sensitivity of WLB alone to diagnose malignancy is 23.3%, in contrast to an added sensitivity of 50% when I-scan was combined with white light (p value < 0.05). The specificity of I-scan could not be assessed in the absence of control cases (true negatives). No major complications or deaths occurred. Haemorrhage and bronchospasm were the commonest minor complications.

Conclusions

The addition of I-scan to the routine white light examination can increase the overall sensitivity of bronchoscopic screening in cases of sputum suspicious for malignancy if put in experienced hand. The suggested increase in procedure duration due to the combined use of I-scan and white light bronchoscopy is not associated with life-threatening complications.

Establishing the diagnosis of lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

Lung cancer is usually suspected in individuals who have an abnormal chest radiograph or have symptoms caused by either local or systemic effects of the tumor. The method of diagnosis of lung cancer depends on the type of lung cancer (small cell lung cancer or non-small cell lung cancer [NSCLC]), the size and location of the primary tumor, the presence of metastasis, and the overall clinical status of the patient. The objective of this study was to determine the test performance characteristics of various modalities for the diagnosis of suspected lung cancer.

METHODS

To update previous recommendations on techniques available for the initial diagnosis of lung cancer, a systematic search of the MEDLINE, Healthstar, and Cochrane Library databases covering material to July 2011 and print bibliographies was performed to identify studies comparing the results of sputum cytology, conventional bronchoscopy, flexible bronchoscopy (FB), electromagnetic navigation (EMN) bronchoscopy, radial endobronchial ultrasound (R-EBUS)-guided lung biopsy, transthoracic needle aspiration (TTNA) or biopsy, pleural fluid cytology, and pleural biopsy with histologic reference standard diagnoses among at least 50 patients with suspected lung cancer. Recommendations were developed by the writing committee, graded by a standardized method (see the article "Methodology for Development of Guidelines for Lung Cancer" in this guideline), and reviewed by all members of the Lung Cancer Guideline Panel prior to approval by the Thoracic Oncology NetWork, the Guidelines Oversight Committee, and the Board of Regents of the American College of Chest Physicians.

RESULTS

Sputum cytology is an acceptable method of establishing the diagnosis of lung cancer, with a pooled sensitivity rate of 66% and a specificity rate of 99%. However, the sensitivity of sputum cytology varies according to the location of the lung cancer. For central, endobronchial lesions, the overall sensitivity of FB for diagnosing lung cancer is 88%. The diagnostic yield of bronchoscopy decreases for peripheral lesions. Peripheral lesions &lt; 2 or &gt; 2 cm in diameter showed a sensitivity of 34% and 63%, respectively. R-EBUS and EMN are emerging technologies for the diagnosis of peripheral lung cancer, with diagnostic yields of 73% and 71%, respectively. The pooled sensitivity of TTNA for the diagnosis of lung cancer was 90%. A trend toward lower sensitivity was noted for lesions &lt; 2 cm in diameter. TTNA is associated with a higher rate of pneumothorax compared with bronchoscopic procedures. In a patient with a malignant pleural effusion, pleural fluid cytology is reported to have a mean sensitivity of about 72%. A definitive diagnosis of metastatic disease to the pleural space can be estalished with a pleural biopsy. The diagnostic yield for closed pleural biopsy ranges from 38% to 47% and from 75% to 88% for image-guided closed biopsy. Thoracoscopic biopsy of the pleura carries the highest diagnostic yield, 95% to 97%. The accuracy in differentiating between small cell and non-small cell cytology for the various diagnostic modalities was 98%, with individual studies ranging from 94% to 100%. The average false-positive and false-negative rates were 9% and 2%, respectively. Although the distinction between small cell and NSCLC by cytology appears to be accurate, NSCLCs are clinically, pathologically, and molecularly heterogeneous tumors. In the past decade, clinical trials have shown us that NSCLCs respond to different therapeutic agents based on histologic phenotypes and molecular characteristics. The physician performing diagnostic procedures on a patient suspected of having lung cancer must ensure that adequate tissue is acquired to perform accurate histologic and molecular characterization of NSCLCs.

CONCLUSIONS

The sensitivity of bronchoscopy is high for endobronchial disease and poor for peripheral lesions &lt; 2 cm in diameter. The sensitivity of TTNA is excellent for malignant disease, but TTNA has a higher rate of pneumothorax than do bronchoscopic modalities. R-EBUS and EMN bronchoscopy show potential for increasing the diagnostic yield of FB for peripheral lung cancers. Thoracoscopic biopsy of the pleura has the highest diagnostic yield for diagnosis of metastatic pleural effusion in a patient with lung cancer. Adequate tissue acquisition for histologic and molecular characterization of NSCLCs is paramount.

Performance characteristics of different modalities for diagnosis of suspected lung cancer: summary of published evidence

STUDY OBJECTIVES

To determine the test performance characteristics of various modalities for the diagnosis of suspected lung cancer.

DESIGN, SETTING, AND PARTICIPANTS

A systematic search of MEDLINE, HealthStar, and Cochrane Library databases to July 2001 and print bibliographies was performed to identify studies comparing the results of sputum cytology, bronchoscopy, transthoracic needle aspirate (TTNA), or biopsy with histologic reference standard diagnoses among at least 50 patients with suspected lung cancer.

MEASUREMENT AND RESULTS

For sputum cytology, the pooled specificity was 0.99 and the pooled sensitivity was 0.66, but sensitivity was higher for central lesions than for peripheral lesions (0.71 vs 0.49, respectively). Studies on bronchoscopic procedures provided data only on diagnostic yield (sensitivity). The diagnosis of endobronchial disease by bronchoscopy in 30 studies showed the highest sensitivity for endobronchial biopsy (0.74), followed by cytobrushing (0.59) and washing (0.48). The sensitivity for all modalities combined was 0.88. Thirty studies reported on peripheral lesions. Cytobrushing demonstrated the highest sensitivity (0.52), followed by transbronchial biopsy (0.46) and BAL/washing (0.43). The overall sensitivity for all modalities was 0.69. Peripheral lesions < 2 cm or > 2 cm in diameter showed sensitivities of 0.33 and 0.62, respectively. Updating a previous meta-analysis with 19 studies revealed a pooled sensitivity of 0.90 for TTNA. A trend toward lower sensitivity was noted for lesions that were < 2 cm in diameter. The accuracy in differentiating between small cell and non-small cell cytology for the various diagnostic modalities was 0.98, with individual studies ranging from 0.94 to 1.0. The average false-positive and false-negative rates were 0.09 and 0.02, respectively.

CONCLUSIONS

The sensitivity of bronchoscopy is high for endobronchial disease and poor for peripheral lesions that are < 2 cm in diameter. The sensitivity of TTNA is excellent for malignant disease. The distinction between small cell lung cancer and non-small cell lung cancer by cytology appears to be accurate.

Diagnostic value of bronchoalveolar lavage and postbronchoscopic sputum cytology in peripheral lung cancer

The objective of this study was to evaluate the value of bronchoalveolar lavage (BAL) and postbronchoscopic sputum cytology in diagnosing peripheral lung cancer. We performed a prospective study in 55 patients with lesions on chest radiographs who were suspected of having lung cancer and had non-endoscopically visible lesions on fiberoptic bronchoscopy. The sequence of procedures in all cases was BAL and transbronchial forceps biopsy. The final diagnosis of these patients were primary lung cancer in 30 patients, metatastic lung cancer in five and benign diseases in 20. In the primary lung cancer group, BAL was positive for malignant cells in 14 of the 30 patients (46.7%). In seven (50%) of these patients, the cell type diagnosed by BAL agreed with the final diagnosis. The diagnostic yield of BAL was influenced by the size and segmental location of the lesion. Bronchoalveolar lavage provided a higher diagnostic yield (46.7%) than transbronchial biopsy (16.7%). In five patients with metastatic lung cancer and 20 patients with benign disease, BAL gave negative results in all. Postbronchoscopic sputum cytology was positive in only two of the 26 patients (7.7%) from whom samples could be obtained. Bronchoalveolar lavage cytology proved to be a valuable diagnostic tool in detecting peripheral, primary lung cancer. Postbronchoscopic sputum cytology provided no significant additional information.

Sputum cytology-positive, bronchoscopically negative adenocarcinoma of the lung

Among a total of 114 cases of resected lung adenocarcinoma that were examined by sputum cytologic study before bronchoscopy, 17 were sputum cytology-positive, but had no abnormal bronchoscopic findings. In most of these cases, the reason for detection was sputum and bloody sputum (58.8 percent). Pathologically, many cases were classified as stage III A or more (82.4 percent) due to mediastinal lymph node metastases. More than 70 percent of the cases showed vascular invasion. The proportion of well-differentiated cases was also high (52.9 percent). The prognosis of these cases was worse than sputum cytology-negative adenocarcinoma without abnormal bronchoscopic findings and better than sputum cytology-positive adenocarcinoma with abnormal bronchoscopic findings. There was no significant difference between these cases and sputum cytology-negative adenocarcinoma with abnormal bronchoscopic findings. Combined with the bronchoscopic findings, sputum cytologic study is useful for preoperative evaluation of lymph node metastasis and prognosis. This combined approach can provide information necessary to perform sufficient dissection of mediastinal lymph nodes and proper adjuvant therapy in sputum cytology-positive adenocarcinoma cases, even though there are no abnormal bronchoscopic findings.

Survey of outpatient sputum cytology: influence of written instructions on sample quality and who benefits from investigation

OBJECTIVES

To evaluated quality of outpatient sputum cytology and whether written instructions to patients improve sample quality and to identify variables that predict satisfactory samples.

DESIGN

Prospective randomised study.

SETTING

Outpatient department of a district general hospital.

PATIENTS

224 patients recruited over 18 months whenever their clinicians requested sputum cytology, randomized to receive oral or oral and written advice.

INTERVENTIONS

Oral advice from nurse on producing a sputum sample (114 patients); oral advice plus written instructions (110).

MAIN MEASURES

Percentages of satisfactory sputum samples and of patients who produced more than one satisfactory sample; clinical or radiological features identified from subsequent review of patients' notes and radiographs associated with satisfactory samples; final diagnosis of bronchial cancer.

RESULTS

588 sputum samples were requested and 477 received. Patients in the group receiving additional written instructions produced 75(34%) satisfactory samples and 43(39%) of them one or more sets of satisfactory samples. Corresponding figures for the group receiving only oral advice (80(31%) and 46(40%) respectively)were not significantly different. Logistic regression showed that radiological evidence of collapse or consolidation (p<0.01) and hilar mass (p<0.05) were significant predictors of the production of satisfactory samples. Sputum cytology confirmed the diagnosis in only 9(17%) patients with bronchial carcinoma.

CONCLUSIONS

The quality of outpatients' sputum samples was poor and was not improved by written instructions. Sputum cytology should be limited to patients with probable bronchial cancer unsuitable for surgery.

IMPLICATIONS

Collection of samples and requests for sputum cytology should be reviewed in other hospitals.

Diagnosis of squamous-cell carcinoma of the lung by sputum cytology: with special reference to correlation of diagnostic accuracy with size and proximal extent of resected tumor

Sputum cytology was performed in 179 cases of squamous-cell carcinoma of the lung; 134 cases were diagnosed as positive. There were no significant differences in diagnostic accuracy of sputum cytology between tumors sizes. In cases with tumors extending proximally into the main, lobar, or segmental bronchi, the diagnostic accuracy of sputum cytology was significantly higher than in cases where the proximal invasion of tumor was limited to the peripheral bronchi. In cases with tumors 3 cm or less in diameter, when tumors extended proximally into main, lobar, or segmental bronchi, the diagnostic accuracy of sputum cytology was significantly higher than in cases with tumors extending proximally into subsegmental or subsubsegmental bronchi. In peripherally located squamous-cell carcinoma, in cases in which the tumor arose in subsegmental or subsubsegmental bronchi, carcinoma could be detected by sputum cytology even when it was roentgenographically occult.

Predictive value of sputum cytology

A 60 year old woman non-smoker with bronchial asthma of 6 years' duration, treated with aminophylline, salbutamol, and oral corticosteroids, was admitted because of increasing dyspnoea and productive cough. On examination she was in moderate respiratory distress with inspiratory and expiratory wheezes. Her chest radiograph was interpreted as normal. Two consecutive sputum examinations requested by a junior doctor reveal "malignant" cells.

Sputum cytology by the Saccomanno method in diagnosing lung malignancy

From 1,488 patients, satisfactory sputum was available for cytologic diagnosis. Overall diagnoses were correct in 85.4% of patients, false negative in 193 patients (13.0%), and false positive in 24 patients (1.6%). In patients with a malignant lung process, cytologic diagnoses were correct in 228 patients (54.2%) and false negative in 193 patients (45.8%). In patients with primary lung cancer, the proportion of correct positive diagnoses increased from 0.47 to 0.87 with one to five sputum specimens examined. In patients with metastatic disease, the figures were 0.35 with one specimen examined and 0.38 with two and more sputum specimens. Cytologic typing accuracy was 67% for large-cell carcinomas, 73% for adenocarcinomas, 91% for small-cell lung cancers, and 98% for squamous-cell carcinomas. For the clinically most relevant groups of nonsmall-cell lung cancer and small-cell lung cancer, these figures were 99% and 91%, respectively.