Sputum cytology by the Saccomanno method in diagnosing lung malignancy

Respiratory cytology in malignant lung disease - The thoracic oncologist's perspective

Respiratory cytology continues to play a central role in the diagnosis and staging of thoracic malignancy, although over time indications have changed. Historically, sputum cytology and endobronchial brushings and washings figured prominently, but with the advent of endobronchial and endoscopic ultrasound much greater emphasis is placed on fine needle aspirates from lymph nodes. The advent of targeted sequencing panels for genomic profiling to identify driver mutations and PD-L1 directed immunotherapy means that there is a need to extract increasing amounts of diagnostic and predictive information from ever smaller amounts of diagnostic material. Recent work has demonstrated that cytology samples are well suited to delivering the information required, but in order to understand the limitations of clinical and laboratory techniques, a close working relationship between pathologist and thoracic oncologist is needed to optimise sample procurement and utilisation.

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.

Molecular sputum analysis for the diagnosis of lung cancer

Lung cancer is the leading cause of cancer mortality rate worldwide, mainly because of the presence of metastatic disease at the time of diagnosis. Early detection of lung cancer improves prognosis, and towards this end, large screening trials in high-risk individuals have been conducted since the past century. Despite all efforts, the need for novel (complementary) lung cancer diagnostic and screening methods still exists. In this review, we focus on the assessment of lung cancer-related biomarkers in sputum in the past decennium. Besides cytology, mutation and microRNA analysis, special attention has been paid to DNA promoter hypermethylation, of which all available literature is summarised without time restriction. A model is proposed to aid in the distinction between diagnostic and risk markers. Research on the use of sputum for non-invasive detection of early-stage lung cancer has brought new insights and advanced molecular techniques. The sputum shows a promising potential for routine diagnostic and possibly screening purposes.

Complete surgical resection of lung tumor decreases exhalation of mutated KRAS oncogene

Exhaled breath condensate (EBC) contains extracellular DNA that may originate from pathological lesions of the respiratory tract and can be a genetic marker of pulmonary malignancy. We tested whether complete surgical excision of lung cancer will decrease exhalation of mutated KRAS oncogene. Fifty seven patients with clinical diagnosis of lung cancer and detectable KRAS mutations in pre-surgery EBC-DNA were qualified for surgical treatment. Point mutations at codon 12 of KRAS oncogene were detected using mutant-enriched PCR technique in DNA from pre-surgery blood, EBC collected before, 7 and 30 days after surgery and from specimens of resected tumor and normal pulmonary parenchyma. The ratio of mutated to wild type KRAS DNA (R mut/wild KRAS) was calculated for each specimen after electrophoresis and densitometry of the final amplification and digestion product. In 46 patients non-small cell lung cancer (NSCLC) and in 11 benign lesion (BL) were confirmed. All blood and tumor specimens were positive for KRAS mutations, while 41 specimens of normal pulmonary parenchyma were negative. In NSCLC patients pre-surgery EBC R mut/wild KRAS of 0.20 ± 0.03 decreased by 1.3- and 3.7-times (p < 0.001) at 7th and 30th day and 10 EBC specimens at day 30th became negative. The highest R mut/wild KRAS was found in NSCLC specimens - 1.36 ± 0.29 while the lowest in pulmonary parenchyma - 0.02 ± 0.03 (p < 0.001). R mut/wild KRAS in EBC did not correlate with the blood and cancer ratios. Determination of mutated KRAS oncogene in EBC can be potentially helpful in the follow-up of surgical treatment of pulmonary malignancy.

Can free DNA be detected in sputum of lung cancer patients?

SUMMARY

Free DNA is present in the serum of cancer patients in a higher concentration than that in non-cancer patients. Free DNA in sputum may originate from malignant or inflammatory diseases. The aim of the study was to examine the presence of free DNA in sputum and the relationship to lung cancer. The contribution of inflammatory cells was established as well. The amount of free and cellular DNA in sputum was determined using real-time beta-globin PCR in 28 lung cancer patients and 68 controls. Free DNA was present in sputum samples of the cancer patients and controls. We found no differences in DNA concentration in sputum of patients with and without lung cancer. For all patients combined the amount of free DNA was related to the amount of inflammation. Further, we found increased hypermethylation of RASSF1A in lung cancer patients compared to controls to show that tumour related DNA is present in sputum. In conclusion, free DNA can be detected in sputum of lung cancer patients. The amount of free DNA is related to the amount of inflammation, but not to the presence of lung cancer.

Initial Diagnosis of Lung Cancer

BACKGROUND

Lung cancer is usually suspected in individuals who have an abnormal chest radiograph finding or have symptoms caused by either local or systemic effects of the tumor. The method of diagnosis of suspected lung cancer depends on the type of lung cancer (ie, small cell lung cancer [SCLC] or non-SCLC [NSCLC]), the size and location of the primary tumor, the presence of metastasis, and the overall clinical status of the patient.

OBJECTIVES

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

METHODS

To update previous recommendations on the initial diagnosis of lung cancer, a systematic search of MEDLINE, Healthstar, and Cochrane Library databases to July 2004, and print bibliographies was performed to identify studies comparing the results of sputum cytology, bronchoscopy, transthoracic needle aspiration (TTNA), or 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, and reviewed by all members of the lung cancer panel prior to approval by the Thoracic Oncology Network, Health and Science Policy Committee, and the Board of Regents of the American College of Chest Physician.

RESULTS

Sputum cytology is an acceptable method of establishing the diagnosis of lung cancer with a pooled sensitivity rate of 0.66 and specificity rate of 0.99. However, the sensitivity of sputum cytology varies by location of the lung cancer. For central, endobronchial lesions, the overall sensitivity of flexible bronchoscopy (FB) for diagnosing lung cancer is 0.88. The diagnostic yield of bronchoscopy decreases for peripheral lesions. Peripheral lesions smaller or larger than 2 cm in diameter showed a sensitivity of 0.34 and 0.63, respectively. In recent years, endobronchial ultrasound (EBUS) has shown potential in increasing the diagnostic yield of FB while dealing with peripheral lesions without adding to the risk of the procedure. In appropriate situations, its use can be considered before moving on to more invasive tests. The pooled sensitivity for TTNA for the diagnosis of lung cancer is 0.90. A trend toward lower sensitivity was noted for lesions < 2 cm in diameter. The accuracy in differentiating between SCLC and NSCLC cytology for the various diagnostic modalities was 0.98, with individual studies ranging from 0.94 to 1.0. The average false-positive rate and FN rate were 0.09 and 0.02, respectively.

CONCLUSIONS

The sensitivity of bronchoscopy is high for the detection of endobronchial disease and poor for peripheral lesions < 2 cm in diameter. Detection of the latter can be aided with the use of EBUS in the appropriate clinical setting. The sensitivity of TTNA is excellent for malignant disease. The distinction between SCLC and NSCLC by cytology appears to be accurate.

Sputum examination for early detection of lung cancer

Conventional sputum cytology can be used for the detection of lung cancer, but has shown a low yield in prospective screening trials. This review focuses on the technical aspects relevant to the outcome of DNA and image analysis in sputum. Published articles are discussed in the light of the technical background. Recent developments in DNA analysis and nuclear image analysis show a clear potential to improve or refine diagnosis beyond that achieved with conventional sputum cytology examination. The challenge for future studies in DNA and nuclear analysis of sputum is to ensure high levels of quality control and to confirm these initial encouraging results.

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.

ACP Broadsheet No 140: July 1993. Techniques in pulmonary cytopathology

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