Usefulness of 5-aminolevulinic acid-photodynamic diagnosis in lung cancer / 대한내과학회지

Lung cancer remains the leading cause of cancer death despite 50 years of antismoking efforts and advances in treatment. Overall, the 5-year survival remains disappointing at 15%. The majority of lung cancers are inoperable at presentation, thereby limiting treatment options and the potential to cure. The best prognosis for lung cancer is expected when the diagnosis is made at an early stage of the disease. At present, the best way to diagnose lung cancer is a combination of three different screening tools: low-dose computed tomography (CT), sputum analyses, and fluorescence bronchoscopy. The tumor marking ability of 5-aminolevulinic acid (5-ALA) has been demonstrated. Inhalation of 5-ALA has been used to detect early lung cancer and is safe and reliable. The data of Yoon et al. in this issue describe the usefulness of photodynamic diagnosis with ALA inhalation.

Histopathologic Findings, and p53 and K-ras Mutational Analysis in Biopsy Specimens Using Fluorescence Bronchoscopy

A fluorescence bronchoscope system has been developed for detecting early lung cancer including dysplasia and carcinoma in situ. To determine the histologic findings and genetic alterations of the lung tissues, which were biopsied by the fluorescence bronchoscope, we analyzed 104 specimens from 62 heavy smokers for their histopathology, cell proliferation index, and genetic mutations of p53 and K-ras. We used immunohistochemistry for MIB-1 and p53, and PCR-SSCP and direct DNA sequencing for p53 and K-ras. The histology was variable from reactive conditions to invasive cancers, and consisted of basal cell hyperplasia (26.9%), dysplasia (4.8%), carcinoma in situ (1.9%), squamous cell carcinoma (7.7%), adenocarcinoma (4.8%), and small cell carcinoma (10.6%). The cellular proliferation index of the lesions increased as their aggressiveness increased. p53 and K-ras mutations were detected in 33.7% and 14.4% of all tissues, respectively. In dysplasia, p53 and K-ras mutations were observed in 3 of 5 and in 2 of 5 tissues, respectively. However, these genetic alterations were not found in carcinoma in situ. Interestingly, 28.6% of basal cell hyperplasia showed p53 mutations. In conclusion, these data suggest that the biopsy specimens using fluorescence bronchoscopy show variable histologic findings, ranging from reactive conditions to invasive cancers. In addition, some of the dysplastic lesions are related to p53 and K-ras mutations, although these genetic alterations are also seen in basal cell hyperplasia.