Malignant neoplasm of the lower respiratory tract at King Chulalongkorn Memorial Hospital: A retrospective study on histological diagnoses of 1,464 cases from 2000 to 2006

Abstract

Introduction : With the advance in molecular targeted therapy on lung cancer, definite distinction of histological subtype becomes more important, which is not always possible in small biopsy. However, there is no well-documented study that describes the whole spectrum of diagnoses among all lung malignancies in Thailand.

Objectives : To describe the incidence of all pathological diagnoses given to lower respiratory tract malignancies at King Chulalongkorn Memorial Hospital from 2000 to 2006.

Materials and Methods : Histological diagnoses of 1,464 lower respiratory tract malignancies from King Chulalongkorn Memorial Hospital and affiliated laboratories from 2000 - 2006 were evaluated using the current classification scheme for lung cancer correlating with age, sex and types of specimen.

Results : Of 1,464 cancers, there are 942 (64.3%) males (3-90 year) and 522 (35.7%) females (12 - 94 years old). There are 338 (23.1%)) resections and 1,126 (76.9%>) biopsies. Most patients (1,392 cases; 95.1%o) were 40 years or older.

For patients who were 40 years or older, 92 cancers are of uncertain primary (0.9%) from resection, 8.3%) from biopsy). Unidentified non-small cell carcinoma is found only in biopsy group (10.7%o). Discarding these two diagnoses, the five most common cancers in male were adenocarcinoma (43.9%o), squamous cell carcinoma (29.9%>), small cell carcinoma (9.5%>), metastasis (6.O%o), and large cell carcinoma (3.4%o). The five most common cancers in female were adenocarcinoma (60.1%)), squamous cell carcinoma (13.5%o), metastasis (11.2%), small cell carcinoma (4.0%)) and hematologic malignancy (3.3%o). Slightly increasing trend of adenocarcinoma was noted in both genders.

In patients who were below 40 years old, the five most common cancers were adenocarcinoma (41.4%o), metastasis (24.3%o), carcinoma of the salivary gland type (7.1%o), mesenchymal tumor (5.7%o); and, two of the five most common malignant tumors were squamous cell carcinoma and hematologic malignancy (4.3%) for each type).

Conclusion : Specimen type greatly affects the incidence of histological diagnosis. Diagnosis of unidentified non-small cell carcinoma is found in one-tenth of biopsy. Adenocarcinoma was the most common cancer in both age groups and relatively frequent in female with slightly increasing trend in both genders. Among those who were below 25 years old, mesenchymal tumor was the most common. Large cell neuroendocrine carcinoma was under-diagnosed. Relatively low incidences of small cell carcinoma and large cell carcinoma were noted. The study provided overall insight of lower respiratory tract malignancy in our institute and provides useful information for improving histological diagnosis in the future.