Chapter 085. Neoplasms of the Lung (Part 1) pps

Neoplasms of the Lung The Magnitude of the Problem In 2007, primary carcinoma of the lung affected 114,760 males and 98,620 females in the United States; 86% die within 5 years of diag

Chapter 085 Neoplasms of the Lung

(Part 1)

Harrison's Internal Medicine > Chapter 85 Neoplasms of the Lung

The Magnitude of the Problem

In 2007, primary carcinoma of the lung affected 114,760 males and 98,620 females in the United States; 86% die within 5 years of diagnosis, making it the leading cause of cancer death in both men and women The incidence of lung cancer peaks between ages 55 and 65 years Lung cancer accounts for 29% of all cancer deaths (31% in men, 26% in women) Lung cancer is responsible for more deaths in the United States each year than breast cancer, colon cancer, and prostate cancer combined; more women die each year of lung cancer than of breast cancer The age-adjusted lung cancer death rate in males is decreasing, but in females it is stable or still increasing These death rates are related to smoking; smoking cessation efforts begun 40 years ago in men are largely responsible for the change

in incidence and death rates However, women started smoking in substantial

numbers about 10–15 years later than men; smoking cessation efforts need to increase for women The 5-year overall lung cancer survival rate (15%) has nearly doubled in the past 30 years The improvement is due to advances in combined-modality treatment with surgery, radiotherapy, and chemotherapy The International Agency for Research on Cancer estimates that there will be over 1.18 million deaths from lung cancer worldwide in 2007, which will rise to 10 million deaths per year by 2030 This represents one lung cancer case for every 3 million cigarettes smoked Thus, primary carcinoma of the lung is a major health problem with a generally grim prognosis

Pathology

The term lung cancer is used for tumors arising from the respiratory

epithelium (bronchi, bronchioles, and alveoli) Mesotheliomas, lymphomas, and stromal tumors (sarcomas) are distinct from epithelial lung cancer Four major cell types make up 88% of all primary lung neoplasms according to the World Health

Organization classification (Table 85-1) These are squamous or epidermoid carcinoma, small cell (also called oat cell) carcinoma, adenocarcinoma (including bronchioloalveolar), and large cell carcinoma The remainder include

undifferentiated carcinomas, carcinoids, bronchial gland tumors (including adenoid cystic carcinomas and mucoepidermoid tumors), and rarer tumor types The various cell types have different natural histories and responses to therapy, and thus a correct histologic diagnosis by an experienced pathologist is the first

step to correct treatment In the past 25 years, adenocarcinoma has replaced squamous cell carcinoma as the most frequent histologic subtype, and the incidence of small cell carcinoma is on the decline

Table 85-1 Frequency, Age-Adjusted Incidence, and Survival Rates for Different Histologic Types of Lung Cancera

Histologic Type of

Thoracic Malignancy

Frequency,

%

Age-Adjusted Rate

5-Year Survival Rate (All Stages)

Adenocarcinoma (and

all subtypes)

Bronchioloalveolar

carcinoma

Squamous cell

(epidermoid) carcinoma

Large cell carcinoma 9 5 11

Mucoepidermoid

carcinoma

Adenoid cystic

carcinoma

Sarcoma and other soft

tissue tumors

All others and

unspecified carcinomas

a

Data on histology frequency and age-adjusted incidence rates per 100,000 U.S population are from 60,514 cases of invasive lung cancer involving all races and both sexes obtained from the data for 1983–1987 of the Surveillance,

Epidemiology, and End Results (SEER) Program of the National Cancer Institute; 5-year relative survival rates for all stages, all races, and both sexes are from the SEER data on 87,128 carcinomas, 1978–1986 NA, not available

Source: Summarized from Travis et al: Cancer 75:191, 1995