Small Cell Lung Cancer
Updated January 2014
About 10-12% of lung cancer patients have small cell anaplastic pathology (Govindan et al. 2006). The incidence is decreasing from a 20% proportion in the 1980’s. The demographics are changing with more women and an older population affected.
Although small cell lung cancer (SCLC) responds more readily to both chemotherapy and radiotherapy than non-small cell lung cancer, the majority of patients develop incurable recurrences. Palliation of symptoms and prolongation of survival can be achieved with chemotherapy in patients with extensive stage SCLC and about 20-25% of patients with limited stage disease become long-term survivors after combined modality therapy including chemotherapy and radiotherapy.
Although the BCCA recommends adoption of the TNM system for small cell lung cancer (Shepherd 2007), the VA staging system (limited versus extensive) continues to be widely used because of its simplicity and clinical utility (Green 1969). Using current staging procedures, about 40% of SCLC patients have limited stage disease defined as tumor confined to the ipsilateral hemithorax and regional nodes (including ipsilateral supraclavicular) suitable for a tolerable radiotherapy port. The assignment of TNM stage provides more precise nodal staging, which is required for conformal radiation techniques. Limited stage corresponds to TNM stages I through IIIB. Sixty-percent have extensive stage disease defined as tumor beyond the boundaries of limited disease including distant metastases, malignant pericardial or pleural effusion, and contralateral hilar and supraclavicular nodes.
Stage is the major prognostic factor for response, progression-free survival, overall survival and long-term survival (cure). Other important prognostic factors include performance status, gender (female better), number of metastatic sites, weight loss, serum lactate dehydrogenase and serum albumin.
In addition to medical history and clinical examination, patients require a CBC, liver enzymes, electrolytes, LDH, renal function tests, and lung function tests (as required for radiotherapy assessment). Scans should include a CT of brain, chest and abdomen plus a bone scan. A PET scan may be helpful in the absence of obvious distant disease and be of utility in planning radiotherapy volumes for localized cases and occasional cases for surgery (Thomson 2011).
1. Govindan R, Page N, Morgensztern D. Et al. Changing epidemiology of small-cell lung cancer in the United States ovewr the last 30 years: analysis of the SEER database. J Clin Oncol 2006:24;4539-44.
2. Shepherd F, Crowley J, Van Houtte P et al. The International Association for the study of lung cancer lung cancer staging project: proposals regarding the clinical staging of small cell lung cancer in the forthcoming (seventh) edition of the tumor, node, metastasis classification for lung cancer. J Thorac Oncol 2:1067-1077:2007.
3. Green RA, Humphrey E, Close H, et al. Alkylating agents in bronchogenic carcinoma. Am J Med 46:516-525, 1969
4. Thomson D, Hulse P, Lorigan P et al. The role of positron emission tomography in management of small cell lung cancer. Lung Cancer 73:121-126, 2011