Did you know...

 
Membrane-bound neurosecretory granules (arrows) seen on electron microscopy, together with a lack of cyptoplasmic organelles, characterize oat cell carcinoma.1  

... that small cell lung carcinoma (SCLC), a lung cancer strongly associated with smoking, is a unique classification of lung cancer?

SCLC, first described as 'oat cell' lung carcinoma because of its flat appearance and scant cytoplasm, was originally classified as lymphosarcoma due to its close resemblance to lymphoma. In 1926, Dr. W.G. Bernard suggested switching the classification to a respiratory epithelial cancer (bronchial carcinoma). Since that time, SCLC has been accepted as a lung cancer, but its origins were widely thought to derive from a variant of squamous cell (epidermoid) carcinoma [2-4]. In 1962, scientists Watson and Berg recognized 'oat cell' bronchiogenic carcinoma as a distinct type of lung cancer; they insisted that the 'oat cell' had origins, symptoms and clinical presentations distinct from known lung cancers and therefore should be assigned its own classification [2]. Studies subsequent to Watson and Berg's paper supported this idea. Besides the dark, prominent nuclei and scant cytoplasm associated with the SCLC, these studies found hormonal disturbances by the cells and neurosecretory granules in SCLC which were not found in any other type of lung cancer [4-6].

The unique hormonal profile of SCLC indicated it might not respond to traditional lung cancer therapy. Although surgical resection was standard cancer therapy, Watson and Berg suggested that SCLC might be better treated by a combination of chemotherapy and radiation [2]. Subsequent studies, including a ten year follow-up published in the Lancet, supported Watson and Berg's idea, concluding that surgery ineffectively treated SCLC [1, 5, 7]. Today, SCLC has both a separate classification and its own staging system (classified as either limited or extensive-stage). It is best treated by a combination of chemotherapy and radiation, unlike other lung tumors classified as non-small cell lung carcinomas (NSCLC), which are best treated surgically [8, 9]. Even with SCLC's responsiveness to chemotherapy and radiation treatment, survival improvement is still modest with a 5-year survival rate of 10-13% or 1-2% depending upon its stage [8, 10]. Given that SCLC still has the lowest survival rate, more attention needs to be focused on improving treatment and developing new therapies for this unique cancer.

References:

  1. Li W, Hammar SP, Jolly PC, et al. Unpredictable course of small cell undifferentiated lung carcinoma. J Thorac Cardiovasc Surg. Jan 1981;81(1):34-43.
  2. Watson WL, Berg JW. Oat cell lung cancer. Cancer. Jul-Aug 1962;15:759-768.
  3. Scannell JG. The problem of oat-cell carcinoma. N Engl J Med. Jan 8 1970;282(2):98-99.
  4. Bensch KG, Corrin B, Pariente R, et al. Oat-cell carcinoma of the lung. Its origin and relationship to bronchial carcinoid. Cancer. Dec 1968;22(6):1163-1172.
  5. Barden RP. Editorial: The "oat-cell" tumors: a medical and biological challenge. Radiology. Sep 1974;112(3):743-744.
  6. Hattori S, Matsuda M, Tateishi R, et al. Oat-cell carcinoma of the lung. Clinical and morphological studies in relation to its histogenesis. Cancer. Oct 1972;30(4):1014-1024.
  7. Fox W, Scadding JG. Medical Research Council comparative trial of surgery and radiotherapy for primary treatment of small-celled or oat-celled carcinoma of bronchus. Ten-year follow-up. Lancet. Jul 14 1973;2(7820):63-65.
  8. Spiro SG, Silvestri GA. One hundred years of lung cancer. Am J Respir Crit Care Med. Sep 1 2005;172(5):523-529.
  9. Roberts W. Lung Cancer Pathology: Process and Classfication. http://willroberts.com/lungcancer/path.html. 2000.

This article written by Darla Reed, Nov. 2008.

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