Small cell lung cancer

* Tobacco: high risk beyond 20 PA; Carcinogenic: benzopyrene and polycyclic hydrocarbons; nitrosamines;phenols; arsenic.

* Other FDR: asbestos (amphibole overcoats, for little or no chrysotile); arsenic; nickel; chromium; iron oxide;hydrocarbons; beryllium; ionizing radiation.

* Genetic factors: HLA B12 group.

* Late effects of tuberculosis -> adenocarcinoma

A- General:

* Natural history: Rapid doubling time, particular clinical presentation, metastatic potential.

* Therapeutic: no surgical indication (with exceptions); but very radiosensitive and chemotherapy

* Poor prognosis, even after complete remission.

* 20% of lung cancer

B- Pathology:

* Comes from the malignant transformation of multipotent cell bronchial stump of endodermal origin, neuroendocrine differentiation (this explains the presence of tumors combined with non-small contingent adénocarcinomateuses or squamous cells).

* Central (main bronchus or lobar) submucosal extension; early lymphatic invasion; common extrathoracic extension at diagnosis.

* Metastatic sites are in descending order: liver, adrenal, bone, CNS, bone marrow.

* Optical Microscopy: oat grain (or oatcell) but can be combined or intermediate (larger) (squamous or glandular contingent of cells).

* Electron microscopy: the presence of neurosecretory grains characteristics

* Markers: do not express lymphocyte markers (Dc differential with lymphoma); ADH; neuropeptides (NSE, VIP).

C- paraneoplastic syndromes endocrinological:

* Inappropriate ADH secretion (Schwartz-Bartter syndrome) involving profound hyponatremia and natriuresis retained.

* Ectopic secretion of ACTH (ACTH like) -> Cushing’s syndrome with melanodermia

* Inappropriate secretion of TRH -> hyperthyroidism

* Inappropriate secretion of insulin -> Hypoglycemia

* Inappropriate secretion of ß-HCG or prolactin -> gynecomastia

D- Paraneoplastic neurological syndromes:

* Lambert-Eaton syndrome: muscle weakness with areflexia (pseudo gravis with blocking presynaptic)

* Denny-Brown: severe sensorimotor neuropathy predominant on the upper limbs

* Other: Myelitis (Landry’s syndrome); limbic encephalitis (rapidly progressive dementia); polymyositis.

E- paraneoplastic syndromes and other skin:

* Acanthosis nigricans: mainly stomach cancer, diabetes field

* Hyperkeratosis painful palms of hands and soles of the feet (basex)

* ++ Recurrent phlebitis

F- Two paraneoplastic syndromes are more often associated with squamous cell carcinoma:

* Hypercalcemia (for secretion of PTH like hormone)

* Syndrome Pierre-Marie and Foix (hypertrophic osteoarthropathy pneumiante) with clubbing, inflammatory arthralgia and periosteal apposition on the shaft of long bones; trophic vasomotor disorders.

G- Investigations:

* X-ray: typical proximal perihilar opacity with hilar lymph node, latérotrachéale

* Required Fibroscopy bronchial biopsies with lesions, aspiration cytology. Usually shows extensive infiltration with extrinsic compression proximal aspect. Biopsies may be falsely negative (submucosal tumor development).

* If negative histology -> quickly realize according to radio-clinical data transparietal aspiration biopsies, mediastinoscopy …

* Assessment of extension: endoscopy, chest CT, CT of the head, abdominal ultrasound, bone scan (systematic even in the absence of clinical signs); CT centered on the adrenal; bone marrow biopsy

* Biology: serum electrolytes, liver function tests, calcium and phosphate, creatinine quarry, NSE (initial value for the treatment followed) and LDH (reflecting tumor mass).

* Pretreatment assessment: EFR (only when chest radiation therapy is contemplated and in very rare cases extirpable tumors surgically). ECG; Echocardiography (if use of anthracycline); markers (NSE, LDH).