Microcitoma (Small Cell Lung Cancer)

5 PROGNOSIS

5.1 Natural history

5.1.1 Natural history
The natural history of SCLC differs from other types of lung cancer in the early and extensive spread of the disease. The vast majority of patients will have dissemination, occult or otherwise, at the time of presentation (70-80% of cases). Furthermore, SCLC has a rapid growth rate and the fastest doubling time (25-160 days). From the time of diagnosis median survival in untreated patients is 3 months for limited disease and 1,5 for extensive disease. It is often difficult to determine the site of origin of lung cancer. SCLCs usually arise in central bronchi, but they may also occur peripherally. They tend to grow rapidly, invade and spread both early and widely. As a result, up to 70-80% of cases have spread beyond the thorax at the time of initial diagnosis. Invasion of adjacent structures is common. External compression or intraluminal invasion of the vascular wall of the superior vena cava (SVC) from direct invasion or from adjacent lymph nodes are well known as SVC syndrome. Pleural effusions may be caused by extension of the cancer to the pleural surface, by thoracic duct involvement in the mediastinum, or by obstruction of pulmonary lymphatics. Hoarseness or dysphagia may be secondary either to invasion of the left recurrent laryngeal nerve or to diaphragmatic paralysis from phrenic nerve involvement.

5.1.2 Lymph node metastases
Lymph node metastases were found in 85% of cases at autopsy and in 90% of patients with distant metastases. Lymphatic spread is similar to the behaviour of non-small cell lung cancer.

5.1.3 Distant metastases
The common sites of extrathoracic metastases are: bone, bone marrow, liver, and the CNS. Other metastases, including those to the remaining lung tissue, opposite lung, pancreas, spleen, heart, thyroid, eye, ovary, kidneys, adrenals, soft tissue, and other internal organs, may be observed. The frequency of metastases rises during the course of the disease. Special therapeutic consideration is given to CNS metastases occurring in approximately 80% of treated patients. Spinal, epidural or leptomeningeal space metastatic disease can be observed.

5.2 Prognostic and predictive factors

5.2.1 Extension of disease
Limited-stage disease is by far the most important favorable prognostic factor. More recently supraclavicular lymphadenopathy and pleural effusions have been included in the limited-stage category, but if they are present, prognosis becomes worse.

5.2.2 Other relevant prognostic factors
Numerous prognostic factors encompassing attributes of both clinical and biological significance have been identified. A review of eleven multivariate statistical analyses published between 1980-1991 of patient groups ranging in size from 411 to more than 2500, provides considerable information about which factors are of independent importance. The most relevant prognostic factors are: stage, performance status, presence of mediastinal involvement, supraclavicular nodes and/or pleural effusion (in patients with limited disease), presence of liver and/or brain metastases. Age (>70 years) is no longer to be considered as a significant adverse prognostic factor both in limited and in extensive disease. Elevated levels of lactate dehydrogenase and alkaline phosphatase, decreased level of sodium, hemoglobin and albumin are associated with poor prognosis being related to tumor dissemination. However, all these prognostic factors are of limited value considering the short life expectancy especially in extensive disease.

References

5.I
Abrams J, Doyle LA, Aisner J. Staging, prognostic features, and special considerations in small cell lung cancer. Semin Oncol 1988; 15:261-227.

5.II
Aisner J. Extensive disease small cell lung cancer: the thrill of victory; the agony of defeat. J Clin Oncol 1996; 14:658-665.

5.III
Albain KS, Crowley JJ, LeBlanc M, et al. Determinants of improved outcome in small cell lung cancer: An analysis of 2,580 patients. Southwest Oncology Group data base. J Clin Oncol 1990; 8:1042-1049.

5.IV
Brigham BA, Bunn PA, Minna JD et al. Growth rates of small cell bronchogenic carcinomas. Cancer 1978;42:2880-2886.

5.V
Carr DT. Malignant lung disease. Hosp Pract 1981;1:97-116.

5.VI
Cerney T, Blair V, Anderson H, et al. Pretreatment prognostic factors and scoring system in 407 small cell lung cancer patients. Int J Cancer 1987;39: 146-149.

5.VII
Chahinian SP, Israel L. Rates and patterns of growth of lung cancer. In: Israel L, Chahinian AP (eds). Lung cancer: natural history, prognosis and therapy. New York: Academic Press, 1976;63-79.

5.VIII
Dearing MP, Stienberg SM, Phelps R et al. Outcome of patients with small cell lung cancer: Effects of changes in staging procedures and imaging technology on prognostic factors over 14 years. J Clin Oncol 1990; 8: 1042-1049.

5.IX
Ihde DC. Staging evaluation and prognostic factors in small cell lung cancer. In: Aisner J, (ed.) Lung cancer. New York: Churchill Livingstone, 1985; 241-268.

5.X
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5.XI
Morittu L, Earl HM, Souhami RL et al. Patients at risk of chemotherapy-associated toxicity in small cell lung cancer. Br J Cancer 1989; 59:801-804.

5.XII
Osterlind K, Anderson PK. Prognostic factors in small cell lung cancer: Multivariate model based on 728 patients with chemotherapy with or without irradiation. Cancer Res 1986; 46:4189-4194.

5.XIII
Quiox E, Hedelin G, Popin E et al. Can we predict very short term survival in small cell lung cancer? Lung Cancer 1993; 10:229-238.

5.XIV
Rawson NSB, Peto J. An overview of prognostic factors in small cell lung cancer: A report from the Subcommittee for the Management of Lung Cancer of the United Kingdom Coordinating Committee on Cancer Research. Br J Cancer 1990; 61:597-604.

5.XV
Sagman U, Maki E, Evans WK, et al. Small-cell carcinoma of the lung: Derivation of a prognostic staging system. J Clin Oncol 1991; 9:1639-1649.

5.XVI
Sculier JP, Feld R, Evans WK et al. Neurologic disorders in patients with small cell lung cancer. Cancer 1987; 60:2275 - 2283.

5.XVII
Siu LL, Shepherd FA, Murray N, et al. Influence of age on the treatment of limited stage small cell lung cancer. J Clin Oncol 1996;14: 821-828

5.XVIII
Souhami RL, Bradbury J, Geddes DM et al. Prognostic significance of laboratory parameters measured at diagnosis in small cell carcinoma of the lung. Cancer Res 1985; 45:2878-2882.

5.XIX
Spiegelman D, Maurer LH, Ware JH et al. Prognostic factors in small-cell carcinoma of the lung: An analysis of 1521 patients. J Clin Oncol 1989; 7:344- 354.

5.XX
Stanley KE. Prognostic factors in lung cancer. In: Aisner J, (ed.). Lung cancer. New York: Churchill Livingstone, 1985:41-66.

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