Lung Cancer
Lung cancers are among the most common malignancies in the Western world and are the leading cause of cancer deaths in both men and women. It is one of the few tumors with a known carcinogen (tobacco smoke) contributing to its etiology. In recent years we have come to appreciate that the initiation of lung cancer is a complex process that also involves certain biologic factors, such as the body’s ability to process carcinogens. This disease is difficult to diagnose and treat, and the overall 5-year survival rate is less than 15%; however if caught early, the survival rate increases to 70%. The staging of lung cancer depends on extent of disease, location of the primary tumor, and associated clinical complications.
Lung Cancer Treatment Summaries
Prophylactic cranial irradiation in small cell lung cancer
Patients with small lung cancer are at high risk of development of brain metastasis. This high rate of brain metastasis is the basis for PCI to prevent the clinical manifestation of previously present but occult CNS disease. The role of PCI has been controversial. Most trials have shown a reduction in CNS relapse rates but little effect on survival. A recent meta analysis of all randomized trials of PCI in patients with small cell lung cancer who achieved a complete or near-complete response to induction chemotherapy (alone or combined with thoracic irradiation), Auperin, A., et. al., New England Journal of Medicine (N. Engl. J. Med.), 1999 August 12: 341, showed a statistically significant improvement in survival in patients treated with PCI (20.7% at three years versus 15.3% in those not given PCI). PCI also increased the rate of disease-free survival, P value < 0.001, and decreased cumulative incidents of brain metastases. The current recommendation is to offer PCI to patients who achieved a complete or near-complete remission of the disease outside the CNS.
Systemic chemotherapy for extensive-stage small cell lung cancer
Two-thirds of small cell lung cancer patients present with extensive disease at diagnosis. Median survival in this group without treatment is 6-8 weeks. Treatment with combination chemotherapy increases the median survival duration up to 8 to 10 months. The combination of cisplatin or carboplatin/etoposide is considered the standard of care in the United States at this time. A recent phase-III trials conducted in Japan (Noda, K., et. al., N. Engl. J. Med., 2002) compared irinotecan/cisplatin vs. etoposide/cisplatin. This trial indicated a 3.4-month improvement in median survival in favor of the irinotecan arm. This improvement in median survival is provocative, however in phase-III trials in the United States (Pfizer Pharmaceutical trial, Henna et al., JC, 2006) failed to show superiority of Irinotecan/Cisplatin over VP-16/Cisplatin. Results of SWOG study expected sometime in 2007.
