Risk Factors Associated With Bleeding in Lung Cancer
Massive acute bleeding in the lung, called pulmonary hemorrhage (PH), is a fatal complication seen in lung cancer patients treated with chemotherapy and/or radiotherapy. A recent study has unveiled the risk factors that predispose patients to pulmonary hemorrhage; major lung cavities and squamous cell variant of lung cancer are independently associated with PH.
Chemoradiotherapy, a combination of chemotherapy and radiotherapy, is a widely used mode of treatment for patients with lung cancer. In patients with locally advanced non-small cell lung cancer (NSCLC), this mode of therapy is known to provide better survival. However, pulmonary hemorrhage is a commonly observed serious event in these patients. The exact risk factors for this complication were unknown so far.
'The presence of major baseline cavitation proved to be a powerful risk factor for fatal PH', reported researchers of the recent study. Lung cancer is an important cause for development of cavities in lungs. The exact mechanism responsible for pulmonary hemorrhage in cavitating lung cancer is not clear. It is thought that tumors invade blood vessels thereby reducing blood supply. Lack of oxygen causes changes like activation of particular transcription factors (proteins that control gene expression), and release of cytokines (proteins that modulate the immune system). This may be one of the causes of PH in case of cancers with cavitation.
The study also found that risk of bleeding may be traced to microscopic pattern of lung cancer. The type of lung cancer called squamous cell carcinoma is associated with PH. Researchers state that 'squamous cell histology is associated with PH, independent of tumor location or the presence of cavitation'. The idea that molecular characteristic alone can serve as a risk factor for pulmonary hemorrhage is new..
Patients of lung cancer who have both the risk factors, squamous cell type of lung cancer and presence of major cavitation, are at a high risk of bleeding leading to death.
Based on the findings of the study, provided they are proved to be authoritative and set as standard references, patients can be identified as 'at high risk of fatal PH'. Unfortunately, the current study has a number of technical limitations. Moreover, even if a patient is identified as at high risk of lung bleeding, the 'appropriate treatment' will still be a question mark. There is no consensus about the treatment that can be initiated for these high-risk patients. It remains unclear which therapeutic modality among surgery, chemotherapy, and radiotherapy should be preferred for patients identified to be at high risk of developing pulmonary hemorrhage.
Researchers believe that the data collected from the current study may aid future trials.
Reference: Risk factors associated with fatal pulmonary hemorrhage in locally advanced non-small cell lung cancer treated with chemoradiotherapy; Masami et al; BMC Cancer 2012.
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