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.
Source-Medindia