Chronic obstructive pulmonary disease or COPD is linked to higher rates of many cancers, including lung, esophagus, colon, bladder and breast cancer.
Often a result of many years of smoking, the disease makes it hard to breathe, leaving patients with lower levels of oxygen and higher levels of carbon dioxide in their blood.
Low oxygen, called hypoxia, is a known feature of the pancreatic cancer microenvironment and a contributor to tumor aggressiveness and resistance to therapy.
However, the impact of high CO2 levels on pancreatic cancer has been considerably less studied.
In a new study, researchers demonstrate that CO2 drives both the aggressiveness of pancreatic tumor cells and their resistance to treatment.
The research was conducted by a team from the Division of Surgical Research in the Jefferson Pancreas, Biliary and elsewhere.
The research finding offers the possibility of correcting these levels prior to treatment.
The team says patients with these respiratory diseases usually start to accumulate excess CO2 in their bodies before they develop a symptomatic lack of oxygen.
If carbon dioxide indeed contributes to disease progression, it is possible to improve treatment response not only by focusing on oxygen but by normalizing carbon dioxide levels in patients as well.
The team looked at both pancreatic tumor cell lines in the lab and historical patient data for associations between obstructive pulmonary diseases and pancreatic cancer.
They showed that increasing the CO2 in cell cultures to levels observed in pulmonary patients was enough to increase their growth and aggressiveness.
When these high-CO2-cultured cells were then treated with common chemotherapeutic agents and radiation therapy, they showed increased resistance compared to cells cultured in normal CO2 conditions.
The researchers also looked at whether they could see the same link in people. They queried pancreatic-cancer patient surgical records for those who also had a diagnosis of asthma or COPD.
Although it was impossible to separate the contribution of CO2 and oxygen levels in these patients, the researchers did see that of the 578 patients they examined, cases with chronic lung disease patients had a 60% increased risk of cancer recurrence.
The team says carbon dioxide levels can be reduced in patients through smoking cessation, using a tailored exercise and respiratory therapy regimen and even changing the diet.
This may help improve the effectiveness of pancreatic cancer treatment.
The lead author of the study is Avinoam Nevler, MD, a researcher with the Sidney Kimmel Cancer Center.
The study is published in the Journal of the American College of Surgeons.
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