Fine particles raise lung cancer risk

A study led by the Barcelona Institute for Global Health (ISGlobal) of the La Caixa Foundation has confirmed that exposure to fine particles increases the risk of developing lung cancer, and that this effect is observed in a similar way in all histological subtypes.

The work, published in the magazine Environmental Pollutionhas analyzed the relationship between different air pollutants and the main subtypes of lung cancer (non-small cell and small cell), ISGlobal reports in a statement this Wednesday.

lung cancer non-small cellwhich represents the majority of diagnoses, includes adenocarcinoma, squamous cell carcinoma, and large cell carcinoma, which are differentiated by the type of cells affected and their location within the lung; the microcyticfor its part, is less frequent but more aggressive and has a strong relationship with smoking.

Numerous studies have already pointed to outdoor air pollutionespecially exposure to fine particles in suspension, as a carcinogen for lung cancer, but it is not completely known how it influences the incidence of the different subtypes of cancer or if it affects how it evolves after diagnosis.

25-year follow-up

The study included more than 122,000 people from the American cohort Cancer Prevention Study IIfrom the American Cancer Society, from 1992whose participants updated each 2 years your personal data and cancer diagnoses up to 2017.

For each participant its annual exhibition was estimated to different pollutants: fine particles PM2.5; PM10; sulfur dioxide (SO2); nitrogen dioxide (NO2) and carbon monoxide (CO).

The analysis took into account variation in exposure over time and adjusted the results for multiple individual factors, including a history of smoking, and detected 4,282 lung cancer cases in the cohort.

Different contaminants

The study confirmed that exposure to fine particles (PM2.5) increases the risk of developing lung cancerand that this effect is observed similarly in all histological subtypes, including adenocarcinoma, squamous cell carcinoma, and large cell carcinoma.

The analysis revealed associations “relevant” with various gaseous pollutants – in particular NO2, O3 and SO2 –, especially in small cell lung cancer.

Nitrogen dioxide (NO2) was the one that showed the strongest relationship with adenocarcinoma, the most common subtype of lung cancerwhile ozone (O3) was linked to an increased risk of large cell carcinoma.

On the other hand, no consistent associations were found between the gas pollutants analyzed and small cell carcinoma, strongly linked to smoking.

Shorter survival in some patients

Regarding survival after diagnosis, no clear associations were observed in all patients, although SO2 was related to lower survival in those who had disease in early stages.

The main author of the article and ISGlobal researcher, Michelle C. Turnerhighlighted that the results reinforce “the importance of integrating local air quality into health care plans, evaluating the environmental exposure of each patient to identify additional risks.”