IPF Worsens Prognosis in Lung Cancer Patients

Idiopathic pulmonary fibrosis (IPF) is associated with poorer prognosis in patients with lung cancer, a study shows.

People with lung cancer showed a higher risk of dying if IPF was present. The findings also suggest that lung cancer treatments, such as chemotherapy, can contribute to poor clinical outcomes by triggering acute IPF exacerbations.

The study, “Impact of idiopathic pulmonary fibrosis on clinical outcomes of lung cancer patients,” was published in Nature Scientific Reports.

Previous studies have shown that patients with IPF have an increased risk of developing lung cancer compared to the general population. IPF patients with cancer are typically older, male, and smokers. However, the association between lung cancer and IPF has not been adequately evaluated since most studies were carried out in small groups and without the appropriate controls.

A team of scientists in Korea investigated the impact of IPF on the clinical outcomes of a large number of patients with lung cancer.

The study included 893 people with IPF diagnosed from January 2007 to December 2015 at the Asan Medical Center in Seoul, South Korea. Of those, 122 (13.7%) patients had developed lung cancer. As controls, the researchers selected 488 IPF-free patients with lung cancer from the lung cancer registry.

Most patients with both IPF and cancer were men (95.9%) with a history of smoking (95.3%). Their mean age was 68 years and 18.7 months was the median follow-up period after lung cancer diagnosis. Coughing, shortness of breath, and decreased lung function were more frequent in patients with IPF and cancer compared to the control group (with lung cancer only).

The team found that prognosis was poorer in patients with both lung cancer and IPF compared to those with only lung cancer. The five-year survival rate was 14.5% versus 30.1% in those without IPF.

Patients were classified based on subtypes of lung cancer: adenocarcinoma, lung squamous cell carcinoma (SqCC), small cell lung cancer (SCLC), and mixed. The presence of IPF had no effect on the survival outcome in patients with SCLC. However, in patients with adenocarcinoma and IPF the median survival was significantly lower compared to the non-IPF group — a median of 11 months versus 26 months. A similar tendency was observed in patients with SqCC and IPF (median survival of 19 versus 30 months).

A statistical analysis taking into account the patient’s lung function revealed that lung cancer patients with IPF had a 1.55 times higher risk of dying. In addition, those with adenocarcinoma and IPF were at 2.17 times higher risk of death.

The association between lung cancer stages (the higher the stage, the worse is the severity of the disease), IPF, and median survival also was evaluated. IPF patients with stage I and III of non-small cell lung cancer (NSCLC) had shorter median survival than patients with the same cancer stages, but without IPF — a median survival of 34 vs. 77 months for stage I, and 13 months vs. 18 months for stage III.

No significant differences were observed in the median survival between the IPF and no-IPF groups in stage II and stage IV (advanced) NSCLC.

In addition, the median survival of patients with and without IPF was similar among those with early SCLC (about 16 months in each group) and advanced stages of SCLC (median of six months vs. nine months in those without IPF).

Of the 122 lung cancer patients with IPF who were analyzed, 101 (82.8%) received some type of anti-cancer treatment including surgery, chemotherapy, or radiation therapy. In general, patients in the IPF group who had undergone lung cancer surgeries still had a shorter median survival period than those in the no-IPF group.

Acute exacerbations (sudden symptom worsening) were experienced by 17 patients (16.8%) within a month from the last treatment. Six patients felt symptom worsening after surgery (10.3% of patients with IPF who had surgery), six after chemotherapy (13.0% of patients with IPF who had chemotherapy), and five after radiation therapy (17.9% of patients with IPF who had radiation therapy).

Patients who had anti-cancer treatments and experienced acute exacerbations had worse prognosis after cancer diagnosis — median survival period of five months versus 16 months in those who did not experience acute exacerbations.

“The treatment outcome of patients with lung cancer and IPF was generally unfavorable, and acute exacerbation triggered by treatment frequently occurred,” the researchers wrote. “These findings suggest that careful monitoring of patients with lung cancer is needed even after treatment.”

The team reported some study limitations. Important data, such as the cause of death, was available for only a few patients. The study, conducted at one South Korean medical center, also may not reflect the reality of other populations and the number of patients is still considered small. Yet, the authors stated the results could “serve as a reference for future studies.”

“In conclusion, our results showed that IPF affects clinical outcomes of patients with lung cancer irrespective of lung function or treatment methods, and AE [acute exacerbations] occurred in a fifth of patients with IPF after lung cancer treatment,” the team wrote. “These findings suggest that treatment strategies tailored to patients with IPF and the prevention of AE are important for improving their prognosis.”