What factors are associated with better outcomes in patients with lung cancer treated with radiotherapy?

The authors evaluated the factors associated with improved outcomes in patients with lung cancer treated with stereotactic body radiotherapy (SBRT).

Stereotactic body radiotherapy (SBRT) is a type of radiotherapy used to treat lung cancer.  With SBRT, a beam of radiation is focused directly on the tumor, limiting the damage to other cells. This treatment is especially effective for small lung tumors and has the added benefit of having a low number of side effects.

SBRT is often considered in people who cannot or have chosen not to have surgery.

In this study, the authors looked at patients who had undergone SBRT looking for shared factors that indicated a positive outcome. 

The authors looked back at the files of 201 patients with 229 tumors in total. Over 80% of these patients had stage I primary lung cancer (cancer that has not spread beyond the lung). The rest of the patients had a primary cancer in another part of the body (such as colorectal cancer) that had spread to the lungs. Patients were followed for an average of 41.9 months following SBRT.

Those treated with SBRT had an average 3-year overall survival rate (time from treatment until death from any cause) of 60.9% and an average 5-year survival rate of 38.1%. SBRT led to a 3-year local control rate (no cancer at the site of the original tumor) of 72.5% and a 5-year local control rate of 67.8%.

Patients with primary lung cancer (the lungs were site of the original tumor) had a 79% decreased risk of recurrence at the original site than did patients with metastatic lung tumors (other cancers that had spread to the lungs). Every 1 cm increase in tumor size increased the risk of local recurrence by 70%.

Patients with primary lung cancer were 55% more likely to survive for the duration of the study compared to those with cancer that had spread to the lungs. Patients with larger tumors were at significantly greater risk. Every 1 cm increase in size increased the risk of a shorter overall survival by 70%. Females had a 44% increased risk of a short overall survival compared to males.

Almost 14% of patients developed mild to severe inflammation of their lungs following SBRT.

This study concluded that SBRT was safe and effective in lung cancer. Patients with primary lung cancer and those with smaller tumors had better survival and local control rates. 

This study analyzed the files of a limited number of patients in one hospital. The number of patients with lung cancer that had spread from other sites (metastases) was particularly low.

Discuss stereotactic body radiotherapy as a treatment option with your doctor.