Can specialized imaging techniques improve how chemo-radiotherapy is administered in locally advanced non-small cell lung cancer?

This study set out to compare conventional-dose chemoradiotherapy (CRT) to reduced CRT based on 18F-FDG PET in locally advanced non-small cell lung cancer (NSCLC). The investigators found that 18F-FDG PET-based CRT improved tumor control without increasing side effects in these patients. 

NSCLC accounts for 85% of all lung cancers. The disease progresses slowly and is often diagnosed at advanced stages. Staging of the tumor is done using a chest CT scan. Staging determines tumor size and spread. It also guides therapy, particularly radiotherapy. 

Radiotherapy is often used when the spread is local or when the tumor cannot be removed surgically. Given that the lungs are highly sensitive to radiation, radiotherapy is associated with side effects. Reducing the volume of tissues targeted can reduce these side effects. 18F-FDG PET scan is a type of imaging technique. It uses a small amount of a radioactive drug to show the difference between healthy and disease tissue.

Whether 18F-FDG PET scans are effective and can help reduce side effects of CRT compared to conventional CRT remains under investigation. 

The study had 172 patients with NSCLC. Group 1 included 84 patients who received conventional CRT (using conventional target volume planning). Group 2 included 85 patients who received CRT after target volumes were reduced based on 18F-FDG PET scans. Patients were followed up for an average of 29 months.

14% of patients in group 2 had cancer progress locally at 1 year compared to 29%. Patients in group 2 had a 43% lower risk of cancer worsening compared to group 1. The overall survival and survival without cancer worsening were similar in the two groups. 

There were no significant differences in toxicity and distant spread of the cancer in both groups. The most common serious side effects included inflammation of the esophagus (the tube that passes food from the mouth to the stomach) or trouble swallowing. This was reported in 16% of patients in each group.

This study concluded that using 18F-FDG PET scans to reduce the target volume of therapy in NSCLC leads to less local progression of the disease with similar toxicity. 

The study had a small sample size. Also, the study design was not strong enough to generate strong conclusions. Further studies are needed.