CT scan of a 72-year-old woman shows dominant pulmonary nodule (arrow) in right lower lobe that proved at pathology to be adenocarcinoma. Image source: American Journal of Roentgenology, Ginsberg et al, 2004

Treating some lung cancer patients with concurrent chemotherapy and radiation therapy significantly increased five-year survival rates vs. waiting to treat patients with radiation therapy after completing chemotherapy, according to a study published Sept. 8 in the Journal of the National Cancer Institute.

The study was conducted by the Radiation Therapy Oncology Group (RTOG) and involved 610 participants at 153 institutions across North America. It is the largest randomized trial to confirm the importance of administering chemotherapy and radiotherapy concurrently, as opposed to sequentially, for patients with locally-advanced non-small cell lung cancer (NSCLC).

“The significant increase in five-year survival for patients receiving concurrent versus sequential treatment establishes a new treatment standard for this large population of lung cancer patients,” Walter J. Curran, Jr., MD, RTOG chair, the trial’s principal investigator and executive director of the Winship Cancer Institute of Emory University in Atlanta, said in a statement. “It is likely the chemotherapy makes the tumor cells more sensitive to radiation therapy, which contributed to the improved long-term patient benefit seen with concurrent therapy.”

The combination of chemotherapy with radiation therapy compared to radiation therapy alone had previously been shown to increase survival rates for patients with stage III NSCLC, but prior to the RTOG study it was not known whether sequential or concurrent delivery of the two therapies was the best strategy.

Participants were divided into three arms: arm 1 received the two therapies sequentially, arm 2 received the therapies once daily concurrently and arm 3 received the therapies twice daily concurrently.

The percentages of study participants living five years post-treatment in arms 1, 2 and 3 were 10 percent, 16 percent and 13 percent, respectively.

Curran and colleagues noted that immediate side effects, particularly inflammation of the esophagus lining, were “significantly worse” with concurrent therapy, but long-term side effects and treatment-related mortality were equivalent across all three study arms.

Another potential limitation of a concurrent treatment regimen is that less than 30 percent of all stage III NSCLC would have met the entry criteria for the study based on their functional status, according to Curran and colleagues. Most patients would have been disqualified from the trial due to disease-related weight loss or other conditions that would make concurrent treatment harder to tolerate.

Despite the negative side effects, the study’s authors said they are hopeful new radiation therapy techniques and chemotherapy drugs may increase the benefit of concurrent treatments by making it more tolerable for patients.

Nearly 50,000 Americans are diagnosed each year with inoperable stage III NSCLC.