Elderly lung cancer patients receiving radiation therapy (RT) after surgical resection may not have improved survival from the treatment, according to a study published online Feb. 13 in Cancer. The findings suggest that physicians should not routinely use radiation after surgery to treat lung cancer that is advanced but has not widely spread, at least in older patients.
A significant proportion of patients who undergo surgery for localized non-small cell lung cancer (NSCLC) have involvement of N2 lymph nodes identified on pathologic staging.
“The prognosis of patients who undergo lung cancer resection depends greatly on the extent of lymph node involvement,” wrote Juan Wisnivesky, MD, DrPH, of the Mount Sinai School of Medicine in New York City, and colleagues. “Although long-term survival may be achieved by approximately 70 percent of patients without lymph node metastasis, it decreases to between 20 percent and 35 percent for those with microscopic N2 disease.”
Because of the risk of recurrence, postoperative radiation therapy (PORT) is often proposed to improve outcomes, but the potential benefit of this strategy has been a subject of debate.
The role of PORT in patients with N2 disease in particular remains uncertain, yet, despite the lack of conclusive evidence, PORT is frequently used to treat elderly patients with N2 disease, according to the authors. Assessment of PORT use in the Surveillance, Epidemiology and End Results (SEER)-Medicare registry showed 34.1 percent of patients in low-use regions received PORT, while 66.7 percent received the treatment in the high-use areas.
To see if this additional treatment extends survival, Wisnivesky et al analyzed information from SEER. The investigators identified 1,307 cases of locally advanced lung cancer between 1992 and 2005.
In all, 710 patients (54 percent) received radiation following surgery, but the therapy was not associated with improved survival in patients with N2 disease. Instrumental variable estimates for the absolute improvement in one-year and three-year survival with PORT were -0.04 and -0.08, respectively. Results were similar regardless of whether or not the patient received chemotherapy and whether the radiotherapy planning was of intermediate or high complexity.
“Our results show that we need more information about the potential benefits of radiation therapy before it is used routinely to treat this subset of lung cancer patients,” Wisnivesky said in a statement.
This information may come from the Lung Adjuvant Radiotherapy Trial, or LungArt, which is an ongoing phase III randomized controlled clinical trial evaluating the effectiveness of radiation following surgery in patients with locally advanced lung cancer.