A new Yale study suggests that patients with a common form of lung cancer may still benefit from delayed chemotherapy started up to four months after surgery, according to the researchers.

The study was published online by JAMA Oncology.

Each year, more people die of lung cancer than of colon, breast, and prostate cancers combined. For patients with non-small-cell lung cancer (NSCLC) — one of two major types of lung cancer — chemotherapy after cancer surgery has been shown to benefit patients with larger tumors or those with cancer in the lymph nodes.

While there is consensus regarding the use of chemotherapy after cancer surgery, the optimal timing is poorly defined. Many clinicians support starting chemotherapy within six to nine weeks after surgery. But factors such as postoperative complications may affect a patient’s ability to tolerate chemotherapy following surgery.

For the study, associate professor of surgery Daniel J. Boffa, MD, and coauthors used data from patients in the National Cancer Database to examine the relationship between the timing of postoperative chemotherapy and five-year mortality.

The study of 12,473 patients with stage I, II, or III disease who received chemotherapy suggests that the initiation of chemotherapy between 57 and 127 days postoperatively led to similar outcomes as patients who started closer to the currently recommended six-to-nine-week window, report the researchers. Furthermore, delayed chemotherapy was associated with a lower risk of death compared to those patients treated only with surgery.

While the study results did not establish causality, they suggest a benefit of delayed chemotherapy for NSCLC patients, says Boffa. “Patients treated surgically for NSCLC continue to benefit from chemotherapy when given outside the traditional postoperative window.

“Clinicians should still consider chemotherapy in appropriately selected patients who are healthy enough to tolerate it, up to four months after NSCLC surgical resection,” he says. “Further study is warranted to confirm these findings.”