Identifying the Initiation of a New Line of Therapy for Metastatic Lung, Breast, and Colorectal Cancer in Real‐World Data: A Scoping Review

Journal article

Plain Language Summary: Cancer treatment approaches are evolving. Cancer treatments that affect the whole body (systemic anti‐cancer therapy (SACT)) can now be offered either earlier or later in the treatment plan to both patients with early stages of cancer and those whose cancer has spread. In response to these changes, cancer researchers who analyze routinely collected healthcare data need clear decision rules for differentiating between SACT given for early‐stage cancer (non‐metastatic) and treatments given for cancer that has spread (metastatic). Research has explored different ways to identify when a new line of treatment begins for metastatic lung, breast, or colorectal cancer, using routinely collected healthcare data. Most studies from the past decade agree that evidence of cancer metastasis must be documented in the medical record before labeling subsequent treatments as new lines of metastatic cancer therapy. However, this review highlights differences in the current definitions which researchers working with routine healthcare databases apply to identify patients with metastatic lung, breast, or colorectal cancer and different gap periods being used to distinguish between metastatic, relative to non‐metastatic treatments for cancer. This study also provides a framework for improving the methods for identifying new lines of therapy for metastatic cancer.

Authors: Onasanya, O; Mahmoudpour, SH; Bates, B; Shui, IM; Liu, G

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: Pharmacoepidemiology & Drug Safety
• Volume: 35
• Issue: 5
• Article number: e70370
• Publication date: 2026-04-27
• Acceptance date: 2026-03-30
• DOI: 10.1002/pds.70370
• EISSN: 1099-1557
• ISSN: 1053-8569
• Language: English
• Keywords: scoping review; algorithms; frameworks; observational studies; line of therapy; LOT; oncology