If cancer was diagnosed 14 months prior actual diagnosis, would that help to extend a patient life?

Often yes: Finding cancers early often means that they can be completely removed by surgery & gives cancer less time to spread. This is rationale for doing colonoscopies to find precancerous or early cancerous lesions the colon. Has significantly reduced death rate from colon cancer. Similar with routine mamograms for early breast and routine psa blood test & biopsies for early prostate cancer detection.