incident cancer (initial diagnosis)

Incident cases are those that are newly diagnosed (ideally those in whom the disease has just developed).

EGC accounts for 15 to 57 percent of incident gastric cancer, depending upon the geographic region, and the presence of screening programs. (See 'Epidemiology' below.)
https://www.uptodate.com/contents/early-gastric-cancer-epide...

The sociodemographic characteristics and cancer sites of BRIGHTLIGHT participants were overall similar to incident AYA cancer cases.
https://www.thelancet.com/journals/lanchi/article/PIIS2352-4...

Mean age was 77.4 years. Treatment group distribution was 20.7% glargine, 60.5% nonglargine, 18.7% combination insulin. We observed 5,466 incident cancers; crude rates did not vary by treatment group.
http://care.diabetesjournals.org/content/34/9/1965

This low predictive value is largely the result of the model's limitation in distinguishing recurrent and secondary malignancies from incident cases and possibly from the model identifying true incident cases not identified by SEER.
https://www.ncbi.nlm.nih.gov/pubmed/10880779