I'm trying to understand the clinical data for the TCGA melanoma (
nationwidechildrens.org_clinical_patient_skcm.txt). From sources like https://cancerstaging.org/references-tools/quickreferences/Documents/MelanomaMedium.pdf, stage 0 (melanoma in situ, also graded Tis) is inherently not metastatic and that is why it is labeled stage 0.
But in the clinical data (partially copied below), samples that are labeled Stage 0 / Tis with no regional or distant metastases (N0 and M0), are also labeled as distant metastases. Also the patients are dead, presumably of their metastatic melanomas. This seems impossible. Maybe it was initially diagnosed as stage 0 and somehow became metastatic anyway? --but then you would not expect that to be the annotation of that tumor data in the clinical file. If I want to find all of the clinically low stage tumors, what would be the best way to do that, if not by using this field? Any ideas? Thank you!
bcr_patient_barcode tumor_status vital_status death_days_to primary_melanoma_known_dx primary_multiple_at_dx primary_at_dx_count breslow_thickness_at_diagnosis clark_level_at_diagnosis primary_melanoma_tumor_ulceration ajcc_tumor_pathologic_pt ajcc_nodes_pathologic_pn ajcc_metastasis_pathologic_pm ldh_level ajcc_pathologic_tumor_stage submitted_tumor_site submitted_tumor_site metastatic_tumor_site primary_melanoma_skin_type TCGA-EE-A20C WITH TUMOR Dead 4601 YES NO [Not Available] [Not Available] I [Unknown] Tis N0 M0 [Not Available] Stage 0 Extremities Distant Metastasis Right back Non-glabrous skin TCGA-ER-A2NE WITH TUMOR Dead 613 YES NO [Not Available] [Not Available] [Not Available] [Not Available] Tis N0 M0 [Not Available] Stage 0 Extremities Distant Metastasis Ileum (serosa) [Not Available] TCGA-D3-A8GR WITH TUMOR Dead 3943 YES NO [Not Available] 0.01 I [Unknown] Tis N0 M0 [Not Available] Stage 0 Extremities Distant Metastasis Small Intestine [Not Available]