Prophase 1 has historically been divided into a series of substages which are named according to the appearance of chromosomes.

前期 1 历来被分成一系列的亚阶段，根据染色体的外观来命名。

Each of these categories have substages: so from T0 to T4, from N0 to N3, and M0 or M1, and the combinations of these substages determine the esophageal cancer stage, from 0 to IV.

以上三类分为以下亚分期：从T0到T4，从N0到N3，从M0到M1，以上亚分期的组合决定了食管癌的分期；分期可处于0到IV期。