深達度による咽頭・食道癌の治療方針

Treatment Strategies for Esophageal and Pharyngeal Cancer Based on the Depth of Invasion

要旨●食道・咽頭表在癌の治療方針はそれぞれで異なる．食道癌は深達度が粘膜上皮，粘膜固有層にとどまれば転移はほとんどないが，粘膜筋板に達するとリンパ節転移が10%程度みられ，粘膜下層浸潤癌ではさらに頻度を増すことから，Stage 0食道癌へは周在性を考慮したうえで内視鏡治療，Stage Iへは根治的化学放射線療法または根治手術が行われる．咽頭には粘膜筋板がないため，深達度は上皮内癌と上皮下層浸潤癌の2つに分類される．筋層・軟骨浸潤のないTis/T1/T2表在癌が内視鏡治療のよい適応である．腫瘍表層からの厚みを計測し，1,000μmを超えると転移頻度が増す．食道では病理結果をもとに追加治療を勧めるが，咽頭では厳重に経過観察されることが多い．

　The treatment strategies for superficial esophageal cancer and pharyngeal cancers are different.

　In esophageal cancer, metastasis is uncommon when the depth of invasion is restricted to the lamina propria. However, when it reaches the muscularis mucosae, lymph node metastasis occurs in about 10% of cases, and the frequency increases further in submucosal invasive cancer. As a result, endoscopic treatment for stage 0 esophageal cancer considers the surrounding area. However, radical treatment options include chemoradiotherapy or surgery for stage I esophageal cancer.

　Because the pharynx lacks a muscularis mucosae, the depth of invasion is divided into two categories：intraepithelial carcinoma and submucosal invasive carcinoma. Endoscopic treatment is appropriate for superficial carcinomas staged as Tis, T1, or T2 without muscular or cartilaginous invasion. A tumor's thickness from the surface layer exceeds 1,000μm, increasing the risk of metastasis significantly. Patients with esophageal cancer often receive additional treatment based on the pathological results. However, for pharyngeal cancer, close monitoring is typically recommended.