10: Overview of Esophageal and Proximal Stomach Malignancy

Introduction

Esophageal cancer is the eighth most frequent cancer worldwide. It is the sixth most common cause of cancer death, accounting for 5.4% of all cancer deaths.¹ Although the annual incidence of esophageal cancer in the United States is 4.5 per 100,000, some of the highest incidences are found in Asia, with roughly 100 per 100,000 individuals affected in the Linxian Province of central China.^2,3 Esophageal cancer remains one of the most lethal of all malignancies, with incidence and mortality rates roughly equal. Once a diagnosis is established, the prognosis is dismal, with a 5-year survival rate of 17%.⁴ The results of single-modality treatment have been poor, with the exception of surgery for early esophageal cancer. More recently, neoadjuvant chemotherapy, radiotherapy, and combined chemoradiation therapy have been added as treatment modalities to enhance local control, increase resectability rates, and improve disease-free survival.⁵ The initial results of these multimodality treatments have been encouraging. Since management of esophageal cancer and survival of patients is stage dependent, accuracy of clinical staging is vital. An array of technologies such as CT, MRI, and PET of the esophagus, as well as endoscopic ultrasound (EUS) and minimally invasive thoracoscopic/laparoscopic staging (Ts/Ls), offer more reliable preoperative diagnosis and staging of patients with esophageal cancer. This may result in allocation of patients to stage-specific regimens with resulting improved cure rates.

Anatomy

The boundaries of the esophagus are the inferior cricopharyngeal constrictor proximally and the esophagogastric junction distally. The esophagus is composed of four layers: mucosa, submucosa or lamina propria, muscularis propria, and adventitia (Fig. 10-1). The esophagus has no serosa, providing a teleologic explanation for the ease of spread of esophageal cancer. Familiarity with the histology of the esophageal wall is critical to understanding the staging system of esophageal cancer (see also Chapters 11 and 12).

Anatomically, the normal adult esophagus is approximately 35 cm in length and 2.5 cm in diameter, although it is not uniform throughout its course. The course of the esophagus begins in the midline in the upper neck at the level of the sixth cervical vertebra, which corresponds roughly to the level of the cricoid cartilage, and then deviates to the left in the lower neck and upper thorax. At the level of the tracheal bifurcation (24 cm from the incisors by endoscopic measurement), the esophagus again returns to the midline only to deviate to the left once again in the lower thorax, where it enters the abdomen through the diaphragmatic hiatus (40 cm from the incisors). Clinically, the esophagus is divided into three segments, the cervical, middle, and distal segments. The cervical segment ranges from the cricoid cartilage to the thoracic inlet (10–18 cm ...