Clinical Approach To Carcinoma Of The Esophagus And Cardia
The selection of a curative versus a palliative operation for cancer of the esophagus is based on the location of the tumor, the patient’s age and health, the extent of the disease, and intraoperative staging. A diagnosis of esophageal malignancy is done when tissue samples are studied under compound light microscopes for biopsy.
Tumor Location
The selection of surgical therapy for patients with carcinoma of the esophagus depends not only on the anatomic stage of the disease and an assessment of the swallowing capacity of the patient, but also on the location of the-primary tumor.
It is estimated that 8% of the primary malignant tumors (diagnosed with the use of compound light microscopes) of the esophagus occur in the cervical portion. They are al¬most always squamous cell lesions with a rare adenocarcinoma arising from a congenital inlet patch of columnar lining. These tu¬mors, particularly those in the postcricoid area as studied with the use of compound light microscopes, represent a separate pathologic entity for a number of reasons: (1) they are more common in females and appear to be a unique entity in this regard; and (2) the efferent lymphatics from the cervical esophagus drain completely differently from those of the thoracic esophagus. The latter drains directly into the paratracheal and deep cervical/internal jugular lymph nodes with a minimal flow in a longitudinal direction. Except in advanced disease, it is unusual for intrathoracic lymph nodes to be involved.
Low cervical lesions that reach the level of the thoracic inlet are usually unresectable due to early invasion of the great vessels and trachea. The length of the esophagus below the cricopharyngeus is insufficient to allow intubation or construction of a proximal anas¬tomosis for a bypass procedure. Consequently, palliation of these tumors that were diagnosed with the use of compound light microscopes is difficult, and patients afflicted with disease at this site have a poor prognosis. Upper airway obstruction or the development of tracheoesophageal fistulas in such tumors may require surgical in¬tervention for palliation. If possible, these tumors should be resected after a preoperative course of chemotherapy has reduced their size.
Tumors that arise within the middle or upper third of the thoracic esophagus lie too close to the trachea and aorta to allow an en bloc resection without removal of these vital structures. Consequently, in this location only tumors that have not penetrated through the esophageal wall and have not metastasized to the regional lymph nodes are potentially curable, as seen under medical microscopes. The resection for a tumor at this level is done similarly whether for palliation or cure, and long¬-term survival is a chance phenomenon. This does not mean that when resecting such tumors, efforts to remove the adjacent lymph nodes should be abandoned. To do so may inadvertently leave unrecognized metastatic disease behind and compromise the patient’s overall survival, because of recurrent local disease and compres¬sion of the trachea. It is recommended that a course of preoperative chemoradiotherapy should be given before resection to shrink the size of the tumor. It is recommended that the radiotherapy be limited to 3.5 Gy to allow for tissue healing.
Tumors of the lower esophagus and cardia, when studied under a microscope, are usually adenocar¬cinomas. However, squamous cell carcinoma of the lower esophagus does occur, also evident when it is examined under a microscope. Both types of tumor are amenable to en bloc resection. Unless preoperative and intraoperative staging clearly demonstrates an incurable lesion, an en bloc resection in continuity with a lymph node dissection should be performed. Because of the propensity of gastrointestinal tumors to spread for long distances submucos¬ally, long lengths of grossly normal gastrointestinal tract should be resected. The longitudinal lymph flow in the esophagus can result in with small foci of tumor above the primary lesion, which underscores the importance of a wide resection of esophageal tu¬mors. Wong has shown that local recurrence at the anastomosis can be prevented by obtaining a 10-cm margin of normal esophagus above the tumor. Anatomic studies have also shown that there is no submucosal lymphatic barrier between the esophagus and the stom¬ach at the cardia, and Wong has shown that 50% of the local recur¬rences in patients with esophageal cancer who are resected for cure occur in the intrathoracic stomach along the line of the gastric resec¬tion. Considering that the length of the esophagus ranges from 17 to 25 cm, and the length of the lesser curvature of the stomach is ap¬proximately 12 cm, a curative resection requires a cervical division of the esophagus and a greater than 50% proximal gastrectomy in most patients with carcinoma of the distal esophagus or cardia. This compromises the length of the stomach and esophagus remaining to re-establish gastrointestinal continuity, and necessitates a colon interposition.
Age
An en bloc resection for cure of carcinoma of the esophagus in a patient older than 75 years is rarely indicated, because of the additional operative risk and the shorter life expectancy. Regardless of how favorable the staging criteria, a palliative resection is per¬formed in these patients. This approach provides relief of symptoms with less extensive surgical procedures, and cure is still a chance possibility.
Cardiopulmonary Reserve
Patients undergoing esophageal resection should have sufficient cardiopulmonary reserve to tolerate the proposed procedure. The respiratory function is best assessed with the forced expiratory volume in 1 second (FEV1), which ideally should be 2 L or more. Any patient with an FEV1 of less than 1.25 L is a poor candidate for surgery, because he or she has a 40% risk of dying from respiratory insufficiency within 4 years. In such a patient, the chances of long-term survival, even if cured from the disease, do not justify an ex¬tensive en bloc resection. Clinical evaluation and electrocardiogram are not sufficient indicators of cardiac reserve. Echocardiography and dipyridamole thallium imaging provide accurate information on wall motion, ejection fraction, and myocardial blood flow. A defect on thallium imaging may require further evaluation with pre¬operative coronary angiography. A resting ejection fraction of less than 40%, particularly if there is no increase with exercise, is an ominous sign. The preference of these authors is to perform a pal¬liative resection in such a patient, regardless of how favorable the other criteria are.
Clinical Stage
Clinical factors that indicate an advanced stage of carcinoma and exclude surgery with curative intent are recurrent nerve paraly¬sis, Homer’s syndrome, persistent spinal pain, paralysis of the dia¬phragm, fistula formation, and malignant pleural effusion. Factors that make surgical cure unlikely include a tumor greater than 8 cm in length, abnormal axis of the esophagus on a barium radiogram, enlarged lymph nodes on computed tomography (CT), a weight loss more than 20%, and loss of appetite. In patients in whom these findings are not present, staging depends primarily on the length of the tumor, as measured with endoscopy, and the degree of wall penetration and lymph node metastasis seen with endoscopic ultra¬sound. Studies indicate that there are several favorable parameters associated with tumors less than 4 cm in length, there are fewer with tumors between 4 and 8 cm, and there are no favorable criteria for tumors greater than 8 cm in length. Consequently, the finding of a tumor over 8 cm in length should exclude curative resection, the finding of a smaller tumor should encourage an aggressive ap¬proach, and the smaller the tumor the more aggressive the approach should be. Endoscopic ultrasound imaging of esophageal tumors has recently become available, and provides further information regard¬ing the size, wall penetration, and lymph node status of the lesion.
Intraoperative Staging
Intraoperative staging allows selection of favorable candidates for a curative en bloc resection. It is based on the fact that there is a low survival rate for patients with a tumor that penetrates through the esophageal wall, or has multiple or distant lymph node metas¬tasis, and requires an approach that allows switching from an en bloc curative dissection to a palliative resection if during the course of an operation one of the following features is revealed: an unre¬sectable primary tumor, cavitary spread of the tumor, distant organ metastasis, extension of the tumor through the mediastinal pleura, multiple gross lymph node metastases, or microscopic evidence of lymph node involvement at the margins of an en bloc resection (i.e., low paratracheal, portal triad, subpancreatic, or periaortic lymph nodes). For cancers of the distal esophagus and cardia, patients with a favorable stage of disease can be identified by a combination of preoperative and intraoperative assessment with 86% accuracy. The overall 5-year survival of these selected patients after a cura¬tive en bloc resection is between 40 and 55%. If the tumor does not extend through the esophageal wall and there are less than five positive lymph nodes, the 5-year survival is 75%. These results support a clinical approach in which an en bloc resection of the esophagus and stomach is advocated only for patients most likely to benefit.
