Oesophageal Cancer Staging: Workup, TNM and Survival

Oesophageal cancer is diagnosed by endoscopy with biopsy and staged with whole-body imaging, ideally PET-CT, supplemented by endoscopic ultrasound in early disease and by bronchoscopy or laparoscopy in selected locally advanced cases. The result is a TNM stage that decides treatment and predicts survival: in stage II disease, five-year survival is roughly 30 to 40%.

Dr. Preeti Vijayakumaran, Consultant, Oncology, Artemis Hospitals, Gurugram, India, divides the evaluation into two distinct tasks: diagnostic investigations that confirm the cancer, and staging investigations that define how far it has spread. This article follows that sequence, then explains the TNM staging system, how to tell a gastro-oesophageal junction tumour from a lower oesophageal one, and why staging matters for prognosis. For the full overview of the disease and its treatment, see the complete guide to oesophageal cancer diagnosis and treatment.

Baseline tests before any oesophageal cancer workup

Every patient has routine blood investigations: a complete haemogram (blood count), liver function tests and renal function tests. These do not diagnose the cancer, but they establish the baseline fitness that, in an older population with several other illnesses, frequently limits which treatments are possible.

How oesophageal cancer is diagnosed: endoscopy and biopsy

Endoscopy with biopsy is the investigation that confirms the diagnosis. Any patient presenting with progressive difficulty in swallowing should have one. In Dr. Vijayakumaran's framing, the endoscopy has two purposes:

1. Identify the intraluminal problem causing the difficulty in swallowing, and biopsy it.
2. Define its extent: exactly where the lesion begins and ends, measured along the oesophagus from the cricopharynx (the muscular ring at the top of the oesophagus) to the gastro-oesophageal junction.

The biopsy establishes the histology, squamous cell carcinoma or adenocarcinoma, which shapes every subsequent decision.

PET-CT staging of oesophageal cancer: what the scan shows

The essential staging investigation is cross-sectional imaging: contrast-enhanced CT of the thorax and abdomen or, increasingly, a whole-body PET-CT. PET-CT combines CT anatomy with a fluorodeoxyglucose (FDG) study of metabolic activity, which gives more accurate staging. Where PET-CT is not available, Dr. Vijayakumaran recommends contrast-enhanced imaging covering the neck, thorax, abdomen and pelvis.

Reading the PET scan, she looks at three things:

• The local extent of the tumour. Whether it involves the upper, middle or lower oesophagus; its circumferential extent around the wall; and how many adjacent structures it abuts, involves or invades.
• Lymph node disease in the thorax, the neck and the abdomen.
• Distant metastasis, such as lung or liver metastases, peritoneal disease (spread to the lining of the abdomen), or nodes beyond the regional nodal basins.

When endoscopic ultrasound (EUS) adds value

After the PET scan, in early disease Dr. Vijayakumaran adds an endoscopic ultrasound (EUS), an endoscopy with an ultrasound probe that images the layers of the oesophageal wall and the nearby lymph nodes. EUS gives a more accurate T stage (depth of invasion) and N stage (nodal involvement) in early oesophageal cancer than CT or PET, and that precision is what decides whether a tumour can be treated endoscopically.

EUS is not always possible. When the tumour is stricturing and tight, the probe cannot pass, and the T and N stage must be judged from axial imaging on CT or PET instead.

Bronchoscopy and laparoscopy in locally advanced disease

Two further investigations are used selectively.

Bronchoscopy is performed when imaging shows a locally advanced tumour closely abutting the carina (where the trachea divides) or the left main bronchus, raising the possibility of airway invasion. It is also indicated when the patient has hoarseness of voice or excessive coughing, which can signal a tracheo-oesophageal fistula (an abnormal channel between the oesophagus and the airway). Bronchoscopy-guided endobronchial ultrasound (EBUS) can also help assess the T and N stage in a patient with a stricturing tumour that endoscopic ultrasound cannot traverse.

Staging laparoscopy is needed mainly for locally advanced adenocarcinoma involving the gastro-oesophageal junction and extending into the proximal stomach, specifically Siewert type II and type III tumours. The purpose is to rule out omental or peritoneal metastases that imaging can miss. The Siewert classification divides junctional adenocarcinomas by the position of the tumour centre: type I lies 1 to 5 cm above the anatomical junction, type II from 1 cm above to 2 cm below it, and type III 2 to 5 cm below it.

Dr. Vijayakumaran's summary: in early disease, PET and EUS together contribute most; in locally advanced disease, PET provides the core information, supplemented by bronchoscopy and laparoscopy where they are indicated.

Gastro-oesophageal junction cancer versus lower oesophageal cancer

The distinction matters because junctional and lower oesophageal tumours can be staged and treated differently. Dr. Vijayakumaran's protocol is endoscopic mapping. The medical gastroenterologists performing the endoscopy record precisely where the tumour sits relative to the gastro-oesophageal junction. The standard landmark is about 40 cm from the incisors, which varies slightly with the length of the patient's oesophagus.

The endoscopic map is then correlated with the junction as it appears on axial imaging. Where the endoscopic and imaging pictures disagree, her team goes with the axial imaging and makes the final diagnosis accordingly. She set out this protocol in answer to a doctor's question, recorded in the Live Discussion from this masterclass.

TNM staging of oesophageal cancer

Staging follows the American Joint Committee on Cancer (AJCC) TNM system, which describes the primary tumour (T), the regional lymph nodes (N) and distant metastasis (M). Understanding it is essential, because each element feeds directly into the treatment decision.

Anatomical divisions

The oesophagus is divided by distance from the incisors (front teeth). The cervical oesophagus runs from 15 to 20 cm. The thoracic oesophagus runs from 20 to 40 cm and is subdivided into upper, middle and lower thirds.

T stage: depth of invasion

The T stage follows the layers of the oesophageal wall, from the inner lining outwards:

The line between T4a and T4b is the line between a tumour that can still be removed and one that cannot.

N stage: regional lymph nodes

M stage: distant spread

Once disease spreads beyond the regional nodes, to organs such as the liver or lungs or to non-regional lymph nodes, it is classified as metastatic (M1).

From TNM to treatment groups

For treatment planning, Dr. Vijayakumaran groups the clinical stage into three categories:

• Early stage: clinically T1a or T1b, N0.
• Intermediate stage: clinically T2 N0.
• Locally advanced stage: anything beyond T2 N0.

Early disease may be suitable for endoscopic treatment. Intermediate and locally advanced disease need multimodality treatment individualised to the patient. Clinically T2 N0 tumours of the mid or lower oesophagus or the gastro-oesophageal junction that are resectable on imaging can be considered for surgery first, but only when the preoperative staging is accurate. That condition is why the staging investigations above carry so much weight.

Oesophageal cancer survival by stage

Oesophageal cancer survival falls steadily with each step up in stage. In stage II disease, approximate five-year survival is around 30 to 40% for both squamous cell carcinoma and adenocarcinoma, with adenocarcinoma doing slightly better. These figures come from the risk-adjusted survival charts Dr. Vijayakumaran presented for each histology.

Staging therefore does two jobs. It decides the treatment plan, and it tells the clinician, the patient and the family how the disease is likely to behave.

The practical message for referring doctors follows. In Dr. Vijayakumaran's experience, most patients present at stage II or later, where survival is already well below what early-stage disease achieves. Every investigation that moves the diagnosis earlier, starting with a prompt endoscopy for persistent difficulty in swallowing, changes what is possible.

How staging leads into treatment

Once stage and histology are known, the next decision is whether the cancer can be treated through the endoscope, by surgery, or with combined treatment. The criteria for endoscopic resection and ablation are covered in the article on treating early oesophageal cancer endoscopically. The neoadjuvant regimens, trials and surgical approaches for locally advanced disease are covered in the article on locally advanced oesophageal cancer.