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QUESTION from Lima, Peru

Introduction

Staging describes the extent or severity of an individual’s cancer.

Staging helps the doctor plan a person’s treatment. Moreover, the stage can be used to estimate the person’s prognosis (life expectancy). So, the more accurate the patient’s staging, better outomes against their illness.

Each Cancer Staging System has been developed since 1943 (Pierre Denoix - France), and yet they keep updating through scientific researches.

Nowadays International Staging System (TNM System) is based on tumor extension (T), lymph nodes dissemination (N) and existence or not of distant tumor spreading (metastasis, M).

Let’s see. If a stage-I-patient (staging usually uses Roman numerals, except zero) goes to a not specialized hospital that hasn’t the adequate means for a standard staging (for example, lack of high resolution computed axial tomography), he may be staged as 0 (meaning no cancer)and sent back home, because they couldn’t find any lesion. So whenever this patient would be diagnosed with cancer, it could be too late and his/her life expectancy would be dramatically decreased.

TNM System

Now we are going to describe the gastric cancer staging, as an example.

First, we should start with some anatomic references of the stomach. The figure shows the 4 layers of the gastric wall:

–Mucosa (M): Internal surface.

–Submucosa (SM): Layer beneath M, rich in blood and lymphatic vessels.

–Muscular (MP): Responsible for the stomach movement.

–Serosa (SE): External surface, thin membrane that covers all the organ.

Extension del Tumor (T)

T0: No evidence of primary tumor

Tis: (Carcinoma in situ) intraepithelial tumor without invasion to SM.

T1: Tumor invades until SM.

T2: Tumour invades until MP

T3: Tumor penetrates serosa without invasion of adjacent structures

T4: Tumour invades adjacent structures

TX: Primary tumor that cannot be classify.

Lymph Nodes Dissemination (N)

N0: No regional lymph node metastasis

N1: Metastasis through the first regional lymph nodes.

N2: Metastasis until the second regional lymph nodes.

N3: Metastasis over the third regional lymph nodes.

NX: Regional lymph nodes that cannot be assessed.

Distant Metastasis (M)

M0: No distant metastasis

M1: Distant metastasis

MX: Distant metastasis cannot be estimate.

Prognosis

Life expectancy depends on many different factors, patient’s as well as medical breakthroughs (drugs, surgical techniques, imaging procedures, etc.). Therefore, patient’s prognosis changes constantly. Obviously, preexisting disease like diabetes and high blood pressure, modify negatively this calculations. That is why, it is very important to check them closely.

In this table, we can see the incredible numbers of the Japanese treatments against gastric cancer (ESD, ganglionar dissection, etc). Japanese people had the World’s Highest Stomach Cancer Mortality by WWII. This shocked them and with extremely limited economic resources, because of the postwar reconstruction, they could implement the nationwide mass screening program for gastric cancer. For western developed countries, as Great Britain, it is too expensive to afford this kind of program.

If we compare it with the developing Peruvian city of Trujillo, although isn’t the capital Lima (nevertheless it doesn’t suffer a postwar state), physicians can offer relatively good prognosis to their patients. However, maybe different with an early cancer screening program.