Some rectal cancers can be treated successfully, without surgery, by contact radiotherapy. Explanations.
Paris Match. What role does rectal cancer play in colorectal cancers?
Pr Jean-Pierre Gerard. The rectum is the terminal part of the large intestine between 15 and 2 centimeters from the margin of the anus. It does not include the anal canal. Of the 43,000 new colorectal cancers detected each year in France, those of the rectum account for approximately 12,000 cases. These are adenocarcinomas. Men are more often affected than women. The average age of discovery is 60; 25% of patients are over 75 years old. The contributing factors are mainly the Western diet (rich in fats, sugars and meat), tobacco, alcohol, obesity, sedentary lifestyle. Certain genetic conditions (familial adenomatous polyposis, Lynch syndrome) as well as inflammatory diseases of the digestive tract (ulcerative colitis, Crohn’s disease) are even more at risk.
Nine times out of ten, the alert comes from visible bleeding in the stool
Pr Jean-Pierre Gerard
How are they discovered? What are the key points of the balance sheet?
Nine times out of ten, the alert comes from visible bleeding in the stool (rectory bleeding), sometimes from examinations for unexplained anemia. The assessment: 1. A colonoscopy, which explores the entire colon and rectum, allows a biopsy of the tumor to analyze its cells and their genomics (search for genetic abnormalities that can lead to targeted immunotherapy). 2. Regional MRI imaging looks for possible lymph node involvement. 3. An endorectal ultrasound clarifies the degree of penetration of the tumor into the wall of the rectum and the fat that surrounds it. 4. A scan of the trunk verifies the existence or not of distant metastases (liver, lungs, lymph nodes). This is how you classify cancer and its stage.
The standard protocol is quite cumbersome,
Pr Jean-Pierre Gerard
Can you summarize the different therapeutic strategies according to the stages?
The standard protocol (99% of cases), quite heavy, combines radiotherapy and chemotherapy before surgery to reduce the size of the tumor. Surgical removal completes the treatment. For very small lesions (precancerous), local excision is sufficient.
A tube emits very superficial radiation that does not irradiate nearby healthy tissue
Pr Jean-Pierre Gerard
Who is contact radiotherapy suitable for and what does it consist of?
To fragile subjects, to those who refuse surgery but also to people selected from operable patients, potentially 15% of all rectal cancers. Sine qua non conditions: 1. The cancer must be small (less than 5 centimeters). 2. Localized to the wall of the rectum more or less deeply, without significant invasion of the perirectal fat and without large suspected lymph nodes. 3. Accessible (up to 10 centimeters from the anal margin). The technique is known, I experimented with it successfully for forty years. It has recently benefited from a revival thanks to a Franco-British collaboration and improved equipment. It includes a hand-held endoscope that locates the tumour, through which a very narrow X-ray tube, called the Papillon, is pushed into contact with it. This tube emits very superficial radiation which does not irradiate the surrounding healthy tissues. Three outpatient sessions of two minutes each spaced fifteen days apart are sufficient. This treatment is combined for five weeks with oral chemotherapy and regional external irradiation (five sessions per week). The main side effect is transient rectal discomfort for three weeks.
The three-year local recurrence rate is 15%.
Pr Jean-Pierre Gerard
What regarding the results of this approach which preserves the rectum?
From my previous studies updated at ten years, we know that the local recurrence rate at three years is 15%, recoverable without loss of chance by surgery (hence regular monitoring every three months for two years then every six month). The Franco-British-Swiss randomized study that we have just published in the “Lancet” shows that 81% of patients have no recurrence at four years, with good rectal function, which is worth the results of surgery. radical from the start. The earlier the diagnosis (the importance of screening with the Hemoccult test), the more this simple, well tolerated and inexpensive approach is applicable.
