The rectum is the last part of the large intestine before the anus. It is about 12-15cm long. It is a pelvic organ and most of it lies outside the peritoneal cavity, which is how it differentiates itself from the rest of the large intestine.
In men it lies behind the bladder, vas deferens and prostate, and in women it is behind the bladder, uterus and vagina.
Anatomically and due to the position of the rectum deep in the pelvis, performing surgical procedures is technically difficult, especially in men and in patients with increased body weight.
Rectal cancer is one of the most common cancers and together with colon cancer is the third most common cancer.
Therefore, preventive testing with colonoscopy – rectoscopy is very important.
The importance of early diagnosis
According to current guidelines, the starting point for screening is the age of 50. If the test prove normal screening should be repeated every 5 years unless there is a personal or family history. It is a widespread feeling, however, among all of us surgeons who deal with colon and rectal surgery, that due to the increased frequency of such incidents and at young ages, the preventive checkup should be taking place much earlier, perhaps even from the age of 40.
The rectum and sigmoid are the anatomical locations where cases of colon cancer are observed with a very high frequency. The reason for that is the accumulation of feces there before defecation, which contain the toxic substances we take in from food we consume.
The progression of a polyp (benign adenoma) to cancer (adenocarcinoma) is slow. It may take 10 years for such a transformation. Therein lies the importance of preventive colonoscopy where such adenomas-polyps can be removed even during the colonoscopy and before they turn into cancer.
Such is the progress of the techniques applied, where even malignant changes at a very early stage (stage T1) can be removed with endoscopic local excisions without the need for a classic surgery.
Early diagnosis with colonoscopy is therefore very important.
What are the symptoms?
Common symptoms of rectal cancer are:
- bleeding during bowel movements
- change in bowel habits (diarrhea-constipation- and alternating between the two)
- pain in the lower abdomen
- anemia (low hematocrit and low iron)
- pain in the region of the anus
- mucus secretion
- local irritation
- asymptomatic or painful swelling
- feeling of incomplete bowel movement
Any discomfort in the anal area should be evaluated immediately by a medical specialist.
How is rectal cancer diagnosed?
Diagnosis is made from the medical history of the patient and the examination of the area, by a specialist surgeon. In addition, a digital examination, rectosigmoidoscopy or proctoscopy can be performed, for identification and differential diagnosis.
Finger examination is very important especially in tumors of the lower part of the rectum. Tumors higher up in the rectum can only be diagnosed with rectoscopy. In any case, rectoscopy-colonoscopy is necessary for taking tissue samples for biopsy and to rule out other polyps – formations.
The biopsy reveals characteristics of the tumor such as differentiation, grade, aggressiveness of the tumor, etc.
FURTHER EXAMINATION AND STAGING
Staging the cancer at diagnosis is the most important factor affecting the success of treatment and the patient’s final life expectancy.
The process of staging includes carrying out:
- CT scan of abdomen-pelvis-chest
- magnetic resonance imaging of the pelvis
- intra-rectal ultrasound
- PET scan, under certain conditions
What is the treatment of rectal cancer?
The treatment of rectal cancer depends on the stage it is in at the time of diagnosis.
In the very early stage I (T1) where the disease is limited to the mucosa, the treatment can be local excision transanally, without surgical incisions on the abdomen, with a simple surgical excision or with the use of a laparoscopic platform (TAMIS, TEMS – Transanal Endoscopic Micro Surgery ).
The recovery is speedy, and the patient can go home from the first day. It is sometimes combined with adjuvant radiation therapy postoperatively. The results are excellent, with cure rates of over 90%.
For cases where there is further infiltration (Stage II and above) (>T2) a total resection of the rectum along with the corresponding lymph nodes is necessary (Total Mesorectal Excision or TEM).
The operation performed to remove rectal tumors is the Low Anterior Resection.
In cases where there is infiltration of the muscularis, the wall of the intestine or even infiltration of the entire thickness of the wall of the intestine and extension into the surrounding fat or even infiltration of the surrounding organs. (Stages T3 and T4) preoperative chemoradiation is necessary.
Surgical removal of the tumor is carried out 6 to 8 weeks after radiation.
The combination of treatments that each patient needs, as well as the order in which they will be applied, is a complex issue that is examined on a case-by-case basis by the surgeon in collaboration with the hospital’s Oncology Board.
Advantages of preoperative radiation and chemotherapy:
- Shrinking the tumor (decrease the stage of the disease)
- In cases where the tumor is low near or above the sphincter, radiation increases the chance of salvaging and preservation of the sphincter to avoid permanent colostomy.
- Safer oncological resection margins.
- Reduced toxicity relative to postoperative radiation
- Disappearance of local disease and micrometastases
- Complete disappearance of rectal cancer by 20-25%
It is important to note that in addition to the significant advantages, the use of preoperative radiation creates fibrosis and complicates the operation as well as the healing after surgery. The healing of the anastomosis is more precarious if radiation has preceded it and for this reason the creation of a prophylactic ileostomy may be necessary.
Colostomy – ileostomy in rectal cancer
If the cancer is very low in the rectum and invades the sphincters, abdominoperineal resection and permanent colostomy is the usual treatment. There are of course cases where radiation can eliminate the disease as we mentioned above, but it is rather unlikely that the patient will avoid surgery entirely.
In some cases of rectal cancer where the anastomosis is carried out very low and there has been previous radiation treatment, it is necessary to make a temporary ileostomy so as to “protect” the anastomosis for a period of 6-8 weeks.
Laparoscopic and robotic surgery
As with cancers of the rest of the colon, so with rectal cancer the use of minimally invasive techniques has prevailed to the extent that with minimal surgical trauma, i.e. small surgical incisions, we achieve an excellent result.
Laparoscopic surgery has been shown to have significant advantages such as faster recovery, fewer complications and better oncological outcome.
Robotic surgery is an evolution of laparoscopic surgery. It offers much better visual access (optics) in the surgical field, much better precision of movements of the surgical tools and greater comfort for the surgeon performing the operation.
The rectum is deep in the pelvis and the use of robotic surgery in a narrow surgical field offers many advantages in theory.
We surgeons who apply it are convinced that it offers significant advantages in the correct preparation of the mid-rectum, in avoiding injury to nerves or vessels and in creating a safe anastomosis especially in cases of tumors located low in the rectum.
After surgery and a recovery period of 4 weeks, postoperative (adjuvant) chemotherapy is recommended depending on the results of the histological examination.
The expertise of the surgeon and his close collaboration with the oncologist and the Oncology Board is essential for a proper follow-up.