COLORECTAL

Question 1

Difference between colon cancer and rectal cancer?

Answer 1

• Colon cancer: since the peritoneum acts as a physical barrier for loco-regional cancer spreading, we do not use neo-adjuvant CRT.
• Rectal cancer: given the absence of the peritoneal physical barrier, we use neo-adjuvant CRT to decrease the likelihood of loco-regional spreading. In the rectum local relapses are more common.

Question 2

Epidemiology of CRC?

Answer 2

More prevalent in first world countries due to higher consumption of red meat and higher rates of obesity.
It is the 3rd cancer in males and 2nd in females in terms of incidence.
In terms of anatomical sites the main sites are the rectum and sigmoid colon.

Question 3

Familial risk factors for CRC?

Answer 3

• FAP (familial adenomatous polyposis): it is a dominant autosomal syndrome characterized by multiple polyps. You have to perform oncological screening in very young people because the risk of developing cancer is 100% and the manifestations occur at 10-15 years of age. Adenomatous polyps also develop in the upper gastrointestinal tract (duodenum), and progress to malignancy in 5% of cases
• Garden syndrome or hereditary multiple polyposis: it is a dominant autosomal syndrome, but the diagnosis is later in respect to FAP. In this case the risk of developing cancers is very high but not 100%.
• Hereditary nonpolyposis colorectal cancer (HNPCC): cancer usually arises at around 40 years of age. This is most prevalent in the right colon. MMR genes like MLH1, MSH2. Long life risk of colon cancer 80%.
• Peutz-Jeghers is an autosomal dominant syndrome characterized by dark blue macules on the lips and the skin.
• Juvenile polyposis syndrome is an autosomal genetic condition characterized by the appearance of
  multiple juvenile hamartosus polyps in the GIT.

Question 4

Screening?

Answer 4

Screening is compulsory for all people over 50 yo.

According to ACS (American Cancer Society) and the ACG (American College of Gastroenterologists) screening should include an hemoccult every year (cheap and non invasive) and colonoscopy (more precise but invasive and expensive) every 5 years.

Question 5

Pre malignant disorders?

Answer 5

80% of invasive cancers arise from pre-malignant lesions like polyps. The risk that polyps transform into a malignant one depends on:
- Histotype: may be tubular (75% of cases but low malignant potential), tubular-villous (20% of cases)
or villous (5% of cases but high malignant potential).
- Size: the largest polyps, higher risk of transforming into a malignant one (diameter >1 cm: 3% at 5 ys, 8% at 10 ys, 25% at 20 ys) .
- Number of polyps: higher the number, the higher the risk of developing cancer.
- Dysplasia degree: higher the dysplasia, the higher the risk of developing colon cancer

Question 6

Symptoms?

Answer 6

You may have changes in bowel motility, bloating, discomfort, general vomiting, blood in the stool and also system symptoms like loss of appetite, fatigue (related to anemia or not) and weight loss.
Sometimes you may have massive bleeding signs like melena, intestinal obstruction, perforations, peritonitis or metastatic dissemination, which is related to a late staged disease.

Cancer of right colon —> anemia, palpable mass, asthenia and obstruction.
Cancer of left colon —> frequent bowel disorder, constipation diarrhea, mucorrhoea, proctorrhagia.

Question 7

Diagnosis?

Answer 7

Colonoscopy, total body contrast enhanced CT, MRI (first choice in non metastatic CRC), and CT-PET.

Question 8

Staging?

Answer 8

Staging is done with TNM.
- T1 tumors invade into but not through the submucosa.
- T2 tumors invade into but not through the muscularis propria.
- T3 tumors invade through the muscularis propria into the subserosa or nonperitonealized pericolic/rectal tissue.
- T4 tumors invade other organs or structures (T4a) or perforate the visceral peritoneum (T4b).

Question 9

Treatment?

Answer 9

Stage I —> only surgery.
Stage II —> first line is surgery. After surgery it is divided in low risk (follow up), intermediate risk (if MSS then follow up if MSI then adjuvant FU based CT), high risk (adjuvant FU or oxaliplatin for 3-6 months).
Stage III —> first line is surgery then all patients receive either FOLFOX or CAPOX.
Stage IV —> we need to distinguish between oligometastatic disease (local ablative treatment), liver limited disease (regional surgery or ablation) or systemic disease based on chemo.

Question 10

Surgery for FAP? Surgery for colon cancer?

Answer 10

FAP :
• Colectomy with ileo-rectal anastomosis: all
the colon is taken out and an anastomosis is made between the ileum and the rectum.
• Proctocolectomy with ileal pouch and anastomosis: the same operation that is done for ulcerative colitis.

For colon cancer : right hemicolectomy, extended right hemicolectomy, transverse colectomy, left hemicolectomy.
In the end an anastomosis is made between ileum and colon.
If the momentum is attached to the tumor it should be removed en bloc.

Question 11

Rectal cancer treatment?

Answer 11

Distal rectum : 0-7 cm from anal verge
Medium rectum :8-11 cm from anal verge
Proximal rectum : 12-15 cm from anal verge

All T3 medium or distal rectal cancer patients or any T1 (stage III) should be managed with preoperative radio and Chemotherapy, then restaged with MRI, CT and eventually Ultrasound and then after 8 weeks operated (neoadjuvant chemotherapy ).

Sparing of anal sphincter in cases of free margin of 2 cm, free circumferential margin of more than 10 mm, continent sphincter, absence of infiltration.

No sparing of anal sphincter in cases of abdomino perineal operation, definitive colostomy.

Question 12

After surgery of CRC we can define different situation based on outcome?

Answer 12

R0 —> completetumor resection with all margins histologically neg.
R1 —> incomplete tumor resection with microscopic margin involvement.
R2 —> incomplete tumor resection with gross residual tumor.