Ca rectum

Ca rectum

Ca rectum

Aetiipahogenesis:

- SAD factors
    Smoking
    Alcohol
    Dietary
- diet rich in red meat has high aminal fat which is responsible for formn of carcinogenic polycyclic aromatic compounds
- colecystectomy- increase in free bile acid conc
- genetic factors

Prrcancerous condns:

- polyps in FAP
- villous adenoma
- ulcerative colitis and cohns dis

Pathological types

- annular-- common at the rectosigmoid jucn, presents with constipation and obstruction, takes abt 12 months for grow to encircle the lumen (napkin ring)
- polypoidal-- common in ampula
- ulcerative-- occures nywhere, hs raised edges and growth occures in transverse direcn
- diffuse-- similar to lininis plastica, develops frm ulcerative colitis, worst prognosis
- colloid-- contents r gelatenous, seen in youngs

C/f

1) constipation requiring incresed dose of pergatives
2) bleeding per rectum--frank blood or mixed with stool, it is never massive, is painless, and is the earliest symptom
3) early morning spurious diarrhoa due to accumulation of mucus overnight ina the ampulla, causes an urgency to pass stools bt results in onlly mucus with minimum stools, thr is always a sence  of incomplete defication
4) tenesmus-- painful incomplete defication asso with bleeding
5) bloody slime-- attempt at defecation results in mucucs mixd with blood
6) loss of apetite, loss of wt due to liver secondaries and abdominal disyension r late features

On exam:

- done in every case of bleeding per rectum
- indurated colinflower like growth or infiltrative ulcer cn b felt
- finger stained with blood
- rectal ca presenting as fistula in ano is equivalent to perforated colon ca, is a bad prognostic sign

DDs

- proctitis
- solitary rectal ulcer syndrome

Spread:

1) local:
    Involves muscle coat and spreads into extrarectal tissue, anteriorly involves prostate seminal vessicals and bladder base in males, and vagina nd uterus in females. Posteriorly sacral plexus
2) lymphatic:
   Frm the upper and middle onethird, spreads upwards first to pararecatl nodes of gerota.
  Frm lowe 1/3 spreads laterally and can involve internal illiac nodes
3) blood spread
 - occures in lung and liver
4) peritoneal spread
 - results in ascitis, malignant nodules

Investigations

-proctoscopy
- signoidoscopy
- barium enema
- colonoscopy
- carcino embryonic antigen levels
- ultrasound for sec
- endorectal ultrasonography
-CT scan

Treatment

# Carcinoma upper 1/3rd of rectum

@  High anterior resection includes removal growth with nodes followed by colorectal anastomosis
@ treatment of choice when growth is situated between 11 to 15cm from anal verge
@ this is sphincter saving surgery

# ca of lower 1/3 of rectum

@ growth within 7cm 4o anal verge
@ abdomino perineal resection
- pt put in Lloyd Davis position [supine with lithotomy]
- 2 surgeons operate simultaneously 1 from abd m one 4m perineum
- abdomen opened 1st growth mobilised 4m sacrum n bladder
- at this stage anus is kept close by perineal surgeon
- rectum n anal canal mobilised
- following structures removed
1 entire rectum m anal canal , 2 fascia propria with papa rectal nodes
3  2/3rd of sigmoid colon n mesocolon with lymphatic n LN
4. Muscle n peritoneum of pelvic floor
5. Wide area of perianal skin with part of ischiorectaj fossa
- this followed by permanent do colostomy by bringing out sigmoid colon outside in left iliac fossa
- it is sphincter sacrificing surgery

@ local excision

mobile tumors < 4cm, less than 40% of rectal wall involvement , located within 6cm of anal verge, lesion should be T1 or T2, no vascular or lymphatic or nodal invasion

# ca middle 1/3rd rectum

@ refers to growth between 7to 11 cm from anal verge
@ APR or low anterior resection can be done
@ in cases of well diff ca 2cm margin n in anaplastic ca 5cm margin clearance necessary

# Hartmann's operation

#Radiotherapy

@ rectal cancers r more radiosensitive  and colonic r more chemo sensitive
@ neutron beam radiation 4000-5000 cGy units
@ pre op radiotherapy when tumor extended thro wall
@ post op 2 reduce recurrence
@ Papillon's intra cavity radiation indicated 4 small localised n exophytic ca as curative therapy

# Chemotherapy

1] inj 5 FU 475mg/m2/daw IV into 5 dayp with inj leucovorhn 30mg/day for 5 days. 3 such courses
2] inj 5 FU with levamisole 150 mg BD for 3 days once in 15 days for 1 yr