Rectal

Question 1

Rectal LC-CRT constraints: small bowel

Answer 1

V50 < 10 cc, D0.03cc < 54

Question 2

Rectal LC-CRT constraints: Bladder

Answer 2

V45 < 15%, Dmean < 40 Gy

Question 3

Rectal LC-CRT constraints: Femoral heads

Answer 3

V45 < 5%

Question 4

Rectal LC-CRT constraints: Genitalia

Answer 4

V20 < 50%

Question 5

Rectal SC-RT constraints: small bowel

Answer 5

Dmax < 27.8 Gy, V22 < 100 cc

Question 6

Rectal SC-RT constraints: Bladder

Answer 6

Dmax < 27.9, V22< 40%

Question 7

Rectal SC-RT constraints: Femoral heads

Answer 7

Dmax < 27.8, V22 < 40%

Question 8

Rectal: Concurrent and neo/adjuvant chemo

Answer 8

Capecitabine (825 mg/m2 bid 5 days per week or 225 mg/m2/d continuous infusion)

FOLFOX (folinic acid, 5-FU and oxaliplatin) or CAPOX

Question 9

Rectal: Indications for RT

Answer 9

Stage II-III (MMR proficient) or locally unresectable or medically inoperable -> TNT

Oligometastatic: Chemo -> RT -> TME -> definitive metastatic disease Tx -> chemo

Question 10

Rectal Cancer Staging: T staging

Answer 10

T1 - tumor invades submucosa
T2 - tumor invades the muscularis propria
T3 - tumor invades into perirectal tissue
T4a - tumor invades through the visceral peritoneum
T4b - tumor directal invades or adheres to adjacent organs or structures

Question 11

Rectal cancer staging: N staging

Answer 11

N1a - 1 regional lymph node
N1b - 2-3 regional lymph nodes
N1c - No regional lymph nodes, but tumor deposits locally
N2a - 4-6 regional lymph nodes
N2b - 7 or more regional lymph nodes

Question 12

Rectal cancer staging: M staging

Answer 12

M1a - metastasis to one site/organ w/o peritoneal mets
M1b - mets to 2 or more sites w/o peritoneal mets
M1c - peritoneal mets w/w/o other site or organ metastasis

Question 13

Rectal Cancer volumes and doses:

Answer 13

45 Gy: GTV + mesorectum, internal iliac, obturator, presacral nodes (inf pelvic floor, up bifurcation of common iliacs)

50.4 Gy: boost - GTV + 2 cm minimum cover mesorectum