Transcript Endoscopic Ultrasound in Rectal Cancer

Endoscopic Ultrasound
in Rectal Cancer
Natasha Schneider
November 15, 2010
Rectal Cancer

41,000 new cases diagnosed/year

Estimated 8,500 deaths

Prognosis and management is dependent upon
stage at time of presentation
 Staging allows for identification of patients in
need of neoadjuvant chemotherapy

Recommended for pts with advanced loco-regional
rectal cancer (T3, T4 N0, TxN1, N2)
Staging

T1-invades submucosa
 T2-invades muscularis propria
 T3-through muscularis propria into subserosa
 T4-into other organs or structures
 Stage:





0: Tis N0 M0
1: T1-2 N0 M0
2: T3-4 N0 M0
3A: T1-4 N1-2 M0
4: Any T Any N M1
Staging
Rectal Cancer

Prognosis of rectal cancer closely related to




Depth of tumoral invasion
Number of metastatic LNs
Involvement of the circumferential margin
Assessment of cancer invasion through the bowel
wall (T stage) remains the primary and most
important factor in treatment
LAR
APR
5 yr survival
 Stage
1: 85-90%
 Stage 2: 60-65%
 Stage 3: 30-40%
 Stage 4: 8-9%
Modalities for preoperative
staging
 CT
 MRI
 ERUS


Rigid probe
Flexible probes
 PET
+/- CT
Siddiqui et al International Sem Surg Onc 2006
Endorectal sonography (ERUS)
 Introduced
in 1983
 Hildebrant and Feifel introduced ERUS in
1985 as means of staging rectal
carcinoma
Technique
 Preferable
to have empty rectum as fecal
material can distort images


Laxative enema
Standard colonoscopy prep
 Well
tolerated
 Often can be performed without sedation
Hyperechoic mucosa
Hypoechoic muscularis mucosa
Hyperechoic submucosa
Hypoechoic muscularis propria
Hyperechoic serosa
Indication for EUS rectal cancer
Savides and Master GIE 2002

42 Studies

T1
Pooled sensitivity – 87.8% (95% CI 85.3-90)
Pooled specificity – 98.3% (95% CI 97.8-98.7)
Only
included
those with
surgical
histology
confirmation
T2
T2
Pooled sensitivity – 80.5% (95% CI 77.9-82.9)
Pooled specificity – 95.6% (95% CI 94.9-96.3)
T3
T3
Pooled sensitivity – 96.4% (95% CI 95.4-97.2)
Pooled specificity – 90.6% (95% CI 89.5-91.7)
T4
T4
Pooled sensitivity – 95.4% (95% CI 92.4-97.5)
Pooled specificity – 98.3% (95% CI 97.8-98.7)
EUS Staging
 42
studies included
EUS Staging
EUS
 Several
studies suggest better than CT or
MRI for T staging
 In a cohort of 80 patients with new
nonmets rectal cancer:

EUS changed management in 1/3 pts, mostly
b/c CT tended to underestimate T stage
• EUS correctly identified 62% pts with T3/4 disease
missed by CT resulting in neoadjuvant therapy for
people who would have otherwise missed this tx
• No pts were overstaged
Harewood, Wiersema, et al. A prospective, blinded assessment of impact of
preoperative staging on the management of rectal cancer. Gastroenterology
2002;123:24.
EUS Issues
 Biggest
problem seems to be overstaging
T2 tumors

Could be secondary to inflammatory infiltrate
–resolution
 Operator experience
 Level of tumor
 Understaging

Reduced accuracy for lower tumors
 Up
to 17% cannot be staged secondary to
inability to traverse
Schwartz DA, Harewood GC, Wiersema MJ. EUS for rectal disease. Gastroint
Endosc 2002;56:100.
• 35 studies included
• Reported accuracy
of CT 55-65% and MRI 60-65%
• Only modest +LR but low –LR
(which is what you want)
• So better used to exclude
Nodal disease rather than
confirm invasion
Nodal disease

Less accurate in diagnosing this


Studies report similar to CT and MRI (60-80%)
Adding FNA-some studies show improved
accuracy, while others did not

Metastatic LN: hypoechoic appearance,
round shape, and a reduced sonar
attenuation coefficient
 Size:


> 0.5 cm: 50% to 70% chance cancer
<0.4 mm: <20%
Schwartz DA, Harewood GC, Wiersema MJ. EUS for rectal disease. Gastroint
Endosc 2002;56:100.
Recurrence

Rectal EUS superior to pelvic CT in detecting
recurrence (sensitivity 100% vs. 85%)


Performance affected by postop chemo/XRT
inflammation/changes
Improved performance with EUS-FNA

In a study of 312 patients, for example, FNA
significantly improved accuracy compared to EUS
alone (92 versus 75 percent)
• The superior accuracy was primarily reflected in better
specificity (93 versus 57 percent for CT)

Similar results from another study of 116 patients
• biggest advantage of EUS FNA was the ability to detect very
small pararectal recurrences (the smallest tumor being 3
mm) allowing for potentially curative resection
Hunerbien et al. The role of TESU guided biopsy in the postoperative follow up of patients with rectal cancer. Surgery
2001;129:64
Lohnert et al. Effectiveness of endoluminal sonography in identification of occult local rectal cancer recurrances. Dis
Colon Rectum 2000;43:483
Recurrance
 No
consensus of timing of follow up
studies currently


In previous study, done every 3 mon for 2 yrs
One author suggested reasonable approach
to do aggressive surveillance on patients with
locally advanced tumors and in those who
had local excision (ie transanal) as these
would have the highest risk recurrence
Savides and Master GIE 2002
Siddiqui et al International Sem Surg Onc 2006
Savides and Master GIE 2002
Siddiqui et al International Sem Surg Onc 2006
Savides and Master GIE 2002
Giovannini and Ardizzone Best Prac Res Clin Gastro 2006
Siddiqui et al International Sem Surg Onc 2006
Cases





Liz – 29628492
Eric - 32007213
Pat - 30920839 (T3 lesion)
31932858 (both of these are large, noninvasive
polyps—may be interesting to show)
 30924781


22012876 (large rectal GIST—would definitely
show this case)

uT1 – does not penetrate muscularis propria
uT2 – penetrates muscularis propria
uT3 – proceeds beyond muscularis propria, infiltrating
perirectal fat
uT4 – infiltrate surrounding organs

Sonographic criteria for involved LNs







Size > 5 mm
Mixed signal intensity
Irregular margins
Spherical rather than ovoid of flat shape