Endoscopic Ultrasound Endoscopic Ultrasound in Rectal Cancerin Rectal Cancer

Natasha SchneiderNatasha Schneider

November 15, 2010November 15, 2010

Rectal CancerRectal Cancer

41,000 new cases diagnosed/year41,000 new cases diagnosed/year Estimated 8,500 deathsEstimated 8,500 deaths

Prognosis and management is dependent upon Prognosis and management is dependent upon stage at time of presentationstage at time of presentation

Staging allows for identification of patients in Staging allows for identification of patients in need of neoadjuvant chemotherapyneed of neoadjuvant chemotherapy Recommended for pts with advanced loco-regional Recommended for pts with advanced loco-regional

rectal cancer (T3, T4 N0, TxN1, N2) rectal cancer (T3, T4 N0, TxN1, N2)

StagingStaging

T1-invades submucosaT1-invades submucosa T2-invades muscularis propriaT2-invades muscularis propria T3-through muscularis propria into subserosaT3-through muscularis propria into subserosa T4-into other organs or structuresT4-into other organs or structures Stage:Stage:

0: Tis N0 M00: Tis N0 M0 1: T1-2 N0 M01: T1-2 N0 M0 2: T3-4 N0 M02: T3-4 N0 M0 3A: T1-4 N1-2 M03A: T1-4 N1-2 M0 4: Any T Any N M14: Any T Any N M1

StagingStaging

Rectal CancerRectal Cancer

Prognosis of rectal cancer closely related toPrognosis of rectal cancer closely related to Depth of tumoral invasionDepth of tumoral invasion Number of metastatic LNsNumber of metastatic LNs Involvement of the circumferential marginInvolvement of the circumferential margin

Assessment of cancer invasion through the bowel Assessment of cancer invasion through the bowel wall (T stage) remains the primary and most wall (T stage) remains the primary and most important factor in treatmentimportant factor in treatment

LAR

APR

5 yr survival5 yr survival

Stage 1: 85-90%Stage 1: 85-90% Stage 2: 60-65%Stage 2: 60-65% Stage 3: 30-40%Stage 3: 30-40% Stage 4: 8-9%Stage 4: 8-9%

Modalities for preoperative Modalities for preoperative stagingstaging

CTCT MRIMRI ERUS ERUS

Rigid probe Rigid probe Flexible probesFlexible probes

PET +/- CTPET +/- CT

Siddiqui et al International Sem Surg Onc 2006

Endorectal sonography (ERUS)Endorectal sonography (ERUS)

Introduced in 1983Introduced in 1983 Hildebrant and Feifel introduced ERUS in Hildebrant and Feifel introduced ERUS in

1985 as means of staging rectal 1985 as means of staging rectal carcinomacarcinoma

TechniqueTechnique

Preferable to have empty rectum as fecal Preferable to have empty rectum as fecal material can distort imagesmaterial can distort images Laxative enemaLaxative enema Standard colonoscopy prepStandard colonoscopy prep

Well toleratedWell tolerated Often can be performed without sedationOften can be performed without sedation

Hyperechoic mucosaHypoechoic muscularis mucosaHyperechoic submucosaHypoechoic muscularis propriaHyperechoic serosa

Indication for EUS rectal cancerIndication for EUS rectal cancer

Savides and Master GIE 2002

42 Studies42 Studies Only Only

included included those with those with surgical surgical histology histology confirmationconfirmation

T1Pooled sensitivity – 87.8% (95% CI 85.3-90)Pooled specificity – 98.3% (95% CI 97.8-98.7)

T2 T2Pooled sensitivity – 80.5% (95% CI 77.9-82.9)Pooled specificity – 95.6% (95% CI 94.9-96.3)

T3 T3Pooled sensitivity – 96.4% (95% CI 95.4-97.2)Pooled specificity – 90.6% (95% CI 89.5-91.7)

T4 T4Pooled sensitivity – 95.4% (95% CI 92.4-97.5)Pooled specificity – 98.3% (95% CI 97.8-98.7)

EUS StagingEUS Staging 42 studies included42 studies included

EUS StagingEUS Staging

EUSEUS

Several studies suggest better than CT or Several studies suggest better than CT or MRI for T stagingMRI for T staging

In a cohort of 80 patients with new In a cohort of 80 patients with new nonmets rectal cancer:nonmets rectal cancer: EUS changed management in 1/3 pts, mostly EUS changed management in 1/3 pts, mostly

b/c CT tended to underestimate T stageb/c CT tended to underestimate T stage• EUS correctly identified 62% pts with T3/4 disease EUS correctly identified 62% pts with T3/4 disease

missed by CT resulting in neoadjuvant therapy for missed by CT resulting in neoadjuvant therapy for people who would have otherwise missed this txpeople who would have otherwise missed this tx

• No pts were overstagedNo 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 IssuesEUS Issues

Biggest problem seems to be overstaging Biggest problem seems to be overstaging T2 tumorsT2 tumors Could be secondary to inflammatory infiltrate Could be secondary to inflammatory infiltrate

Understaging –resolutionUnderstaging –resolution Operator experienceOperator experience Level of tumorLevel of tumor

Reduced accuracy for lower tumorsReduced accuracy for lower tumors Up to 17% cannot be staged secondary to Up to 17% cannot be staged secondary to

inability to traverseinability to traverseSchwartz 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 diseaseNodal disease

Less accurate in diagnosing thisLess accurate in diagnosing this Studies report similar to CT and MRI (60-80%)Studies report similar to CT and MRI (60-80%) Adding FNA-some studies show improved Adding FNA-some studies show improved

accuracy, while others did notaccuracy, while others did not Metastatic LN: hypoechoic appearance, Metastatic LN: hypoechoic appearance,

round shape, and a reduced sonar round shape, and a reduced sonar attenuation coefficientattenuation coefficient

Size: Size: > 0.5 cm: 50% to 70% chance cancer> 0.5 cm: 50% to 70% chance cancer <0.4 mm: <20%<0.4 mm: <20%

Schwartz DA, Harewood GC, Wiersema MJ. EUS for rectal disease. Gastroint Endosc 2002;56:100.

RecurrenceRecurrence Rectal EUS superior to pelvic CT in detecting Rectal EUS superior to pelvic CT in detecting

recurrence (sensitivity 100% vs. 85%)recurrence (sensitivity 100% vs. 85%) Performance affected by postop chemo/XRT Performance affected by postop chemo/XRT

inflammation/changesinflammation/changes Improved performance with EUS-FNA Improved performance with EUS-FNA

In a study of 312 patients, for example, FNA In a study of 312 patients, for example, FNA significantly improved accuracy compared to EUS significantly improved accuracy compared to EUS alone (92 versus 75 percent)alone (92 versus 75 percent)

• The superior accuracy was primarily reflected in better The superior accuracy was primarily reflected in better specificity (93 versus 57 percent for CT)specificity (93 versus 57 percent for CT)

Similar results from another study of 116 patientsSimilar results from another study of 116 patients• biggest advantage of EUS FNA was the ability to detect very biggest advantage of EUS FNA was the ability to detect very

small pararectal recurrences (the smallest tumor being 3 small pararectal recurrences (the smallest tumor being 3 mm) allowing for potentially curative resectionmm) 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;129:64Lohnert et al. Effectiveness of endoluminal sonography in identification of occult local rectal cancer recurrances. Dis Colon Rectum 2000;43:483

RecurranceRecurrance

No consensus of timing of follow up No consensus of timing of follow up studies currentlystudies currently In previous study, done every 3 mon for 2 yrsIn previous study, done every 3 mon for 2 yrs One author suggested reasonable approach One author suggested reasonable approach

to do aggressive surveillance on patients with to do aggressive surveillance on patients with locally advanced tumors and in those who locally advanced tumors and in those who had local excision (ie transanal) as these had local excision (ie transanal) as these would have the highest risk recurrencewould 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

CasesCases Liz – 29628492Liz – 29628492 Eric - 32007213 Eric - 32007213 Pat - 30920839 (T3 lesion)Pat - 30920839 (T3 lesion)    31932858 (both of these are large, noninvasive 31932858 (both of these are large, noninvasive

polyps—may be interesting to show)polyps—may be interesting to show) 3092478130924781    22012876 (large rectal GIST—would definitely 22012876 (large rectal GIST—would definitely

show this case)show this case)

uT1 – does not penetrate muscularis propriauT1 – does not penetrate muscularis propria uT2 – penetrates muscularis propriauT2 – penetrates muscularis propria uT3 – proceeds beyond muscularis propria, infiltrating uT3 – proceeds beyond muscularis propria, infiltrating

perirectal fat perirectal fat uT4 – infiltrate surrounding organsuT4 – infiltrate surrounding organs

Sonographic criteria for involved LNsSonographic criteria for involved LNs Size > 5 mmSize > 5 mm Mixed signal intensityMixed signal intensity Irregular marginsIrregular margins Spherical rather than ovoid of flat shapeSpherical rather than ovoid of flat shape