Endoscopic Ultrasound in Rectal Cancer Natasha Schneider November 15, 2010

Rectal Cancer  41,000 new cases diagnosed/year Estimated 8,500 deaths 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) 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 0: Tis N0 M0 1: T1-2 N0 M0 1: T1-2 N0 M0 2: T3-4 N0 M0 2: T3-4 N0 M0 3A: T1-4 N1-2 M0 3A: T1-4 N1-2 M0 4: Any T Any N M1 4: Any T Any N M1

Staging

Rectal Cancer  Prognosis of rectal cancer closely related to Depth of tumoral invasion Depth of tumoral invasion Number of metastatic LNs Number of metastatic LNs Involvement of the circumferential margin Involvement of the circumferential margin Assessment of cancer invasion through the bowel wall (T stage) remains the primary and most important factor in treatment 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 Rigid probe Flexible probes 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 Laxative enema Standard colonoscopy prep 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 Only included those with surgical histology confirmation Only included those with surgical histology confirmation T1 Pooled sensitivity – 87.8% (95% CI ) Pooled specificity – 98.3% (95% CI )

T2 Pooled sensitivity – 80.5% (95% CI ) Pooled specificity – 95.6% (95% CI )

T3 Pooled sensitivity – 96.4% (95% CI ) Pooled specificity – 90.6% (95% CI )

T4 Pooled sensitivity – 95.4% (95% CI ) Pooled specificity – 98.3% (95% CI )

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 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 txEUS 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 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 Issues  Biggest problem seems to be overstaging T2 tumors Could be secondary to inflammatory infiltrate Could be secondary to inflammatory infiltrate  Understaging –resolution  Operator experience  Level of tumor Reduced accuracy for lower tumors 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%) Studies report similar to CT and MRI (60-80%) Adding FNA-some studies show improved accuracy, while others did not 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 > 0.5 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.

Recurrence  Rectal EUS superior to pelvic CT in detecting recurrence (sensitivity 100% vs. 85%) Performance affected by postop chemo/XRT inflammation/changes 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) 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)The superior accuracy was primarily reflected in better specificity (93 versus 57 percent for CT) Similar results from another study of 116 patients 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 resectionbiggest 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 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 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 –  Eric  Pat (T3 lesion)   (both of these are large, noninvasive polyps—may be interesting to show)    (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 Size > 5 mm Mixed signal intensity Mixed signal intensity Irregular margins Irregular margins Spherical rather than ovoid of flat shape Spherical rather than ovoid of flat shape