(GYN-Oncology). Another fairly com­monly seen situation occurs when colon cancers at the hepatic exure invade the duodenum. Preoperative endoscopic evalu­ation should be done as it provides crucial information regarding location of the invading neoplasm in relationship to the ampullary structures and informs decision-making.

F. The primary goal of surgical resection for

tures and organs in the retroperitoneum. The ability to mobilize and get margins on an intraperitoneal structure such as an ovary, uterus, or fallopian tube is quite straightfor­ward whereas invasion into the ureters pres­ents a distinctly difcult scenario. Ureteral invasion, because of the close margins involved and lack of lateral and retroperito­neal space, is a poor prognostic feature. Hydroureter on preoperative imaging con­notes a grave scenario and distinctly poor outcome. It is more commonly seen inlocally invasive rectal cancers but can be a problem in more proximal tumors as well. Mid and distal ureters should be resected en bloc with the tumor. A psoas hitch procedure or Boari ap may be used to reconstruct the urinary system in these cases. Mid or more proximal ureteral resections may be accom­panied by either ureteroureterostomy or mobilization of the kidney and collecting system to facilitate a ureteroureteral anasto­mosis over a stent—although this has a higher rate of stricture, this can be useful in very proximal resections. Invasion of the upper ureter near the renal collecting system or invasion of the collecting system may require nephrectomy. Again, preoperative anticipation of this situation from imaging is helpful. Preoperative determination of con-

tralateral renal function may help make dif­cult decisions regarding kidney salvage or sacrice easier intraoperatively. Duodenal invasion can be difcult to determine preop­eratively. Supercial invasion is suspected when the colon cannot be mobilized off of the duodenum easily. It is often possible, because invasion occurs on the antimesen­teric aspect of the duodenum, to resect the wall of the duodenum en bloc with the colon and then reconstruct the duodenum after­wards either with a TA stapler or with sutures. In rare cases of ampullary or pan­creatic invasion, it may be necessary to per­form a pancreaticoduodenectomy with intent to cure. Although this is a morbid and rare operation for this indication, the prognosis for a true T4b (with or without nodal involve­ment) colon cancer completely resected with negative margins is far better than that for a pancreatic primary lesion. Careful examina­tion of the liver and intraperitoneal surfaces to rule out metastatic disease should be undertaken prior to embarking on this operation.

high risk for recurrent disease and confer a poorer prognosis than tumors that lack locally invasive features. T4b tumors are thought to be higher risk for both local and distant failure. Chemotherapy is suggested in about 20% of those patients who present with Stage II disease and T4 status is one of the features that most oncologists would agree deserves adjuvant chemotherapy and constitutes “high risk” for recurrence along with inadequately sampled lymph nodes, perforation at the tumor site, poor differen­tiation and lymphovascular invasion. It should be noted that there are no randomized trials directly comparing chemotherapy to no chemotherapy for high risk Stage II tumors including T4a and b tumors and there are no trials demonstrating benet from chemo for those with high risk features. Also, no treatment comparison data exists between high and low risk Stage II patients either. However, the clinical rationale for chemotherapy in these patients is compel­ling enough to base the recommendation for chemotherapy on underpowered subset anal­yses of existing studies as well as extrapo­lated data from Stage III patients, and the knowledge that overall survival in this par­ticular high risk cohort is signicantly less than Stage III cancers. The use of infusional 5-uorouracil (5-FU) with oxaliplatin is typ­ically recommended in patients with no con­traindications to these agents although the data comparing the use of 5-FU (plus levam­isole) alone versus 5-FU with oxaliplatin is underpowered, and existing subset analysis shows no difference in overall survival between high risk and low risk Stage II patients. Those with locally invasive high risk features were not individually analyzed. Alternatively, capecitabine is an option in lieu of 5-FU.Those patients whose tumors are microsatellite unstable-high, may actu­ally do worse than those who exhibit micro­satellite stable tumors and in general, chemotherapy is not recommended for these Stage II patients.

radiation for locally advanced colon cancers with a goal of reducing tumor volume and increasing resectability is not well studied for several reasons: pathologic staging of colon cancer has always been the basis of treatment; the presence of local tumor extension is often only appreciated intraoperatively, intra­abdominal radiation is associated with dam­age to adjacent structures that are difcult to protect and exquisitely radiosensitive such as small bowel, there is very little data to suggest that preoperative chemotherapy is benecial, and there is real danger of over- treating a large percentage of patients based on clinical imag­ing who may do well with surgery alone. If imaging suggests the presence of a T4b lesion, the use of chemotherapy may be appropriate if resectability is in question and the patient is relatively asymptomatic. Lesions with retro­peritoneal or solid organ involvement, may be candidates for a neoadjuvant approach, for example. Those with malignant stulas into genitourinary structures are often thought to be at higher risk for sepsis while on chemo­therapy. In general, these are best resected pri­marily if amenable, or diverted proximally if not. There are no randomized trials of pre­versus post-operative chemotherapy for any stage colon cancer.

conclusive, but they do show that subsets of T4b patients who are also node positive with R1 or R2 resection margins may have some benet and enjoy better overall and disease­free survival. Outlining the resection bed with surgical clips intraoperatively can often help the radiation oncologist be more specic in targeting the residual or “at-risk” areas. The use of radiation is suggested on a case­ by case basis and existing data suggests that radiation in patients with tumors that have a retroperitoneal location, margin positivity, and malignant regional lymphadenopathy may be benecial.