Nilesh A. Patel, M.D., David S. Medich, M.D., James P. Celebrezze, M.D., David S. Parda, M.D., and Mark S. Roh, M.D.

Current management of locally advanced distal rectal cancer (LADRC) with preoperative chemoradiotherapy (CRT) has increased sphincter preservation and reduced locoregional recurrence. In our experience, this regimen has enabled greater than 90% of patients presenting with LADRC to undergo sphincter preservation with a locoregional recurrence rate of approximately 3%. With improved locoregional control, there has been the clinical impression of an increased incidence of systemic only failure. We hypothesize that the degree of tumor response and specific pathologic features following CRT for LADRC will predict systemic recurrence and can more accurately define postoperative adjuvant chemotherapy.

From December 1994 to March 2001, eighty-four consecutive patients presenting with LADRC were retrospectively reviewed. Preoperative staging included endorectal ultrasound and CT of the chest, abdomen and pelvis. Patients with stage 11-Ill disease were treated with pelvic radiation (45.0- 55. 8Gy in fractions of 1 8OcGy/day) and 5-fluorouracil and leucovorin based chemotherapy 6-8 weeks prior to definitive surgery. All patients received postoperative adjuvant chemotherapy consisting of 5FU and leucovorin.

Sixty-eight patients were included in this study. Sixteen patients were excluded: 9 with Stage 1V disease and 7 surgically treated by transanal excision. Mean follow-up was 37 months. The cancer specific mortality was 3%. Tumor recurrence was correlated with degree of response to CRT: complete (CR), >50% (PR), or none (NR)

Response	Patients	Locoregional Reoccurance	Locoregional + Systemic Reoccurance	Systemic Reoccurance
Overall	68	3%	1%	13%
Complete	7	0%	0%	0%
Partial	56	4%	0%	11%
None	5	0%	20%	60%

As shown in the table below, recurrence in patients with a CR or a PR is significantly less than those with NR where p= 0.0007 and p= 0.0002 respectively. Nearly 90% of patients had less than a CR. In these patients, 32% recurred if lymph node positive and 11% if lymph node negative (p= 0.05). Similarly, 55% of patients with adverse histological features (poor differentiation and/or lymphvascular invasion) developed recurrences as compared to only 12% if not present (p= 0.00 12). Tumor fixation, clinical node status at presentation and residual tumor size after CRT did not correlate with recurrence.

Conclusion:

1) Tumor response to CRT correlates with systemic recurrence. 2) Pathologic nodal status and the presence of adverse histological features are correlated with recurrence. 3) Tumor fixation, nodal status at presentation and residual tumor size after CRT do not correlate with recurrence. 4) Presence of adverse factors following CRT identifies a subset of patients that could benefit from aggressive adjuvant therapy.

Upon the completion of this program, participants should be able to appreciate the value of pathologic tumor response in identifying patients at increased risk for systemic recurrence following preoperative chemoradiation for locally advanced distal rectal tumors



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