Chemotherapy first, followed by chemoradiation (CRT) and then surgery, in the management of locally advanced rectal cancer (LARC).

Abstract

3605 Background: Standard pre-op CRT and post-op chemo for LARC delays the start of optimal systemic therapy by 18-22 weeks. To more promptly address micrometastases that could lead to distant failure, and supported by evidence of excellent primary tumor response to FOLFOX, we began offering FOLFOX as initial treatment for patients (pts) with high-risk LARC. More recently, we have begun offering all planned FOLFOX prior to CRT and surgery. Methods: We obtained an IRB waiver to review records of all clinical stage II/III RC pts treated with initial FOLFOX followed by CRT and total mesorectal excision (TME) at our institution between 2007 and 2012. Of approximately 300 rectal pts treated with CMT, 61 received some or all of their planned FOLFOX as initial therapy. Results: The median age of these 61 pts was 52 years, 54% male. At diagnosis, 84% had T3N1-2 or T4N0-1 tumors and 16% had T3N0 tumors. Of these, 57 received induction FOLFOX (median 7 cycles) then received pre-op CRT, while 4 pts achieved an excellent response to chemotherapy alone, declined CRT, and went directly to TME. Twelve pts did not undergo surgery; 9 had a complete clinical response and elected to be managed non-operatively; 1 refused recommended surgery despite incomplete tumor regression, 1 had surgery deferred due to comorbidities, and 1 developed distant metastatic disease prior to planned surgery. Of the 61 patients, 19 (31%) had either a pathCR (14) or a complete clinical response (5) leading to non-operative management. Of the 49 pts who underwent TME, all had R0 resections and 23 (47%) had tumor response >90%, including 13 (27%) with pathCR. Of the 28 patients who received all 8 cycles of initial FOLFOX, 8 achieved a pathCR (29%) and 3 achieved a complete clinical responses (11%), managed non-operatively. All patients completed therapy as planned. There were no SAEs requiring delay in treatment during either FOLFOX or CMT. Conclusions: FOLFOX before CRT results in substantial tumor regression, a high rate of delivery of all planned therapy, and a substantial rate of pathCRs. Chemo and CMT before planned TME provides a favorable opportunity for consideration of non-operative management.