Pathological Response after Chemoradiation for T3 Rectal Cancer

Department of Radiation Oncology, Stanford University Medical Center, Stanford, CA, USA.
Colorectal Disease (Impact Factor: 2.35). 07/2009; 12(7 Online):e24-30. DOI: 10.1111/j.1463-1318.2009.02013.x
Source: PubMed


The aim of this study was to investigate the effect of preoperative chemoradiotherapy (CRT) on nodal disease in locally advanced rectal adenocarcinoma.
Thirty-two patients staged uT3N0 and 27 patients staged uT3N1 rectal adenocarcinoma who underwent pre-CRT staging using endoscopic ultrasound or rectal protocol CT were included. The median radiation dose was 50.4 Gy (range: 45-50.4 Gy) at 1.8 Gy per fraction and all patients received concurrent 5-FU or capecitabine-based chemotherapy. Low anterior resection or abdomino-perineal resection occurred at a median of 46 days (range: 27-112 days) after CRT.
Eleven of 32 uT3N0 patients (34.4%) and 13 of 26 uT3N1 patients (50.0%) had ypN+ (P = 0.29). For patients with uT3N0, 10 of 20 (50.0%) with ypT2-3 and 1 of 12 (8.3%) with ypT0-1 were ypN+ (P = 0.02). For patients with uT3N1, 12 of 20 (60.0%) with ypT2-3 and 1 of 6 (16.7%) with ypT0-1 were ypN+ (P = 0.16). Overall, the ypN+ rate was 11.1% in the ypT0-yT1 group compared with 55.0% in the ypT2-yT3 group (P = 003). Among patients with uT3N0 disease, the ypN+ rate in patients who had surgery > 46 days vs<or= 46 days was 7.1%vs 55.6% (P = 0.01) respectively. Among patients with uT3N1 disease, the ypN+ rate in patients who had surgery > 46 days vs<or= 46 days was 54.5%vs 46.7%, (P = 0.99) respectively. Overall, the ypN+ rate in patients who had surgery > 46 days vs<or= 46 days was 28.0%vs 51.5% (P = 0.11).
The risk of residual nodal disease after CRT is significant. Primary tumour response is associated with nodal response.

1 Follower
32 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: : After the impressive response of rectal cancers to neoadjuvant therapy, it seems reasonable to ask: can we can excise the small ulcer locally or avoid a radical resection if there is no gross residual tumor? Does gross response reflect what happens to tumor cells microscopically after radiation? : The aim of this study was to identify microscopic tumor cell response to radiation. : This study is a retrospective review of a prospectively collected database. : This investigation was conducted at a single tertiary medical center. : Patients were selected who had elective radical resection for rectal cancer after preoperative chemotherapy and radiation performed by 2 colorectal surgeons between 2006 and 2011. : The primary outcome measured was tumor presence after radiation therapy : Of the 75 patients, 20 patients were complete responders and 55 had residual cancer. Of these patients, 28 had no tumor cells seen outside the gross ulcer, and 27 (49.1%) had tumor outside the visible ulcer or microscopic tumor present with no overlying ulcer. Of these tumors, 81.5% were skewed away from the ulcer center. The mean distance of distal scatter was 1.0 cm from the visible ulcer edge to a maximum of 3 cm; 3 patients had tumor cells more than 2 cm distal to the visible ulcer edge. Tumor scatter outside the ulcer was not associated with poor prognostic factors, such as nodal and distant disease, perineural invasion, or mucin; however, it was associated with lymphovascular invasion (χ2 = 4.12, p = 0.038) : There was limited access to clinical information gathered outside our institution. : Our study suggests that 1) after radiation, the gross ulcer cannot be used to determine the sole area of potential residual tumor, 2) cancer cells may be found up to 3 cm distally from the gross ulcer, so the traditional 2-cm margin may not be adequate, and 3) local excision of the ulcer or no excision after apparent complete response appears to be insufficient treatment for rectal cancer.
    No preview · Article · Dec 2012 · Diseases of the Colon & Rectum