pT3N0 Rectal Cancer Research Articles

The impact of intensity-modulated radiotherapy in conjunction with chemotherapy on proximal pT3N0 rectal cancer patients after total mesorectum excision.

This study aimed to ascertain if the incorporation of intensity-modulated radiotherapy (IMRT) with chemotherapy (CTx) offered any advantages for patients diagnosed with stage pT3N0 rectal cancer located in the proximal (upper) region following a complete total mesorectum excision (TME). We retrospectively examined medical records of stage II/III rectal cancer patients who had undergone CTx or concurrent chemoradiation (CCRT) with IMRT after a successful TME. We juxtaposed a variety of survival outcomes across two patient cohorts. Each outcome was further classified according to Gunderson's risk stratification between proximal and distal (middle and low) rectal cancer patients, and we evaluated the factors associated with each outcome. The median follow-up duration was 4.9 years. Our research comprised 236 rectal adenocarcinoma patients treated at our institution between 2007 and 2019. They received either the CTx (n = 135) or the CCRT (n = 101) with 10-year locoregional recurrence-free survival (LRRFS) of 90.1% and 96.1%, respectively (p = 0.163). However, after performing multivariate adjustments, a pattern emerged hinting at a better LRRFS for the CCRT group (p = 0.052). Perforation had a strong correlation with locoregional recurrence. No significant differences were observed in other survival between the two treatment arms and their respective subgroups. The CCRT group witnessed significantly higher immediate and chronic complications with p = 0.007 and 0.009, respectively. The CCRT group had two secondary cancer-related fatalities (2%, one attributed to IMRT), and another reported by the CTx group (1%). The sole classified locoregional recurrence within the cohort of 37 individuals treated with CTx for proximal pT3N0 rectal cancer was, in fact, the development of sigmoid colon cancer. The results suggest that for patients with proximal pT3N0 rectal cancer post-TME, IMRT is better when not combined with CTx, except in highly perilous scenarios or those involving perforation.

MSI analysis in patients with GIST with lynch syndrome.

e23510 Background: Lynch Syndrome due to mutations in one of DNA mismatch repair (MMR) genes, is found in patients with colon cancer (3%).The mutations in these DNA repair genes induce genetic instability and development of ovarian, endometrial, urothelial, gastrointestinal and biliary tract carcinoma. Methods: In our center, 31 patients with Lynch syndrome are followed in Oncology Department in multidisciplinary team according to regional diagnostic therapeutic assistance paths and international guidelines. Immunohistochemical staining (IC) for mismatch repair proteins (MLH1, MSH2, MSH6, PMS2) and microsatellite instability testing (MSI) by PCR real time easyPGX were performed in colon cancer, genetic testing has been preceded by genetic counseling. When GIST diagnosis occurred in patients with colon cancers and Lynch syndrome, IC and MSI were performed in GIST too. Results: MSI-H has been detected in synchronous colo-rectal cancer in 2 patients with GIST. Pathogenetic germline mutations in MSH2 gene were observed in both patients. In 1 female patient with gist of duodenum (very low risk according to Miettinen classification) with previous endometrial cancer and sincronous PT3N0 rectal cancer, we observed MSI-stable in IC and PCR, KIT/PDGFRα wild type in Next GenSequencing analysis, BRAF wild type (PCR-real time), SDH-B + (IC), NTRK 1 (exon 9-10, exon 1-12 del, exon 12), NTRK 2 (exon 12-15.exon 16-17), exon 14, NTRK 3 (exon 14, exon 15) no gene fusion by PCR-real time (CE.IVD kit easy NTRK). In 1 male patient with ileal GIST (intermediate risk according to Miettinen classification ) with ileal adenocarcinoma pT3N0, we observed KIT exon 11 mutated, MSI-stable in IC, when we repeated the analysis using PCR real time EasyPGX, we observed high instability of microsatellites. Conclusions: For the first time we observed in Lynch Syndrome MSH2 mutated, simolutaneous GIST and colon cancer in the same site of ileum and PCR analisys detected a rare exemple of microsatellite instability in GIST.

The role of adjuvant therapy in the treatment of pT3N0 rectal cancer

The role of adjuvant therapy in the treatment of pT3N0 rectal cancer

PO-1097: Who needs postoperative CCRT in patients with pT3N0 rectal cancer with negative resection margin?

PO-1097: Who needs postoperative CCRT in patients with pT3N0 rectal cancer with negative resection margin?

Determining whether postoperative chemoradiotherapy is required in patients with pathologic T3N0 rectal cancer with negative resection margin.

This study aimed to identify the risk factors for locoregional recurrence (LR) and determine possible candidates for postoperative concurrent chemoradiotherapy (CCRT) in pathologic T3N0 (pT3N0) rectal cancer patients with a negative resection margin after total mesorectal excision (TME). Data from 365 patients who had pT3N0 rectal cancer between 2003 and 2012 in the Samsung Medical Center were reviewed. All patients underwent upfront surgery without preoperative treatment. Postoperative management involved either no adjuvant therapy (n = 122), chemotherapy alone (n = 100), or CCRT (n = 143). The median follow-up duration was 71 months. The 5-year overall survival, disease-free survival, and LR-free survival (LRFS) rates were 95.9%, 86.9%, and 96.3%, respectively. When comparing the three groups (surgery alone [n = 122], chemotherapy alone [n = 100], and CCRT [n = 143]), there was no significant difference in LRFS among them (94.0%, 93.4%, and 99.2%, respectively; p = 0.20). However, when patients were stratified by risk factors (distance from anal verge ≤ 5 cm and distal resection margin [DRM] ≤ 2 cm), the 5-year LRFS improved by more than 10% by adding CCRT (98.9% with CCRT vs. 87.4% without CCRT, p = 0.006) in those with more than one risk factor. Postoperative CCRT did not affect the 5-year LRFS (100% with CCRT vs. 99.0% without CCRT, p = 0.66) in patients with no risk factors. Postoperative CCRT significantly decreased LR in patients with pT3N0 rectal cancer with a negative resection margin but having a distance from the anal verge ≤ 5 cm or DRM ≤ 2 cm.

Patterns of care and outcomes for adjuvant treatment of pT3N0 rectal cancer using the National Cancer Database.

The standard of care in locally advanced rectal cancer is preoperative chemoradiation followed by surgical resection. However, the optimal treatment paradigm is currently controversial for patients with pathological T3N0 (pT3N0) in the era of total mesorectal excision (TME). Given the paucity of data, we conducted an analysis using the National Cancer Database (NCDB) to identify patterns of care and outcomes. We utilized the NCDB to identify 7,836 non-metastatic, pT3N0 rectal cancer patients who did not receive neoadjuvant therapy from 2004-2014. Univariate and multivariable analysis for factors affecting treatment selection were completed using logistic regression. Overall survival (OS) analyses were completed using Cox regression modeling, incorporating propensity scores with inverse probability of treatment weighting (IPTW) and conditional landmark analysis. There was a significant improvement in OS in patients receiving adjuvant chemotherapy (P<0.01) or radiotherapy (RT) with chemotherapy (P<0.01) vs. observation alone. There was no significant difference between RT vs. observation (P=0.54) and chemotherapy vs. chemotherapy with RT cohorts (P=0.15). Multivariable analysis showed age, gender, race, insurance status, income, Charlson-Deyo Comorbidity Condition (CDCC) score, facility location, grade, surgical margin, RT, and chemotherapy to be statistically significant predictors of OS. After correcting for indication and immortal time biases, chemotherapy, with or without RT, improved OS compared with observation [hazard ratio (HR) 0.48, P<0.001]. This benefit was maintained in the margin negative cohort. Practice patterns vary in the management of pT3N0 rectal cancer patients. This analysis suggests that the use of adjuvant therapy, particularly adjuvant chemotherapy with or without RT, appears to improve OS.

Risk factors for locoregional recurrence in patients with pathologic T3N0 rectal cancer with negative resection margin treated by surgery alone.

PurposeThis study aimed to identify prognostic factors for locoregional recurrence (LRR) in pT3N0 rectal cancer patients who were treated with surgery alone and had negative resection margin including circumferential resection margin (CRM) for optimal indication of adjuvant radiotherapy.Materials and MethodsWe reviewed patients with pT3N0 rectal cancer who were treated via upfront surgery and had no other adjuvant treatment from January 2003 to December 2012. In total, 122 patients who had negative resection margin including negative CRM were included in the analysis.ResultsThe median follow-up period after surgery was 60 months (range, 3 to 161 months). During this time, 6 patients (4.9%) experienced LRR at the anastomotic site (4 patients), and regional lymphatic area (2 patients). The estimated 5-year rates of overall survival, recurrence-free survival, and LRR-free survival were 96.7%, 84.6%, and 94.0%, respectively. Multivariate analysis showed that level of tumor ≤5 cm was a significant prognostic factor for LRR-free survival (LRRFS) (p = 0.04; hazard ratio = 7.08; 95% confidence interval, 1.06–47.30). Patients with level of tumor ≤5 cm had an estimated 5-year LRRFS of 66.8%, which was much higher than 2.3% in patients with level of tumor >5 cm. There was no significant factor for recurrence-free survival or overall survival.ConclusionIn T3N0 rectal cancer, adjuvant chemoradiotherapy should be recommended in patients with level of tumor ≤5 cm for better local control. However, in patients with pT3N0 disease, negative resection margin, and level of tumor >5 cm, adjuvant chemoradiotherapy should be carefully suggested.

Role of postoperative radiotherapy in pT3N0 rectal cancer: A risk-stratification system based on population analyses.

The impact of adjuvant radiotherapy in pT3N0 rectal cancer is controversial. We aimed to determine the risk factors for cancer‐specific survival (CSS) among these patients and to develop a risk‐stratification system to identify which of these patients would benefit from adjuvant radiotherapy. In this review of the Surveillance, Epidemiology, and End Results database (2010‐2014), we analyzed the data of pT3N0 rectal cancer patients who had not undergone neoadjuvant radiotherapy. Prognostic factors were identified using the Cox proportional hazards model, and risk scores were derived according to the β regression coefficient. A total of 1021 patients were identified from the database search. The overall 5‐year CSS was 86.31%. Multivariate analysis showed that age (P < 0.001), tumor differentiation (P = 0.044), number of nodes resected (P = 0.032), marital status (P = 0.005), and radiotherapy (P = 0.006) were independent prognostic factors for CSS. A risk‐stratification system composed of age, tumor differentiation, and number of nodes resected was generated. Low‐risk patients had better CSS than high‐risk patients (92.13% vs 72.55%, P < 0.001). The addition of radiotherapy to surgery doubled the CSS among the high‐risk patients (42.06% vs 91.26%, P = 0.001) but produced no survival benefit among the low‐risk patients (93.36% vs 96.38%, P = 0.182). Our risk‐stratification model based on age, tumor differentiation, and number of nodes resected predicted the outcomes of pT3N0 rectal cancer patients. This model could help identify patients who may benefit from adjuvant radiotherapy.

Tumor location as an indication for adjuvant radiotherapy in pT3N0 rectal cancer after surgery

BackgroundThe optimal care for pT3N0 rectal cancer remains controversial. And whether tumor location can be used to guide the administration of adjuvant radiotherapy for pT3N0 rectal cancer is not fully confirmed. The current study was designed to identify the benefit of adjuvant radiotherapy for pT3N0 rectal cancer.MethodsWe performed a retrospective study of 265 pT3N0 rectal cancer patients who were treated by surgery and adjuvant therapy from Mar. 2005 to Sept. 2015. All patients were divided into two groups according to receiving adjuvant radiotherapy or not. Overall survival (OS), disease-free survival (DFS) were compare between patients who did and did not receive adjuvant radiotherapy. Multivariate analysis was performed to explore clinical factors significantly associated with DFS, local recurrence-free survival (LRFS) and distant metastasis-free survival (DMFS).ResultsFor patients with lower tumor, DFS in adjuvant chemo-radiotherapy group was higher than that in adjuvant chemotherapy group. Besides, the rates of local recurrence and distant metastasis were found lower in patients who did receive adjuvant radiotherapy than those who did not. For patients with upper tumor, the 5-year OS and DFS were similar between groups of adjuvant chemotherapy and adjuvant chemo-radiotherapy. Multivariable analysis indicated both the CEA and tumor location were independent predictors of LRFS. And adjuvant radiotherapy predicted the DFS, LRFS and DMFS in lower rectal cancer patients.ConclusionTumor location can serve as an indication for the administration of adjuvant radiotherapy in pT3N0 rectal cancer patients.

The total number of lymph nodes harvested from pathological T3N0 rectal cancer patients

Lymph node status is important in staging colorectal cancer. The use of combination treatment for pathological T3N0 (pT3N0) rectal cancer patients has been controversial. We aimed to explore the prognostic significance of the total number of lymph nodes harvested from pT3N0 rectal cancer patients. Between June 2004 and November 2011, 289 pT3N0 rectal cancer patients who received total mesorectal excision (TME) with or without postoperative chemotherapy were retrospectively reviewed. The main independent variable was the total number of harvested lymph nodes, and the endpoints included local recurrence-free survival (LRFS), disease-free survival (DFS), and overall survival (OS). The patients had a median of 13 lymph nodes harvested. When compared with patients who had < 12 lymph nodes harvested, patients who had ≥12 lymph nodes harvested had higher 5-year LRFS (84.7% vs. 98.0%, P < 0.001), DFS (71.4% vs. 86.8%, P < 0.001), and OS (77.6% vs. 94.9%, P < 0.001) rates. Multivariate analysis demonstrated that the patients who had ≥12 lymph nodes harvested had a significantly lower risks of local relapse (hazard ratio [HR], 0.099; P < 0.001), treatment failure (HR: 0.291; P < 0.001), and death (HR: 0.231; P < 0.001) when compared with patients who had <12 lymph nodes harvested. The number of lymph nodes harvested was independently associated with local relapse, treatment failure, and OS rates in pT3N0 rectal cancer patients who received initial TME with or without postoperative chemotherapy. Postoperative radiotherapy should not be omitted for pT3N0 rectal cancer patients who had <12 lymph nodes harvested.

Value of postoperative adjuvant radiotherapy for pT3N0 rectal cancer

Objective To evaluate the value of adjuvant radiotherapy after radical resection for pT3N0 rectal cancer. Methods The clinical data of 125 patients with pT3N0 rectal cancer who were diagnosed and given total mesorectal excision in our hospital from 2003 to 2010 were retrospectively analyzed. All patients received postoperative adjuvant chemotherapy, while 40 out of them received postoperative adjuvant radiotherapy in addition. Survival rates were estimated using the Kaplan-Meier method, and univariate prognostic analysis was performed using the log-rank test. Multivariate analysis of influencing factors for local recurrence(LR)rate was performed using the Cox regression model. Results The 5-year sample size was 35. The 5-year overall survival(OS)and disease-free survival(DFS)rates were 82. 3% and 72. 4%, respectively. There was no significant difference in the 5-year OS rate between the postoperative chemoradiotherapy group and the postoperative chemotherapy group(12% vs. 83%, P= 0.911). Multivariate analysis suggested that the number of lymph nodes and perirectal fat infiltration were independent prognostic factors for LR rate(P = 0. 045 ;P = 0. 021). There was no significant difference in LR rate between the low-risk group(no high-risk factors)and the high-risk group(the number of high-risk factors ≥1)(2. 5% vs.11.8%, P=0. 060). Conclusions Postoperative radiotherapy cannot improve the OS and LR rates for pT3N0 rectal cancer without any high-risk factors. The value of postoperative adjuvant radiotherapy for pT3N0 rectal cancer needs further evaluation. Key words: Rectal neoplasms/post-operative radiotherapy; Rectal neoplasms/post-operative chemotherapy; Prognosis factors

A Low Lymphocyte-to-Monocyte Ratio Predicts Unfavorable Prognosis in Pathological T3N0 Rectal Cancer Patients Following Total Mesorectal Excision.

Neoadjuvant radio-chemotherapy followed by total mesorectal excision (TME) is the standard treatment option for stage II and III rectal cancer. However, for pT3N0 rectal cancer patients who receive upfront TME, the lack of an efficient method to predict their prognosis hampers postoperative treatment. A low lymphocyte-to-monocyte ratio (LMR) is associated with an unfavorable prognosis for certain malignancies; however, this association has not been investigated in rectal cancer. The purpose of this study was to evaluate whether LMR can predict the prognosis of pT3N0 rectal cancer patients following TME. Rectal cancer patients who received radical TME without preoperative treatment between June 2004 and Nov. 2011 at the Sun Yat-sen University Cancer Center were retrospectively reviewed. Counts for pre-surgery peripheral absolute lymphocytes and monocytes were obtained and used to calculate the LMR. A retrospective cohort of 280 pT3N0 rectal cancer patients who received TME was recruited. Significantly worse disease-free survival can be observed in patients with lower LMR levels (<3.78) using univariate and multivariate analyses (P=0.01 and P=0.015, respectively). Subgroup analysis in patients with elevated carcinoembryonic antigen (CEA) and LMR <3.78 exhibited an accumulated 5-year disease failure rate of approximately 40%, whereas patients with normal CEA regardless of LMR and patients with LMR ≥3.78 exhibited accumulated 5-year disease failure rates of only approximately 15%. Low pre-surgery peripheral LMR was significantly unfavorable for pT3N0 rectal cancer patient prognosis, especially in patients with elevated CEA. This easily obtained variable might serve as a valuable marker to predict the outcomes of pT3N0 rectal cancer and indicate appropriate postoperative management.

The location of locoregional recurrence in pathologic T3N0, non-irradiated lower rectal cancer

PurposeTo investigate the patterns of locoregional recurrence of pathologic T3N0 (pT3N0) lower rectal cancer omitting postoperative radiotherapy (RT) and explore the potential of modification of a RT field.Materials and MethodsFrom Jan 2003 to Nov 2011, 35 patients omitting preoperative or postoperative RT for pT3N0 lower rectal cancer were included. We defined the lower rectal cancer as the tumor with the inferior margin located below the virtual line-a convergent level between rectal wall and levator ani muscle. All patients had radiologic examinations for recurrence evaluation during the follow-up duration.ResultsThe median follow-up duration was 66.4 months (range, 1.4 to 126.1 months). Eight (22.9%) of the 35 patients had recurrence. Three (8.6%) was local recurrence (LR) only, 3 (8.6%) was distant metastasis (DM) only, and 2 (5.7%) was LR with DM. All LR were located at primary tumor sites. The overall survival rate, LR-free survival rate, and DM-free survival rate at 5 years was 79.8%, 83%, and 87%, respectively. All LR developed from tumors over 5 cm. However, there was no statistical significance (p = 0.065). There was no other risk factor for LR.ConclusionEven though the patients included in this study had pathologically favorable pT3N0 rectal cancer, LR developed in 14.3% of patients. Most of the LR was located at primary tumor sites prior to surgery. Based on these findings, it might seem reasonable to consider postoperative RT with a smaller radiation field to the primary tumor site rather than the conventional whole pelvic irradiation.

Outcomes of unselected patients with pathologic T3N0 rectal cancer

Background and purposeThis study compares the outcomes of patients with pathological (p) T3N0 rectal cancer treated with surgery alone (S), surgery and radiation (SR) or surgery, radiation and chemotherapy (SRC), in a population based setting. MaterialsThree hundred and seven patients with operable, macroscopically resected pT3N0 rectal cancer referred to the BC Cancer Agency between 2000 and 2004 were segregated by treatment type: S (n=65), SR (n=97) and SRC (n=145). Patient characteristics, 5-year locoregional recurrence (LRR) and disease-specific survival (DSS) were compared between treatment cohorts. ResultsMedian age differed significantly between S, SR and SRC patient cohorts: 76, 72 and 64years respectively. Five-year LRR differed by treatment group, with 29% for S, 6.3% for SR and 3.84% for SRC patients. DSS was superior in SRC compared to S patients (hazard ratio=0.31 [0.17, 0.60]). Co-morbidities and patient preference were most common reasons for omission of radiation. ConclusionsUnselected patients with pT3N0 rectal cancer not treated with peri-operative radiation experience a high rate of LRR and reduced DSS in comparison to patients treated with bimodality and trimodality therapies. Advanced age is significantly associated with omission of therapy in patients with early stage rectal cancer.

Role of trimodality therapy versus dual-modality in T3N0 rectal cancer patients.

597 Background: Adjuvant radiation (R) and chemotherapy (C) is generally recommended for patients (pts) with pT3N0 rectal cancer, although there is no data to support the use of adjuvant chemotherapy. This study examines the whether there is benefit with trimodality therapy vs. dual modality in this population. Methods: The BCCA Colorectal Cancer Outcomes Unit database was used to identify referred pts with pT3N0 rectal carcinoma diagnosed between 2000-2004. The data from this cohort has been previously reported (Johal et al. ASCO Annual Meeting 2007) During this period, “short course” R (25Gy/5, surgery within 10 days) was recommended for resectable cT3 tumors followed by 6 months of C. If not treated pre-operatively (pre-op), guidelines specified post-op “long course” (45Gy/25) R and C. Three treatment groups were identified: Surgery alone (S), S and R (SR), and S, R and C (SRC). Eligible pts had complete surgical resection with or without total mesorectal Excision (TME). Pts treated with “downstaging” pre-op long course R, with S and C only (13 pts) or with R2 resection were excluded. Locoregional Recurrence (LR) and Distant Recurrence (DR) rates determined. Reasons for non-treatment were determined by chart review. Due to the heterogeneity between the groups, a univariate and multivariate analysis was performed. Results: The patient characteristics have been previously reported. 5-yr LR was similar between SR and SRC (3.84 %vs. 6.34% p=0.474). 5-yr DR were 24.81% (SR), and 17.56% (SRC) p=0.0354 and 5 yr OS 68.4% (SR), and 86% (SRC) p=.0002. On multivariate analysis, chemotherapy did impact on OS with a HR of 0.532, p=0.0462. Conclusions: Treatment of pT3N0 rectal cancer was variable in clinical practice despite established guidelines. There was significant heterogeneity with respect to comorbid medical conditions between groups receiving SR and SRC which limits comparability between groups. However, those patients who received tri-modality therapy experienced less distant relapse and an increase in overall survival. No significant financial relationships to disclose.

Perineural invasion in pT3N0 rectal cancer

The authors' purpose was to explore the incidence and prognostic significance of perineural invasion (PNI) in pT3N0 rectal cancer. Pathologic materials from resected specimens of 173 patients with pT3N0 rectal cancer were retrospectively collected. PNI-positivity was categorized into 2 groups: surrounding the nerve sheath (SS-PNI) and invading through the nerve sheath (TS-PNI). The rate of PNI-positivity was compared with PNI as initially recorded in the original reports. Patients' outcome was studied in groups with different PNI status, and multivariate analysis was performed to determine its prognostic value. In this retrospective analysis, PNI-positivity was found in 24.3% of all cases, in which SS-PNI and TS-PNI were 11% and 13.3%, respectively, and was related to lymphovascular invasion. Only 7.5% of patients' specimens were reported as PNI-positive in the original reports. Detection of SS-PNI was likelier to be missed than TS-PNI. The rates of local recurrence, disease-free survival, and overall survival at 5 years were similar between the groups of SS-PNI and TS-PNI. The 5-year local recurrence rate was more than 2.5-fold higher in the PNI-positive group compared with the PNI-negative group (22.7% vs 7.9%, respectively; P = .017). Multivariate analysis proved that PNI-positivity was the only independent risk factor for predicting 5-year local recurrence rate, whereas only sampled lymph nodes was related to 5-year disease-free survival and overall survival. PNI is a common pathologic feature in rectal cancer. The definition of PNI should include SS-PNI and TS-PNI. Rectal cancer patients who are PNI-positive are at higher risk of local recurrence and should be considered for more intensive treatment.

Treatment patterns and outcomes of patients with pT3N0 rectal cancer in a population-based setting

4039 Background: Adjuvant radiation (R) and chemotherapy (C) is generally recommended for patients (pts) with pT3N0 rectal cancer. Patterns of adjuvant therapy and outcomes among pts with pT3N0 rectal cancer referred to the British Columbia Cancer Agency (BCCA) were determined. Methods: The BCCA Colorectal Cancer Outcomes Unit database was used to identify referred pts with pT3N0 rectal carcinoma diagnosed between 2000–2004. During this period, “short course” R (25Gy/5, surgery within 10 days) was recommended for resectable cT3 tumors followed by 6 months of C. If not treated pre-operatively (pre-op), guidelines specified post-op “long course” (45Gy/25) R and C. Three treatment groups were identified: Surgery alone (S), S and R (SR), and S, R and C (SRC). Eligible pts had complete surgical resection with or without Total Mesorectal Excision (TME). Pts treated with “downstaging” pre-op long course R, with S and C only (13 pts) or with R2 resection were excluded. Locoregional Recurrence (LR) and Distant Recurrence (DR) rates determined. Reasons for non-treatment were determined by chart review. Results: 303 pts were identified, with median follow-up of 33.5 months. Significant differences in age, tumor height, grade, and R therapy existed between groups ( Table I ). TME status, R status and Radial Margin positivity were similar. LR rates were 15% (S), 2% (SR) and 1.4% (SRC). DR rates were 11.7% (S), 7.9% (SR) and 8.5% (SRC). Median Overall Survival (OS) and Disease Free Survival (DFS) was not reached. Conclusions: Treatment of pT3N0 rectal cancer was variable and significant heterogeneity existed between groups receiving S, SR and SRC. Nevertheless, LR rates were very low in pts receiving R and substantially higher in pts who did not. DR rates were similar across groups, irrespective of C history. Reasons for not receiving R or C were primarily patient related (medical/post- operative considerations, patient refusal). Potential physician related factors (non-referral) accounted for 28% of lack of C treatment in the SR group. [Table: see text] No significant financial relationships to disclose.