Treatment outcomes for stage T1b-2 esophagogastric adenocarcinomas.

e16085 Background: Treatment of localized esophageal, gastroesophageal junction (GEJ), and stomach cancer is neoadjuvant therapy with either chemoradiation or chemotherapy followed by surgery. Treatment for T1b-2 stage disease is not well evaluated and this stage is underrepresented in prospective studies. The aim of this study is to evaluate survival outcomes among the three treatment modalities (neoadjuvant chemotherapy (NACT), neoadjuvant chemoradiation (NACRT), and upfront surgery (US)) in this population using the National Cancer Database (NCDB). Methods: Patients (pts) with clinical stage T1b-2N0 and any pathological stage (excluding metastatic) adenocarcinoma of the esophagus, GEJ, and stomach treated with neoadjuvant therapy or upfront surgery, with or without adjuvant chemotherapy (AC), were identified between 2004 and 2015 in the NCDB. Univariate and multivariable analyses were conducted, and Kaplan-Meier analysis and Cox proportional hazard models were used to identify the association between the three treatment modalities and overall survival (OS). Results: A total of 2260 pts were analyzed. The median follow-up was 66.6 months. The median age was 67 years. Most pts were White (86%) and male (77%). 1018 (45%) had moderately-differentiated grade, while 946 (42%) had poorly-differentiated/undifferentiated grade. The most common site of disease was the lower third of esophagus (34.1%). 161 pts (7%) received NACT, of whom 45 pts received AC; 537 pts (24%) received NACRT, of whom 40 pts received AC. 1562 pts (69%) underwent US, of whom 146 pts received AC. US with AC was associated with the best survival, followed by NACT with AC; median OS was 90.1 and 86.8 months for surgery with AC and NACT with AC, respectively. NACRT was associated with the worst survival (39.5 and 40.2 months with and without AC, respectively). The 5-year OS rates were 59.8%, 58.5%, 52.1%, 44.9%, 37.3%, and 37.8%, for US, NACT, and NACRT, with and without AC, respectively. The rate of tumor upstaging was highest in the NACT group, followed by the NACRT group, and lowest in the US group. Postsurgically, 62 (39%) and 48 (30%) pts in the NACT group and 198 (37%) and 161 (30%) pts in the NACRT group had upstaging in their T and N stages, respectively, compared to 214 (13%) and 326 (21%) pts in the US group. For the 1107 pts who also had pathological T1b-2N0 stage disease following US, no difference in survival was observed with or without AC. Conclusions: Upfront surgery with adjuvant chemotherapy and perioperative chemotherapy are associated with the best survival compared to preoperative radiotherapy. This is the largest study to address the best approach for the treatment of T1b-2 stage disease.

Does “low risk” muscle invasive bladder cancer actually exist?

308 Background: Despite level one evidence demonstrating improved survival with neoadjuvant chemotherapy (NAC), studies suggest that many eligible patients with muscle invasive bladder cancer (MIBC) never receive it prior to radical cystectomy (RC). Our objective was to determine if the absence of known pre-operative risk factors can indeed stratify for low risk of extravesical disease with RC alone. Methods: We identified consecutive NAC-naive patients with clinical stage cT2N0M0 urothelial type bladder cancer treated with RC at our center. cT2 patients with either hydronephrosis, transurethral resection (TUR) specimens containing lymphovascular invasion (LVI), or mixed variant histology were grouped as high risk. Clinicopathologic and survival outcomes were compared to cT2 patients without these adverse features, who were grouped as low risk. Results: Of 251 cT2 patients, 119 (47.4%) were high risk [LVI=31, hydronephrosis=69, mixed histology=54; ≥2 risk factors=70]. High and low risk cohorts did not differ in age, gender, race, BMI, smoking, co-morbidities, prior intravescial therapy, or treatment delay. At time of RC, high risk patients more often had lymph node metastasis (38.6% v. 26.7% p=0.04) & tumor upstaging to pT3/4 (53.7% v. 40.2 p<0.001), with significantly less achieving pT0 (2.5% v. 12.1% p=0.004). There was no difference in adjuvant chemotherapy rates (26.4% v. 25% p=0.8). Two and five year cancer-specific survival (CSS) was 84.8% and 62.3% for low risk patients, but only 59.5% and 42% for high risk patients (p=0.008), with competing risk analysis revealing worse bladder cancer specific mortality (BCSM) (sub HR=2.08 [95%CI=1.36 – 3.2]). Odds Ratio for BCSM was 1.29 (95%CI=0.68-2.5) if one risk factor was present, & 3.2 (95%CI=1.7-5.8) if two risk factors. Only hydronephrosis (2.2 [95%CI=1.2-4.2]) and mixed histology (2.4 [95%CI=1.2-4.8]) were independently associated with worse BCSM on multi-variable analysis. Conclusions: Good cancer control is provided by RC alone to many patients with cT2 MIBC without adverse risk factors, particularly if hydronephrosis & mixed variant histology is absent. However, tumor upstaging and lymph node involvement is not trivial even in low risk patients, which must be included in informed decision making on NAC.