Tumor Downstaging Research Articles

Differences in Clinicopathologic Features and Response to Neoadjuvant Radiotherapy for Early- Versus Late-Onset Stage II-III Rectal Adenocarcinoma

The incidence of rectal cancer in adolescents and young adults (AYA) is increasing. While randomized trials in older adults have established neoadjuvant radiotherapy (nRT) as a standard treatment for stage II-III disease, there is limited evidence supporting this regimen in AYA. We hypothesized that AYA with rectal cancer have a different underlying biology and response to nRT compared to older adults. To investigate this, we conducted a database study comparing clinicopathologic features at diagnosis and response to treatment in AYA vs older adults with stage II-III rectal adenocarcinoma. Patients diagnosed with stage II-III rectal adenocarcinoma between 2004-2016 were identified in the National Cancer Database. Early-onset (EO-RC) and late-onset rectal cancer (LO-RC) were defined as aged 15-39 and 40-90 at diagnosis. For overall survival (OS) analyses, the LO-RC cohort was subdivided into middle-onset (age 40-65) and late-onset (age 66-90) groups to adjust for differences in life expectancy and selection bias. Chi-squared and t-tests were used to compare clinicopathologic features between groups. Unadjusted OS was estimated using the Kaplan-Meier method, with groups compared by log-rank test. Of 55,093 patients with stage II-III rectal adenocarcinoma, 2,785 (5%) had EO-RC. Patients with EO-RC had fewer comorbidities (7% vs 21% Charlson/Deyo score ≥1, p<0.001) and presented with more advanced disease at diagnosis, including a higher rate of nodal metastases (53% vs 41%, p<0.001). Among patients who received nRT, those with EO-RC had similar rates of pathologic complete response (11% vs 12%, p = 0.17) and sphincter-preserving resection (71% vs 71%, p = 0.56) compared to LO-RC, but were slightly less likely to have pathologic downstaging of the primary tumor (47% vs 50%, p = 0.04) and nodal metastases (60% vs 66%, p<0.001). The EO-RC cohort had better 90-day post-operative mortality (0.3% vs 1.6%, p<0.001) than the LO-RC cohort. Unadjusted OS analyses showed that nRT receipt was not associated with OS in early-onset or middle-onset patients (p>0.05); however, nRT was associated with improved OS in LO-RC patients (p<0.001). The estimated 10-year OS for patients aged 15-39, 40-65, and 66-90 at diagnosis was 67%, 60%, and 37%, respectively (p<0.001). AYA with stage II-III rectal adenocarcinoma were more likely to present with nodal metastases, slightly less likely to have pathologic downstaging following nRT, and demonstrated no OS benefit from nRT as compared to older adults. Since AYA have fewer medical comorbidities and higher long-term survival, they may be at increased risk of late radiation-related toxicities. Further research to appropriately identify a cost-effective screening strategy in high-risk AYA is crucial to decrease morbidity and mortality.

Response to neoadjuvant treatment among rectal cancer patients in a population-based cohort

BackgroundIn rectal cancer, prediction of tumor response and pathological complete response (pCR) to neoadjuvant treatment could contribute to refine selection of patients who might benefit from a delayed- or no-surgery approach. The aim of this study was to explore the association of clinical and molecular characteristics of rectal cancer with response to neoadjuvant treatment and to compare patient survival according to level of response.MethodsResected rectal cancer patients were selected from a population-based cohort study. Molecular tumor markers were determined from the surgical specimen. Tumor response and pCR were defined as downstaging in T or N stage and absence of tumor cells upon pathological examination, respectively. The associations of patient and tumor characteristics with tumor response and pCR were explored, and patient survival was determined by degree of response to neoadjuvant treatment.ResultsAmong 1536 patients with rectal cancer, 602 (39%) received neoadjuvant treatment. Fifty-five (9%) patients presented pCR, and 239 (49%) and 250 (53%) patients showed downstaging of the T and N stages, respectively. No statistically significant associations were observed between patient or tumor characteristics and tumor response or pCR. Patients who presented any type of response to neoadjuvant treatment had significantly better cancer-specific and overall survival compared with non-responders.ConclusionIn this study, patient characteristics were not associated with response to neoadjuvant treatment, and molecular characteristics determined after surgical resection of the tumor were not predictive of pCR or tumor downstaging. Future studies should include molecular biomarkers from biopsy samples before neoadjuvant treatment.

Liver transplantation after tumor downstaging in hepatocellular carcinoma

Liver transplantation after tumor downstaging in hepatocellular carcinoma

Randomized Phase III Trial of Dose-dense Methotrexate, Vinblastine, Doxorubicin, and Cisplatin, or Gemcitabine and Cisplatin as Perioperative Chemotherapy for Patients with Muscle-invasive Bladder Cancer. Analysis of the GETUG/AFU V05 VESPER Trial Secondary Endpoints: Chemotherapy Toxicity and Pathological Responses

BackgroundPerioperative chemotherapy (neoadjuvant or adjuvant) has been developed to increase overall survival for nonmetastatic muscle-invasive bladder cancer (MIBC). Retrospective studies or prospective phase II trials have been reported to use dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin (dd-MVAC) or gemcitabine and cisplatin (GC). As dd-MVAC has shown higher response rates in metastatic disease, better efficacy is expected in the perioperative setting. ObjectiveWe designed a randomized phase III trial to compare the efficacy of dd-MVAC or GC in MIBC perioperative (neoadjuvant or adjuvant) setting. Design, setting and participantsA total of 500 patients were randomized from February 2013 to March 2018 in 28 centers and received either six cycles of dd-MVAC every 2 wk or four cycles of GC every 3 wk. Outcome measurements and statistical analysisThe primary endpoint (progression-free survival at 3 yr) was not reported. We focused on secondary endpoints: chemotherapy toxicity and pathological responses. Results and limitationsIn the neoadjuvant group, 218 patients received dd-MVAC and 219 received GC. Of the patients, 60% received six cycles in the dd-MVAC arm and 84% received four cycles in the GC arm; 199 (91%) and 198 (90%) patients underwent surgery, respectively. Complete pathological response (ypT0pN0) was observed in 84 (42%) and 71 (36%) patients, respectively (p=0.2). An organ-confined status (<ypT3pN0) was obtained in 154 (77%) and 124 (63%) patients, respectively (p=0.001). In the adjuvant group, 40% of patients received six cycles in the dd-MVAC arm and 60% received four cycles in the GC arm. Most of Common Terminology Criteria for Adverse Events (CTCAE) grade ≥3 toxicities concerned hematological toxicities, reported for 129 (52%) patients in the dd-MVAC group and 134 (55%) patients in the GC group. Gastrointestinal (GI) grade ≥3 disorders were more frequently observed in the dd-MVAC arm (p=0.003), as well as asthenia of grade ≥3 (p<0.001). ConclusionsThe toxicity of dd-MVAC was manageable with more severe asthenia and GI side effects than that of GC in perioperative chemotherapy. A higher local control rate (complete pathological response, tumor downstaging, or organ confined) was observed in the dd-MVAC arm (p=0.021). However, such data have to be confirmed on progression-free survival, with primary endpoint data expected in mid-2021. Patient summaryThe authors have designed a randomized phase III controlled study comparing the efficacy of gemcitabine and cisplatin, and dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin (dd-MVAC) in patients for whom chemotherapy has been decided, before or after radical cystectomy. Higher toxicity regarding asthenia and gastrointestinal side effects along with a better bladder control rate were observed in the dd-MVAC arm. However, such data have to be confirmed on progression-free survival, with primary endpoint data expected in mid-2021.

Outcome after endoscopic treatment for dysplasia and superficial esophageal cancer – a cohort study

Background Dysplasia and superficial esophageal cancer should initially be treated endoscopically. Little is known about post-procedural health-related quality of life (HRQL). The aim of this study was to present our results with endoscopic treatment and post-procedural HRQL. Materials and methods From June 2014 to December 2018, all patients treated with endoscopic mucosal resection (EMR) and/or radiofrequency ablation (RFA) for low-grade dysplasia (LGD), high-grade dysplasia (HGD), T1a and a minority of patients with T1b at Oslo University Hospital were prospectively included. In June 2019, all patients alive were scored according to the Ogilvie dysphagia score as well as the QLQ-C30 and QLQ-OG25 for assessment of HRQL. Results Eighty-six patients were treated out of whom 22 (26%) had LGD, 44 (51%) HGD, 13 (15%) T1a, and six patients (7%) T1b. Histology revealed adenocarcinoma in 18 (21%) and squamous cell carcinoma in one (1%), respectively. The mean follow-up was 22.9 months. Tumor regression or downstaging was archived in 78% of the patients with LGD, 66% of patients with HGD and in 89% of patients with T1a/b. Five patients (6%) had esophagectomy. There were few and no serious complications. The 90-days mortality was 1%. Fifty-two patients (88%) experienced no dysphagia (Ogilvie score 0). There was no difference in 11 out of the 15 variables in QLQ-C30 when compared to a non-cancerous reference population. Conclusions Endoscopic treatment is safe and efficient for treatment of dysplasia and superficial esophageal cancer. The two-years post-procedural level of HRQL and dysphagia was satisfactory.

Significance of Lymph Node Resection After Neoadjuvant Therapy in Pancreatic, Gastric, and Rectal Cancers.

Gastrointestinal cancers are increasingly being treated with NAT before surgical resection. Currently, quality metrics are linked to the number of LNs resected to determine subsequent treatment and prognosis. We hypothesize that NAT decreases LN metastasis, downstages patients, and decreases overall lymph node yields (LNY) compared to initial surgical resection. With increasing use of NAT, this brings into question the validity of quality metrics. Gastric (stage II/III), pancreatic (stage I/II/III), and rectal cancers (stage II/III) (2010-2015) treated with surgery with/without NAT were identified in National Cancer Database. We evaluated total LNY and LN metastasis with/without NAT and clinical and pathological stage to evaluate rates of downstaging. A total of 7934 gastric, 15,908 pancreatic, and 21,354 rectal cancer patients were included of which 61.1%, 21.2%, and 85.7% received NAT, respectively. NAT patients were more likely to be downstaged (39.9% vs 11.1% gastric P< 0.001, 30.6% vs 3.2% pancreatic P< 0.001, 52.0% vs 16.3% rectal P< 0.001), have lower LNYs (18.8 vs 19.1 gastric P = 0.239, 18.4 vs 17.5 pancreatic P< 0.001, 15.7 vs 20.0 rectal P< 0.001) and have N0 pathologic disease (43.6% vs 26.7% gastric P< 0.001, 51.1% vs 30.9% pancreatic P< 0.001, 65.9% vs 49.4% rectal P< 0.001) when compared to initial surgical resection. NAT for gastrointestinal cancers results in overall lower LN yields, lower LN metastases, and significant downstaging of tumors. As all patients undergoing NAT receive multimodality therapy, LN yield recommendations may not be true quality metric changing.

Neo-adjuvant chemotherapy alone for the locally advanced rectal cancer: a systematic review.

Neo-adjuvant chemoradiation (NA-CRT) is the standard of management for the locally advanced rectal cancer (LARC), achieving very low rates of local recurrence (LR). However, NA-CRT fails to control distant recurrence and improve survival, whilst it is associated with increased postoperative morbidity and increased acute and late toxicity. In recent years, neo-adjuvant chemotherapy (NACTx) appears in the literature as an alternative to NA-CRT in patients with LARC. In the present study, the authors review all current evidence on the specific subject. Following a systematic search of the literature, 25 studies were identified reporting on short- or long-term outcomes of NACTx for LARC. Seventeen studies were prospective or retrospective series, and 8 comparative. Of the comparative studies, one was a randomized control trial (RCT) comparing NACTx to NA-CRT and to the combination of NACTx/NA-CRT, and another a non-randomized study comparing NACTx to NA-CRT. Chemotherapeutic regimens were 5-fluoropyrimidine and oxaliplatin based. In some of them, irinotecan or/and bevacizumab was added. A pooled analysis showed that NACTx is associated with a mean anastomotic leak rate of 6.8%. In the RCT, postoperative morbidity and overall toxicity was significantly less in the NACTx group. Mean T downstaging (ypStage 0-I) was 49.6%, mean N downstaging 69.6% and mean pathologic complete response (pCR) 10.7%. The RCT showed an inferior pCR rate after NACTx than after NA-CRT, but similar rates of T downstaging. Mean LR was 8.6% and mean distant recurrence 17.2%. Satisfactory survival rates are reported by several studies. NACTx seems to be an alternative to NA-CRT for patients with LARC, associated with low anastomotic leak, adequate tumour downstaging, low LR and rather high survival rates. Further data deriving from high-quality studies are necessary to assess safety and efficacy of NACTx as a substitute to NA-CRT, for at least a subset of patients with LARC.

Positive Ki-67 and PD-L1 expression in post-neoadjuvant chemotherapy muscle-invasive bladder cancer is associated with shorter overall survival: a retrospective study.

There is an unmet need to develop prognostic biomarkers in post-neoadjuvant chemotherapy (NAC) muscle-invasive bladder cancer (MIBC) patients. We examine whether Ki-67 and PD-L1 expression can be used to guide adjuvant therapy. Tissue microarrays were constructed from 130 post-NAC radical cystectomy samples. Up to 5 cores per sample were included. Expressions of Ki-67 and PD-L1 were evaluated using immunohistochemistry (IHC). Using a Cox regression model, positive Ki-67 expression in post-NAC radical cystectomy samples was associated with poorer overall survival (OS) (HR = 2.412, 95% CI, 1.076-5.408), independent of the pathological lymph node/N-stage. Positive Ki-67 expression was also associated with lack of tumor downstaging in a multivariable logistic regression model analysis (OR = 0.081, 95% CI, 0.014-0.464). PD-L1- and PD-L1+ expression was associated with a median OS of 49.8months and 26.9months, respectively, which did not reach statistical significance. Patients with Ki-67/PD-L1 double-negative tumors had a significantly longer median OS of 98.2months versus 29.9 and 26.9months in PD-L1-/Ki-67+ and PD-L1+/Ki-67+ tumors, respectively. Lack of tumor downstaging was significantly associated with positive Ki-67 and positive PD-L1 expression. Positive Ki-67 and PD-L1 expression in post-NAC radical cystectomy samples was associated with inferior OS and absence of tumor downstaging. IHC on Ki-67 and PD-L1 would help to select patients for adjuvant therapy in post-NAC muscle-invasive bladder cancer.

Application Value of Shear Wave Elastography in the Evaluation of Tumor Downstaging for Locally Advanced Rectal Cancer After Neoadjuvant Chemoradiotherapy.

The aim of this study was to assess the application value of shear wave elastography in the evaluation of tumor downstaging for locally advanced rectal cancer after neoadjuvant chemoradiotherapy. A retrospective analysis was conducted using data from patients with locally advanced rectal cancer treated in our hospital who received endorectal ultrasound (ERUS) and shear wave elastographic examinations before and after chemoradiotherapy. The cases were grouped according to the postoperative pathologic tumor-staging scores. The lesions were divided into 2 groups: 1 showing and the other not showing tumor downstaging. The efficacy of ERUS in diagnosis of tumor downstaging was calculated. The differences in the mean and maximum values of the Young modulus of the lesions before and after chemoradiotherapy between the groups were calculated and compared. Receiver operating characteristic curves were constructed by using the differences in the 2 kinds of values of the Young modulus. The mean and maximum values of the Young modulus before and after chemoradiotherapy were significantly different (P < .05). The differences in the mean and maximum values of the Young modulus of rectal lesions between groups were statistically significant (P < .05). The results of the receiver operating characteristic curve showed that a difference in the mean value at 34.7 kPa was the optimal diagnostic threshold. Compared with ERUS, this standard showed a significant difference in diagnosis of tumor downstaging (P < .05). Shear wave elastography is an effective ultrasound elastographic technique to assist ERUS in evaluating lesions after chemoradiotherapy in rectal cancer. It can improve the diagnostic efficacy of tumor downstaging and provide effective imaging conclusions for clinical decision making.

Consolidation chemotherapy may improve pathological complete response for locally advanced rectal cancer after neoadjuvant chemoradiotherapy: a retrospective study.

BackgroundPatients with locally advanced rectal cancer (LARC) have an improved prognosis if achieved a pathological complete response (pCR) on account of neoadjuvant chemoradiation therapy (nCRT). However, the proportion of patients achieving pCR is only 8–24%. The purpose of this study was to explore whether the addition of consolidation chemotherapy to nCRT could improve pCR rate in patients with LARC.Materials and MethodsThe subjects were 144 individuals with clinical stage II (T3–4, N0) or III (any T, N1–2) LARC who had received neoadjuvant CRT followed by total mesorectal excision (TME). Eighty-three patients in the consolidation chemotherapy group received two cycles XELOX between CRT and TME, while 61 patients in the standard treatment group without consolidation chemotherapy. The pCR (ypT0N0), tumor downstaging (ypT0-2N0) after TME and adverse events (AEs) during and post treatment were compared between the treatment groups using multivariable logistic regression analysis. To adjust the unbalanced variables for the primary endpoint, logistic regression analysis and stratified analysis were performed.ResultsThe consolidation chemotherapy group improved pCR rate (19.3% vs 4.9%, p = 0.01) and tumor downstaging rate (45.8% vs 24.6%, p = 0.009) compared to the standard treatment group. After adjustment for clinical tumor stage, clinical nodal stage and time interval to surgery, patients with consolidation chemotherapy were more likely to reach pCR (adjusted odds ratio 4.91, 95% CI [1.01–23.79], p = 0.048). AEs during and post treatment in the two groups were 54.1% vs 49.3% (p = 0.57), respectively. In addition, the incidence of any grade 1–2 AEs in the two groups was 93.4% vs 95.1% (p = 0.93), while the incidence of grade 3 AEs was 1.6% versus 2.4% (p = 0.74), respectively. No grade 4 AEs occurred in two groups.ConclusionsThe addition of neoadjuvant consolidation chemotherapy after CRT significantly increased the pCR rate and did not increase the AEs during and post treatment and in patients with LARC.

Effects of Ketogenic metabolic therapy on patients with breast cancer: A randomized controlled clinical trial

Ketogenic metabolic therapy (KMT) using ketogenic diets (KD) is emerging as viable alternative or complementary strategy for managing cancer; however, few clinical trials have been reported. The present study aimed to evaluate the effects of a KD in patients with locally advanced and metastatic breast cancer receiving chemotherapy. A total of 80 patients undergoing treatment with chemotherapy were randomly assigned to KD or control group for 12 weeks. Concurrent with the admission, midway point, and at 12 weeks, fasting blood samples were collected for evaluation of insulin, IGF-1, CEA, CA15-3, ESR, CRP, IL-10, and TNF-α. Sonography for patients with locally advanced disease and CT or MRI scans for patients with metastatic disease were done on admission and at 12 weeks. At the completion of the chemotherapy, patients with locally advanced disease underwent surgery and stage was recalculated. Also patients with metastases were evaluated for response rate. TNF-α decreased significantly after 12 weeks of treatment (MD: 0.64 [CI 95%:-3.7, 5] P<0.001), while IL-10 increased (MD: 0.95 [CI 95%:-1,3] P<0.001) in the intervention compared to the control group. Patients in the KD group had lower adjusted serum insulin compared to the control group (MD:-1.1 [CI 95%:-3,1] p<0.002). KD lead to a reduction in tumor size in the KD compared to the control (27 vs 6mm, P=0.01). Stage decreased significantly in patients with locally advanced disease in the KD group after 12 weeks (P<0.01). No significant differences in response rate were observed in patients with metastatic disease. KMT in breast cancer patients might exert beneficial effects through decreasing TNF-α and insulin and increasing IL-10. KD may result in a better response through reductions in tumor size and downstaging in patients with locally advanced disease; however, more studies are needed to elucidate the potential beneficial effects of KD in patients with metastases. This trial has been registered on Iranian Registry of Clinical Trials (IRCT) under the identification code: IRCT20171105037259N2. https://www.irct.ir/trial/30755.

Mismatch Repair-Deficient Rectal Cancer and Resistance to Neoadjuvant Chemotherapy.

Evaluate response of mismatch repair-deficient (dMMR) rectal cancer to neoadjuvant chemotherapy. dMMR rectal tumors at Memorial Sloan Kettering Cancer Center (New York, NY) were retrospectively reviewed for characteristics, treatment, and outcomes. Fifty patients with dMMR rectal cancer were identified by IHC and/or microsatellite instability analysis, with initial treatment response compared with a matched MMR-proficient (pMMR) rectal cancer cohort. Germline and somatic mutation analyses were evaluated. Patient-derived dMMR rectal tumoroids were assessed for chemotherapy sensitivity. Of 21 patients receiving neoadjuvant chemotherapy (fluorouracil/oxaliplatin), six (29%) had progression of disease. In comparison, no progression was noted in 63 pMMR rectal tumors (P = 0.0001). Rectal cancer dMMR tumoroids reflected this resistance to chemotherapy. No genomic predictors of chemotherapy response were identified. Of 16 patients receiving chemoradiation, 13 (93%) experienced tumor downstaging; one patient had stable disease, comparable with 48 pMMR rectal cancers. Of 13 patients undergoing surgery, 12 (92%) had early-stage disease. Forty-two (84%) of the 50 patients tested positive for Lynch syndrome with enrichment of germline MSH2 and MSH6 mutations when compared with 193 patients with Lynch syndrome-associated colon cancer (MSH2, 57% vs 36%; MSH6, 17% vs 9%; P < 0.003). Over one-fourth of dMMR rectal tumors treated with neoadjuvant chemotherapy exhibited disease progression. Conversely, dMMR rectal tumors were sensitive to chemoradiation. MMR status should be performed upfront in all locally advanced rectal tumors with careful monitoring for response on neoadjuvant chemotherapy and genetic testing for Lynch syndrome in patients with dMMR rectal cancer.

The safety and efficacy of radical surgery after modified total neoadjuvant therapy for locally advanced rectal cancer

Objective: To analyze the clinical-pathological data of patients with locally advanced rectal cancer who underwent modified total neoadjuvant therapy (TNT), and to evaluate the safety and efficacy of radical surgery after modified total neoadjuvant therapy. Methods: The clinical-pathological data of 30 locally advanced rectal cancer patients who underwent modified TNT (mTNT) followed by radical resection were retrospectively analyzed. The surgical procedure, postoperative complications, tumor regression grade, tumor downstaging and prognosis were analyzed. Results: The 30 patients included 24 males and 6 females with a median age of 55.5 years. All patients underwent radical surgery after neoadjuvant therapy, 14 patients received low anterior resection, 14 patients received abdominal perineal resection, and the other 2 patients received Hartmann procedure. All patients achieved R0 resection with a median operative time 220 minutes and the median intraoperative blood loss was 200 ml. The morbidity of postoperative complications was 20% (6/30), including dysuria in 2 patients, delayed healing of perineal incision in 2 patients, intestinal obstruction in 1 patient and pelvic hemorrhage in 1 patient. The median time to first flatus after surgery was 3 days and the median postoperative hospital stay was 8 days. Postoperative pathological results showed that 15 patients (50.0%) had severe tumor regression, including 4 patients (13.3%) achieved pathological complete response (pCR), 12 patients (40.0%) had moderate tumor regression, and 3 patients (10.0%) had minor tumor regression. Twenty patients had detailed pre-treatment clinical stage, and among those 20 patients, 15 patients (75.0%) and 13 patients (65.0%) achieved downstaging of tumor T stage and N stage, respectively. Only 2 patients appeared distant metastasis, and no patient had local recurrence. Conclusions: For locally advanced rectal cancer patients, mTNT doesn't increase the morbidity of postoperative complication and is a safe and effective treatment strategy with satisfactory short-term result.

A Prospective Observational Study Comparing Long-Course Conventional Neoadjuvant Chemoradiotherapy with Short-Course Radiotherapy Followed by Consolidation Chemotherapy with Delayed Surgery in Locally Advanced Rectal Cancer.

Background Polish and Australian randomized studies compared short-course radiotherapy (RT) with immediate surgery and long-course chemoradiotherapy (CRT) with delayed surgery. In these studies, similar long-term survival and local control have been reported for both these approaches, but pathological complete response (pCR) is not better with short-course RT. Moreover, studies have shown better tumor downstaging with delayed surgery. In this context, the use of short-course RT with delayed surgery may have some advantages and needs to be tested in clinical trials. Patients and Methods This was a two-arm, prospective, observational study, in which preoperative short-course RT followed by two cycles of chemotherapy was compared with the conventional neoadjuvant CRT in locally advanced rectal cancer. The primary end points were the rate of complete response and toxicity profile. The secondary end points were the rate of R0 resection, overall survival, and progression-free survival. The data obtained from the two arms were analyzed using Pearson’s chi-square test to determine the statistical significance between the two treatment arms. Results The pCR rate was 6.7% in the study arm and 0 in the control arm ( p = 0.343). The RO resection rates were 92.8 and 92.3% in the study and control arms, respectively. The rates of grade 3and 4 acute toxicity in the study and control arms were 14.2 and 61.5%, respectively ( p = 0.011). The rates of grade 3 and 4 late toxicity in the study and control arms were 21.4 and 15.3%, respectively ( p = 0.686). Conclusions The pCR rates and the late toxicities in both arms are comparable. The major advantages of the 5 × 5 Gy regimen with chemotherapy in a neoadjuvant setting are a significant reduction in acute toxicities and better patient compliance along with similar efficacy as that of the standard regimen.

Editorial comment: the effect of neoadjuvant chemotherapy on tumour downstaging and outcomes in patients with muscle invasive bladder cancers

Editorial comment: the effect of neoadjuvant chemotherapy on tumour downstaging and outcomes in patients with muscle invasive bladder cancers

Induction chemotherapy with mFOLFOXIRI in cT4N+ locally advanced rectal cancer: Subgroup analysis from a prospective trial.

e16136 Background: FOLFOXIRI had been recommended as induction treatment for patients with T4N+ rectal cancer in the latest NCCN guideline. However, no prospective study to support this recommendation in his population. Here, we tried to analyze the efficacy of FOLFOXIRI as induction chemotherapy in the subgroup of rectal cancer patients with T4N+ from a prospective trial. Methods: A phase II trial exploring the efficacy of mFOLFOXIRI as neoadjuvant chemotherapy in locally advanced rectal cancer had been conducted in our center recently. The subgroups of patients with clinical T4N+ rectal cancer were extracted for further analysis. All candidates were to receive 4 to 6 cycles of mFOLFOXIRI. MRI will be performed every two cycles to assess clinical responses. And then the patients would receive total mesorectal excision directly or proceed to chemoradiotherapy according to the result of restaging evaluation. Postoperative FOLFOX chemotherapy was recommended. The primary endpoint is the ratio of tumor downstaging to ypT0-2N0M0. Results: There were 27 patients with cT4N+. There were twenty male and 7 female, with the median age of 46 years old. MRF involved was observed in 14 patients. Neoadjuvant chemotherapy with mFOLFOXIRI was performed for at least 4 cycles. Six patients received radiotherapy before total mesorectal excision, including short-term radiation in 1 patient. R0 resection was achieved in all the patients (100%) and 24 (88.9%) of patients had received sphincter-saving operation. According to the pathologic result, all patients showed regression in the primary tumor (ypT0-3). The pCR rate was 22.2% (6/27) and the tumor downstaging (ypStage 0-I) rate was 29.6%. Another 13 (48.1%) patients showed downstaging to ypStage II. The main grade 3/4 adverse event was neutropenia (35.7%). With a median follow-up of 25 months, no local recurrence was observed. Only 3 patients developed distant metastasis. The 2-year survival rate for this group of population was 85.0%. Conclusions: mFOLFOXIRI showed high tumor downstaging rate in locally advanced rectal cancer. It could be reasonable to use mFOLFOXIRI as induction chemotherapy for cT4N+ rectal cancer patients. Clinical trial information: NCT02217020 . [Table: see text]

Long-term outcomes of preoperative radiotherapy in locally advanced breast cancer: Analysis of Surveillance, Epidemiology, and End Results (SEER) database.

e12600 Background: Currently the treatment paradigm for locally advanced breast cancer (LABC) is multimodality therapy with neoadjuvant systematic treatment, surgery and postoperative radiation therapy (RT). However, with improving outcomes from systematic therapy, the survival rates remain unpromising, which leads to the investigation of the concept of preoperative RT in LABC due to the potential advantages including a possible tumor downstaging and better cosmetic outcomes. We evaluated the overall survival (OS) and breast cancer specific survival (BCSS) of preoperative versus postoperative RT in LABC patients. Methods: Patients diagnosed with non-inflammatory LABC (defined as T3 N1, T4 N0, any N2 or N3, and M0) who received RT before or after surgery between 2010 and 2015 were identified using the SEER database. OS and BCSS were analyzed using Kaplan-Meier method and multivariate Cox proportional hazards model. Results: Among 19249 patients with LABC, 140 (0.7%) received preoperative RT and 19109 (99.3%) received postoperative RT. Overall, 5-year survival and BCSS are 59% and 63% in the preoperative RT group while 77% and 80% in the postoperative RT group. In all patients, treatment with preoperative RT was significantly associated with poor OS (HR 1.82, 95%CI 1.25 to 2.45, P &lt; 0.001) and BCSS (HR 2.00, 95%CI 1.46 to 2.73, P &lt; 0.001) after adjustment for other clinically relevant factors. However, there were no significant difference in terms of both OS and BCSS in ER+ (OS: HR 1.44, 95%CI 0.91 to 2.27, P = 0.12; BCSS: HR 1.55, 95%CI 0.94 to 2.54, P = 0.08) and HER2+ patients (OS: HR 1.33, 95%CI 0.55 to 3.22, P = 0.53; BCSS: HR 1.64, 95%CI 0.67 to 3.97, P = 0.28). Conclusions: Overall, preoperative RT in LABC may reduce overall survival and breast cancer specific survival. However, OS and BCSS were independent of radiation sequence for ER+ and HER2+ patients. This finding warrants further exploration of potential mechanisms of the disparity and the definitive role of preoperative RT in the multimodality therapy of LABC patients.

Diagnostic accuracy of CT-staging of advanced gastric cancer following neoadjuvant chemotherapy.

4551 Background: Neoadjuvant or perioperative chemotherapy has been accepted as a standard treatment globally in patients (pts) with locally advanced gastric cancer (LAGC). In PRODIGY phase III study (n = 530), we have demonstrated that neoadjuvant chemotherapy with DOS regimen (docetaxel, oxaliplatin, S-1) led to significant tumor downstaging and improved PFS in Korean LAGC pts (Kang, et al. ESMO 2019). Although CT has been performed to re-stage the tumor after neoadjuvant chemotherapy, there has been a relative paucity of diagnostic accuracy data. This study is to evaluate the diagnostic performance of restaging of LAGC after neoadjuvant chemotherapy using CT in PRODIGY study population. Methods: Of 266 pts, who had been diagnosed LAGC of T2-4 or N+ stage as assessed with CT and randomized to neoadjuvant chemotherapy arm (CSC) in PRODIGY study, 214 pts underwent gastrectomy were included in this analysis. The post-chemotherapy T- and N- stage was determined based on CT scan taken just prior to surgery and compared with the pathologic stage (AJCC 7th edition). Two experienced radiologists independently evaluated depth of primary tumor and reached consensus if any discrepancy between two readers. Diameter of short axis of the largest regional lymph node was measured to predict metastatic lymph node. Result of histopathologic T- and N-staging using surgical specimen was used as reference standard. Results: The study cohort consisted of pathologic T0 (n = 22), T1(n = 39), T2(n = 31), T3(n = 79), and T4(n = 43). The overall diagnostic accuracy of CT was 45%. For each T-stage, accuracy of T0,T1,T2,T3, and T4 was 0%, 26%, 29%, 55% and 79%, respectively. Rate of over- and under- staging was 47% and 8%, respectively. Accuracy for prediction of downstaging to early gastric cancer (T0-T1) was 83%. Interobserver agreement of T-staging was moderate (k = 0.41). There were 98 patients of N+ and 116 patients of N- at histopathology. Area under the curve of receiver operating characteristics to differentiate lymph node metastasis was 0.63. Sensitivity and specificity of size criteria of the largest lymph node (cut off value: &gt; 6mm, &gt; 7mm, and &gt; 8mm) to predict pathologic N+ were 90% and 17%, 78% and 34%, and 68% and 51%, respectively. Conclusions: Re-staging using CT after neoadjuvant chemotherapy showed suboptimal accuracy and over-staged residual tumor. However, it predicted downstaging of gastric cancer with high accuracy.

Survival outcomes of patients with resectable pancreatic cancer treated with upfront surgery versus neoadjuvant chemotherapy: A retrospective tertiary care center experience.

4623 Background: The role of neoadjuvant chemotherapy (NAC) for resectable pancreatic cancer (RPC) remains controversial. We sought to compare the outcomes of NAC with upfront surgery (UFS). Methods: The study retrospectively enrolled patients with RPC who had UFS or received neoadjuvant FOLFIRINOX (FFX) or gemcitabine plus albumin-bound paclitaxel (GA). Between-group differences were assessed with T-test for continuous variables, and Chi-square / Fisher’s exact test for categorical variables. The overall survival (OS) and recurrence-free survival (RFS) were determined by the Kaplan-Meier method with Wilcoxon test for the difference between groups. The effects of NAC vs. UFS on OS and RFS were further estimated using Cox regression controlling the effects of age and CA 19-9. Results: Between 2011 and 2019, 131 patients with RPC underwent UFS followed by adjuvant chemotherapy (gemcitabine, n = 65; gemcitabine/capecitabine, n = 18; FFX, n = 9). Up to 32 patients (24.4%) could not receive adjuvant chemotherapy due to surgical complications or poor recovery. Total 50 patients with RPC received NAC (FFX, n = 32; GA, n = 18). Median of 5.5 cycles of FFX or 3 cycles of GA were given prior to surgery. Resection rate was 72% (FFX 62.5%; GA 88.9%). The rest (28%) were no longer surgical candidates due to disease progression rather than toxicities from NAC. On surgical pathological review, complete resection (R0) was achieved in 83.3% of resected cases after NAC (FFX 90%; GA 75%) and 79.4% with UFS. The tumor size distribution was: pT1 11.1%, pT2 41.7%, pT3 44.4% with NAC; pT1 5.4%, pT2 18.3%, pT3 76.3% with UFS. The nodal status distribution was: pN0 27.8%, pN1 55.5%, pN2 16.7% with NAC; pN0 23.7%, pN1 71.0%, pN2 5.3% with UFS. Median pre-treatment CA 19-9 was 321.95 unit/mL in the NAC group and 79.99 unit/mL in the UFS group (p = 0.009). Median age was 70.5 in the NAC group and 72 in the UFS group (p = 0.374). There was no significant difference in the performance status between the two groups. In Kaplan-Meier analysis, there was a significant difference of OS between UFS and NAC with median OS of 648 days under UFS versus 884 days under NAC (p = 0.029); the median of RFS was 390 days under UFS versus 392 days under NAC (p = 0.953). The hazard ratio (NAC vs UFS) adjusted for CA19-9 and age was 0.7 (p = 0.176) for OS and 0.98 (p = 0.918) for RFS. Conclusions: We observed a signal of tumor downstaging, higher R0 rate, and improved OS with NAC compared with UFS. Further prospective trials are needed to validate these results.

Phase II trial of induction chemotherapy plus chemoradiotherapy with aspirin or placebo in high-risk rectal cancer (ICAR).

e16131 Background: Induction chemotherapy (IC) followed by chemoradiation (CRT) is an attractive approach in locally-advanced, high-risk rectal cancer. Additionally, aspirin has shown potential to lower recurrence rate in colorectal cancer, and improve outcomes alongside CRT in rectal cancer, with higher rate of tumor downstaging. Methods: Randomized, double-blind phase 2 trial to evaluate induction treatment with XELOX, followed by capecitabine-based chemoradiotherapy with aspirin or placebo in a high risk population selected by MRI. The aim of this study was to evaluate MRI response after total neoadjuvant treatment with aspirin or placebo. Results: Of the 25 pts who started treatment between January 2018 and March 2019, 4 pts did not complete (1 pt grade 5 diarrhea; 1pt treatment adherence). Median age was 55yo (32.9 - 73.6), 8 pts (32%) were women, and 80% had 3 or more high-risk criteria. 20 pts (80%) showed symptom improvement in the first cycle of IC. Of the 21 patients who finished treatment until interim analysis, 11 pts received aspirin (2 pts had MRI complete response (CR), 3 pts had minor/no response, and 3 pts had progression disease (PD)). 10 pts received placebo (4 MRI CR, 3 pts had minor/no response, and no PD). Conclusions: Aspirin added to chemoradiotherapy was safe but did not improve response to total neoadjuvant treatment. The study was closed due absence of benefit. Clinical trial information: NCT03170115 .