Preoperative Chemoradiotherapy Research Articles

273P Pathological complete response following pre-operative chemoradiotherapy in locally advanced rectal cancer: An institutional analysis

273P Pathological complete response following pre-operative chemoradiotherapy in locally advanced rectal cancer: An institutional analysis

Identification of lateral pelvic nodes without metastasis in patients with rectal cancer treated with preoperative chemoradiotherapy or chemotherapy based on magnetic resonance imaging.

Intensive localized therapy is promising for the treatment of rectal cancer. In Japan, chemoradiotherapy (CRT) and neoadjuvant chemotherapy (NAC) are used as preoperative treatments for this disease. Magnetic resonance imaging (MRI) is used to diagnose lateral pelvic node (LPN) metastases, but the changes in LPN findings on MRI following preoperative treatment are unclear. Furthermore, there may be patients in whom LPN dissection can be omitted after CRT/NAC. Patients who underwent total mesorectal excision with LPN dissection after CRT/NAC at 13 Japanese Society for Cancer of the Colon and Rectum member institutions between 2017 and 2019 were included. Changes in the short diameter of the LPNs after CRT/NAC and the reduction rate were examined. A total of 101 LPNs were examined in 28 patients who received CRT and 228 in 47 patients who received NAC. Comparison of LPNs before and after CRT/NAC showed that most LPNs shrank after CRT but that the size reduction was variable after NAC. Although some LPNs with a short diameter of <5 mm showed residual metastasis, no metastases were observed in LPNs that were <5 mm in short diameter before and after CRT/NAC and did not shrink after treatment. Although the short diameter of LPNs was significantly reduced by both CRT and NAC, even LPNs with a short diameter of <5 mm could have residual metastases. However, dissection may be omitted for LPNs <5 mm in short diameter that do not shrink after preoperative CRT or NAC.

Assessing response and adherence to neoadjuvant treatment in soft tissue sarcomas of the extremities.

e23559 Background: The standard treatment for large, intermediate, and high-grade extremity soft tissue sarcoma (ESTS) involves surgery and radiotherapy. The addition of chemotherapy has improved oncological outcomes, such as reduced recurrence and prolonged survival. However, the relationship between neoadjuvant treatment and tumor response in ESTS is not well understood. Pathological evaluation of viable tumor cells after treatment is an indicator of tumor response, yet the proportion of viable tumor cells remains high, particularly in high-risk sarcomas. Combining radiotherapy with chemotherapy may enhance the response of tumor cells. Objective: This study aims to evaluate the effects of neoadjuvant chemotherapy (NCT) and chemoradiotherapy (CRT) on patients with high-risk ESTS and to determine its impact on the pathological response. Methods: We enrolled adult patients with high-risk ESTS (SARCULATOR OS &lt; 60%) at a single center in Latin America. The study was designed to analyze the pathological response in patients with high-risk sarcomas who underwent neoadjuvant CRT and resection and to correlate these responses with various variables. The treatment response was evaluated using the EORTC–STBSG criteria. Results: Thirty-four patients were recruited, with a median age of 44 years (IQR 23-74). Fifty-two percent had T3 tumors (mean size 18 cm), and 79.4% were diagnosed at stage III. The predominant histological subtypes were synovial sarcoma (35.3%) and dedifferentiated liposarcoma (29.4%). The most used NCT regimen was doxorubicin/ifosfamide (84.4%), with 62.5% receiving a dosage intensity of Q4W, affected by overcapacity, and 25% received Q3W. Concurrent CRT was administered to 64.7% of patients, with a median delay to onset of 36 days due to overcapacity (43.5%). Only 79.4% completed three preoperative cycles of treatment. As for the response, 41.2% had an EORTC-E response, and 17.6% had an EORTC-D response. Grade 3 neutropenia and anemia occurred in 17.2% and 8.8% of patients, respectively. Disease progression during NCT was observed in six patients. No significant difference was found in the pathological response between the Q4W and Q3W dosage intensities (p = 0.62). Conclusions: The impact of NCT on pathological responses was not significantly high, which may be due to the predominant histological type in our series. The main cause of treatment delay at our center was due to overcapacity; however, this did not influence the pathological response relative to dose intensity. Additional follow-up assessments are required to determine the influence on relapse-free and overall survival based on the response after preoperative CRT.

413P Following planned pre-operative (pre-op) chemo-radiotherapy (CRT) for squamous cell cancer (SCC) of the esophagus (eso), why do some patients not undergo surgery (sx)? A service evaluation from a tertiary care hospital in a Low-Middle Income Country (LMIC)

413P Following planned pre-operative (pre-op) chemo-radiotherapy (CRT) for squamous cell cancer (SCC) of the esophagus (eso), why do some patients not undergo surgery (sx)? A service evaluation from a tertiary care hospital in a Low-Middle Income Country (LMIC)

Pathologic Complete Response, Total Neoadjuvant Therapy and the Survival Paradox in Locally Advanced Rectal Cancer.

Pathologic complete response (pCR) after preoperative chemoradiation (nCRT) correlates with improved overall survival for patients with locally advanced rectal cancers (LARCs). Escalation protocols including total neoadjuvant therapy (TNT), which delivers multi-agent chemotherapy and chemoradiation before surgery, are associated with increased complete response rates. However, TNT is not associated with improved overall survival. The authors hypothesized that the route to pCR may be an important predictor of oncologic outcome. Adults with LARC between 2006 and 2017 were identified in the National Cancer Database. The cohort was limited to those who received neoadjuvant radiation (45-70 Gy) and underwent proctectomy. Of 25,880 patients, 16 % received TNT and 84 % had nCRT followed by either multi-agent (27 %), single-agent (14 %), or no adjuvant chemotherapy (44 %). Overall, 18 % achieved pCR, with higher rates in the TNT cohort than in the nCRT (18 %) or multi-agent (14 %) chemotherapy cohorts. With control for covariates, the OS in the pCR cohort was similar for the patients that received single-agent therapy and those that received multi-agent adjuvant therapy, and superior to the TNT and no adjuvant therapy cohorts. Conversely, among the patients who did not achieve pCR, those who received single-agent chemotherapy had OS comparable with those who had multi-agent adjuvant therapy and TNT, which was better than no adjuvant therapy. Patients achieving pCR after TNT had worse OS than those who had CRT alone, suggesting that the neoadjuvant route by which pCR is achieved is prognostically relevant. Therefore, in the era of neoadjuvant therapy escalation, pCR does not necessarily portend a uniformly favorable prognosis.

Nutritional Status Indicators Predict Tolerability to Adjuvant Chemotherapy in Patients with Stage II/III Rectal Cancer Undergoing Neoadjuvant Chemoradiotherapy

Introduction: Adjuvant chemotherapy (AC) after radical surgery following preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer (LARC) is now the standard of care. The identification of risk factors for the discontinuation of AC is important for further improvements in survival. We herein examined the prognostic impact of chemotherapy compliance and its relationship with the prognostic nutritional index (PNI) before surgery. Methods: A total of 335 stage II–III LARC patients who underwent preoperative CRT between 2003 and 2022 at the University of Tokyo Hospital were retrospectively reviewed. We excluded patients with recurrence during AC and those who had not received AC. The relationship between AC and long-term outcomes and that between PNI values and the duration of AC were examined. Results: Thirty-one patients discontinued AC and 62 continued AC. Recurrence-free survival (RFS) was significantly shorter in patients who discontinued AC (p = 0.0056). The discontinuation of AC was identified as an independent risk factor for RFS (hazard ratio [HR]: 2.24, p = 0.0233). Twenty-one patients were classified as having low PNI (less than 40), which correlated with an older age, low body mass index, and incomplete AC. Low PNI was an independent risk factor for a shorter duration of AC (HR: 2.53, p = 0.0123). Conclusion: The discontinuation of AC was related to poor RFS in patients with LARC undergoing preoperative CRT. Furthermore, a low PNI value was identified as a risk factor for a shorter duration of AC.

Preoperative chemoradiotherapy in older patients with rectal cancer guided by comprehensive geriatric assessment within a multidisciplinary team—a multicenter phase II trial

BackgroundThe purpose of this study was to evaluate the safety and efficacy of preoperative concurrent chemoradiotherapy (preCRT) for locally advanced rectal cancer in older people who were classified as “fit” by comprehensive geriatric assessment (CGA).MethodsA single-arm, multicenter, phase II trial was designed. Patients were eligible for this study if they were aged 70 years or above and met the standards of “fit” (SIOG1) as evaluated by CGA and of the locally advanced risk category. The primary endpoint was 2-year disease-free survival (DFS). Patients were scheduled to receive preCRT (50 Gy) with raltitrexed (3 mg/m2 on days 1 and 22).ResultsOne hundred and nine patients were evaluated by CGA, of whom eighty-six, eleven and twelve were classified into the fit, intermediate and frail category. Sixty-eight fit patients with a median age of 74 years were enrolled. Sixty-four patients (94.1%) finished radiotherapy without dose reduction. Fifty-four (79.3%) patients finished the prescribed raltitrexed therapy as planned. Serious toxicity (grade 3 or above) was observed in twenty-four patients (35.3%), and fourteen patients (20.6%) experienced non-hematological side effects. Within a median follow-up time of 36.0 months (range: 5.9-63.1 months), the 2-year overall survival (OS), cancer-specific survival (CSS) and disease-free survival (DFS) rates were 89.6% (95% CI: 82.3-96.9), 92.4% (95% CI: 85.9-98.9) and 75.6% (95% CI: 65.2-86.0), respectively. Forty-eight patients (70.6%) underwent surgery (R0 resection 95.8%, R1 resection 4.2%), the corresponding R0 resection rate among the patients with positive mesorectal fascia status was 76.6% (36/47).ConclusionThis phase II trial suggests that preCRT is efficient with tolerable toxicities in older rectal cancer patients who were evaluated as fit based on CGA.Trial registrationThe registration number on ClinicalTrials.gov was NCT02992886 (14/12/2016).

Development of perioperative immune checkpoint inhibitor therapy for locally advanced esophageal squamous cell carcinoma.

The standard preoperative treatment for resectable locally advanced esophageal squamous cell carcinoma (ESCC) is chemoradiotherapy in western countries (based on the CROSS trial) and triplet chemotherapy in Japan (based on the JCOG1109 trial). Postoperative nivolumab has recently been shown to improve disease-free survival in resectable locally advanced esophageal cancer after preoperative chemoradiotherapy in patients who had residual pathological disease, based on the CheckMate 577 trial. Furthermore, preoperative immune checkpoint inhibitor-containing treatments have also been developed. The JCOG1804E trial is presently evaluating the safety and efficacy of preoperative nivolumab-containing chemotherapy for resectable locally advanced ESCC. This review discusses the treatment of resectable locally advanced ESCC and future perspectives on perioperative immune checkpoint inhibitor-containing treatments.

Prediction of combination therapy efficacy in patients with locally advanced squamous cell oropharyngeal carcinoma

Background. Oropharyngeal squamous cell carcinoma (OPSCC) is characterized by late-stage diagnosis and high rate of mortality. Combined modality treatment including preoperative chemoradiotherapy (CRT) is the standard of care for OPSCC. The search for criteria for predicting the efficacy of preoperative chemoradiotherapy with a view to prescribe it to those patients for whom it is really indicated and will be effective remains challenging. The aim of the study was to identify serum actin-binding proteins that can predict preoperative therapy efficacy in patients with OPSCC. Material and methods. Blood serum from 45 patients with stage II–IV OPSCC was studied. all patients received preoperative chemotherapy with paclitaxel and carboplatin. Radiation therapy in a standard mode was given 2 weeks after chemothetapy. serum levels of actin-binding proteins (CAP1, fascin, ezrin, gelsolin, and profiling) were determined before treatment using ELISA. Results. complete or partial response to preoperative CRT was achieved in 27 patients. Disease progression or stabilization was observed in 18 patients. A comparison of the serum levels of actin-binding proteins before treatment with those obtained after preoperative CRT showed that the serum level of ezrin was lower in patients who did not respond to preoperative CRT than in patients with partial or complete response to therapy. ROC-analysis showed that the serum level of ezrin of less than 2.50 ng/ml can predict the tumor response to CRT as unfavorable (less than 75 % according to the RECIST scale). The sensitivity was 72 % and the specificity was 71 %. Conclusion. Determination of the serum level of ezrin in patients with OPSCC has a predictive value in relation to preoperative chemoradiotherapy.

2981: Inflammatory indexes prognostic value in STS patients treated with preoperative chemoradiation

2981: Inflammatory indexes prognostic value in STS patients treated with preoperative chemoradiation

The Right Gastroepiploic Artery as a Potential Organ at Risk in Neoadjuvant Chemoradiation for Esophageal and Gastroesophageal Cancers.

Preoperative chemoradiation is a standard of care for esophageal and gastroesophageal cancer. A gastric conduit is usually used for anastomosis with the right gastroepiploic artery (RGEA) being the sole arterial supply to the gastric remnant after such surgeries. Hence, lowering the radiation dose to this vessel may lower the risks of postoperative complications related to poor vasculature. Herein, we report our experience in contouring and replanning cases of distal esophageal/gastroesophageal carcinomas so that the radiation doses to the RGEA could be minimized. Radiation plans of patientswith lower esophageal/gastroesophageal carcinomas were retrieved from our database. Identification and delineation of the RGEA was done and replanning was performed with the aim to keep the maximal and mean doses as well as the V10Gy and V20Gy of the RGEA as low as possible without compromising target volume coverage. Results: We achieved significant dose reductions in most of the dosimteric parameters in our selected cases without compromising target coverage. Lowering the dose to the RGEA, a potential organ-at-risk that may impact the postoperative course after neoadjuvant chemoradiation, is feasible.

Evaluation of the prognostic impact of pathologic tumor regression grade on patients with colorectal cancer after preoperative chemoradiotherapy.

The prognostic value of the pathological response to preoperative chemoradiotherapy (CRT) in rectal cancer (RC) remains unknown. We aimed to assess the predictive value of the response to CRT that was derived from an evaluation of the histological findings (whole-section vs. representative-section sampling) and attempted to determine an objective cut-off value for the tumor regression grade (TRG). We examined the association of the TRG with the outcomes (recurrence-free survival [RFS] and overall survival [OS]) of 78 patients with RC. Patients with RC treated with preoperative CRT were divided into development (30 cases) and validation (48 cases) cohorts. The TRG was classified as grades I (Ia, Ib), II, and III. The cut-off value was determined by receiver operating characteristic (ROC) curve analysis. The TRG determined from whole-section sampling versus representative-section sampling was more strongly correlated with patient survival. We found that in both cohorts, patients with a cut-off value of <73% had a poor prognosis. Finally, the cut-off value was found to be an independent predictive factor in both univariate and multivariate analysis. The TRG that was used to evaluate patients with RC who underwent preoperative CRT was an independent prognostic factor for outcome.

Colorectal cancer-specific IFNβ delivery overcomes dysfunctional dsRNA-mediated type I interferon signaling to increase the abscopal effect of radiotherapy

BackgroundCancer-intrinsic type I interferon (IFN-I) production triggered by radiotherapy (RT) is mainly dependent on cytosolic double-stranded DNA (dsDNA)-mediated cGAS/STING signaling and increases cancer immunogenicity and enhances the antitumor immune response...

Treatment Outcome in Locally Advanced Rectal Carcinoma and Its Correlation with Hypo-Fractionated Radiotherapy and Concurrent Chemoradiotherapy

Introduction: Rectal cancer is the second most common type within the large intestine, posing significant health risks globally. In Bangladesh, it ranks high among diagnosed cancers. Improved diagnostic methods aid in early detection, which is crucial for effective management. Treatment typically involves a combination of surgery, radiotherapy, and chemotherapy. Preoperative chemoradiotherapy is a standard approach. However, newer methods like preoperative hypo-fractionated radiotherapy with surgery promise better outcomes, including reduced recurrence rates and enhanced survival, with potential cost and time savings. Aim of the Study: The study aims to evaluate and contrast the efficacy of hypofractionated radiotherapy and concurrent chemoradiotherapy in patients with locally advanced rectal carcinoma. Methods: The study, conducted at the Department of Clinical Oncology at Bangabandhu Sheikh Mujib Medical University Shahbagh, Dhaka, Bangladesh and the Department of Radiation Oncology at the National Institute of Cancer Research and Hospital (NICR&amp;H) in Mohakhali, Dhaka, Bangladesh, aimed to compare treatments for locally advanced rectal cancer over 1.5 years (From January 2018 to June 2019). A total of 80 patients were divided into two groups; Group A received hypofractionated radiotherapy, while Group B received oral capecitabine alongside external beam radiotherapy. Inclusion criteria involved confirmed adenocarcinoma within specified stages, with ethical clearances obtained. Patients underwent evaluations before treatment and response assessments posttreatment. Treatment modalities were defined, focusing on radiotherapy and chemotherapy. Data were analyzed using SPSS software, employing various statistical tests. Results aimed to address study objectives while minimizing biases. Result: The study involved 80 patients, divided into Groups A and B, each with 40 individuals. Group A mainly comprised individuals aged 41-50 (45%), followed by 31-40 (25%). Group B had the highest proportion aged 31-40 (30%) and 41-50 (32.50%). Both groups showed male predominance (1.3:1). Moderately differentiated tumors were common, with Group A having more poorly differentiated tumors. Stage III was predominant pre-treatment (65% Group A, 70% Group B). Most patients presented with per rectal bleeding (80%) and alteration of bowel habits (56.25%). Response rates to treatment were similar between groups. Tumor downsizing was more frequent in Group B. Sphincter-sparing surgery was feasible in both groups with no significant difference. Conclusion: The study comparing preoperative hypofractionated radiotherapy (RT) to concurrent chemoradiotherapy (CCRT) for locally advanced rectal carcinoma found similar efficacy in tumor response, downsizing, and sphincter preservation. Statistical analysis showed no significant differences. Both approaches showed acceptable short-term outcomes, offering clinicians options based on patient and resource considerations.

Evaluation of anorectal function using real-time tissue elastography before and after preoperative chemoradiotherapy

PurposeThis study aimed to clarify the relationship between changes in elasticity and anorectal function before and after chemoradiotherapy.MethodsThis is a single-center prospective cohort study (Department of Surgical Oncology, The University of Tokyo). We established a technique to quantify internal anal sphincter hardness as elasticity using transanal ultrasonography with real-time tissue elastography. Twenty-seven patients with post-chemoradiotherapy rectal cancer during 2019–2022 were included. Real-time tissue elastography with transanal ultrasonography was performed before and after chemoradiotherapy to measure internal anal sphincter hardness as “elasticity” (hardest (0) to softest (255); decreased elasticity indicated sclerotic changes). The relationship between the increase or decrease in elasticity pre- and post-chemoradiotherapy and the maximum resting pressure, maximum squeeze pressure, and Wexner score were the outcome measures.ResultsA decrease in elasticity was observed in 16/27 (59.3%) patients after chemoradiotherapy. Patients with and without elasticity decrease after chemoradiotherapy comprised the internal anal sphincter sclerosis and non-sclerosis groups, respectively. The maximum resting pressure post-chemoradiotherapy was significantly high in the internal anal sphincter sclerosis group (63.0 mmHg vs. 47.0 mmHg), and a majority had a worsening Wexner score (60.0% vs. 18.2%) compared with that of the non-sclerosis group. Decreasing elasticity (internal anal sphincter sclerosis) correlated with a higher maximum resting pressure (r = 0.36); no correlation was observed between the degree of elasticity change and maximum squeeze pressure.ConclusionInternal anal sphincter sclerosis due to chemoradiotherapy may correlate to anorectal dysfunction.

Number of Healthy Teeth Can Predict the Response of Rectal Cancer to Chemoradiotherapy: A Retrospective Study.

It has been reported that the oral and gut microbiomes are associated with the prognosis in patients who undergo surgery, chemotherapy, and radiation for colorectal cancer. This study is the first to identify a correlation between the number of healthy teeth, which is an oral health indicator, and the efficacy of preoperative chemotherapy for rectal cancer. This retrospective single-center study included 30 patients who underwent radical surgery after preoperative chemoradiotherapy (CRT) between December 2013 and June 2021. The relationship between number of teeth before CRT and the efficacy of CRT, CRT-related adverse events, postoperative complications, and long-term postoperative outcomes was examined. The number of healthy teeth was significantly greater in patients with downstaging of their disease than in those without downstaging (P = .027) and in patients with a complete response according to the Response Evaluation Criteria in Solid Tumors than in those who did not have a complete response (P = .014). Patients were divided into two groups according to whether they had ≥15 teeth or ≤14 teeth. There was no significant between-group difference in CRT-related adverse events. The incidence of all postoperative complications and grade II postoperative complications tended to be higher in patients with ≥15 teeth (P = .071 and P = .092, respectively), as did the 5-year overall survival rate (P = .083) and the 5-year disease-free rate (P = .007). The number of healthy teeth predicted the response to preoperative CRT, postoperative complications, and the outcome of subsequent surgery in patients with rectal cancer.

Abstract CT130: Epacadostat with preoperative chemoradiation in locally advanced rectal cancer (LARC): Results of a translational phase I clinical trial

Abstract BACKGROUND: In preclinical studies, we found that the immuno-oncology target and tryptophan metabolizing enzyme indoleamine 2, 3-dioxygenase 1 (IDO1) promotes resistance to radiation in rectal cancer regardless of MSI status. Furthermore, IDO1 inhibition with epacadostat improved tumor radiosensitivity, abrogated immunosuppression, limited distal recurrence, and was radioprotective of the normal intestine. This trial aimed to evaluate the safety of IDO1 inhibition when combined with neoadjuvant short-course radiation (SCRT) and chemotherapy with capecitabine and oxaliplatin (CAPOX) for LARC. METHODS: The primary objective was to determine the recommended phase II dose (RP2D) of epacadostat for combination with SCRT and CAPOX. Secondary objectives included determining antitumor activity as measured by neoadjuvant rectal (NAR) score and pathological or clinical complete responses. During the dose escalation phase, 3 doses of epacadostat (300mg, 400mg, &amp; 600mg BID) were explored. Epacadostat was combined with SCRT (5Gy x 5 fractions) followed by 6 cycles of CAPOX chemotherapy, until the day of surgery (~24 wks). Tissues and blood were collected for correlative studies. A control cohort was generated from patients receiving the same treatment without epacadostat. NCT03516708 RESULTS: Seventeen patients were enrolled from 4/2019 to 8/2023. RP2D of epacadostat in combination with SCRT and CAPOX chemotherapy was determined to be 400mg BID. Two patients experienced dose-limiting toxicities (DLT) at 600mg dose level, one with G2 elevated ALT and another with G3 maculopapular rash. No DLT was reported at other dose levels. Of six patients who underwent surgery, the mean NAR score was 7.46 (SD 7.11; range 0 - 20.4), indicating potentially better response compared to the mean NAR of 17.8 in an institutional 2:1 matched control cohort (p=0.03). Tumor tissue revealed increased IDO1 expression and kynurenine levels in all patient tumors after radiation. After epacadostat, serum levels of kynurenine were reduced while TNFα, IFNγ, and MIP1a were all increased. Global metabolomics and RNAseq revealed a distinct pattern of serum biomarkers and immunophenotype respectively in patients after treatment. Tumoroids were evaluated as ex vivo models of treatment response. CONCLUSION: Epacadostat in combination with SCRT and CAPOX was well-tolerated. An NCI supported Phase 2 trial is ongoing to further evaluate the promising disease responses reported in dose escalation phase. Citation Format: Haeseong Park, Katrina Pedersen, Katherine Huang, Matthew Mutch, Hyun Kim, Nikolaos Trikalinos, Olivia Aranha, Benjamin Tan, Rama Suresh, Lee Ratner, Moh'd Khushman, John Visconti, Kian-Huat Lim, Lauren Henke, Maddie Swiecicki, Jingxia Liu, Parag Parikh, Matthew Ciorba. Epacadostat with preoperative chemoradiation in locally advanced rectal cancer (LARC): Results of a translational phase I clinical trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT130.

Fluorescence guidance using near-infrared fluorescent clips in robotic rectal surgery: a case series

PurposeTattoo markings are often used as preoperative markers for colorectal cancer. However, scattered ink markings adversely affect tumor site recognition intraoperatively; therefore, interventions for rectal cancer may lead to an inaccurate distal resection margin (DRM) and incomplete total mesorectal excision (TME). This is the first case series of fluorescence-guided robotic rectal surgery in which near-infrared fluorescence clips (NIRFCs) were used to localize rectal cancer lesions.MethodsWe enrolled 20 consecutive patients who underwent robotic surgery for rectal cancer between December 2022 and December 2023 in the current study. The primary endpoints were the rate of intraoperative clip detection and its usefulness for marking the tumor site. Secondary endpoints were oncological assessments, including DRM and the number of lymph nodes.ResultsClip locations were confirmed in 17 of 20 (85%) patients. NIRFCs were not detected in 3 out of 7 patients who underwent preoperative chemoradiation therapy. No adverse events, including bleeding or perforation, were observed at the time of clipping, and no clips were lost. The median DRM was 55 mm (range, 22–86 mm) for rectosigmoid (Rs), 33 mm (range, 16–60 mm) for upper rectum (Ra), and 20 mm (range, 17–30 mm) for low rectum (Rb). The median number of lymph nodes was 13 (range, 10–21).ConclusionThe rate of intraoperative clip detection, oncological assessment, including DRM, and the number of lymph nodes indicate that the utility of fluorescence-guided methods with NIRFCs is feasible for rectal cancer.

Abstract 6683: The abundance of Fusobacteria nucleatum in tumor tissue is a prognostic factor in patients of right-sided colorectal cancer

Abstract Background: A significant association between the gut microbiome and colorectal carcinogenesis, as well as cancer progression. It has been reported that Fusobacteria nucleatum (F. nucleatum) is one of the most famous bacteria associated with colorectal cancer (CRC). It has been reported that the abundance of F. nucleatum is associated with colorectal cancer-specific survival (CSS), however it remains unclear for association with F. nulceatum and relapse-free survival (RFS). If F. nucleatum has a significant involvement in tumor progression of colorectal cancer, the abundance of F. nucleatum should be associated with not only CSS but also RFS in colorectal cancer. In this study, we measured the bacterial mass of F. nucleatum in tumor tissue of CRC patients in Stage II-III to explore the differences in prognosis. Methods: We included patients with CRC in stage II-III who underwent surgical treatment at Nippon Medical School Hospital between January 2017 and December 2020 except patients who received preoperative chemoradiotherapy and had multiple cancers. We measured the absolute of F. nucleatum copy number of the DNA exacted tumor tissues using droplet digital PCR. Results: 253 patients with CRC were included. 128 patients had pathological stage II and 125 patients had pathological stage III. Among 253 patients, 104 patients had right-sided CRC, 89 patients had left-sided, and 60 patients had rectal cancer. F. nucleatum was detected in 166 patients (65.6%), and the median of F. nucleatum copy number was 1.08 (range; 0.00 -2791.3). F. nucleatum copy number was more abundant in right-sided CRC than in left-sided and rectal cancer (p= 0.02, p=0.01). There was no significant difference between stage II CRC and stage III. We categorized patients into two groups based on the median cut point of F. nucleatum copy number: the F. nucleatum-high group and the F. nucleatum-low group for comparison with clinicopathological features and prognosis. Patients with high abundance of F. nucleatum exhibited T4 of tumor depth (p=0.03), right-sided CRC (p=0.01), longer tumor circumference (p &amp;lt;0.001), longer tumor length (p &amp;lt;0.001), and no lymph node metastasis (p=0.024). There was no significant difference in relapse-free survival between the F. nucleatum-high group and F. nucleatum-low group among whole patients (p=0.53). Analyzing divided tumor location, in right-sided CRC high abundance of F. nucleatum was significantly associated with shorter relapse-free survival than low abundance (p=0.02), while in left-sided and rectal cancer there was no significant difference (p=0.61). Conclusion: F. nucleatum was more abundant in right-sided CRC and associated with relapse-free survival only in right-sided CRC. F. nucleatum may make a greater impact on right-sided CRC than on left-sided and rectal cancer. Citation Format: Toshimitsu Miyasaka, Takeshi Yamada, Sho Kuriyama, Akihisa Matsuda, Kay Uehara, Seiichi Shinji, Yasuyuki Yokoyama, Goro Takahashi, Takuma Iwai, Kohki Takeda, Shintaro Kanaka, Hiroshi Yoshida. The abundance of Fusobacteria nucleatum in tumor tissue is a prognostic factor in patients of right-sided colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6683.

Survival benefits of adjuvant chemotherapy for patients with residual pathologic disease after neoadjuvant chemotherapy and surgery for locally advanced esophageal squamous cell carcinoma

Background and purposeAlthough preoperative neoadjuvant chemotherapy (NACT) or chemoradiation is the current standard of care for esophageal cancer in China, the impact of subsequent adjuvant therapy on patient prognosis remains unknown. This study aims to analyze the effect of adjuvant chemotherapy (ACT) on the survival rates of patients who have achieved a non-pathological complete response (non-pCR) after NACT and subsequent surgery. MethodsWe reviewed the data of 2193 patients with locally advanced thoracic esophageal squamous cell carcinoma (ESCC) who underwent radical surgery between January 2006 and January 2016. Of these patients, 46 received NACT and ACT, while 109 received NACT only. Propensity score matching was used to compare 86 patients, with 43 patients in the NACT+ACT group and 43 patients in the NACT group.Univariate analysis was performed using the Kaplan-Meier method and Log-rank test, while Cox regression analysis was used for multivariate analysis. ResultsMultivariate analysis revealed that pathological lymph node status (positive vs. negative) (P<0.001) and treatment modalities (NACT+ACT vs. NACT) (P=0.005) were independent prognostic factors. There was a significant difference in long-term survival rates between the NACT+ACT and NACT groups, with 5-year survival rates of 55.8% vs. 39.5%, respectively (c2=4.270, P=0.039). In patients with ypN+ status, the 5-year survival rate was 31.8% for those who received ACT after NACT and surgery, compared to 10.0% for those who did not receive additional ACT (c2=6.101, P=0.014). The corresponding percentages in patients with ypN- were 81.0% and 65.2%, respectively (c2=1.993, P=0.158). ConclusionAdjuvant chemotherapy should be recommended for locally advanced ESCC patients with residual cancer after NACT and surgery, especially for patients with nodal metastases after NACT.