Clinical parameters predicting pathologic tumor response after preoperative chemoradiotherapy for rectal cancer

Tumor response rates based on initial TNM stage and tumor size in locally advanced rectal cancer: a useful tool for shared decision-making

BACKGROUND

It is accepted that tumor stage and size can influence response to neoadjuvant therapy in locally advanced rectal cancer (LARC). Studies on organ preservation to date have included a wide variety of size and TNM stage tumors. The aim of this study was to report tumor response based on each relevant TNM stage and tumor size.

METHODS

Patients treated with LARC from 2014 to 2021 with cT2-3NxM0 tumors who received neoadjuvant chemoradiotherapy with or without induction chemotherapy were included. Tumors were staged and tumor size calculated on pelvic MRI at the time of diagnosis (cTNM). Tumor size was based on the largest dimension taken on the longest axis of each tumor. Clinical response was defined on the basis of post-treatment pelvic MRI and pathological response following surgery, when performed. Statistical analysis was performed using IBM SPSS Statistics™, version 20. Data from 432 patients were analyzed as follows: cT2N0 (n = 51), cT2N+ (n = 36), cT3N0 (n = 76), cT3N+ (n = 270).

RESULTS

The rate of complete or near-complete response (cCR or nCR) varied from 77% in cT2N0 ≤ 3 cm to 20% in cT3N+ > 4 cm. Organ preservation without recurrence at 2 years was achieved in 86% of patients with cT2N0, 50% in cT2N+, 39% in cT3N0, and 12% in cT3N+.

CONCLUSION

There is significant variation in tumor response according to tumor stage and size. Tumor response appears inversely proportional to increasing TNM stage and tumor size. This data can support both refinement of selective patient recruitment to organ preservation programs and shared decision-making.

Rectal Cancer: Clinical and Molecular Predictors of a Complete Response to Total Neoadjuvant Therapy

BACKGROUND

Total neoadjuvant therapy in rectal cancer may increase pathological complete response rates, potentially allowing for a nonoperative approach.

OBJECTIVE

The objective of this study was to identify patient and tumor characteristics that predict a complete response following total neoadjuvant therapy.

DESIGN

This was a retrospective cohort study.

SETTINGS

This study was conducted at a university-based National Cancer Institute-designated Comprehensive Cancer Center.

PATIENTS

The patients include those with stage 2 or 3 rectal adenocarcinoma.

INTERVENTIONS

Interventions included total neoadjuvant therapy, total mesorectal excision, and nonoperative management.

MAIN OUTCOME MEASURES

Complete response was defined as either patients with a clinical complete response undergoing nonoperative management who remained cancer-free or patients undergoing surgery with a pathological complete response.

RESULTS

Among 102 patients, median age was 54 years, 69% were male, median carcinoembryonic antigen level was 3.0 ng/mL, and the median distance of the tumor above the anorectal ring was 3 cm. Thirty-eight (37%) patients had a complete response, including 15 of 18 (83%) nonoperative patients who remained cancer free at a median of 22 months (range, 7-48 months) and 23 of 84 (27%) patients who underwent surgery and had a pathological complete response. The incomplete response group consisted of 61 patients who underwent initial surgery and 3 nonoperative patients with regrowth. There were no differences in gender, T-stage, or tumor location between groups. Younger age (median, 49 vs 55 years), normal carcinoembryonic antigen (71% vs 41%), clinical node-negative (24% vs 9%), smaller tumors (median 3.9 vs 5.4 cm), and wild-type p53 (79% vs 47%) and SMAD4 (100% vs 81%) were more likely to have a complete response (all p < 0.05).

LIMITATIONS

This was a retrospective study with a small sample size.

CONCLUSIONS

In patients with rectal cancer treated with total neoadjuvant therapy, more than one-third will achieve a pathological complete response or sustained clinical complete response with nonoperative management, making oncological resection superfluous in these patients. Smaller, wild-type p53 and SMAD4, and clinically node-negative cancers are predictive features of a complete response. See Video Abstract at http://links.lww.com/DCR/B889 .

CNCER DE RECTO PREDICTORES CLNICOS Y MOLECULARES DE UNA RESPUESTA COMPLETA A LA TERAPIA NEOADYUVANTE TOTAL

ANTECEDENTES:La terapia neoadyuvante total en el cáncer de recto puede aumentar las tasas de respuesta patológica completa y permitir potencialmente un enfoque no quirúrgico.OBJETIVO:El objetivo fue identificar las características tanto del paciente y del tumor que logren predecir una respuesta completa después de la terapia neoadyuvante total.DISEÑO:Este fue un estudio de cohorte retrospectivo.AJUSTES:Este estudio se realizó en un Centro Integral de Cáncer designado por el Instituto Nacional del Cáncer con sede universitaria.PACIENTES:Los pacientes incluyen aquellos con adenocarcinoma de recto en estadio 2 o 3.INTERVENCIONES:Terapia neoadyuvante total, escisión total del mesorrecto, manejo conservador no quirúrgico.PRINCIPALES MEDIDAS DE RESULTADO:La respuesta completa se definió como pacientes con una respuesta clínica completa sometidos a tratamiento no quirúrgico que permanecieron libres de cáncer o pacientes sometidos a cirugía con una respuesta patológica completa.RESULTADOS:Entre 102 pacientes, la mediana de edad fue de 54 años, el 69% fueron hombres, la mediana del nivel de antígeno carcinoembrionario fue de 3.0 ng/ml y la mediana de la distancia del tumor por encima del anillo anorrectal fue de 3 cm. Thirty-eight (37%) pacientes tuvieron una respuesta completa que incluyó a 15 de 18 (83%) pacientes con manejo no operatorio y que permanecieron libres de cáncer en una mediana de 22 meses (rango 7- 48 meses) y 23 de 84 (27%) pacientes que fueron sometidos a cirugía y tuvieron una respuesta patológica completa. El grupo de respuesta incompleta consistió en 61 pacientes que fueron sometidos inicialmente a cirugía y 3 pacientes no quirúrgicos con recrecimiento. No se encontró diferencias de género, estadio T o ubicación del tumor entre los grupos. Edad más joven (mediana 49 frente a 55), antígeno carcinoembrionario normal (71% frente a 41%), ganglios clínicos negativos (24% frente a 9%), tumores más pequeños (mediana de 3,9 frente a 5,4 cm) y p53 de tipo salvaje (79 % vs 47%) y SMAD4 (100% vs 81%) tenían más probabilidades de tener una respuesta completa (todos p < 0,05).LIMITACIONES:Este fue un estudio retrospectivo y con un tamaño de muestra pequeño.CONCLUSIONES:En pacientes con cáncer de recto tratados con terapia neoadyuvante total, más de un tercio logrará una respuesta patológica completa o una respuesta clínica completa sostenida con manejo no operatorio, logrando que la resección oncológica sea superflua en estos pacientes. Los cánceres más pequeños, clínicamente con ganglios negativos, con p53 de tipo salvaje y SMAD4, son características predictoras de una respuesta completa. Consulte Video Resumen en http://links.lww.com/DCR/B889 . (Traducción-Dr. Osvaldo Gauto ).

Radiomics Approaches for the Prediction of Pathological Complete Response after Neoadjuvant Treatment in Locally Advanced Rectal Cancer: Ready for Prime Time?

In recent years, neoadjuvant therapy of locally advanced rectal cancer has seen tremendous modifications. Adding neoadjuvant chemotherapy before or after chemoradiotherapy significantly increases loco-regional disease-free survival, negative surgical margin rates, and complete response rates. The higher complete rate is particularly clinically meaningful given the possibility of organ preservation in this specific sub-population, without compromising overall survival. However, all locally advanced rectal cancer most likely does not benefit from total neoadjuvant therapy (TNT), but experiences higher toxicity rates. Diagnosis of complete response after neoadjuvant therapy is a real challenge, with a risk of false negatives and possible under-treatment. These new therapeutic approaches thus raise the need for better selection tools, enabling a personalized therapeutic approach for each patient. These tools mostly focus on the prediction of the pathological complete response given the clinical impact. In this article, we review the place of different biomarkers (clinical, biological, genomics, transcriptomics, proteomics, and radiomics) as well as their clinical implementation and discuss the most recent trends for future steps in prediction modeling in patients with locally advanced rectal cancer.

Active surveillance in long period of total neoadjuvant therapy in rectal cancer: Early prediction of poor regression response

Aim

To analyze locally advanced rectal cancer (LARC) patients and tumor characteristics during the period of total neoadjuvant therapy (TNT) and explore the risk factors that may predict poor tumor regression in response to TNT.

Materials and methods

The data of 120 LARC patients who received TNT from December 2016 and September 2019 in our hospital were retrospectively analyzed. The clinicopathological characteristics of patients with different tumor regression responses were compared. Then we divided patients into two groups according to the carcinoembryonic antigen (CEA) clearance pattern after chemoradiation to explore risk factors that might predict the tumor regression response.

Results

Of 120 LARC patients, 34 (28.3%) exhibited poor regression. Stratified analysis by tumor response showed that patients with poor response to TNT were more likely to obtain elevated CEA during the course of TNT (all P < 0.05). For those with elevated pretreatment CEA, fewer patients with poor response obtained normal CEA after chemoradiation (13.6% vs. 72.7%, P < 0.001). Besides, less patients’ CEA levels in the poor response group decreased by greater than 50% after chemoradiation when compared with that in the good response group (18.2% vs. 60.6%, P = 0.002). Stratified analysis by CEA clearance pattern after chemoradiation showed patients who obtained an elevated pretreatment CEA and decreased by less than 50% after chemoradiation were more likely to have poor response to TNT compared to others (76.2% vs. 18.2%, P < 0.001). Logistic multivariate analysis revealed that cN2 (95% CI 1.553-16.448), larger tumors (95% CI 2.250-21.428) and CEA clearance pattern after chemoradiation (95% CI 1.062-66.992) were independent risk factors for poor tumor regression response.

Conclusion

Approximately one-fourth of LARC patients with TNT achieved a poor regression response. Here, cN2, larger tumor size before treatment and elevated CEA levels were considered predictive features of a poor response. Active surveillance of CEA levels during the TNT course are potentially important, and CEA levels after chemoradiation might have important implications for the tumor response to TNT.

Predicting stage ypT0–1N0 for nonradical management in patients with middle or low rectal cancer who undergo neoadjuvant chemoradiotherapy: a retrospective cohort study

Purpose

It is important to discover predictive factors that can identify rectal cancer patients who will respond well to neoadjuvant concurrent chemoradiotherapy (CCRT) to develop management strategies, preserve sphincter and avoid over-treatment. This study explored clinical factors that would predict the adequacy of nonradical management after CCRT in patients with middle or low rectal cancer.

Methods

We retrospectively evaluated 447 patients with middle or low rectal cancer who were treated with curative surgery after neoadjuvant CCRT between January 2010 and December 2019. The good response group comprised patients with stages ypT0–1N0 on resection after CCRT; the remaining patients were included in the poor response group.

Results

Of 447 patients (mean age, 60.37 ± 11.85 years), 108 (24.2%) had ypT0–1N0 (71.3% with ypT0N0, 4.6% with ypTisN0, and 24.1% with ypT1N0). Overall, 19 patients with cT1–2 (50.0% vs. 21.8% with cT3–4, P < 0.001), 22 with well-differentiated tumors (51.2% vs. 21.3% with moderately/poorly differentiated tumors, P < 0.001), 16 with fungating tumors (47.1% vs. 22.3% with other types, P = 0.001), and 66 with anterior/posterior circumference direction (28.9% vs. 19.2% with lateral/encircling direction, P = 0.016) had stage ypT0–1N0. On multivariable analysis, cT1–2 (P = 0.021) and well-differentiated tumor (P = 0.001) were independent predictors of ypT0–1N0. Fungating tumors were not significantly associated with ypT0–1N0 (P = 0.054).

Conclusion

Stage cT1–2 and well differentiation are predictors of ypT0–1N0, while fungating tumors could be considered clinically meaningful, possibly identifying candidates for nonradical treatment post-CCRT.

Factors influencing downstaging after neoadjuvant long-course chemoradiotherapy in rectal carcinoma

PURPOSE

This single-centre cohort study was designed to identify factors that can predict primary tumour downstaging by neoadjuvant chemoradiotherapy (nCRT) in rectal carcinoma.

METHODS

Prospectively collected data from 555 patients with clinical T category (cT) cT3-4 rectal carcinoma treated between 1995 and 2019 were retrospectively analysed. All patients received long-term neoadjuvant chemoradiotherapy followed by surgery with curative intent at the Department of Surgery, University Hospital Erlangen, Germany. Patient-, tumour- and treatment-related factors with a potential impact on the downstaging of rectal carcinoma to pathological T category (pT) ≤ ypT2 and ypT0 were analysed in univariate and multivariate logistic regression analyses. The prognosis of patients with and without downstaging of the primary tumour was compared.

RESULTS

A total of 288 (51.9%) patients showed downstaging to ≤ ypT2. Eighty-six (15.5%) patients achieved clinical complete regression (ypT0). In the multivariate logistic regression analysis, the factors cT category, BMI, ECOG score, CEA, histological type, extension in the rectum and year of the start of treatment were found to be independent factors for predicting downstaging to ≤ ypT2 after neoadjuvant chemoradiotherapy. The year of treatment initiation also remained an independent significant predictor for pathological complete regression. The prognosis was superior in patients with downstaging to ≤ ypT2 in terms of locoregional and distant recurrence as well as disease-free and overall survival.

CONCLUSION

Factors predicting downstaging after long-term nCRT could be identified. This may be helpful for counselling patients and selecting the optimal treatment for patients with advanced rectal carcinoma.

Histopathological, Radiological, and Demographic Factors Predicting the Response to Neoadjuvant Therapy for Rectal Cancer

BACKGROUND/AIM

While the treatment for early stage rectal cancer is surgery, when a diagnosis is made at a locally advanced stage, it is recommended to start treatment with neoadjuvant chemoradiotherapy. Therefore, it is important to determine which patients will respond best to neoadjuvant treatment. The aim of this study was to investigate which hematological, histopathological, and radiological parameters can predict the response to chemoradiotherapy.

METHODS AND MATERIAL

A retrospective examination was made of 43 patients who underwent surgery following neoadjuvant chemoradiotherapy because of locally advanced stage rectal cancer. Demographic data were collected from the patient files, and the radiological, histopathological, and laboratory findings before neoadjuvant chemoradiotherapy were compared with the findings after treatment.

RESULTS

In the postoperative evaluation, a pathological complete response was determined in 25.50% of the patients. Lymphovascular invasion, perineural invasion, and absence of necrosisis were seen to be statistically related to major response (p < 0.05), and in patients where the tumor was closer than 6 cm to the anal verge, the response was better CONCLUSION: When the findings were examined, histopathological lymphovascular invasion, perineural invasion, the presence of necrosis, and the anal verge distance were evaluated as parameters predicting the response to neoadjuvant chemoradiotherapy in rectal cancer.

Beneficial effects of modulated electro-hyperthermia during neoadjuvant treatment for locally advanced rectal cancer

PURPOSE

Modulated electro-hyperthermia (mEHT) may enhance the tumor response, although the effectiveness of combined neoadjuvant therapy remains unclear. Therefore, we investigated the role of mEHT with neoadjuvant therapy for locally advanced rectal cancer.

MATERIALS AND METHODS

Clinical data were analyzed for 120 patients who received neoadjuvant treatment for locally advanced rectal cancer (T3/4 or N+, M0) from May 2012 to December 2017. Capecitabine or 5-fluorouracil was administered along with radiotherapy. Patients were categorized into mEHT group (62 patients) and non-mEHT group (58 patients) depending on whether mEHT was added. Surgery was performed 6-8 weeks after the end of radiotherapy.

RESULTS

The median age was 59 years (range, 33-83). The median radiation dose was significantly less for mEHT group (40 Gy) than for non-mEHT group (50.4 Gy). In mEHT group, 80.7% showed down-staging compared with 67.2% in non-mEHT group. For large tumors of more than 65 cm³ (mean), improved tumor regression was observed in 31.6% of mEHT group compared with 0% of non-mEHT group (p = .024). The gastrointestinal toxicity rate of mEHT group was 64.5%, which was found to be statistically significantly less than 87.9% of non-mEHT group (p = .010). The 2-year disease-free survival was 96% for mEHT group and 79% for non-mEHT group (p = .054).

CONCLUSION

The overall mEHT group had a comparable response and survival using less radiation dosing compared with standard care; the subgroup with large tumors showed improved efficacy for tumor regression after mEHT.

The value of the tumour-stroma ratio for predicting neoadjuvant chemoradiotherapy response in locally advanced rectal cancer: a case control study

BACKGROUND

The tumour-stroma ratio (TSR) is recognized as a practical prognostic factor in colorectal cancer. However, TSR assessment generally utilizes surgical specimens. This study aims to investigate whether the TSR evaluated from preoperative biopsy specimens by a semi-automatic quantification method can predict the response after neoadjuvant chemoradiotherapy (nCRT) of patients with locally advanced rectal cancer (LARC).

METHODS

A total of 248 consecutive patients diagnosed with LARC and treated with nCRT followed by resection were included. Haematoxylin and eosin (HE)-stained sections of biopsy specimens were collected, and the TSR was evaluated by a semi-automatic quantification method and was divided into three categories, using the cut-offs determined in the whole cohort to balance the proportion of patients in each category. The response to nCRT was evaluated on the primary tumour resection specimen by an expert pathologist using the four-tier tumour regression grade (TRG) system.

RESULTS

The TSR can discriminate patients that are major-responders (TRG 0-1) from patients that are non-responders (TRG 2-3). Patients were divided into stroma-low (33.5%), stroma-intermediate (33.9%), and stroma-high (32.7%) groups using 56.3 and 72.8% as the cutoffs. In the stroma-low group, 58 (69.9%) patients were major-responders, and only 39 (48.1%) patients were considered major-responders in the stroma-high group (P = 0.018). Multivariate analysis showed that the TSR was the only pre-treatment predictor of response to nCRT (adjusted odds ratio 0.40, 95% confidence interval 0.21-0.76, P = 0.002).

CONCLUSION

An elevated TSR in preoperative biopsy specimens is an independent predictor of nCRT response in LARC. This semi-automatic quantified TSR could be easily translated into routine pathologic assessment due to its reproducibility and reliability.

Predictive factors associated with complete pathological response after neoadjuvant treatment for rectal cancer

PURPOSE

A proportion of 10 to 30% of patients treated by chemoradiotherapy followed by total mesorectal excision surgery for a locally advanced rectal cancer can achieve a complete pathological response. We aimed to identify predictive factors associated with complete pathological response or no response and to assess the impact of each response on survival rates.

PATIENTS AND METHODS

Patients treated with long course chemoradiotherapy for locally advanced and/or node positive rectal cancer from 2010 to 2016 were retrospectively reviewed. Statistical analysis was carried out to determine predictors of tumor regression and treatment outcomes.

RESULTS

Records were available on 70 patients. In the univariate analysis, clinical factors associated with complete tumor response were tumor mobility in digital rectal examination (P=0.047), a limited parietal invasion (P=0.001), clinically negative lymph node (P<0.001) and a circumferential extent greater than 50% (P=0.001). On the other hand, a T4 classification and an endoscopic tumor size greater than 6cm were associated with no response to treatment (P=0.049 and P=0.017 respectively). On multivariate analysis, T2 clinical classification and N0 statement before treatment were independent predictive factors of pathologic complete response (P<0.001 and P=0.001) and a delayed surgery after 12 weeks was associated with no response to treatment (P=0.001).

CONCLUSION

The identification of predictive factors of histological response may help clinicians to predict the prognosis and to propose organ preservation for good responders.

γ-H2AX as a potential indicator of radiosensitivity in colorectal cancer cells

Preoperative radiotherapy improves local disease control and disease-free survival in patients with advanced rectal cancer; however, a reliable predictive biomarker for the effectiveness of irradiation has yet to be elucidated. Phosphorylation of H2A histone family member X (H2AX) to γ-H2AX is induced by DNA double-strand breaks and is associated with the development of colorectal cancer (CRC). The current study aimed to clarify the relationship between γ-H2AX expression and CRC radiosensitivity in vitro and in vivo. H2AX levels were analyzed in datasets obtained from cohort studies and γ-H2AX expression was investigated by performing immunohistochemistry and western blotting using clinical CRC samples from patients without any preoperative therapy. In addition, the CRC cell lines WiDr and DLD-1 were subjected to irradiation and/or small interfering RNA-H2AX, after which the protein levels of γ-H2AX were examined in samples obtained from patients undergoing preoperative chemoradiotherapy. To quantify the observable effect of treatment on cancer cells, outcomes were graded as follows: 1, mild; 2, moderate; and 3, marked, with defined signatures of cellular response. Datasets obtained from cohort studies demonstrated that H2AX mRNA levels were significantly upregulated and associated with distal metastasis and microsatellite instability in CRC tissues, in contrast to that of normal tissues. In addition, γ-H2AX was overexpressed in clinical samples. In vitro, following irradiation, γ-H2AX expression levels increased and cell viability decreased in a time-dependent manner. Combined irradiation and γ-H2AX knockdown reduced the viability of each cell line when compared with irradiation or γ-H2AX knockdown alone. Furthermore, among clinical CRC samples from patients undergoing preoperative chemoradiotherapy, levels of γ-H2AX in the grade 1 group were significantly higher than those in grade 2 or grade 3. In conclusion, γ-H2AX may serve as a novel predictive marker and target for preoperative radiotherapy effectiveness in patients with CRC.

Nomogram for predicting pathological complete response and tumor downstaging in patients with locally advanced rectal cancer on the basis of a randomized clinical trial

Background

Preoperative fluoropyrimidine with radiotherapy was regarded as the standard of care for locally advanced rectal cancer (LARC). The model for predicting pCR in LARC patients was based on standard treatment only. This study aimed to establish a nomogram with pretherapeutic parameters and different neoadjuvant regimens for predicting pathologic complete response (pCR) and tumor downstaging or good response (ypT0-2N0M0) after receiving neoadjuvant treatment in patients with LARC based on a randomized clinical trial.

Methods

Between January 2011 and February 2015, 309 patients with rectal cancer were enrolled from a prospective randomized study (NCT01211210). All pretreatment clinical parameters were collected to build a nomogram for predicting pCR and tumor downstaging. The model was subjected to bootstrap internal validation. The predictive performance of the model was assessed with concordance index (C-index) and calibration plots.

Results

Of the 309 patients, 53 (17.2%) achieved pCR and 132 (42.7%) patients were classified as tumor downstaging with ypT0-2N0M0. Based on the logistic-regression analysis and clinical consideration, tumor length (P = 0.005), tumor circumferential extent (P = 0.036), distance from the anal verge (P = 0.019), and neoadjuvant treatment regimen (P < 0.001) showed independent association with pCR following neoadjuvant treatment. The tumor length (P = 0.015), tumor circumferential extent (P = 0.001), distance from the anal verge (P = 0.032), clinical T category (P = 0.012), and neoadjuvant treatment regimen (P = 0.001) were significantly associated with good tumor downstaging (ypT0-2N0M0). Nomograms were developed to predict the probability of pCR and tumor downstaging with a C-index of 0.802 (95% confidential interval [CI], 0.736–0.867) and 0.730 (95% CI, 0.672–0.784). Internal validation revealed good performance of the calibration plots.

Conclusions

The nomogram provided individual prediction responses to different preoperative treatment for patients with rectal cancer. This model might help physicians in selecting an optimized treatment, but warrants further external validation.

Predictors of Early Distant Relapse in Rectal Cancer Patients Submitted to Preoperative Chemoradiotherapy

BACKGROUND

Neoadjuvant chemoradiotherapy (CRT) is a standard treatment for locally advanced rectal cancer. CRT leads to a better local control; however, this does not translate into a survival benefit. Long-term survival is mostly affected by the development of distant metastases after surgery. This study aimed to evaluate predictive clinical factors for the development of early metastatic disease after CRT.

METHODS

Clinical data of patients with stage II/III rectal cancer submitted to CRT between January 2000 and October 2014 were collected from prospectively maintained electronic databases of three Italian institutes. Patients were divided into two groups: those who developed metastasis within 12 months from surgical resection (Group A) and patients without or with late distant relapse (Group B).

RESULTS

Among 635 patients, 86 (13.5%) had early distant relapse within 1 year from surgery (Group A), and 549 (86.5%) did not (Group B). A higher rate of early distant relapse was associated with CEA levels above 3 ng/dL (20% vs. 10%; p <0.001), tumor lying under 5 cm from anal verge (20% vs. 9%; p <0.001), and age under 63 years (17% vs. 11%; p = 0.036). Multivariate analysis confirmed these factors to be independently correlated with a higher risk of early metastasis.

CONCLUSIONS

Younger age, low tumors, and high serum CEA may be associated with unfavorable early oncological outcomes after CRT and surgery for rectal cancer. These clinical factors could be useful to select patients for more aggressive therapeutic strategies.

Predictive value of serum and tissue carcinoembryonic antigens for radiologic response and oncologic outcome of rectal cancer

PURPOSE

The clinical importance of tissue CEA levels for predicting tumor response to preoperative chemoradiotherapy (CRT) for rectal cancer has not been studied.

METHODS

Serum CEA levels and tissue CEA expressions for 117 patients who underwent preoperative CRT for rectal cancer, were prospectively collected and analyzed at a tertiary university hospital RESULTS: The median follow-up time was 49 months (range, 3-61 months), and the 5-year disease-free survival (DFS) rate was 68.3 %. In multivariate analysis, serum CEA (log-transformed value) [odds ratio (OR) = 0.741, 95 % confidence interval (CI) 1.588-40.422, P =  0.021], tissue CEA/GAPDH ratio (OR = 3.673, 95 % CI 1.316-12.081, P =  0.019), and tumor circumferentiality (OR = 2.960, 955 CI, 1.101-8.999, P =  0.040) were the independent predictors for good tumor response to CRT. Serum CEA level was significant prognostic factor for DFS (P =  0.004) in multivariate analysis. However, tissue CEA was not associated with DFS.

CONCLUSIONS

Both serum and tissue CEA were significant factors for predicting good tumor response following preoperative CRT. However, tissue CEA was not associated with the oncologic outcome. The possibility of radiologic resistance of high CEA tumors is expected to be investigated through further studies.

A Multigene Model for Predicting Tumor Responsiveness After Preoperative Chemoradiotherapy for Rectal Cancer

PURPOSE

Although preoperative chemoradiotherapy (PCRT) is regarded as a standard treatment for locally advanced rectal cancer, there is no reliable biomarker for predicting responsiveness to PCRT. We aimed to develop a biomarker model for predicting response to PCRT.

METHODS AND MATERIALS

We included 184 patients who received PCRT followed by surgical resection and categorized them as good responders (complete or near-complete regression) or poor responders (all other patients). Candidate gene mRNAs were isolated from formalin-fixed paraffin-embedded tumor specimens and analyzed using the NanoString nCounter gene expression assay. Stepwise logistic regression analysis was used to select genes in discovery and training phases. A quantitative radio-responsiveness prediction model was developed and validated using internal cross-validation groups, and the model's predictive value was assessed based on the area under the receiver operating characteristic curve (AUC).

RESULTS

By comparing the gene expressions between good and poor responders, we created a multigene mRNA model using FZD9, HRAS, ITGA7, MECOM, MMP3, NKD1, PIK3CD, and PRKCB. This panel showed good ability to predict treatment response (AUC: 0.846 for the whole data set). Internal cross-validation was performed to evaluate the model's predictive stability among 3 cohorts, which provided AUC values of 0.808-0.909. The satisfactory diagnostic performance of the radio-response prediction index persisted regardless of other clinicopathologic features such as clinical T or N stage, interval between radiation and surgery, and pretreatment carcinoembryonic antigen levels (P = .001, 95% CI, 0.686-0.905).

CONCLUSIONS

We developed a multigene mRNA-based biomarker model that allows prediction of rectal cancer response to PCRT, which may help identify patients who will benefit most from PCRT.

Predictors and Risk Factors of Pathologic Complete Response Following Neoadjuvant Chemoradiotherapy for Rectal Cancer: A Population-Based Analysis

Background: Patients with rectal cancer who achieve pathologic complete response (pCR) after neoadjuvant chemoradiotherapy (nCRT) may have a better prognosis and may be eligible for non-operative management. The aim of this research was to identify variables for predicting pCR in rectal cancer patients after nCRT and to define clinical risk factors for poor outcome after pCR to nCRT and radical resection in rectal cancer patients. Methods: A retrospective review was performed using the Surveillance, Epidemiology, and End Results (SEER) database from 2004 to 2013. Non-metastatic rectal cancer patients who received radical resection after neoadjuvant chemoradiotherapy were included in this study. Multivariate analysis of the association between clinicopathological characteristics and pCR was performed, and a logistic regression model was used to identify independent predictors for pCR. A nomogram based on the multivariate logistics regression was built with decision curve analyses to evaluate the clinical usefulness. Results: A total of 6,555 patients were included in this study. The proportion of patients with pCR was 20.5% (n = 1,342). The nomogram based on multivariate logistic regression analysis showed that clinical T4 and N2 stages were the most significant independent clinical predictors for not achieving pCR, followed by mucinous adenocarcinoma and positive pre-treatment serum CEA results. The 3-year overall survival rate was 92.4% for those with pCR and 88.2% for those without pCR. Among all the pCR patients, mucinous adenocarcinoma patients had the worst survival, with a 3-year overall survival rate of 67.5%, whereas patients with common adenocarcinoma had an overall survival rate of 93.8% (P < 0.001). Univariate and multivariate analyses showed that histology and clinical N2 stage were independent risk factors. Conclusion: Mucinous adenocarcinoma, positive pre-treatment serum CEA results, and clinical T4 and N2 stages may impart difficulty for patients to achieve pCR. Mucinous adenocarcinoma and clinical N2 stage might be indicative of a prognostically unfavorable biological tumor profile with a greater propensity for local or distant recurrence and decreased survival.

Pretreatment Tumor Thickness as a Predictor of Pathologic Complete Response to Neoadjuvant Chemoradiation Therapy for Stage II/III Rectal Adenocarcinoma

OBJECTIVES

To evaluate pretreatment tumor thickness in predicting pathologic complete response (pCR) of stage II/III rectal adenocarcinoma to neoadjuvant chemoradiation (chemoradiotherapy [CRT]).

METHODS

We retrospectively analyzed 185 patients who were diagnosed with stage II or III rectal adenocarcinoma from January 2011 to July 2013 and treated with neoadjuvant intensity-modulated radiation therapy (45 Gy in 1.8-Gy fractions to pelvis and 50 Gy in 2-Gy fractions to rectal tumor as an integrated boost) or 3 dimensionally conformal radiation therapy (45 Gy in 1.8-Gy fractions to pelvis followed by an additional 5.4-Gy to rectal tumor) concurrently with two 3-week cycles of chemotherapy (oxaliplatin 130 mg/m on day 1 and capecitabine 825 mg/m, twice per day from day 1 to 14, cycle 2 starts on week 4). One week after CRT, 36% patients received 1 more cycle of the above chemotherapy and 55% received 1 to 2 cycles of FOLFOX6. Tumor response was categorized as pCR and non-pCR. Tumor thickness measured on magnetic resonance imaging was collected. A multivariate logistic regression model was used to evaluate the association of potential predictors and pCR.

RESULTS

Thirty-eight patients (20.5%) reached pCR. Multivariate analysis found the pretreatment tumor thickness to be associated with higher probability of pCR after adjusting for radiation therapy-surgery interval time and pretreatment carcino-embryonic antigen level. The pretreatment carcino-embryonic antigen level was associated with pCR in the univariate analysis but lost the association in the multivatiate model. The pretreatment T or N stage, tumor volume, distance from tumor to anal verge, craniocaudal length of tumor, radiation therapy technique, and patient age and sex were not associated with pCR.

CONCLUSIONS

We concluded that pretreatment tumor thickness is an independent predictor for pCR of stage II/III rectal adenocarcinoma to the neoadjuvant CRT.

Analysis of unexplained carcinoembryonic antigen elevation after curative treatment of locally advanced rectal cancer

BACKGROUND

To analyze the causes and patterns of unexplained carcinoembryonic antigen (CEA) elevation after curative treatment in locally advanced rectal cancer patients.

METHODS

Among the 1309 locally advanced rectal cancer patients treated with curative resection and radiotherapy between January 2001 and June 2011, 325 patients who postoperatively developed abnormal CEA elevation were reviewed. The unexplained CEA elevation was defined as a CEA level higher than 5 ng/mL with no evidence of cancer recurrence at the time of elevation.

RESULTS

Of the 325 patients, 143 (44%) had unexplained CEA elevations. The causes were categorized as delayed recurrence (n = 29, 20%), non-colorectal malignancy (n = 10, 7%), and non-malignancy-related conditions (n = 104, 73%). Shorter intervals between treatment and the first CEA elevation, and a higher peak CEA level, were observed in the delayed recurrence group compared with the non-colorectal malignancy or non-malignancy-related group (intervals of 6.8 vs. 44.9 vs. 23.2 months, respectively, p = 0.002; and peak CEA levels of 9.9 vs. 7.1 vs. 6.2 ng/mL, respectively, p = 0.034). In patients who showed delayed recurrence, the interval between the first CEA elevation and diagnosis of recurrence was a median of 13.0 months (range 3.8-60.6 months). Smoking was the most common cause for non-malignancy-related conditions. The patterns of unexplained CEA elevations were defined as sporadic (n = 78, 55%), stationary (n = 37, 26%), and increasing (n = 28, 20%). The patterns were significantly different depending on the cause (p < 0.001).

CONCLUSIONS

Analysis of the patterns of unexplained CEA elevations is a reasonable approach to predict the cause of the cancer.

Carcinoembryonic antigen as a marker of radioresistance in colorectal cancer: a potential role of macrophages

Background

We sought to identify the carcinoembryonic antigen (CEA) as a marker of radioresistance in rectal cancer.

Methods

From July 1997 to January 2008, 104 patients with stage II or III rectal cancer who were treated with post-operative radiotherapy (PORT) were included in this study. The doses of radiotherapy ranged from 45 to 54.6 Gy. The CEA levels were measured before surgery. We analyzed the actuarial rates of overall survival (OS), distant metastasis (DM), and local recurrence (LR) using Kaplan-Meier curves. Multivariate analyses were performed with Cox regression models. We used THP-1 monocyte cell lines for macrophage differentiation (M0, M1 or M2). The RNA extracted from the macrophages was analyzed via a genomic method in the core laboratory. The radiosensitivities of CEA-rich LS1034 cells were compared between cells with and without the conditioned media from CEA-stimulated macrophages.

Results

Preoperative CEA levels ≥10 ng/mL were independent predictive factors for OS (p = 0.005), DM (p = 0.026), and LR (p = 0.004). The OS rates among the patients with pretreatment CEA levels < 10 ng/mL and ≥10 ng/mL were 64.5% and 35.9% (p = 0.004), respectively. The corresponding rates of DM were 40.6% and 73.1% (p = 0.024). The corresponding rates of LR were 6.6% and 33.9% (p = 0.002). In the M0 macrophages, exogenous CEA elicited a dose-response relationship with M2 differentiation. In the CEA-stimulated M0 cells, some mRNAs were upregulated by as much as 5-fold, including MMP12, GDF15, and JAG1. In the CEA-stimulated M2 cells, a 4-fold up-regulation of GADD45G mRNA was noted. The conditioned media from the CEA-stimulated M2 cells elicited an increase in the numbers of LS180, SW620, and LS1034 cells after irradiation. CEA caused the M2 differentiation of the macrophages.

Conclusion

Pretreatment CEA levels ≥10 ng/mL are a significant risk factor for OS, DM, and LR following PORT for rectal cancer. CEA causes radioresistance in the presence of M2 macrophages. More comprehensive examinations prior to surgery and intensive adjuvant therapy are suggested for patients with CEA levels ≥10 ng/mL. Further studies of these mechanisms are needed.

Watch-and-Wait as a Therapeutic Strategy in Rectal Cancer

Purpose of Review

Pathological complete response is seen in approximately one fifth of rectal cancer patients following neoadjuvant chemoradiation. Since these patients have excellent oncological outcomes, there has been a rapidly growing interest in organ preservation for those who develop a clinical complete response. We review the watch-and-wait strategy and focus on all aspects of this hot topic, including who should be considered for this approach, how should we identify treatment response and what are the expected outcomes.

Recent Findings

The major challenges in interpreting the data on watch-and-wait are the significant heterogeneity of patients selected for this approach and of methods employed to identify them. The evidence available comes mostly from retrospective cohort studies, but has shown good oncological outcomes, including the rate of successful salvage surgery, locoregional control and overall survival.

Summary

There is currently not enough and not robust enough evidence to support watch-and-wait as a standard approach, outside a clinical trial, for patients achieving clinical complete response following neoadjuvant chemoradiation. Furthermore, there is a lack of data on long-term outcomes. However, the results we have so far are promising, and there is therefore an urgent need for randomised control studies such as the TRIGGER trial to confirm the safety of this strategy.

Importance of the Circumferential Extent of Tumors and Clinical Lymph Node Status as Prognostic Factors after Preoperative Chemoradiotherapy and Surgery in Patients with Rectal Cancer

Aims and background

To evaluate the clinical factors that influence pathological and clinical outcomes after preoperative concurrent chemoradiotherapy in patients with rectal cancer.

Methods

Between 1999 and 2004, 121 patients with cT3-4 or node-positive rectal cancer received preoperative chemoradiotherapy and surgery. Preoperative radiation therapy with 45 Gy was delivered. Fluorouracil-based chemotherapy was administered to most of the patients.

Results

Pathological complete remission was 14.3% after preoperative chemoradiotherapy. More than 60% tumor circumferential extent was an independent adverse factor for complete remission (P = 0.011, HR 4.643, 95% CI 1.415–15.231). Local recurrence developed in 9.9% of the cases. Serum CEA level ≥5 ng/ml (P = 0.057, HR 3.022, 95% CI 0.967–9.441) and >60% circumferential extent of tumor (P = 0.064, HR 4.232, 95% CI 0.918–19.531) were marginal adverse factors for local recurrence. Five-year disease-free survival and overall survival were 72.2% and 86.6%, respectively. Disease-free survival was poor for patients with the lymph nodes ≥1 cm in diameter (P = 0.028), cN2 stage disease (P = 0.047) and >60% circumferential extent of tumor (P = 0.058). Multivariate analysis for disease-free survival showed that the lymph node size ≥1 cm was an adverse factor (P = 0.019, HR 2.380, 95% CI 1.115–4.906). Patients with >60% circumferential extent of tumor and cN2 stage had a more unfavorable survival than the other patients (disease-free survival, P = 0.018; overall survival, P = 0.015). Patients with >60% circumferential extent of tumor and/or lymph node ≥1 cm also had an unfavorable survival (disease-free survival, P = 0.016; overall survival, P = 0.049).

Conclusions

In rectal cancer, circumferential extent of tumor and clinical lymph node status were important factors for preoperative chemoradiotherapy and surgery. A further prospective study is needed to confirm and expand these findings.

Predictors of Sensitivity to Preoperative Chemoradiotherapy of Rectal Adenocarcinoma

Objectives

The purpose of the study was to identify predictive factors of tumor response to preoperative chemoradiotherapy for rectal adenocarcinoma.

Methods

Ninety-eight patients with nonmetastatic rectal adenocarcinoma received preoperative concurrent chemoradiotherapy and underwent mesorectal excision. After treatment, tumor response according to tumor regression grade were evaluated. The correlation of clinicopathologic factors to tumor response was analyzed.

Results

The results from a univariate analysis indicated that pretreatment carcinoembryonic antigen level ≤3.0 ng/ml (P = 0.002), non-fixed tumor (P = 0.001), and tumor circumferential extent ≤50% (P = 0.001) were associated significantly with a good tumor response. They also indicated that pretreatment positive lymph nodes (P = 0.032) were associated significantly with a poor tumor response. In multivariate analysis, the results indicated that pretreatment carcinoembryonic antigen level (hazard ratio, 2.930; P = 0.003), tumor mobility (hazard ratio, 2.651; P = 0.002) and circumferential extent of tumor (hazard ratio, 2.394; P = 0.019) independently predicted a good pathologic response rate. Pretreatment positive lymph nodes were not significantly associated with a good response (hazard ratio, 0.361; P = 0.191).

Conclusions

Pretreatment carcinoembryonic antigen level, tumor mobility and circumferential extent of tumor may be helpful in predicting responsiveness in rectal adenocarcinoma to preoperative chemoradiotherapy, although the results should be confirmed in larger, more homogeneous studies.

Can an IL13 -1112 C/T (rs1800925) polymorphism predict responsiveness to neoadjuvant chemoradiotherapy and survival of Chinese Han patients with locally advanced rectal cancer?

We sought to determine whether a polymorphism in the Interleukin 13 gene (IL13), 1112 C/T (rs1800925) predicts responsiveness to neoadjuvant chemoradiotherapy (neoCRT) and prognosis in Chinese Han patients with locally advanced rectal cancer (LARC). Pre-treatment biopsies of primary rectal lesion and surgical specimens were collected from 58 patients with LARC, who were treated with neoCRT and surgery. Tumor DNA was extracted from these biopsies and sequenced to analyze the rs1800925 polymorphism. The tumor response to neoCRT was categorized using a tumor regression grade (TRG, 0-2 were poor responders; 3-4 were good responders). Analyses of progression free survival (PFS) and overall survival (OS) were carried out using the Kaplan-Meier method. Of the forty-six patients for whom tumor DNA was successfully sequenced, 23 were good responders to neoCRT (11 patients with a pathological complete response, i.e. pCR) and the other 23 were poor responders. Good and poor responders were equally likely to have a C/C genotype at rs1800925 (73.9%) as a T/T or C/T genotype (26.1%). There were no differences between the C/C and T/T+C/T genotypes with respect to the ypT0-2 ratio (38.2% vs. 41.7%, P = 1.0), ypN0 nodal status (67.6% vs. 50.0%, P= 0.314), 6-year PFS (67.6% vs. 50%, P=0.274), or 6-year OS (76.5% vs. 66.7%, P=0.441). Thus, the IL13-1112 C/T (rs1800925) polymorphism does not predict responsiveness to neoCRT or prognosis of Chinese Han patients with LARC.

Relations of Changes in Serum Carcinoembryonic Antigen Levels before and after Neoadjuvant Chemoradiotherapy and after Surgery to Histologic Response and Outcomes in Patients with Locally Advanced Rectal Cancer

OBJECTIVES

The histologic response to neoadjuvant chemoradiotherapy (nCRT) has been intimately related to outcomes in locally advanced rectal cancer. Serum carcinoembryonic antigen (CEA) levels change after nCRT and after surgery as compared with before nCRT.

METHODS

The subjects were 149 patients with locally advanced rectal cancer who received nCRT between 2005 and 2013. The patients were divided into 4 groups according to the serum CEA levels: group 1, 55 patients with negative serum CEA levels before nCRT; group 2, 41 patients with positive serum CEA levels before nCRT that became negative after nCRT; group 3, 37 patients with positive serum CEA levels after nCRT that became negative after surgery; and group 4, 16 patients with positive serum CEA levels after nCRT as well as after surgery.

RESULTS

Pathological complete response, T downstaging, and tumor shrinkage were significantly higher in group 1 than in other groups. Disease-free survival was significantly poorer in group 4. The lack of a decrease in the serum CEA level in group 4 was most likely attributed to the persistence of micrometastases outside the resection field.

CONCLUSIONS

Changes in serum CEA levels measured before nCRT, after nCRT, and after surgery can be used to reliably predict the histologic response to nCRT and outcomes.

Elevated CEA is associated with worse survival in recurrent rectal cancer

This study investigated the prognostic impact of serum carcinoembryonic antigen (CEA) level in recurrent rectal cancer. We reviewed 745 patients who developed recurrence after curative treatment for rectal cancer between January 2000 and December 2012. Multivariate analyses for survival revealed that age > 60 years (p = 0.005), r-CEA ≥ 5 ng/ml (p < 0.001), disease free interval (DFI) < 12 months (p < 0.001), and palliative or conservative treatment (p < 0.001) were unfavorable factors.

Endoscopic assessment of tumor regression after preoperative chemoradiotherapy as a prognostic marker in locally advanced rectal cancer

PURPOSE

This study was designed to evaluate tumor regression endoscopic criteria for predicting the post-chemoradiotherapy (CRT) prognosis of patients with locally advanced rectal cancer.

MATERIAL AND METHODS

A total of 425 patients with rectal cancer who received radical surgery after CRT were included in this study. All patients were divided into two groups according to post-CRT preoperative endoscopic findings: 1) good response (E-GR): scar, telangiectasia, or erythema; 2) minimal or no response (E-MR): nodules, ulcers, strictures, or remnant tumor. Cox proportional hazard models were used to analyze the effect of preoperative clinicopathological variables on disease-free survival (DFS) and overall survival (OS).

RESULTS

The independent prognostic factors for DFS were tumor location less than 5 cm from anal verge (hazard ratio [HR] 1.92, 95% confidence interval [CI] 1.27 to 2.88), pre-CRT carcinoembryonic antigen (CEA) > 5 ng/mL (HR 2.10, 95% CI 1.41 to 3.14), histologic high grade (HR 2.96, 95% CI 1.51 to 5.81), and E-GR (HR 0.26, 95% CI 0.08 to 0.83). The independent prognostic factors for OS were age over 65 years, tumor location, pre-CRT CEA, histologic grade, and E-GR (HR 0.13, 95% CI 0.02 to 0.99).

CONCLUSIONS

Post-CRT endoscopic findings were predictors of prognosis in patients with rectal cancer. If endoscopic findings are simultaneously used with certain preoperative prognostic factors, rectal cancer patients will potentially have more treatment options.

The neutrophil to albumin ratio as a predictor of pathological complete response in rectal cancer patients following neoadjuvant chemoradiation

Pathological complete response (pCR) following neoadjuvant chemoradiotherapy (nCRT) and total mesorectal excision (TME), in patients with locally advanced rectal cancer, occurs in 15-27% of patients. Because blood cell counts and albumin are a direct indicator of the host environment, a response to nCRT might be predicted by these markers. This study was carried out to determine whether the neutrophil to albumin ratio (NAR) was predictive of pCR in veteran patients. Ninety-eight patients with rectal cancer who underwent standard nCRT, followed by TME were analyzed. Pre-nCRT and post-nCRT hematologic data were collected. Univariate and multivariate analyses were carried out. Kaplan-Meier curves were constructed with our primary endpoint of pCR. Male patients (99%), age 62.4±9.1 years, BMI=27.4±5.9 kg/m, rectal cancer distance from anal verge=7.1±4.5 cm (SD), interval between nCRT and TME=8 weeks, 55% patients=low anterior resection, 95% received 5-fluorouracil, and all patients received radiation, with 15% achieving a pCR. Univariate analysis showed that pre-nCRT carcinoembryonic antigen (15.8±45.1 vs. 3.5±5.3 ng/dl; P=0.002) and the pre-nCRT NAR (16.4±4.8 vs. 14.2±1.6; P=0.002) were associated with pCR. On multivariate analysis, pre-nCRT carcinoembryonic antigen (odds ratio=0.41, 95% confidence interval 0.22-0.77) and pre-nCRT NAR (odds ratio=0.76, 95% confidence interval 0.60-0.97) remained independent predictors of pCR. Overall survival between nonresponders and pCR patients at 1, 5, and 10 years was 96, 62, and 44% versus 93, 85, and 61%, P=0.13, and disease-free survival was 95, 60, and 47% versus 93, 85, and 61%, P=0.17; respectively. Our study shows that the pre-nCRT NAR is an independent predictor of pCR. These findings should be applied to other cohorts to determine its validity and reliability for use as a potential predictor of pCR.

Predicting response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer with serum biomarkers

Introduction The aim of this study was to identify patient factors including serum biomarkers that may predict response to neoadjuvant chemoradiotherapy (CRT) in patients with locally advanced rectal cancer staged on magnetic resonance imaging. Prediction of response may be helpful when selecting patients for a non-operative programme. Methods A retrospective review was carried out of patients undergoing neoadjuvant CRT for rectal cancer, conducted at the Royal Devon and Exeter Hospital. All patients were managed through the multidisciplinary team. Receiver operating characteristic (ROC) curve analysis was undertaken to assess the ability of biomarkers to predict response to neoadjuvant CRT. The biomarkers assessed included neutrophils, lymphocytes, monocytes, haemoglobin, platelets, C-reactive protein and carcinoembryonic antigen. Results Seventy-three patients underwent neoadjuvant CRT between January 2006 and December 2011. Nine (12.3%) of these experienced a clinical complete response and were managed with a 'watch and wait' approach. An additional ten patients (13.7%) had a pathological complete response following surgery. Using ROC curve analysis, the biomarkers with the largest area under the curve (AUC) were pre-CRT haemoglobin and post-CRT lymphocyte concentrations, producing AUC values of 0.673 and 0.618 respectively for clinical complete response. Pre-CRT haemoglobin and neutrophil concentrations produced the highest AUC values for pathological complete response at 0.591 and 0.614 respectively. Conclusions None of the assessed biomarkers offer the ability to predict response to neoadjuvant CRT in patients with rectal cancer. They cannot therefore assist in identifying complete clinical or pathological responders who could be considered for a non-operative, observational approach.

Oncogene mutation profile predicts tumor regression and survival in locally advanced rectal cancer patients treated with preoperative chemoradiotherapy and radical surgery

Tumor response to preoperative chemoradiotherapy and postoperative survival differs among patients with locally advanced rectal cancer. The objective was to find correlations of mutated oncogenes and clinical outcomes in locally advanced rectal cancer. A total of 70 patients with preoperative preoperative chemoradiotherapy followed by radical surgery at a single cancer center between 2006 and 2012 were enrolled. Pretreatment tumor biopsy samples were assayed for 238 mutation hotspots harboring 19 oncogenes by time-of-flight mass spectrometry and OncoCarta Array. Oncogene mutations were found in 48.6% of patients (34/70). KRAS was the most frequent driver mutation, found in 35.7% of patients (25/70), followed by PIK3CA (14.3%), NRAS (5.7%), FLT3 (2.9%), and BRAF (1.4%). Multiple gene mutations were observed in eight patients (11.4%). Tumors with KRAS mutations responded poorly to preoperative chemoradiotherapy (p = 0.044). Patients with oncogene mutations had worse 3-year disease-free survival than those without mutations (67.2% vs 94.2%, p = 0.010). Patients with KRAS or RAS mutations had lower 3-year disease-free survival (68% vs 88.3%, p = 0.016; 65.5% vs 92.3%, p = 0.004, respectively) and 3-year overall survival (88% vs 95.4%, p = 0.020; 89.7% vs 94.9%, p = 0.036, respectively) than those without KRAS or RAS mutations. Oncogene mutation status affected tumor response to treatment and long-term survival in locally advanced rectal cancer.

Prediction of radio-responsiveness with immune-profiling in patients with rectal cancer

We evaluate whether the tumor immune infiltrate (TIL) could be used for prediction of responsiveness to preoperative chemoradiotherapy (PCRT) in rectal cancers. Using formalin-fixed paraffin-embedded slides of pretreatment biopsies, co-stain for CD4, CD8, CD274 (PD-L1), FOXP3, cytokeratin, and DAPI was performed with Opal multi staining kit (Perkin-Elmer, Waltham, MA). Multispectral imaging and digital analysis to visualize and quantify specific immune infiltrates were performed using the Vectra imaging system (Perkin-Elmer). The density (number of cells per mm²) and proportion of total TILs and specific cell types in the stroma were calculated by inForm™ 2.2.1 software (Perkin-Elmer). The density and proportion of total TILs and specific cell types in the stroma were calculated by inForm™ 2.2.1 software (Perkin-Elmer, Waltham, MA). Patients were classified as group with total regression (TR, n = 25) and group with residual disease (near total, moderate, and minimal regression, RD, n = 50). The mean density of T cell infiltration and CD274 (PD-L1)+ lymphocyte were significantly higher in TR (p = 0.005, p = 0.001). The proportion of CD4+ lymphocyte (p=0.042) and CD274 (PD-L1)+ lymphocyte (p = 0.002) were different between 2 groups. The TR group has lower CD4+ and higher CD274 (PD-L1)+ proportions than RD group. The ratio among CD4+, CD8+, CD274 (PD-L1)+, FOXP3+ T cell was different between groups. TR group showed lower CD4/ CD274 (PD-L1) (p = 0.007), CD8/ CD274 (PD-L1) (p = 0.02), and FOXP3/ CD274 (PD-L1) (p = 0.003) ratio than RD group. The determination of the immune infiltrate in biopsies before treatment could be a valuable information for the prediction of responsiveness to PCRT.

What has preoperative radio(chemo)therapy brought to localized rectal cancer patients in terms of perioperative and long-term outcomes over the past decades? A systematic review and meta-analysis based on 41,121 patients

We asked what preoperative radiotherapy/chemoradiotherapy (PRT/PCRT) has brought to patients in terms of perioperative and long-term outcomes over the past decades. A systematic review and meta-analysis was conducted using PubMed, Embase and Web of Science databases. All original comparative studies published in English that were related to PRT/PCRT and surgical resection and which analyzed survival, postoperative and quality of life outcomes were included. Data synthesis and statistical analysis were carried out using Stata software. Data from 106 comparative studies based on 80 different trials enrolling 41,121 patients were included in our study. Based on our overall analyses, PRT/PCRT significantly improved patients' local recurrence-free survival (LRFS), but neither overall survival (OS) nor metastasis-free survival (MFS) showed improvement. In addition, PRT significantly increased the postoperative morbidity and mortality but PCRT did not have a significant effect. Furthermore, PRT/PCRT significantly increased the risk of postoperative wound complications but not anastomotic leakage and bowel obstruction. Our comprehensive subgroup analyses further supported the aforementioned results. Meanwhile, long-term anorectal symptoms (impaired squeeze pressures, use of pads, incontinence and urgency) and erectile dysfunction were also significantly increased in patients after PRT/PCRT. The benefits of PRT/PCRT as applied over the last several decades have not been sufficient to improve OS. Metastases of primary tumor and postoperative adverse effects were the two primary obstacles for an improved OS. In fact, the greatest advantage of PRT/PCRT is still local tumor control and a significantly improved LRFS.

Predictive and Prognostic Molecular Biomarkers for Response to Neoadjuvant Chemoradiation in Rectal Cancer

The standard of care in locally advanced rectal cancer is neoadjuvant chemoradiation (nCRT) followed by radical surgery. Response to nCRT varies among patients and pathological complete response is associated with better outcome. However, there is a lack of effective methods to select rectal cancer patients who would or would not have a benefit from nCRT. The utility of clinicopathological and radiological features are limited due to lack of adequate sensitivity and specificity. Molecular biomarkers have the potential to predict response to nCRT at an early time point, but none have currently reached the clinic. Integration of diverse types of biomarkers including clinicopathological and imaging features, identification of mechanistic link to tumor biology, and rigorous validation using samples which represent disease heterogeneity, will allow to develop a sensitive and cost-effective molecular biomarker panel for precision medicine in rectal cancer. Here, we aim to review the recent advance in tissue- and blood-based molecular biomarker research and illustrate their potential in predicting nCRT response in rectal cancer.

Tumor compactness improves the preoperative volumetry-based prediction of the pathological complete response of rectal cancer after preoperative concurrent chemoradiotherapy

In addition to clinical factors (tumor and node stage) and treatment factors (equivalent radiotherapy dose and chemotherapy regimen), we assessed whether different performances of various tumor volume measurements help predict the pathological complete response (pCR) of locally advanced rectal cancer (LARC) after preoperative concurrent chemoradiotherapy (CCRT). A total of 122 patients with LARC treated with a long course of CCRT, between December 2009 and March 2015, were enrolled in this bi-institutional study. Tumor delineation was based on standard T2-weighted magnetic resonance imaging or contrast-enhanced computed tomography before CCRT. Tumor compactness was defined as the ratio of the volume and the surface area. The tumor compactness-corrected TV (TCTV) was defined as the ratio of the real TV (RTV) and tumor compactness. Twenty-three (18.9%) patients had a pCR. Areas under the curve of the receiver operating characteristic for pCR prediction calculated using the RTV, cylindrical approximated TV (CATV), and TCTV were 0.724, 0.747, and 0.780, respectively. The prediction performance of TCTV was significantly more efficient than that of both RTV (P = 0.0057) and CATV (P = 0.0329). Multivariate logistic regression analysis revealed tumor compactness (P = 0.001), RTV (P = 0.042), and preoperative clinical nodal status (P = 0.044) as significant predictors of a pCR. In addition, poor tumor compactness was closely associated with lymphovascular space invasion (P = 0.008) and pathological nodal status (P = 0.003). For patients with LARC receiving preoperative CCRT, tumor compactness is a useful radiomic parameter for improving the volumetric based prediction model.

Potential predictive factors for pathologic complete response after the neoadjuvant treatment of rectal adenocarcinoma: a single center experience

OBJECTIVE

: To assess the response rate of patients with rectal adenocarcinoma to neoadjuvant therapy and to identify the predictors of histological regression after neoadjuvant radiotherapy (RT) or concurrent chemoradiotherapy (CCRT).

METHODS

: This study recruited 64 patients. The patients had resectable cancer of the lower and the middle rectum (T3/T4 and/or N+) without distant metastasis and received neoadjuvant RT or CCRT followed by radical surgery with total mesorectal excision (TME) between January 2006 and December 2011. The patients were classified into non-response (NR), partial response (PR), and pathologic complete response (pCR) based on the Dworak tumor regression grading system.

RESULTS

: The median age of patients was 57 years (ranging from 22 to 85). A total of 24 patients were treated with neoadjuvant CCRT, whereas 40 patients were treated with RT alone. Abdominoperineal resection (APR) was performed on 29 patients (45%). Anterior resection with TME was performed on 34 patients (53%). One patient had local resection. Histologically, 12 (19%), 24 (73%), and 28 (44%) patients exhibited pCR, PR, and NR, respectively. Univariate analysis revealed that the predictors of tumor regression were as follows: the absence of lymph node involvement from initial imaging (cN0) (P=0.021); normal initial carcinoembryonic antigen (CEA) level (P=0.01); hemoglobin level ≥12 g/dl (P=0.009); CCRT (P=0.021); and tumor downstaging in imaging (P=0.001). Multivariate analysis showed that the main predictors of pCR were CT combined with neoadjuvant RT, cN0 stage, and tumor regression on imaging.

CONCLUSIONS

: Identifying the predictors of pCR following neoadjuvant therapy aids the selection of responsive patients for non-aggressive surgical treatment and possible surveillance.

NEOADJUVANT THERAPY AND SURGERY FOR RECTAL CANCER. Comparative study between partial and complete pathological response

BACKGROUND

The approach of locally advanced extra-peritoneal rectal adenocarcinoma implies a treatment with neoadjuvant chemoradiotherapy associated with total mesorectal excision surgery. However, the tumors respond variably to this neoadjuvant therapy, and the mechanisms for response are not completely understood.

OBJECTIVE

Evaluate the variables related to the complete tumor response and the outcomes of patients who underwent surgery, comparing those with partial tumor regression and those with total remission of rectal lesion, at the pathological examination.

METHODS

Retrospective analysis of medical records of 212 patients operated between 2000 and 2010, in which 182 (85.9%) obtained partial remission at neoadjuvant therapy (Group 1) and 30 (14.1%), total remission (Group 2).

RESULTS

No difference was found between the groups in relation to gender, ethnicity, age, tumor distance from the anal verge, occurrence of metastases and synchronous lesions on preoperative staging, dose of radiotherapy and performed surgery. In Group 2, was verified high rate of complete remission when the time to surgery after neoadjuvant therapy was equal or less than 8 weeks (P=0.027), and a tendency of lower levels of pretreatment carcinoembryonic antigen (P=0.067). In pathological analysis, the Group 1 presented in relation to Group 2, more affected lymph nodes (average 1.9 and 0.5 respectively; P=0.003), more angiolymphatic (19.2% and 3.3%; P=0.032) and perineural involvement (15.4% and 0%; P=0.017) and greater number of lymph nodes examined (16.3 and 13.6; P=0.023). In the late follow-up, Group 1 also had lower overall survival than Group 2 (94.1 months and 136.4 months respectively; P=0.02) and disease-free survival (85.5 months and 134.6 months; P=0.004). There was no statistical difference between Group 2 and Group 1 in local recurrence (15% and 3.4%, respectively) and distant metastasis (28% and 13.8%, respectively).

CONCLUSION

In this study, the only factor associated with complete remission of rectal adenocarcinoma was the time between neoadjuvant therapy and surgery. This group of patients had less affected lymph nodes, less angiolymphatic and perineural involvement, a longer overall and disease-free survival, but no significant statistical difference was observed in local recurrence and distant metastasis. Although the complete pathologic remission was associated with better prognosis, this not implied in the cure of the disease for all patients.

Can serum dynamics of carcinoembryonic antigen level during neoadjuvant chemoradiotherapy in rectal cancer predict tumor response and recurrence? A multi-institutional retrospective study

PURPOSE

We evaluate whether the change of carcinoembryonic antigen (CEA) level before and after preoperative chemoradiotherapy (CRT) in rectal cancer affects tumor response and recurrence or not.

METHODS

We retrospectively analyzed 1447 rectal cancer patients who underwent preoperative CRT followed by curative surgery. All patients received preoperative radiotherapy of 50.4 Gy in 28 fractions with 5-fluorouracil or capecitabine. Total mesorectal excision was performed 4 to 8 weeks after preoperative CRT. CEA levels were checked before and after CRT. Clinical and pathologic factors were analyzed for tumor response and recurrence.

RESULTS

Post-CRT CEA level (cutoff value, 2.5 ng/mL) was not a significant factor for tumor response on the multivariate analysis (p = 0.095). Patients were categorized according to the pre- and post-CRT CEA level (group A: pre-CRT CEA ≤5 ng/mL; group B: pre-CRT CEA >5 ng/mL and post-CRT CEA ≤2.5 ng/mL; group C: pre-CRT CEA >5 ng/mL and post-CRT CEA >2.5 ng/mL). The relapse-free survival (RFS) at 5 years was significantly higher in group A than in groups B and C (82.6 vs. 73.7 % vs. 72.2 %, p < 0.001). The overall survival (OS) at 5 years was significantly higher in group A than in groups B and C (90.1 vs. 84.4 % vs. 83.4 %, p < 0.001). However, there is no significant difference for RFS and OS between groups B and C (all, p > 0.05).

CONCLUSIONS

Decline of elevated CEA level (>5 ng/mL) during preoperative chemoradiotherapy has no significant effect on tumor response and recurrence in rectal cancer.

Can clinical factors be used as a selection tool for an organ-preserving strategy in rectal cancer?

BACKGROUND

Rectal cancer patients who achieve a good response to chemoradiotherapy (CRT), may be offered less invasive surgery or even no surgery at all. Implementation of such a policy, however, requires precise patient selection. This study identifies pretreatment clinical factors that are associated with pathological complete response (pCR) and ypT0-1N0 and evaluates their performance as a selection tool for organ-preserving strategies.

MATERIAL AND METHODS

Patients with rectal cancer treated with CRT and total mesorectal excision between January 2000 and December 2014 were retrospectively included. Following clinical characteristics were extracted from the medical files: age, gender, body mass index, ASA score, cT-stage, cN-stage, distance from the anal verge, pretreatment carcinoembryonic antigen (CEA), pretreatment hemoglobin and distance from the mesorectal fascia. Univariable and multivariable binary logistic regression models were used to predict pCR and ypT0-1N0. The discriminative ability of the prediction models was evaluated by receiver operating characteristic analysis.

RESULTS

A total of 620 patients were included of whom 120 experienced a pCR (19%) and 170 patients achieved ypT0-1N0 response (27%). A low pretreatment CEA, a high pretreatment hemoglobin and a high cN-stage were associated with pCR in multivariable analysis. A low pretreatment CEA, a low cT-stage and a high cN-stage were associated with ypT0-1N0. After cross validation, the area under the curve for the pCR and ypT0-1N0 prediction model equaled 0.609 and 0.632, respectively.

CONCLUSION

Despite their statistical significance, the value of pretreatment clinical variables in the prediction of pCR and ypT0-1N0 is very limited. To safely select patients for organ preservation, other strategies need to be explored.

Clinical factors of post-chemoradiotherapy as valuable indicators for pathological complete response in locally advanced rectal cancer

OBJECTIVES

Pathological complete response has shown a better prognosis for patients with locally advanced rectal cancer after preoperative chemoradiotherapy. However, correlations between post-chemoradiotherapy clinical factors and pathologic complete response are not well confirmed. The aim of the current study was to identify post-chemoradiotherapy clinical factors that could serve as indicators of pathologic complete response in locally advanced rectal cancer.

METHODS

This study retrospectively analyzed 544 consecutive patients with locally advanced rectal cancer treated at Sun Yat-sen University Cancer Center from December 2003 to June 2014. All patients received preoperative chemoradiotherapy followed by surgery. Univariate and multivariate regression analyses were performed to identify post-chemoradiotherapy clinical factors that are significant indicators of pathologic complete response.

RESULTS

In this study, 126 of 544 patients (23.2%) achieved pathological complete response. In multivariate analyses, increased pathological complete response rate was significantly associated with the following factors: post-chemoradiotherapy clinical T stage 0-2 (odds ratio=2.098, 95% confidence interval=1.023-4.304, p=0.043), post-chemoradiotherapy clinical N stage 0 (odds ratio=2.011, 95% confidence interval=1.264-3.201, p=0.003), interval from completion of preoperative chemoradiotherapy to surgery of >7 weeks (odds ratio=1.795, 95% confidence interval=1.151-2.801, p=0.010) and post-chemoradiotherapy carcinoembryonic antigen ≤2 ng/ml (odds ratio=1.579, 95% confidence interval=1.026-2.432, p=0.038).

CONCLUSIONS

Post-chemoradiotherapy clinical T stage 0-2, post-chemoradiotherapy clinical N stage 0, interval from completion of chemoradiotherapy to surgery of >7 weeks and post-chemoradiotherapy carcinoembryonic antigen ≤2 ng/ml were independent clinical indicators for pathological complete response. These findings demonstrate that post-chemoradiotherapy clinical factors could be valuable for post-operative assessment of pathological complete response.

Increased tumor response to neoadjuvant therapy among rectal cancer patients taking angiotensin-converting enzyme inhibitors or angiotensin receptor blockers

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are commonly used antihypertensive medications that have been reported to affect aberrant angiogenesis and the dysregulated inflammatory response. Because of such mechanisms, it was hypothesized that these medications might affect the tumor response to neoadjuvant radiation in patients with rectal cancer.

METHODS

One hundred fifteen patients who were treated with neoadjuvant radiation at the University of Wisconsin (UW) between 1999 and 2012 were identified. Univariate analyses were performed with anonymized patient data. In a second independent data set, 186 patients with rectal cancer who were treated with neoadjuvant radiation at the Queen's Medical Center of the University of Hawaii (UH) between 1995 and 2010 were identified. These data were independently analyzed as before. Multivariate analyses were performed with aggregate data.

RESULTS

Among patients taking ACEIs/ARBs in the UW data set, a significant 3-fold increase in the rate of pathologic complete response (pCR) to neoadjuvant therapy (52% vs 17%, P = .001) was observed. This finding was confirmed in the UH data set, in which a significant 2-fold-increased pCR rate (24% vs 12%, P = .03) was observed. Identified patient and treatment characteristics were otherwise balanced between patients taking and not taking ACEIs/ARBs. No significant effect was observed on pCR rates with other medications, including statins, metformin, and aspirin. Multivariate analyses of aggregate data identified ACEI/ARB use as a strong predictor of pCR (odds ratio, 4.02; 95% confidence interval, 2.06-7.82; P < .001).

CONCLUSIONS

The incidental use of ACEIs/ARBs among patients with rectal cancer is associated with a significantly increased rate of pCR after neoadjuvant treatment. Cancer 2016;122:2487-95. © 2016 American Cancer Society.

Focal adhesion kinase: predictor of tumour response and risk factor for recurrence after neoadjuvant chemoradiation in rectal cancer

Rectal cancer represents about 30% of colorectal cancers, being around 50% locally advanced at presentation. Chemoradiation (CRT) followed by total mesorectal excision is the standard of care for these locally advanced stages. However, it is not free of adverse effects and toxicity and the complete pathologic response rate is between 10% and 30%. This makes it extremely important to define factors that can predict response to this therapy. Focal adhesion kinase (FAK) expression has been correlated with worse prognosis in several tumours and its possible involvement in cancer radio‐ and chemosensitivity has been suggested; however, its role in rectal cancer has not been analysed yet. To analyse the association of FAK expression with tumour response to CRT in locally advanced rectal cancer. This study includes 73 patients with locally advanced rectal cancer receiving standard neoadjuvant CRT followed by total mesorectal excision. Focal adhesion kinase protein levels were immunohistochemically analysed in the pre‐treatment biopsies of these patients and correlated with tumour response to CRT and patients survival. Low FAK expression was significantly correlated with local and distant recurrence (P = 0.013). Low FAK expression was found to be a predictive marker of tumour response to neoadjuvant therapy (P = 0.007) and patients whose tumours did not express FAK showed a strong association with lower disease‐free survival (P = 0.01). Focal adhesion kinase expression predicts neoadjuvant CRT response in rectal cancer patients and it is a clinically relevant risk factor for local and distant recurrence.

Predicting pathological complete response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer: a systematic review

AIM

Approximately 20% of patients treated with neoadjuvant chemoradiotherapy (nCRT) for locally advanced rectal cancer achieve a pathological complete response (pCR) while the remainder derive the benefit of improved local control and downstaging and a small proportion show a minimal response. The ability to predict which patients will benefit would allow for improved patient stratification directing therapy to those who are likely to achieve a good response, thereby avoiding ineffective treatment in those unlikely to benefit.

METHOD

A systematic review of the English language literature was conducted to identify pathological factors, imaging modalities and molecular factors that predict pCR following chemoradiotherapy. PubMed, MEDLINE and Cochrane Database searches were conducted with the following keywords and MeSH search terms: 'rectal neoplasm', 'response', 'neoadjuvant', 'preoperative chemoradiation', 'tumor response'. After review of title and abstracts, 85 articles addressing the prediction of pCR were selected.

RESULTS

Clear methods to predict pCR before chemoradiotherapy have not been defined. Clinical and radiological features of the primary cancer have limited ability to predict response. Molecular profiling holds the greatest potential to predict pCR but adoption of this technology will require greater concordance between cohorts for the biomarkers currently under investigation.

CONCLUSION

At present no robust markers of the prediction of pCR have been identified and the topic remains an area for future research. This review critically evaluates existing literature providing an overview of the methods currently available to predict pCR to nCRT for locally advanced rectal cancer. The review also provides a comprehensive comparison of the accuracy of each modality.

Association of pretreatment serum carcinoembryonic antigen levels with chemoradiation-induced downstaging and downsizing of rectal cancer

The aim of this study was to identify pretreatment clinical parameters associated with preoperative chemoradiotherapy (CRT)-induced downstaging and downsizing of locally advanced rectal cancer (LARC T3-4 or N+). Data from 51 LARC patients, who received preoperative CRT and radical surgery between 2010 and 2013, were retrospectively analyzed. Rectal adenocarcinoma was histologically confirmed in all patients, who ranged in age between 41 and 81 years (median, 64 years). CRT consisted of 50.4 Gy pelvic radiotherapy with concurrent chemotherapy using 5-fluorouracil and leucovorin. After a median interval of 7 weeks post-CRT, the patients underwent total mesorectal excision. Downstaging was defined as the transition from cStage II-III to ypStage 0-I. The longest tumor diameter was measured pre- and post-CRT using computed tomography or magnetic resonance imaging, and based on the surgical specimen, respectively. Downstaging was observed in 16 (31.4%) patients, including 5 (9.8%) with a pathological complete response. The median downsizing rate was 60%. The serum carcinoembryonic antigen (CEA) levels were 0.8-153.9 ng/ml (median, 4.4 ng/ml). The maximum standardized uptake value was 4.7-33.9 (median, 10.8). On univariate analysis, cT stage, tumor size and CEA level were associated with downstaging. On multivariate analysis, only CEA level (≤5 ng/ml) was a significant predictor of downstaging (odds ratio = 16.0; 95% confidence interval: 1.8-146.7; P=0.014). CEA level was the only factor significantly associated with downsizing (>60%) in the univariate analysis. These results demonstrated that pretreatment serum CEA levels are significantly associated with downstaging as well as downsizing of LARC following preoperative CRT. Therefore, this parameter may be useful in personalizing the management of LARC patients.

Predictors of Complete Response and Disease Recurrence Following Chemoradiation for Rectal Cancer

OBJECTIVE

Approximately 10-40% of rectal patients have a complete response (CR) to neoadjuvant chemoradiation (CRT), and these patients have improved survival. Thus, non-operative management ("watch-and-wait" approach) may be an option for select patients. We aimed to identify clinical predictors of CR following CRT.

METHODS

Patients treated with definitive CRT for T3-T4, locally unresectable T1-T2, low-lying T2, and/or node-positive rectal cancer from August 2004 to February 2015 were retrospectively reviewed. Most patients were treated with 50.4 Gy radiation and concurrent 5-fluoruracil or capecitabine. Patients were considered to have a CR if surgical pathology revealed ypT0N0M0 (operative management), or if they had no evidence of residual disease on clinical and radiographic assessment (non-operative management). Statistical analysis was carried out to determine predictors of CR and long-term outcomes.

RESULTS

Complete records were available on 138 patients. The median follow-up was 24.5 months. Thirty-six patients (26.3%) achieved a CR; 30/123 operatively managed patients (24.5%) and 6/15 (40%) non-operatively managed patients. None of the 10 patients with mucinous adenocarcinoma achieved a CR. Carcinoembryonic antigen (CEA) ≥5 μg/L at diagnosis (OR 0.190, 95% CI 0.037-0.971, p = 0.046), tumor size ≥3 cm (OR 0.123, 95% CI 0.020-0.745, p = 0.023), distance of tumor from the anal verge ≥3 cm (OR 0.091, 95% CI 0.013-0.613, p = 0.014), clinically node-positive disease at diagnosis (OR 0.201, 95% CI 0.045-0.895, p = 0.035), and interval from CRT to surgery ≥8 weeks (OR 5.267, 95% CI 1.068-25.961, p = 0.041) were independent predictors of CR. The CR group had longer 3-year distant metastasis-free survival (DMFS) (93.7 vs. 63.7%, p = 0.016) and 3-year disease-free survival (DFS) (91.1 vs. 67.8%, p = 0.038). Three-year locoregional control (LRC) (96.6 vs. 81.3%, p = 0.103) and overall survival (97.2 vs. 87.5%, p = 0.125) were higher in the CR group but this did not achieve statistical significance. CR was not an independent predictor of LRC, DMFS, or DFS.

CONCLUSION

CEA at diagnosis, tumor size, tumor distance from the anal verge, node positivity at diagnosis, and interval from CRT to surgery were predictors of CR. These clinical variables may offer insight into patient selection and timing of treatment response evaluation in the watch-and-wait approach.

Predictors of Pathologic Complete Response Following Neoadjuvant Chemoradiotherapy for Rectal Cancer

BACKGROUND

Some patients with rectal cancer who receive neoadjuvant chemoradiotherapy (nCRT) achieve a pathologic complete response (pCR) and may be eligible for less radical surgery or non-operative management. The aim of this study was to identify variables that predict pCR after nCRT for rectal cancer and to examine the impact of pCR on postoperative complications.

METHODS

A retrospective review was performed of the NCDB from 2006 to 2011. Patients with rectal cancer who received nCRT followed by radical resection were included in this study. Multivariable analysis of the association between clinicopathologic characteristics and pCR was performed, and propensity-adjusted analysis was used to identify differences in postoperative morbidity between pCR and non-pCR patients.

RESULTS

A total of 23,747 patients were included in the study. Factors associated with pCR included lower tumor grade, lower clinical T and N stage, higher radiation dose, and delaying surgery by more than 6-8 weeks after the end of radiation, while lack of health insurance was linked with a lower likelihood of pCR. Complete response was not associated with an increased risk of major postoperative complications.

CONCLUSIONS

Several clinical, pathologic, and treatment variables can help to predict which patients are most likely to have pCR after nCRT for rectal cancer. Awareness of these variables can be valuable in counseling patients regarding prognosis and treatment options.

Carcinoembryonic antigen has prognostic value for tumor downstaging and recurrence in rectal cancer after preoperative chemoradiotherapy and curative surgery: A multi-institutional and case-matched control study of KROG 14-12

BACKGROUND AND PURPOSE

The Korean Radiation Oncology Group evaluated the significance of carcinoembryonic antigen (CEA) levels both as a predictor of tumor response after CRT and as a prognosticator for recurrence-free survival.

METHODS AND MATERIALS

1804 rectal cancer patients, staged cT3-4N0-2M0, participated in a multicenter study. The patients were administered preoperative radiation of 50.4 Gy in 28 fractions with 5-FU or capecitabine, followed by total mesorectal excision. Patients with elevated CEA levels (>5 ng/mL) were matched at a 1 (n=595):1 (n=595) ratio with patients with normal CEA (⩽5 ng/mL). The tumor response after CRT and the recurrence-free survival (RFS) rates were evaluated and compared between two arms.

RESULTS

An elevated CEA level (p<0.001) was determined to be a significant negative predictor of downstaging after CRT. The downstaging rate was 42.9% for normal CEA and 23.4% for elevated CEA. A multivariate analysis also revealed that cT (p=0.021) and cN classification (p=0.001), tumor size (p=0.002), and tumor location from the anal verge (p=0.006) were significant predictors for tumor downstaging. The 5-year RFS rates were significantly higher for the normal CEA arm than for the elevated CEA arm (74.2 vs. 63.5%, p<0.001).

CONCLUSIONS

Elevated CEA (>5 ng/mL) is a negative predictor of tumor downstaging after CRT and also has a negative impact on RFS in rectal cancer.

Clinical parameters predicting pathologic complete response following neoadjuvant chemoradiotherapy for rectal cancer

Introduction

Preoperative chemoradiotherapy (CRT), followed by total mesorectal excision, has become the standard of care for patients with clinical stages II and III rectal cancer. Patients with pathologic complete response (pCR) to preoperative CRT have been reported to have better outcomes than those without pCR. However, the factors that predict the response to neoadjuvant CRT have not been well defined. In this study, we aimed to investigate the impact of clinical parameters on the development of pCR after neoadjuvant chemoradiation for rectal cancer.

Methods

A total of 323 consecutive patients from a single institution who had clinical stage II or III rectal cancer and underwent a long-course neoadjuvant CRT, followed by curative surgery, between 2005 and 2013 were included. Patients were divided into two groups according to their responses to neoadjuvant therapy: the pCR and non-pCR groups. The clinical parameters were analyzed by univariate and multivariate analyses, with pCR as the dependent variable.

Results

Of the 323 patients, 75 (23.2%) achieved pCR. The two groups were comparable in terms of age, sex, body mass index, tumor stage, tumor location, tumor differentiation, radiation dose, and chemotherapy regimen. On multivariate analysis, a pretreatment carcinoembryonic antigen (CEA) level of ≤5 ng/mL [odds ratio (OR) = 2.170, 95% confidence interval (CI) = 1.195–3.939, P = 0.011] and an interval of >7 weeks between the completion of chemoradiation and surgical resection (OR = 2.588, 95% CI = 1.484–4.512, P = 0.001) were significantly associated with an increased rate of pCR.

Conclusions

The pretreatment CEA level and neoadjuvant chemoradiotherapy-surgery interval were independent clinical predictors for achieving pCR. These results may help clinicians predict the prognosis of patients and develop adaptive treatment strategies.

Biomarkers and Molecular Imaging as Predictors of Response to Neoadjuvant Chemoradiotherapy in Patients With Locally Advanced Rectal Cancer

Standard treatment of patients with locally advanced rectal cancer (LARC) includes neoadjuvant chemoradiotherapy (NCRT) followed by surgery. Tumor regression after NCRT varies substantially among individuals and pathological complete response is a known prognostic factor for LARC. The identification of a predictive model for response to chemoradiotherapy would help clinicians to identify patients who would probably benefit from multimodal treatment and to perform an early assessment of individual prognosis. Carcinoembryonic antigen has proven to be a good predictor of response in several clinical trials. Other widely studied predictive models in LARC include molecular biomarkers, analyzed at various levels and by different techniques, and molecular imaging, in particular magnetic resonance imaging and positron emission tomography/computed tomography. Although none of the studied markers have been approved in clinical practice, their evaluation in larger, prospective trials and in combined predictive models could be of use to define tailored therapeutic strategies.