Locally advanced rectal cancer: time for precision therapeutics

Development and Assessment of a Clinical Calculator for Estimating the Likelihood of Recurrence and Survival Among Patients With Locally Advanced Rectal Cancer Treated With Chemotherapy, Radiotherapy, and Surgery

IMPORTANCE

Predicting outcomes in patients receiving neoadjuvant therapy for rectal cancer is challenging because of tumor downstaging. Validated clinical calculators that can estimate recurrence-free survival (RFS) and overall survival (OS) among patients with rectal cancer who have received multimodal therapy are needed.

OBJECTIVE

To develop and validate clinical calculators providing estimates of rectal cancer recurrence and survival that are better for individualized decision-making than the American Joint Committee on Cancer (AJCC) staging system or the neoadjuvant rectal (NAR) score.

DESIGN, SETTING, AND PARTICIPANTS

This prognostic study developed risk models, graphically represented as nomograms, for patients with incomplete pathological response using Cox proportional hazards and multivariable regression analyses with restricted cubic splines. Because patients with complete pathological response to neoadjuvant therapy had uniformly favorable outcomes, their predictions were obtained separately. The study included 1400 patients with stage II or III rectal cancer who received treatment with chemotherapy, radiotherapy, and surgery at 2 comprehensive cancer centers (Memorial Sloan Kettering [MSK] Cancer Center and Siteman Cancer Center [SCC]) between January 1, 1998, and December 31, 2017. Patients from the MSK cohort received chemoradiation, surgery, and adjuvant chemotherapy from January 1, 1998, to December 31, 2014; these patients were randomly assigned to either a model training group or an internal validation group. Models were externally validated using data from the SCC cohort, who received either chemoradiation, surgery, and adjuvant chemotherapy (chemoradiotherapy group) or short-course radiotherapy, consolidation chemotherapy, and surgery (total neoadjuvant therapy with short-course radiotherapy group) from January 1, 2009, to December 31, 2017. Data were analyzed from March 1, 2020, to January 10, 2021.

EXPOSURES

Chemotherapy, radiotherapy, chemoradiotherapy, and surgery.

MAIN OUTCOMES AND MEASURES

Recurrence-free survival and OS were the outcome measures, and the discriminatory performance of the clinical calculators was measured with concordance index and calibration plots. The ability of the clinical calculators to predict RFS and OS was compared with that of the AJCC staging system and the NAR score. The models for RFS and OS among patients with incomplete pathological response included postoperative pathological tumor category, number of positive lymph nodes, tumor distance from anal verge, and large- and small-vessel venous and perineural invasion; age was included in the risk model for OS. The final clinical calculators provided RFS and OS estimates derived from Kaplan-Meier curves for patients with complete pathological response and from risk models for patients with incomplete pathological response.

RESULTS

Among 1400 total patients with locally advanced rectal cancer, the median age was 57.8 years (range, 18.0-91.9 years), and 863 patients (61.6%) were male, with tumors at a median distance of 6.7 cm (range, 0-15.0 cm) from the anal verge. The MSK cohort comprised 1069 patients; of those, 710 were assigned to the model training group and 359 were assigned to the internal validation group. The SCC cohort comprised 331 patients; of those, 200 were assigned to the chemoradiotherapy group and 131 were assigned to the total neoadjuvant therapy with short-course radiotherapy group. The concordance indices in the MSK validation data set were 0.70 (95% CI, 0.65-0.76) for RFS and 0.73 (95% CI, 0.65-0.80) for OS. In the external SCC data set, the concordance indices in the chemoradiotherapy group were 0.71 (95% CI, 0.62-0.81) for RFS and 0.72 (95% CI, 0.59-0.85) for OS; the concordance indices in the total neoadjuvant therapy with short-course radiotherapy group were 0.62 (95% CI, 0.49-0.75) for RFS and 0.67 (95% CI, 0.46-0.84) for OS. Calibration plots confirmed good agreement between predicted and observed events. These results compared favorably with predictions based on the AJCC staging system (concordance indices for MSK validation: RFS = 0.69 [95% CI, 0.64-0.74]; OS = 0.67 [95% CI, 0.58-0.75]) and the NAR score (concordance indices for MSK validation: RFS = 0.56 [95% CI, 0.50-0.63]; OS = 0.56 [95% CI, 0.46-0.66]). Furthermore, the clinical calculators provided more individualized outcome estimates compared with the categorical schemas (eg, estimated RFS for patients with AJCC stage IIIB disease ranged from 7% to 68%).

CONCLUSIONS AND RELEVANCE

In this prognostic study, clinical calculators were developed and validated; these calculators provided more individualized estimates of the likelihood of RFS and OS than the AJCC staging system or the NAR score among patients with rectal cancer who received multimodal treatment. The calculators were easy to use and applicable to both short- and long-course radiotherapy regimens, and they may be used to inform surveillance strategies and facilitate future clinical trials and statistical power calculations.

Preoperative assessment of lymph node metastasis in clinically node-negative rectal cancer patients based on a nomogram consisting of five clinical factors

Background

Currently, reliable approaches for accurate assessment of lymph node metastases (LNM), which is an important indication of preoperative chemoradiotherapy (CRT), are not available for clinically node-negative rectal cancer patients. This study aims to identify clinical factors associated with LNM and to establish a nomogram for LNM prediction in clinically node-negative rectal cancer patients.

Methods

The least absolute shrinkage and selection operator (LASSO) aggression and multivariate logistic regression analyses were applied to identify clinical factors associated with LNM. A nomogram was established to predict the probability of LNM in clinically node-negative rectal cancer patients based on the multivariate logistic regression model.

Results

Six potential risk factors were selected on the basis of LASSO aggression analysis, and five of them were identified as independent risk factors for LNM based on multivariate analysis, including MRI-reported tumor location, clinical T classification, MRI-reported tumor diameter, white blood cell count (WBC), and preoperative elevated tumor markers. A nomogram consisting of the five clinical factors was established and showed good discrimination. Decision curve analysis demonstrated that the established nomogram was reliable and accurate for LNM prediction in clinically node-negative rectal cancer patients.

Conclusions

A nomogram based on five clinical factors, including MRI-reported tumor location, clinical T classification, MRI-reported tumor diameter, WBC, and preoperative elevated tumor markers, are useful for assessing LNM in clinically node-negative rectal cancer patients, which is important for preoperative CRT regimens.

Systematic review of treatment intensification using novel agents for chemoradiotherapy in rectal cancer

BACKGROUND

With the well established shift to neoadjuvant treatment for locally advanced rectal cancer, there is increasing focus on the use of radiosensitizers to improve the efficacy and tolerability of radiotherapy. There currently exist few randomized data exploring novel radiosensitizers to improve response and it is unclear what the clinical endpoints of such trials should be.

METHODS

A qualitative systematic review was performed according to the PRISMA guidelines using preset search criteria across the PubMed, Cochrane and Scopus databases from 1990 to 2017. Additional results were generated from the reference lists of included papers.

RESULTS

A total of 123 papers were identified, of which 37 were included; a further 60 articles were obtained from additional referencing to give a total of 97 articles. Neoadjuvant radiosensitization for locally advanced rectal cancer using fluoropyrimidine-based chemotherapy remains the standard of treatment. The oral derivative capecitabine has practical advantages over 5-fluorouracil, with equal efficacy, but the addition of a second chemotherapeutic agent has yet to show a consistent significant efficacy benefit in randomized clinical assessment. Preclinical and early-phase trials are progressing with promising novel agents, such as small molecular inhibitors and nanoparticles.

CONCLUSION

Despite extensive research and promising preclinical studies, a definite further agent in addition to fluoropyrimidines that consistently improves response rate has yet to be found.

Potential of memory T cells in bridging preoperative chemoradiation and immunotherapy in rectal cancer

The management of locally advanced rectal cancer has passed a long way of developments, where total mesorectal excision and preoperative radiotherapy are crucial to secure clinical outcome. These and other aspects of multidisciplinary strategies are in-depth summarized in the literature, while our mini-review pursues a different goal. From an ethical and medical standpoint, we witness a delayed implementation of novel therapies given the cost/time consuming process of organizing randomized trials that would bridge an already excellent local control in cT3-4 node-positive disease with long-term survival. This unfortunate separation of clinical research and medical care provides a strong motivation to repurpose known pharmaceuticals that suit for treatment intensification with a focus on distant control. In the framework of on-going phase II-III IG/IMRT-SIB trials, we came across an intriguing translational observation that the ratio of circulating (protumor) myeloid-derived suppressor cells to (antitumor) central memory CD8+ T cells is drastically increased, a possible mechanism of tumor immuno-escape and spread. This finding prompts that restoring the CD45RO memory T-cell pool could be a part of integrated adjuvant interventions. Therefore, the immunocorrective potentials of modified IL-2 and the anti-diabetic drug metformin are thoroughly discussed in the context of tumor immunobiology, mTOR pathways and revised Warburg effect.

The survival and clinicopathological differences between patients with stage IIIA and stage II rectal cancer: An analysis of 12,036 patients in the SEER database

BACKGROUND

Stage IIIA rectal cancer has distinctive oncological features, including limited depth of intestinal wall invasion and early regional lymph node metastasis. We aim to compare survival outcomes and clinicopathological features for stage IIIA rectal cancer with those for stage II rectal cancer.

METHODS

We analyzed patients with stage II or stage IIIA rectal cancer treated with surgery without receiving preoperative radiotherapy based on data from the US Surveillance, Epidemiology, and End Results (SEER) database between 1988 and 2003. Survival curves were plotted using the Kaplan-Meier method. Multivariate Cox proportional analyses were utilized to analyze independent prognostic factors for cancer-specific survival (CSS).

RESULTS

We included 12,036 rectal cancer patients (10,132 stage II and 1,904 stage IIIA) from the SEER database. Patients with stage IIIA rectal cancer had smaller tumor size than patients with stage II rectal cancer. A multivariate analysis suggested that compared with patients with stage IIIA rectal cancer, patients with stage II disease were more likely to have more unfavorable CSS (HR 1.195, 95% CI 1.079-1.324, p=0.001). When stage II rectal cancer was further analyzed as stage IIA, IIB and IIC rectal cancer, the multivariate analysis indicated that compared with patients with stage IIIA rectal cancer, patients with stage IIA rectal cancer (HR 1.113, 95% CI 1.003-1.235, p=0.044), stage IIB rectal cancer (HR 1.493, 95% CI 1.267-1.758, p<0.001) and stage IIC rectal cancer (HR 2.712, 95% CI 2.319-3.171, p<0.001) were also more likely to exhibit more unfavorable CSS.

CONCLUSIONS

Patients with stage IIIA rectal cancer had more favorable survival outcomes and smaller tumor size compared with patients with stage II rectal cancer.

Cetuximab Combined With Induction Oxaliplatin and Capecitabine, Followed by Neoadjuvant Chemoradiation for Locally Advanced Rectal Cancer: SWOG 0713

BACKGROUND

Neoadjuvant chemoradiation (NCRT) is standard treatment for locally advanced rectal cancer. Pathologic complete response (pCR) has associated with improved survival. In modern phase III trials of NCRT, pCR ranges from 10% to 20%. Cetuximab improves response in KRAS (KRAS proto-oncogene) wild type (wt) metastatic colorectal cancer. S0713 was designed to assess improvement in pCR with additional use of cetuximab with induction chemotherapy and NCRT for locally advanced, KRAS-wt rectal cancer.

PATIENTS AND METHODS

Patient eligibility: stage II to III biopsy-proven, KRAS-wt rectal adenocarcinoma; no bowel obstruction; adequate hematologic, hepatic and renal function; performance status of 0 to 2. Target enrollment: 80 patients.

TREATMENT

induction chemotherapy with wCAPOX (weekly capecitabine and oxaliplatin) and cetuximab followed by the same regimen concurrent with radiation (omitting day 15 oxaliplatin). If fewer than 7 pCRs were observed at planned interim analysis after 40 patients received all therapy, the study would close. Eighty eligible patients would provide 90% power given a true pCR rate > 35% at a significance of 0.04. The regimen would lack future interest if pCR probability was ≤ 20%.

RESULTS

Between February 2009 and April 2013, 83 patients registered. Four were ineligible and 4 not treated, leaving 75 evaluable for clinical outcomes and toxicity, of whom 65 had surgery. Of 75 patients, 20 had pCR (27%; 95% confidence interval [CI], 17%-38%); 19 (25%) had microscopic cancer; 36 (48%) had minor/no response (including 10 without surgery). Three-year disease-free survival was 73% (95% CI, 63%-83%).

CONCLUSION

Our trial did not meet the pCR target of 35%. Toxicity was generally acceptable. This regimen cannot be recommended outside the clinical trial setting.

Oral versus intravenous fluoropyrimidines for colorectal cancer

BACKGROUND

Patients prefer oral to intravenous (IV) palliative chemotherapy, provided that oral therapy is not less effective. We compared the efficacy and safety of oral and IV fluoropyrimidines for treatment of colorectal cancer (CRC).

OBJECTIVES

To compare the effects of oral and IV fluoropyrimidine chemotherapy in patients treated with curative or palliative intent for CRC.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 5), along with OVID MEDLINE, OVID Embase, and Web of Science databases, in June 2016. We also searched five clinical trials registers, several conference proceedings, and reference lists from study reports and systematic reviews. We contacted pharmaceutical companies to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing oral and IV fluoropyrimidine chemotherapy in patients treated with curative or palliative intent for CRC.

DATA COLLECTION AND ANALYSIS

Three review authors extracted data and assessed risk of bias independently. We assessed the seven domains in the Cochrane 'Risk of bias' tool and three additional domains: schedules of outcome assessment and/or follow-up; use of intention-to-treat analysis; and baseline comparability of treatment arms.

MAIN RESULTS

We included nine RCTs (total of 10,918 participants) that examined treatment with curative intent for CRC with neoadjuvant and/or adjuvant chemotherapy. We included 35 RCTs (total of 12,592 participants) that examined treatment with palliative intent for inoperable advanced or metastatic CRC with chemotherapy (31 first-line studies, two second-line studies, and two studies of first- or second-line chemotherapy). All studies included male and female participants, and no studies included participants younger than 18 years of age. Patients treated with curative intent for CRC with neoadjuvant and/or adjuvant chemotherapy • Disease-free survival (DFS): DFS did not differ between participants treated with oral versus IV fluoropyrimidines (hazard ratio (HR) 0.93, 95% confidence interval (CI) 0.87 to 1.00; seven studies, 8903 participants; moderate-quality evidence).• Overall survival (OS): OS did not differ between participants treated with oral versus IV fluoropyrimidines (HR 0.92, 95% CI 0.84 to 1.00; seven studies, 8902 participants analysed; high-quality evidence).• Grade ≥ 3 adverse events (AEs): Participants treated with oral fluoropyrimidines experienced less grade ≥ 3 neutropenia/granulocytopenia (odds ratio (OR) 0.14, 95% CI 0.11 to 0.16; seven studies, 8087 participants; moderate-quality evidence), stomatitis (OR 0.21, 95% CI 0.14 to 0.30; five studies, 4212 participants; low-quality evidence), and any grade ≥ 3 AEs (OR 0.82, 95% CI 0.74 to 0.90; five studies, 7741 participants; low-quality evidence). There was more grade ≥ 3 hand foot syndrome (OR 4.59, 95% CI 2.97 to 7.10; five studies, 5731 participants; low-quality evidence) in patients treated with oral fluoropyrimidines. There were no differences between participants treated with oral versus IV fluoropyrimidines in occurrence of grade ≥ 3 diarrhoea (OR 1.12, 95% CI 0.99 to 1.25; nine studies, 9551 participants; very low-quality evidence), febrile neutropenia (OR 0.59, 95% CI 0.18 to 1.90; four studies, 2925 participants; low-quality evidence), vomiting (OR 1.05, 95% CI 0.83 to 1.34; eight studies, 9385 participants; low-quality evidence), nausea (OR 1.21, 95% CI 0.97 to 1.51; seven studies, 9233 participants; low-quality evidence), mucositis (OR 0.64, 95% CI 0.25 to 1.62; four studies, 2233 participants; very low-quality evidence), and hyperbilirubinaemia (OR 1.67, 95% CI 0.52 to 5.38; three studies, 2757 participants; very low-quality evidence). Patients treated with palliative intent for inoperable advanced or metastatic CRC with chemotherapy • Progression-free survival (PFS): Overall, PFS was inferior in participants treated with oral versus IV fluoropyrimidines (HR 1.06, 95% CI 1.02 to 1.11; 23 studies, 9927 participants; moderate-quality evidence). Whilst PFS was worse in participants treated with oral compared with IV fluoropyrimidines when UFT/Ftorafur or eniluracil with oral 5-fluorouracil (5-FU) was used, PFS did not differ between individuals treated with oral versus IV fluoropyrimidines when capecitabine, doxifluridine, or S-1 was used.• OS: Overall, OS did not differ between participants treated with oral versus IV fluoropyrimidines (HR 1.02, 95% CI 0.99 to 1.05; 29 studies, 12,079 participants; high-quality evidence). OS was inferior in participants treated with oral versus IV fluoropyrimidines when eniluracil with oral 5-fluorouracil (5-FU) was used.• Time to progression (TTP): TTP was inferior in participants treated with oral versus IV fluoropyrimidines (HR 1.07, 95% CI 1.01 to 1.14; six studies, 1970 participants; moderate-quality evidence).• Objective response rate (ORR): ORR did not differ between participants treated with oral versus IV fluoropyrimidines (OR 0.98, 95% CI 0.90 to 1.06; 32 studies, 11,115 participants; moderate-quality evidence).• Grade ≥ 3 AEs: Participants treated with oral fluoropyrimidines experienced less grade ≥ 3 neutropenia/granulocytopenia (OR 0.17, 95% CI 0.15 to 0.18; 29 studies, 11,794 participants; low-quality evidence), febrile neutropenia (OR 0.27, 95% CI 0.21 to 0.36; 19 studies, 9407 participants; moderate-quality evidence), stomatitis (OR 0.26, 95% CI 0.20 to 0.33; 21 studies, 8718 participants; low-quality evidence), mucositis (OR 0.17, 95% CI 0.12 to 0.24; 12 studies, 4962 participants; low-quality evidence), and any grade ≥ 3 AEs (OR 0.83, 95% CI 0.74 to 0.94; 14 studies, 5436 participants; low-quality evidence). There was more grade ≥ 3 diarrhoea (OR 1.66, 95% CI 1.50 to 1.84; 30 studies, 11,997 participants; low-quality evidence) and hand foot syndrome (OR 3.92, 95% CI 2.84 to 5.43; 18 studies, 6481 participants; moderate-quality evidence) in the oral fluoropyrimidine arm. There were no differences between oral and IV fluoropyrimidine arms in terms of grade ≥ 3 vomiting (OR 1.18, 95% CI 1.00 to 1.40; 23 studies, 9528 participants; low-quality evidence), nausea (OR 1.16, 95% CI 0.99 to 1.36; 25 studies, 9796 participants; low-quality evidence), and hyperbilirubinaemia (OR 1.62, 95% CI 0.99 to 2.64; nine studies, 2699 participants; low-quality evidence).

AUTHORS' CONCLUSIONS

Results of this review should provide confidence that treatment for CRC with most of the oral fluoropyrimidines commonly used in current clinical practice is similarly efficacious to treatment with IV fluoropyrimidines. Treatment with eniluracil with oral 5-FU was associated with inferior PFS and OS among participants treated with palliative intent for CRC, and eniluracil is no longer being developed. Oral and IV fluoropyrimidines have different patterns of side effects; future research may focus on determining the basis for these differences.

The Addition of Target Therapy to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer: A Review

Currently, neoadjuvant fluoropyrimidine-based chemoradiotherapy (CRT) is standard practice in the management of locally advanced rectal cancer (LARC). In the last decade there has been a lively interest in the improvement of clinical outcomes by modifying this standard regimen by the addition of further agents. We review combinations of targeted therapies and conventional CRT currently under investigation in LARC patients.

Clinical benefit of adding oxaliplatin to standard neoadjuvant chemoradiotherapy in locally advanced rectal cancer: a meta-analysis : Oxaliplatin in neoadjuvant treatment for rectal cancer

Background

Neoadjuvant fluoropirimidine (5FU)-based chemoradiotherapy (CRT) has been considered the standard of care for locally advanced rectal cancer (LARC). Whether addition of oxaliplatin (OXP) will further improve clinical outcomes is still debated. We conducted a meta-analysis to evaluate the role of OXP in this patient population.

Methods

Literature searches were carried out in PubMed, Medline and Scopus databases. End points were overall survival (OS), disease free survival (DFS), local failure (LF) and distant failure (DF). Odd ratio (OR) with 95% confidence interval (CI) was calculated using random effects model.

Results

Four randomized trials were included. Patients treated with OXP-5FU CRT had significantly decreased DF (OR = 0.76; 95% CI, 0.60 to 0.97; p = 0.03) compared to standard CRT. OS, DFS and LF were not significantly different between groups.

Conclusions

OXP significantly decreased DF, but does not improve OS e DFS compared to 5FU CRT. Precise role of OXP in neoadjuvant setting of LARC remains to be determined.

High tumor glycine concentration is an adverse prognostic factor in locally advanced rectal cancer

BACKGROUND AND PURPOSE

Recognizing the link between altered tumor metabolism and disease aggressiveness, this study aimed to identify associations between tumor metabolic profiles and therapeutic outcome in locally advanced rectal cancer (LARC).

MATERIALS AND METHODS

Pretreatment tumor metabolic profiles from 54 LARC patients receiving combined-modality neoadjuvant treatment and surgery were acquired by high-resolution magic angle spinning magnetic resonance spectroscopy (HR MAS MRS). Metabolite concentrations were correlated to TNM and the presence of disseminated tumor cells (DTC) at diagnosis, ypTN and tumor regression grade (TRG) following neoadjuvant treatment, and progression-free survival (PFS).

RESULTS

Pretreatment tumor metabolite concentrations showed no significant associations to TNM, DTC, ypTN or TRG. In univariate regression analysis, high concentrations of glycine, creatine and myo-inositol were significantly associated with poor PFS, with metastasis as main PFS event. In multivariate analysis, high glycine concentration remained most significantly associated with poor PFS (hazard ratio=4.4, 95% confidence interval=1.4-14.3, p=0.008).

CONCLUSIONS

High tumor glycine concentration was identified as adverse prognostic factor for PFS in LARC. In a patient population treated with curative intent but with metastatic disease as main PFS event further investigations of glycine as early predictor of metastatic progression and therapeutic target are warranted.