Treatment planning for patients with low rectal cancer in a multicenter prospective organ preservation study

BACKGROUND

Non-surgical management of rectal cancer relies on (chemo)radiotherapy as the definitive treatment modality. This study reports and evaluates the clinical high dose radiotherapy treatment plans delivered to patients with low resectable rectal cancer in a Danish multicenter trial.

METHODS

The Danish prospective multicenter phase II Watchful Waiting 2 trial (NCT02438839) investigated definitive chemoradiation for non-surgical management of low rectal cancer. Three Danish centers participated in the trial and committed to protocol-specified treatment planning and delivery requirements. The protocol specified a dose of 50.4 Gy in 28 fractions to the elective volume (CTV-/PTV-E) and a concomitant boost of 62 Gy in 28 fractions to the primary target volume (CTV-/PTV-T).

RESULTS

The trial included 108 patients, of which 106 treatment plans were available for retrospective analysis. Dose coverage planning goals for the main target structures were fulfilled for 94% of the treatment plans. However, large intercenter differences in doses to organs-at-risk (OARs) were seen, especially for the intestines. Five patients had a V60Gy>10 cm3 for the intestines and two patients for the bladder.

CONCLUSION

Prescribed planning goals for target coverage were fulfilled for 94% of the treatment plans, however analysis of OAR doses and volumes indicated intercenter variations. Dose escalation to 62 Gy (as a concomitant boost to the primary tumor) introduced no substantial high dose volumes (>60 Gy) to the bladder and intestines. The treatment planning goals may be used for future prospective evaluation of highdose radiotherapy for organ preservation for low rectal cancer.

Risk factors and outcome following salvage surgery for squamous cell carcinoma of the anus

BACKGROUND

Chemoradiotherapy is the primary treatment for anal cancer. 15-33% of patients will have persistent or recurrent disease after treatment requiring salvage surgery. Relapse after surgery, postoperative complications, and mortality as well as possible risk factors are not fully understood due to the rareness of the disease. The aim of the study was to report outcomes after salvage surgery as well as evaluate risk factors for postoperative complications, cancer relapse and survival.

METHODS

Data were retrospectively collected from electronical patients charts and pathology reports from all patients undergoing salvage surgery from July 1st, 2011 to July 1st, 2021 at the Department of Surgery, Aarhus University Hospital, Denmark.

RESULTS

A total of 98 patients were included in the study. The 5-year overall survival was 61.8%. Relapse after surgery occurred in 36.7% of patients and was significantly associated with R1-resection (HR = 4.4) and preoperative nodal metastases (HR = 4.5). Negative prognostic factors for survival were found to be R1-resection (HR = 3.2), preoperative nodal metastases (HR = 2.9), and male gender (HR = 0.5). There was no association found between complications and survival (HR 1.2). None of the possible risk factors were associated with major postoperative complications.

CONCLUSIONS

An acceptable overall survival after surgery was found. Survival and relapse-free survival was negatively associated with R1 resections and positive preoperative lymph nodes. Complications did not influence long-term survival.

Delta tocotrienol as a supplement to FOLFOXIRI in first-line treatment of metastatic colorectal cancer. A randomized, double-blind, placebo-controlled phase II study

PURPOSE

Triplet chemotherapy might be more effective than doublet chemotherapy in metastatic colorectal cancer (mCRC), but it may also be marked by increased toxicity. To investigate whether δ-tocotrienol, a vitamin E analogue, with possible neuroprotective and anti-inflammatory effects, reduces the toxicity of triplet chemotherapy, we conducted a randomized, double-blind, placebo-controlled trial in mCRC patients receiving first-line 5-fluorouracil, oxaliplatin and irinotecan (FOLFOXIRI).

MATERIAL AND METHODS

Seventy patients with mCRC were randomly assigned (1:1) to receive FOLFOXIRI plus either δ-tocotrienol or placebo at the Department of Oncology, Vejle Hospital, Denmark. Eligibility criteria were adenocarcinoma in the colon or rectum, age 18-75 years and ECOG performance status 0-1. FOLFOXIRI was given in eight cycles followed by four cycles of 5-fluorouracil. δ-tocotrienol 300 mg or placebo × 3 daily was added during chemotherapy and for a maximum of two years. The primary endpoint was time to hospitalization or death during treatment with chemotherapy.

RESULTS

Median time to first hospitalization or death was 3.7 months in the placebo group (95% CI 1.93-not reached (NR)), and was NR in the δ-tocotrienol group (95% CI 1.87-NR) with a hazard ratio of 0.70 (95% CI 0.36-1.36). Grade 3-4 toxicities were uncommon in both groups, except for neutropenia, which occurred in 19 patients (58%) in the placebo group and 17 patients (50%) in the δ-tocotrienol group. There were no grade 3 or 4 peripheral sensory neuropathy. In the placebo group, 24 patients (71%) had oxaliplatin dose reductions compared to 17 patients (47%) in the δ-tocotrienol group (p = 0.047).

CONCLUSION

The addition of δ-tocotrienol to FOLFOXIRI did not statistically significant prolong the time to first hospitalization or death compared to FOLFOXIRI plus placebo. Toxicity was manageable and not statistically different. There was a statistically significant difference in dose reductions of oxaliplatin pointing to a possible neuroprotective effect of δ-tocotrienol.

Nordic anal cancer (NOAC) group consensus guidelines for risk-adapted delineation of the elective clinical target volume in anal cancer

Background: To date, anal cancer patients are treated with radiotherapy to similar volumes despite a marked difference in risk profile based on tumor location and stage. A more individualized approach to delineation of the elective clinical target volume (CTVe) could potentially provide better oncological outcomes as well as improved quality of life. The aim of the present work was to establish Nordic Anal Cancer (NOAC) group guidelines for delineation of the CTVe in anal cancer.Methods: First, 12 radiation oncologists reviewed the literature in one of the following four areas: (1) previous delineation guidelines; (2) patterns of recurrence; (3) anatomical studies; (4) common iliac and para-aortic recurrences and delineation guidelines. Second, areas of controversy were identified and discussed with the aim of reaching consensus.Results: We present consensus-based recommendations for CTVe delineation in anal cancer regarding (a) which regions to include, and (b) how the regions should be delineated. Some of our recommendations deviate from current international guidelines. For instance, the posterolateral part of the inguinal region is excluded, decreasing the volume of irradiated normal tissue. For the external iliac region and the cranial border of the CTVe, we agreed on specifying two different recommendations, both considered acceptable. One of these recommendations is novel and risk-adapted; the external iliac region is omitted for low-risk patients, and several different cranial borders are used depending on the individual level of risk.Conclusion: We present NOAC consensus guidelines for delineation of the CTVe in anal cancer, including a risk-adapted strategy.

NPY Gene Methylation in Circulating Tumor DNA as an Early Biomarker for Treatment Effect in Metastatic Colorectal Cancer

Despite several limitations, the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) are still the gold standard in response evaluation of metastatic colorectal cancer (mCRC). The aim of the present study was to investigate hypermethylated neuropeptide Y circulating tumor DNA (meth-NPY) as an early biomarker for treatment effect and monitoring in 70 mCRC patients receiving first-line treatment in the FOLFOXIRI-Toco trial. Meth-NPY was analyzed using droplet digital PCR, and the response rate was defined as the fraction of patients converting from a baseline detectable level to an undetectable level after the first treatment cycle (responders). A significant increase in meth-NPY was defined as a value with no overlap between the 95% CI of the current and preceding measurement. Progression-free survival (PFS) was significantly longer in meth-NPY responders compared to non-responders, 10.1 and 7.6 months, respectively (p = 0.02, HR = 0.43). Patients with response according to RECIST 1.1 had a PFS of 10.1 compared to 7.3 months for non-responders (p = 0.17, HR = 0.65). A significant increase in meth-NPY was found with a median of 49 days before radiological progression. In conclusion, early meth-NPY response proved superior to response according to RECIST 1.1 with respect to predicting improved PFS. Meth-NPY is an early indicator of progression, allowing treatment reorientation at an earlier timepoint.

Curative chemoradiation for low rectal cancer: Primary clinical outcomes from a multicenter phase II trial

LBA3514

Background: Organ preserving treatment strategies based on chemoradiotherapy may spare rectal cancer patients of major surgery and stoma. We suggest substantially improved tumor control by increasing the radiotherapy dose, without significant increase in the rate of late effects. We designed a prospective phase II trial to test high-dose radiotherapy of low rectal cancer for organ preservation in a multicenter setting. Methods: We enrolled patients with localized T1-3 N0-1 M0 rectal cancer within 6 cm from the anal verge and in performance status 0-2. Any N1-nodes had to be at the level of the tumor and included in the primary tumor-volume. Radiotherapy consisted of 62 Gy to the tumor and 50.4 Gy to the regional lymph nodes, delivered in 28 fractions using intensity modulated radiation therapy and daily image guidance. Capecitabine 825 mg/m2 BID. Patients with clinical complete response (cCR) 6–12 weeks after end of treatment were allocated to follow-up. Surgery was offered only in case of residual cancer or later re-growth. The primary endpoint was the proportion of patients with locoregional tumor control after two years by chemoradiation alone. Secondary endpoints included long-term side effects (CTCAE grading), cCR, rate of distant metastases, and overall survival. Results: Three Danish centers enrolled 107 patients between 2015 and 2019. Baseline classifications were T1/T2/T3 and N1 in 15%/54%/31% and 29%, respectively. The median age was 71 years and 64% were male. 92 (86.0%) had cCR and were allocated to observation. Four patients drew consent or died leaving 103 observed for at least 2 years. 23 had regrowth after cCR, five of whom had organ preserving transanal endoscopic microsurgery, 15 other curative surgery, and three palliation. 63 had no locoregional regrowth. Thus 61% (63/103) of patients with 2 years of follow-up had locoregional tumor control with chemoradiation alone. The actuarial estimate of locoregional control at 2 years from start of observation was 73.8% (95%CI 63.2-81.8). Calculated from time of enrollment, metastasis-free and overall survival at 30 months was 85.4% (95%CI 76.5-91.1) and 94.8% (95%CI 87.8-97.8). In the 63 patients with complete response at 2 years, ‘Low Anterior Resection Syndrome-score’ was None=37%, Minor=28%, and Major=35%. The most severe toxicity was erectile dysfunction grade 3 (n=3), grade 2 (n=4), grade 1 (n=6), and grade 0 (n=26). Grade 2 diarrhea, constipation, fecal incontinence, rectal bleeding and decreased libido were each reported in one case, while urinary frequency grade 2 was seen in four patients. Conclusions: The vast majority of patients with low rectal cancer can be cured by modern radiotherapy 62 Gy in 28 fractions with excellent patient-reported outcomes, toxicity, tumor control, and survival. The treatment is feasible in a multicenter setting. We suggest this approach as a standard of care option. Clinical trial information: NCT02438839.

Re-exposure to immunotherapy in metastatic colon cancer: A case report

Re-exposure to immunotherapy in metastatic colorectal cancer may be indicated in selected patients that previously benefitted from immunotherapy with tolerable irAEs.

Functional precision medicine in colorectal cancer based on patient-derived tumoroids and in-vitro sensitivity drug testing

e15567

Background: Precision oncology based on in-vitro, functional assays has potential advantages compared to the much more common molecular approach, but the clinical benefit is unknown. We here report the results from the largest prospective interventional clinical trial testing the clinical outcome in colorectal cancer patients treated with drugs showing cytotoxic effect in matched patient-derived tumoroids. Methods: This single-center, phase II trial included patients with metastatic colorectal cancer previously exposed to all standard therapies. Specimens from one to three 18-16 G core needle biopsies were manually dissected, enzymatically treated, cultivated, and incubated to form 3D spherical microtumors, i.e. tumoroids. In the assay for in-vitro sensitivity testing, the tumoroids were challenged with single drugs and combinations thereof to determine patient-specific responses. Using tumoroid screening technology (IndiTreat, 2cureX, Copenhagen, Denmark), results were generated by comparing the sensitivity of the individual patient’s tumoroids with a reference panel from other patients. The testing included standard cytostatics and drugs with proven effect in previous early-phase clinical trials, a total of 15 drugs. The primary endpoint was the fraction of patients with progression-free survival (PFS) at two months. Based on placebo arms in randomized last-line trials, a minimal relevant difference of 20% (20% to 40%) was stated. Using Simon's two-stage design, a sample size of 45 patients was calculated with at least 14 PFS at two months (significance 5%, power 90%). Results: Ninety patients were enrolled from 9/2017 to 9/2020. Biopsies from 82 patients were obtained and sent for tumoroid formation of which 44 (54%, 95% CI 42-65) were successful and at least one treatment was suggested. Thirty-four patients initiated treatment according to the response obtained in the drug assays within a median of 51 days from inclusion (IQR 39-63). The primary endpoint, PFS at two months, was met in 17 of 34 patients (50%, 95%CI 32-68). There were no radiological responses. Median PFS was 81 days (95% CI 51-112) and median OS was 189 days (95% CI 103-277). Conclusions: Precision oncology using a functional approach with patient-derived tumoroids and in-vitro drug sensitivity testing seems feasible. The approach is limited by the fraction of patients with successful tumoroid development. The primary endpoint was met, as half of the patients were without progression at two months. Further clinical studies are justified. Clinical trial information: NCT03251612.

Nonplatinum-based therapy with Paclitaxel and Capecitabine for advanced squamous cell carcinomas of the anal canal: A population-based Danish anal cancer group study

Background

First‐line platinum‐based therapy for advanced squamous cell carcinomas of the anal canal (SCCA) implies a risk of substantial side effects, and data on second‐line treatment options are limited. Paclitaxel and Capecitabine are a well‐known regimen with a moderate toxicity profile, but its efficacy has not been evaluated.

Methods

We conducted a retrospective study using Danish Hospital Registers of patients treated with Paclitaxel and Capecitabine for inoperable, recurrent, or advanced metastatic SCCA in Denmark, between January 2000 and July 2018.

Results

A total of 52 patients met the eligibility criteria. Median age was 60.7 years (range 42–83). Efficacy was observed, with an overall response rate in patients receiving first‐line (N = 28) and second‐line (N = 23) Paclitaxel and Capecitabine of 39.3% (2 with complete responses) and 17.4%, respectively. Median progression‐free survival (PFS) was 4.5 months (95% CI 3.3–5.9) and 3.8 months (95% CI 2.4–5.5) with OS of 6.7 months (95% CI 5.9–8.5) and 5.9 months (95% CI 3.9–14), respectively. Performance status ≥2 and neutrophil to lymphocyte ratio ≥4 were significantly associated with a short PFS.

Conclusion

This study recognizes Paclitaxel and Capecitabine as a potential regimen for advanced SCCA, when recommended first‐line therapy is not feasible or as a potential second‐line treatment after failure of platinum‐based chemotherapy.

Comprehensive Analysis of DNA Methylation and Prediction of Response to NeoadjuvantTherapy in Locally Advanced Rectal Cancer

The treatment for locally advanced rectal carcinomas (LARC) is based on neoadjuvant chemoradiotherapy (nCRT) and surgery, which results in pathological complete response (pCR) in up to 30% of patients. Since epigenetic changes may influence response to therapy, we aimed to identify DNA methylation markers predictive of pCR in LARC patients treated with nCRT. We used high-throughput DNA methylation analysis of 32 treatment-naïve LARC biopsies and five normal rectal tissues to explore the predictive value of differentially methylated (DM) CpGs. External validation was carried out with The Cancer Genome Atlas-Rectal Adenocarcinoma (TCGA-READ 99 cases). A classifier based on three-CpGs DM (linked to OBSL1, GPR1, and INSIG1 genes) was able to discriminate pCR from incomplete responders with high sensitivity and specificity. The methylation levels of the selected CpGs confirmed the predictive value of our classifier in 77 LARCs evaluated by bisulfite pyrosequencing. Evaluation of external datasets (TCGA-READ, GSE81006, GSE75546, and GSE39958) reproduced our results. As the three CpGs were mapped near to regulatory elements, we performed an integrative analysis in regions associated with predicted cis-regulatory elements. A positive and inverse correlation between DNA methylation and gene expression was found in two CpGs. We propose a novel predictive tool based on three CpGs potentially useful for pretreatment screening of LARC patients and guide the selection of treatment modality.

Locally advanced rectal cancer transcriptomic-based secretome analysis reveals novel biomarkers useful to identify patients according to neoadjuvant chemoradiotherapy response

Most patients with locally advanced rectal cancer (LARC) present incomplete pathological response (pIR) to neoadjuvant chemoradiotherapy (nCRT). Despite the efforts to predict treatment response using tumor-molecular features, as differentially expressed genes, no molecule has proved to be a strong biomarker. The tumor secretome analysis is a promising strategy for biomarkers identification, which can be assessed using transcriptomic data. We performed transcriptomic-based secretome analysis to select potentially secreted proteins using an in silico approach. The tumor expression profile of 28 LARC biopsies collected before nCRT was compared with normal rectal tissues (NT). The expression profile showed no significant differences between complete (pCR) and incomplete responders to nCRT. Genes with increased expression (pCR = 106 and pIR = 357) were used for secretome analysis based on public databases (Vesiclepedia, Human Cancer Secretome, and Plasma Proteome). Seventeen potentially secreted candidates (pCR = 1, pIR = 13 and 3 in both groups) were further investigated in two independent datasets (TCGA and GSE68204) confirming their over-expression in LARC and association with nCRT response (GSE68204). The expression of circulating amphiregulin and cMET proteins was confirmed in serum from 14 LARC patients. Future studies in liquid biopsies could confirm the utility of these proteins for personalized treatment in LARC patients.

Single nucleotide polymorphisms in the HIF-1α gene and chemoradiotherapy of locally advanced rectal cancer

The aim of this study was to investigate the predictive impact of polymorphisms in the HIF-1α gene on the response to chemoradiotherapy (CRT) in rectal cancer. This study included two cohorts of patients with locally advanced rectal cancer receiving long-course CRT. The HIF-1α C1772T (rs11549465), G1790A (rs11549467) and c(*)191T>C (rs2057482) polymorphisms were investigated in the test cohort (n=65), and HIF-1α c(*)191T>C was analysed in the validation cohort (n=198). No correlations were identified between the polymorphisms and clinicopathological factors. The HIF-1α C1772T and HIF-1α G1790A polymorphisms demonstrated no correlation with tumour response to CRT in the test cohort. The HIF-1α c(*)191T>C CC genotype was marginally associated with a higher rate of complete tumour response (P=0.05) in the test cohort, while the HIF-1α c(*)191T>C CC genotype was associated with a poor tumour response (P=0.03) in the validation cohort. In conclusion, these results suggest that HIF-1α polymorphisms have no value as predictors of response to neoadjuvant CRT in rectal cancer. The results of the HIF-1α c(*)191T>C in two cohorts differ and emphasise the importance of biomarker validation.

Immunohistological expression of HIF-1α, GLUT-1, Bcl-2 and Ki-67 in consecutive biopsies during chemoradiotherapy in patients with rectal cancer

The aim of this study was to describe the dynamics of HIF-1α, GLUT-1, Bcl-2 and Ki-67 during chemoradiotherapy (CRT) of rectal cancer, and to investigate the fluctuation of these biomarkers in relation to pathological response to CRT. The study included 86 patients with rectal adenocarcinoma receiving preoperative CRT (>50.4 Gy and Uracil/Tegafur). Immunohistological expressions of HIF-1α, GLUT-1, Bcl-2 and Ki-67 were investigated in biopsies taken before treatment, after 2, 4 and 6 weeks of CRT and in specimens from the operation. Decreasing expressions of HIF-1α, Bcl-2 and Ki-67 were observed during CRT, whereas GLUT-1 overall was unchanged. No significant changes of the markers were observed in the interval between CRT and surgery. A significant association was observed between the presence of residual carcinoma after 6 weeks of treatment and pathological response to CRT, but no association was seen between the fluctuations of any of the markers and response to CRT. This unique material containing specimens before, after and during CRT for rectal cancer demonstrated biological dynamics in HIF-1α, Bcl-2 and Ki-67, but not GLUT-1, expression during CRT, and a significant association was seen between the presence of residual carcinoma after 6 weeks of treatment and pathological response to CRT.

Pretreatment HIF-1α and GLUT-1 expressions do not correlate with outcome after preoperative chemoradiotherapy in rectal cancer

The aim of the present study was to investigate hypoxia-inducible factor 1α (HIF-1α) and glucose transporter-1 (GLUT-1) expressions as predictors of response and survival after chemoradiotherapy in pretreatment biopsy specimens from patients with rectal cancer.

MATERIALS AND METHODS

The immunohistological expressions of HIF-1α and GLUT-1 were investigated in pretreatment biopsies from 86 patients with rectal cancer receiving long course preoperative chemoradiotherapy. The immunohistological stainings were scored semi-quantitatively (percentage of stained cells and staining intensity), and an immunoreactive score was calculated. The response to the chemoradiotherapy was assessed by the Mandard Tumour Regression Grade system (TRG).

RESULTS

No association was found between HIF-1α or GLUT-1 and clinicopathological variables. HIF-1α and GLUT-1 expression had no predictive impact regarding response to chemoradiotherapy measured by TRG and was not associated with overall survival.

CONCLUSION

The present study did not suggest any predictive or prognostic value of pretreatment HIF-1α or GLUT-1 expression in patients with rectal cancer treated with preoperative chemoradiotherapy.