Precision medicine applied to metastatic colorectal cancer using tumor-derived organoids and in-vitro sensitivity testing: a phase 2, single-center, open-label, and non-comparative study

BACKGROUND

Patients with colorectal metastatic disease have a poor prognosis, limited therapeutic options, and frequent development of resistance. Strategies based on tumor-derived organoids are a powerful tool to assess drug sensitivity at an individual level and to suggest new treatment options or re-challenge. Here, we evaluated the method's feasibility and clinical outcome as applied to patients with no satisfactory treatment options.

METHODS

In this phase 2, single-center, open-label, non-comparative study (ClinicalTrials.gov, register NCT03251612), we enrolled 90 patients with metastatic colorectal cancer following progression on or after standard therapy. Participants were 18 years or older with an Eastern Cooperative Oncology Group performance status of 0-2, adequate organ function, and metastasis available for biopsy. Biopsies from the metastatic site were cultured using organoids model. Sensitivity testing was performed with a panel of drugs with proven activity in phase II or III trials. At the discretion of the investigator considering toxicity, the drug with the highest relative activity was offered. The primary endpoint was the proportion of patients alive without disease progression at two months per local assessment.

RESULTS

Biopsies available from 82 to 90 patients were processed for cell culture, of which 44 successfully generated organoids with at least one treatment suggested. The precision cohort of 34 patients started treatment and the primary endpoint, progression-free survival (PFS) at two months was met in 17 patients (50%, 95% CI 32-68), exceeding the pre-defined level (14 of 45; 31%). The median PFS was 67 days (95% CI 51-108), and the median overall survival was 189 days (95% CI 103-277).

CONCLUSIONS

Patient-derived organoids and in-vitro sensitivity testing were feasible in a cohort of metastatic colorectal cancer. The primary endpoint was met, as half of the patients were without progression at two months. Cancer patients may benefit from functional testing using tumor-derived organoids.

TRIAL REGISTRATION

ClinicalTrials.gov, register NCT03251612.

Diffusion-Weighted MRI in Patients with Testicular Tumors—Intra- and Interobserver Variability

In general, magnetic resonance (MR) diffusion-weighted imaging (DWI) has shown potential in clinical settings. In testicles parenchyma, the DW imaging helps differentiate and characterize benign from malignant lesions. Placement and size of the region of interest (ROI) may affect the ADC value. Therefore, the aim of this study was to investigate the intra- and interobserver variability in testicular tumors when measuring ADC using various types of regions of interest (ROI). Two observers performed the ADC measurements in testicular lesions based on three ROI methods: (1) whole volume, (2) round, and (3) small sample groups. Intra- and interobserver variability was analyzed for all ROI methods using intraclass correlation coefficients (ICC) and bland-altman plots. The two observers performed the measurements twice, three months apart. A total of 26 malignant testicle tumors were included. Interobserver agreement was excellent in tumor length (ICC = 0.98) and tumor width (ICC = 0.98). In addition, intraobserver agreement was excellent in tumor length (ICC = 0.98) and tumor width (ICC = 0.99). The whole volume interobserver agreement in the first reading was excellent (ICC = 0.93). Round ADC had an excellent (ICC = 0.93) and fair (ICC = 0.58) interobserver agreement, in the first and second reading, respectively. Interobserver agreement in ADC small ROIs was good (ICC = 0.87), and good (ICC = 0.78), in the first and second reading, respectively. Intraobserver agreement varied from fair, good to excellent agreement. The ROI method showed varying inter- and intraobserver agreement in ADC measurement. Using multiple small ROI conceded the highest interobserver variability, and, thus, the whole volume or round seem to be the preferable methods.

Intra- and Interobserver Variability in Magnetic Resonance Imaging Measurements in Rectal Cancer Patients

Colorectal cancer is the second most common cancer in Europe, and accurate lymph node staging in rectal cancer patients is essential for the selection of their treatment. MRI lymph node staging is complex, and few studies have been published regarding its reproducibility. This study assesses the inter- and intraobserver variability in lymph node size, apparent diffusion coefficient (ADC) measurements, and morphological characterization among inexperienced and experienced radiologists. Four radiologists with different levels of experience in MRI rectal cancer staging analyzed 36 MRI scans of 36 patients with rectal adenocarcinoma. Inter- and intraobserver variation was calculated using interclass correlation coefficients and Cohens-kappa statistics, respectively. Inter- and intraobserver agreement for the length and width measurements was good to excellent, and for that of ADC it was fair to good. Interobserver agreement for the assessment of irregular border was moderate, heterogeneous signal was fair, round shape was fair to moderate, and extramesorectal lymph node location was moderate to almost perfect. Intraobserver agreement for the assessment of irregular border was fair to substantial, heterogeneous signal was fair to moderate, round shape was fair to moderate, and extramesorectal lymph node location was substantial to almost perfect. Our data indicate that subjective variables such as morphological characteristics are less reproducible than numerical variables, regardless of the level of experience of the observers.

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.

Perforated adenocarcinoma of the colon within a scrotal hernia imaged by CT: case report and literature review

Colorectal cancer is one of the most common cancers in the developed countries, and colon cancer is well documented. However, it is very rare for a primary colon cancer to exist in a scrotal hernia, and even rarer for the scrotal hernia to perforate. Here, we describe an unusual case where a 75-year-old patient with a colon tumor that perforated in a scrotal hernia. The teaching point is to highlight the computed tomography scan imaging characteristics of this rare finding in patients with both abdominal and scrotal pain.

Abstract P2-09-34: An mRNA-based method to measure PI3K activity in cancer tissue using a computational pathway model to assess FOXO transcriptional activity

Introduction

The PI3K signaling pathway is frequently active in breast cancer, and therapeutic inhibitors have been developed. However, it has proven difficult to correctly predict treatment response. We developed a method that measures functional activity of the PI3K pathway using a computational model that infers transcriptional FOXO activity (downstream of PI3K) from expression levels of its target genes. In principle, PI3K pathway activity inhibits transcriptional FOXO activity, hence inactive FOXO is indicative of active PI3K.

Method

We developed a knowledge-based computational model to infer transcriptional FOXO activity from cancer tissue mRNA expression levels, using a Bayesian network approach (Verhaegh et al., Cancer Res 2014). Model calibration was done on microarray data from HUVEC cells with inducible FOXO3.A3-ER (GSE16573).

Results

The FOXO model was biologically validated with in-house microarray data from independent breast cancer cell lines. ER positive, PIK3CAE545K mutant MCF7 and triple negative MDA-MB-231 cells were stably transduced with a doxycycline inducible FOXO3.A3 expression vector, allowing controlled induction of FOXO3 protein activity. FOXO activity was determined to be low in untreated and 20% FBS treated MCF7 cells, and high after doxycycline, LY294002, and combination treatment.

Next, we tested our FOXO model on independent MCF7, BT-20 and MDA-MB-453 cell line data treated with EGFR inhibitor erlotinib (GSE30516), showing an increase of FOXO activity upon treatment, due to reduced PI3K pathway activity (combined Wilcox rank sum test p = 7.8x10−5).

We further analyzed independent publicly available data from breast cancer patients. FOXO was generally active in healthy breast tissue. Compared to healthy breast tissue, FOXO activity was higher in normal-like and luminal A breast cancer samples (p = 1.9x10−6 and 0.025, resp.), and lower in luminal B samples (p = 4.2x10−7).

In addition to the above mechanism for regulating FOXO activity, literature suggests that FOXO can also be activated by cellular oxidative stress, which is often associated with PI3K signaling. This may be assessed using expression levels of the FOXO target gene SOD2, which is differentially expressed between the two FOXO activity modes, and whose function is to reduce oxidative stress. Public data shows an increasing percentage of elevated SOD2 levels among FOXO-active samples with increasing breast cancer aggressiveness: 7% in normal-like, 5% in luminal A, 18% in luminal B, 31% in HER2-enriched and 74% in basal like breast cancer.

Conclusion

Our computational model to measure PI3K activity using FOXO target gene mRNA levels was able to measure increased FOXO activity in multiple cancer cell lines after PI3K inhibition. FOXO activity was measured high in healthy breast tissue and in normal-like and luminal A breast cancer, and lower in luminal B, indicating PI3K activity in the latter group. In more aggressive subtypes, FOXO activity was increasingly accompanied by high SOD2 expression, suggesting oxidative stress with associated PI3K activity as the FOXO activating mechanism.

Clinical utility for improved response prediction and monitoring of PI3K pathway inhibitors is being investigated with clinical partners.

Citation Format: Verhaegh W, van Ooijen H, Hornsveld M, Dam C, Eijkelenboom A, Dou M, Velter R, Burgering B, van de Stolpe A. An mRNA-based method to measure PI3K activity in cancer tissue using a computational pathway model to assess FOXO transcriptional activity [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-09-34.

Local staging of sigmoid colon cancer using MRI

Background

An accurate radiological staging of colon cancer is crucial to select patients who may benefit from neoadjuvant chemotherapy.

Purpose

To evaluate the diagnostic accuracy of preoperative magnetic resonance imaging (MRI) in identifying locally advanced sigmoid colon cancer, poor prognostic factors, and the inter-observer variation of the tumor apparent diffusion coefficient (ADC) values of diffusion-weighted imaging (DWI).

Material and Methods

Using 1.5 T MRI with high resolution T2-weighted (T2W) imaging, DWI, and no contrast enhancement, 35 patients with sigmoid colon cancer were assessed. T-stage, N-stage, extramural vascular invasion (EMVI), and ADC values of the tumors were assessed and blindly compared by two observers using postoperative histopathological examination as the gold standard. Early tumors were defined as T1 to T3ab, and advanced tumors as T3cd or T4.

Results

The accuracy of the two radiologists in staging early versus advanced tumors, N-stage, and identification of EMVI was 94%/89%, 60%/66%, and 77%/60% with an inter-observer agreement of к = 0.86 (95% confidence interval [CI] = 0.67–1.00), к = 0.64 (95% CI = 0.39–0.90), and к = 0.52 (95% CI = 0.23–0.80). All the measured mean ADC values were below 1.0 × 10⁻³ mm²/s with an intra-class correlation coefficient in T3cd–T4 tumors of 0.85.

Conclusion

Preoperative MRI can identify locally advanced sigmoid colon cancer and has potential as the imaging of choice to select patients for neoadjuvant chemotherapy. Initial experience with ADC measurement was achieved with an excellent inter-observer agreement in advanced tumors.

Computed tomography assessment of early response to neoadjuvant therapy in colon cancer

INTRODUCTION

Using multidetector computed tomography, we aimed to assess the early response of neoadjuvant drug therapy for locally advanced colon cancer.

METHODS

Computed tomography with IV contrast was acquired from 67 patients before and after up to three cycles of preoperative treatment. All patients had histologically confirmed colon cancer, a T4 or T3 tumour with extramural invasion ≥ 5 mm and no distant metastases or peritoneal nodules. The patients were treated with oxaliplatin and capecitabine. In addition, those with no mutations in the KRAS, BRAF and PIK3CA genes were also treated with panitumumab. Before and after treatment, we measured the tumour diameter in two different planes, the extension of the extramural tumour invasion, and the number and size of enlarged lymph nodes.

RESULTS

The mean tumour length was 7.8 cm (95% confidence interval (CI): 5.3-10.4) at baseline and 4.34 cm (95% CI: 4.0-4.9) after treatment. The mean extramural tumour invasion was 10.6 mm (95% CI: 9.5-11.8) at baseline and 5.7 mm (95% CI: 4.7-6.7) after treatment. The mean number of enlarged lymph nodes was 4.1 (95% CI: 3.4-4.9) at baseline and 2.1 (95% CI: 1.4-2.7) after treatment. According to RECIST 1.1, 45% (95% CI: 34-57) of the patients had a response and 55% (95% CI: 43-67) had stable disease. None of the patients showed progressive disease.

CONCLUSION

Using CT, we demonstrated a significant reduction in tumour size, extramural tumour invasion, number and size of enlarged lymph nodes following neoadjuvant treatment.

FUNDING

not relevant.

TRIAL REGISTRATION

Registered with ClinicalTrials.gov (NCT 01108107).

Selection of colon cancer patients for neoadjuvant chemotherapy by preoperative CT scan

OBJECTIVE

Preoperative staging is essential to plan correct treatment of colon cancer and calls for objective, accurate methods for the introduction of neoadjuvant chemotherapy, which represents a new treatment option.

PURPOSE

To evaluate the diagnostic accuracy of multislice computed tomography (CT) in local staging of colon cancer correlated with histopathological parameters, including criteria for adjuvant chemotherapy.

MATERIAL AND METHODS

A total of 74 included patients had preoperative CT scans and surgical resection of their colon tumors. Tumor stage (T-stage), extramural tumor invasion (ETI), nodal stage (N-stage), extramural venous invasion (EVI) and the distance from tumor to nearest retroperitoneal fascia (DRF) were retrospectively assessed on the CT scan and compared blindly with the results of the pathological examination, including evaluation of the criteria for adjuvant chemotherapy. Advanced tumors were defined as T3 with ETI ≥5 mm or T4.

RESULTS

Sixty-nine percent of the tumors were correctly T-staged by CT, 7% were overstaged and 24% were understaged. As to correct recognition of ETI on the CT scan, the observer was 73% accurate compared with histology (70% sensitivity (95% CI: 53-82%), 78% specificity (95% CI: 60-90%), 81% positive predictive value (PPV) (95% CI: 63-91%) and 66% negative predictive value (NPV) (95% CI: 49-80%). N-stage, EVI and DRF had poor accuracy: 53%, 53% and 64%. All patients with advanced tumors on CT fulfilled the criteria for adjuvant chemotherapy. Positive predictive value: 100% (95% CI: 88-100%).

CONCLUSION

CT has a potential in the preoperative selection of advanced tumors suitable for neoadjuvant chemotherapy without overtreatment of low-risk patients.

Ultrasound follow-up for gallbladder polyps less than 6 mm may not be necessary

INTRODUCTION

The management of ultrasound (US) detected gallbladder (GB) polyps remains a dilemma. The aim of this study was to assess the size distribution and the outcome of US follow-up of GB polyps.

MATERIAL AND METHODS

The study was approved by the Danish Data Protection Agency. US reports from patients examined with abdominal US in our department from January 2008 to the end of December 2009 were reviewed with a view to including all patients with GB polyps. Patients with GB polyps are routinely recommended a 2-year follow-up with US every six months. The GB polyp size was recorded at baseline and at subsequent US reports. Pathology reports were finally reviewed for all patients with GB polyps to check who underwent cholecystectomy and to register the histological diagnosis.

RESULTS

A total of 203 patients (median age 54 years; range 19-95 years) with GB polyps were included; 89 (44%) men and 114 (56%) women. The mean polyp size was 5 mm (range 2-40 mm). In 143 patients (70%) the GB polyp diameter was less than 6 mm. The first US follow-up was performed in 120 patients (59%), and only 31 (15%) completed the full 2-year US follow-up programme. Polyp size was stable in 100 patients, decreased in five patients, increased in eight and resolved in 15 patients. A total of 13 patients (6%) underwent cholecystectomy. Of the 203 patients, none showed neoplastic or malignant GB polyps.

CONCLUSION

We recommend that follow-up US of patients with GB polyps < 6 mm is avoided. Alternatively, the intervals between US follow-up of GB polyps < 6 mm may be extended.

FUNDING

not relevant.

TRIAL REGISTRATION

not relevant.

[MRI of rectal stromal tumour]

A 39-year-old man was referred to hospital with a rectal tumour and underwent gastrointestinal endoscopy and diagnostic imaging. The tumour had immunohistochemical characteristics for gastrointestinal stromal tumour (GIST). The differential diagnosis of GIST to adenocarcinoma is important to be aware of for the rectal multidisciplinary team. On suspicion of GIST, patients should be referred to a sarcoma centre. The diagnosis of rectal GIST can be suggested on MRI by the presence of a well-defined heterogeneously large mass with a necrotic center associated with a prominent extra-luminal component and hyperechoic appearance on ultrasound.

[Erythropoietic protoporphyria. A rare inherited metabolic disorder with skin symptoms]

Erythropoietic protoporphyria (EPP) is a rare inherited metabolic disorder, resulting from a deficiency of a specific enzyme, ferrochelatase, in the haem biosynthesis pathway. Early and late skin symptoms in EPP are demonstrated by three case stories. Diagnosis depends on characteristic skin symptoms and raised level of protoporphyrin in erythrocytes. The cases illustrate the aspect of inheritance, prophylaxis and recommended follow-up in EPP.