The prospective non-randomized study Locally Advanced Rectal Cancer—Radiation Response Prediction (Principal Investigators: Ree, Flatmark, Dueland) offers a unique opportunity to explore the concept of tumuor hypoxia in a defined clinical context. The trial was designed with the notion that a second cytotoxic drug as additional component of the established neoadjuvant fluorouracil-based chemoradiotherapy (CRT) regimen might improve the rate of complete tumour response and hence, long-term outcome. The study enrolled more than 100 patients from October 2005 to March 2010, all of whom were followed for five years. The treatment protocol included two cycles of neoadjuvant chemotherapy (the Nordic FLOX regimen) followed by long-course CRT (2-Gy radiation fractions five days per week over a 5-week period with concomitant oxaliplatin weekly and daily capecitabine). Radical surgery was planned 6–8 weeks after completion of the neoadjuvant treatment. In accordance with national guidelines, patients did not proceed to further treatment after surgery. The clinical endpoints were adverse events (toxicity) during neoadjuvant treatment, histologic tumuor response, and progression-free survival. Patients have also prospectively reported quality-of-life scores. The study has generated an extensive biobank and imaging databank, consisting of tumour biopsies, surgical specimens, bone marrow and serial blood samples, functional imaging readouts, and radiation treatment-planning histograms, as well as a comprehensive clinical database on disease outcome parameters (response and toxicity data).
Completed biomarker investigations: Hypothesising that a composite pattern of tumour kinase signaling activity defines tumour response to radiation and the propensity of metastatic disease progression, we initially applied kinase substrate array technology to analyse the study patients’ tumour biopsies sampled at the time of diagnosis. Receptor tyrosine kinase activities integrated by high phosphatidylinositol 3-kinase (PI3K) signaling were found to correlate both with poor tumour response to the neoadjuvant treatment and adverse progression-free survival [Folkvord et al., 2010; Saelen et al., 2011; Ree et al., 2012]. Recognising that major signaling pathways are routed through PI3K and reflect tumour cell adaptation responses within a hostile hypoxic microenvironment, the specific tumour signature of PI3K signaling activity may point to actionable therapy targets in patients with hypoxic disease features.
Ongoing activity: The above findings have led us to a series of ongoing investigations. Firstly, using an antibody array technology to analyse serial serum samples collected throughout the course of neoadjuvant treatment, circulating factors reflecting tumour hypoxia are sought [Ree et al, 2014]. Next, hypoxic tumour metabolites are being sought through high-resolution magic angle spinning magnetic resonance spectroscopic analysis of tumour biopsies [Seierstad et al, 2008] for correlation to patient survival outcome. Additionally, high-throughput molecular analysis of tumour micro-RNA and DNA methylation profiles are currently being undertaken. Importantly, in pelvic curative CRT, the development of adverse intestinal toxicity represents the major limitation to delivering the intended radiation dose, and acute enteritis is strongly associated with interruption or premature cessation of the treatment and hence, adverse patient outcome. Thus, we have hypothesised that a serum protein profile specific for mucosal inflammation (enteritis) may be biomarker of intestinal treatment toxicity since enteropathy generally is strongly associated with activation of mucosal inflammatory cytokines. We therefore envisage that the serum array data will provide insight into circulating cytokines of treatment toxicity, which was prospectively assessed according to a validated toxicity scoring tool, the Common Terminology Criteria for Adverse Events, during the conduct of the study.
Locally Advanced Rectal Cancer – Radiation Response Prediction: design and conduct of the translational combined-modality radiotherapy and biomarker study. At baseline, tumour extension within the pelvic cavity was examined by magnetic resonance imaging, tumour biopsies were sampled at endoscopy, and bone marrow was aspired for determination of disseminated tumour cells. The treatment protocol consisted of two cycles of neoadjuvant chemotherapy (NACT) followed by chemoradiotherapy (CRT) and definitive surgery. Repeat magnetic resonance imaging was undertaken immediately after completion of NACT and prior to surgery. The primary endpoint was histological tumour response. The 5-year patient follow-up included body computed tomography scans at defined intervals. Locally recurrent and metastatic disease and death from any cause were recorded as clinical endpoints, along with adverse events during the neoadjuvant treatment. Blood samples were collected at baseline, following NACT and CRT, before surgery, and at defined intervals during the follow-up period. Toxicity recordings were performed at the neoadjuvant blood sampling points. High-throughput -omics and functional imaging technologies have been applied to determine tumour and circulating molecular, metabolic, and imaging signatures descriptive for the individual patient’s tumour and normal tissue constitution. Curated phenomic data from clinical endpoint assessments (treatment toxicity and efficacy) are being integrated together with the biological data to define possible biomarkers of therapeutic response and tolerability for further improvement of personalized therapy in rectal cancer.
- Redalen KR, Sitter B, Bathen TF, Grøholt KK, Hole KH, Dueland S, Flatmark K, Ree AH and Sierstad T. (2016). High tumor glycine concentration is an adverse prognostic factor in locally advanced rectal cancer. Radiotherapy and Oncology, Vol 118(2), pp. 393-398. Link to article.
- Dueland S, Ree AH, Grøholt KK, Saelen MG, Folkvord S, Hole KH, Sierstad T, Larsen SG, Giercksky KE, Wiig JN, Boye K and Flatmark K. (2016). Oxaliplatin-containing Preoperative Therapy in Locally Advanced Rectal Cancer: Local Response, Toxicity and Long-term Outcome. Clinical Oncology, Vol 28(8), pp. 532-539. Link to article.
- Meltzer S, Kalanxhi E, Hektoen HH, Dueland S, Flatmark K, Redalen KR and Ree AH. (2016). Systemic release of osteoprotegerin during oxaliplatin-containing induction chemotherapy and favorable systemic outcome of sequential radiotherapy in rectal cancer. Oncotarget, Vol 7(23), pp. 34907-34917. Link to article.
- Kalanxhi E, Hektoen HH, Meltzer S, Dueland S, Flatmark K and Ree AH. (2016). Circulating proteins in response to combined-modality therapy in rectal cancer identified by antibody array screening. BMC Cancer, Vol 16, pp. 536. Link to article.
- Flatmark K, Saelen MG, Hole KH, Abrahamsen TW, Fleten KG, Hektoen HH, Redalen KR, Sierstad T, Dueland S and Ree AH. (2016). Individual tumor volume responses to short-course oxaliplatin-containing induction chemotherapy in locally advanced rectal cancer – Targeting the tumor for radiation sensitivity?. Radiotherapy and Oncology, Vol 119(3), pp. 505-511. Link to article.
- Hektoen HH, Flatmark K, Andersson Y, Dueland S, Redalen KR and Ree AH. (2015). Early increase in circulating carbonic anhydrase IX during neoadjuvant treatment predicts favourable outcome in locally advanced rectal cancer. BMC Cancer, Vol 15, pp. 543. Link to article.
- Ree AH, Flatmark K, Saelen MG, Folkvord S, Dueland S, Giesler J and Redalen KR. (2015). Tumor phosphatidylinositol 3-kinase signaling in therapy resistance and metastatic dissemination of rectal cancer: opportunities for signaling-adapted therapies. Critical Reviews in Oncology/Haematology, Vol 95(1), pp. 114-124. Link to article.
- Ree AH, Meltzer S, Flatmark K, Dueland S and Kalanxhi E. (2014). Biomarkers of treatment toxicity in combined-modality cancer therapies with radiation and systemic drugs: study design, multiplex methods, molecular networks. International Journal of Molecular Sciences, Vol 15(12), pp. 22835-22856. Link to article.
- Ree AH, Kristensen AT, Saelen MG, de Wijn R, Edvardsen H, Jovanovic J, Abrahamsen TW, Dueland S and Flatmark K. (2012). Tumor phosphatidylinositol-3-kinase signaling and development of metastatic disease in locally advanced rectal cancer. PLoS One, Vol 7(11), pp. e50806. Link to article.
- Saelen MG, Flatmark K, Folkvord S, de Wijn R, Rasmussen H, Fodstad Ø and Ree AH. (2011). Tumor kinase activity in locally advanced rectal cancer: angiogenic signaling and early systemic dissemination. Angiogenesis, Vol 14(4), pp 481-489. Link to article.
- Folkvord S, Flatmark K, Dueland S, de Wijn R, Grøholt KK, Hole KH, Nesland JM, Ruijtenbeek R, Boender PJ, Johansen M, Giercksky KE and Ree AH. (2010). Prediction of response to preoperative chemoradiotherapy in rectal cancer by multiplex kinase activity profiling. International Journal of Radiation Oncology, Biology and Physics, Vol 78(2), pp. 555-562. Link to article.
- Seierstad T, Røe K, Sitter B, Halgunset J, Flatmark K, Ree AH, Olsen DR, Gribbestad IS and Bathen TF. (2008). Principal component analysis for the comparison of metabolic profiles from human rectal cancer biopsies and colorectal xenografts using high-resolution magic angle spinning 1H magnetic resonance spectroscopy. Molecular Cancer, Vol 7, pp. 33. <ahref=”https://www.ncbi.nlm.nih.gov/pubmed/18439252″>Link to article.