B-0949 MRI-based selection of clinical complete and good responders after chemoradiation for rectal cancer allows for successful minimal invasive treatment
L. Heijnen, M. Maas, M.H. Martens, D.M.J. Lambregts, J.W.A. Leijtens, R.G.H. Beets-Tan, G.L. Beets | Monday, March 11, 14:00 – 15:30 / Room E2
Purpose: Patients with good or complete response after neoadjuvant chemoradiation have excellent long-term outcome. Minimal invasive treatment (i.e. transanal endoscopic microsurgery (TEM) and wait-and-see policy) are increasingly considered as an alternative to major surgery. With this prospective cohort study we aimed to evaluate long-term outcome of strictly MR-based selected patients who have been treated with minimal invasive treatment.
Methods and Materials: Eight weeks after chemoradiation, endoscopy and restaging MRI were performed (including diffusion-weighted MRI for yT-staging and gadofosveset-enhanced MRI for yN-staging). Complete responders were selected for wait-and-see policy and good responders with small tumour remnant for TEM. Both treatment groups underwent intensive 3-to-6 monthly follow-up, using MR imaging (DWI+gadofosveset), CEA, CT of thorax and abdomen and endoscopy was performed. Long-term outcome was estimated with Kaplan-Meier curves.
Results: Forty-one patients were included, thirty-three in the wait-and-see group and eight in the TEM-group. Mean follow-up was 26 months (range 6-91). For the TEM-group, 4 patients had ypT0 and 4 had ypT2. Two patients, both in the wait-and-see group, developed a local recurrence within two years and underwent surgery, leading to a 2-year local recurrence rate of 9 %. Both recurrences were detected on (DWI-)MRI in an early stage. The cumulative probabilities of 2-year disease-free survival and overall survival were 93 % and 100 %, respectively. No recurrences occurred in the TEM-group.
Conclusion: Both selection and follow-up of good and complete responders after chemoradiation for rectal cancer with MRI is feasible. Long-term outcome so far is excellent. (DWI-)MRI seems to be a reliable tool for early recurrence detection.
B-0948 Computed tomography of the bowel: a prospective comparison study between four techniques
M. Revelli, F. Paparo, L. Bacigalupo, A. Garlaschi, L. Cevasco, E. Biscaldi, G. Rollandi | Monday, March 11, 14:00 – 15:30 / Room E2
Purpose: Our purposes were to compare the grade of bowel distension obtained with four different CT techniques dedicated for examination of small intestine (CT-enteroclysis and CT-enterography), colon (CT with water enema), or both (CT-enterography with water enema) and to assess patient tolerance towards each protocol.
Methods and Materials: We recruited four groups of 30 patients. Each group corresponded to a specific CT technique, for a total of 120 consecutive patients (65 male, 55 female; mean age 51.09±13.36 years). CT studies were evaluated in consensus by two gastrointestinal-dedicated radiologists who performed quantitative and qualitative analysis of bowel distension. Presence and type of adverse effects were recorded.
Results: CT-enteroclysis provided the best distension of jejunal loops (median diameter 27mm; range 17-32mm) compared with all other techniques (p<0.0001). Frequency of patients with an adequate distension of the terminal ileum was not significantly different among the four groups (p=0.0608). At both quantitative and qualitative analysis CT with water enema and CT-enterography with water enema determined a greater and more consistent luminal filling of the large intestine compared with the one provided by both CT-enteroclysis and CT-enterography (p<0.0001 for all colonic segments). Adverse effects were more frequent in patients from the CT-enteroclysis group (p<0.0028).
Conclusion: CT-enteroclysis allows an optimal distension of jejunal loops, but it is the most uncomfortable CT protocol. When performing CT with water enema, an adequate retrograde distension of the terminal ileum was provided in a high percentage of patients. CT-enterography with water enema provides a simultaneous optimal distension of both small and large bowel.
B-0323 Apparent diffusion coefficient for evaluating early tumour response to neoadjuvant chemo-radiotherapy in locally advanced cervical cancer: correlation with histopathology. Preliminary results
M. Iacobucci, M. Miccò, A.L. Valentini, B. Gui, A.M. De Gaetano, L. Bonomo | Friday, March 8, 10:30 – 12:00 / Room F1
Purpose: To evaluate diagnostic accuracy of diffusion-weighted magnetic resonance imaging (DWI) in predicting response to neo-adjuvant chemo-radiotherapy (nCRT) in patients with locally advanced cervical carcinoma using apparent diffusion coefficient (ADC). Cervical lesions ADC were correlated with post-surgical histopathology.
Methods and Materials: 24 women (FIGO>IB Bulky) underwent MRI and DWI prior to, after 2 weeks and at the end of nCRT, using 1.5 T scanner. Cervical lesion volume and ADC were measured at each assessment. Radical hysterectomy was performed 4 weeks after MRI. Treatment response was determined based on histopathology and was classified as complete response (CR), residual (RD) or stable disease (SD). Mean ADCs (mADC), ADC increase and volume reduction (VR) rates were compared using histopathology as reference standard
Results: According to histology, 13/24 (54%) had CR, 11/24 (46%) had RD <1 cm. 2 patients presented SD. Before therapy, in the study population mADC was 0.96±0.06×10-³ mm²/s but it was lower in SD (0.76±0.1×10-³ mm²/s). After 2 weeks of nCRT, mADC correlated with tumour response: a) in CR with 23 % percent change (1.20±0.02×10-³ mm²/s vs 0.98±0.06×10-³ mm²/s; P<0.001); b) in RD with 10 % percent change (1.05±0.02×10-³ mm²/s vs 0.93±0.06×10-³ mm²/s; P<0.001). Tumour volume decreased in CR and RD with reduction rate of 48 % and 46 %, respectively. At the end of CRT, no significant differences on ADC between CR and RD (mADC 1.20±0.07×10-³ mm²/s vs 1.17±0.06×10-³ mm²/s; P>1) were observed. All CR had local inflammation at histology.
Conclusion: ADC is early indicator of tumour response in patients with advanced cervical cancer.
B-0627 Additional value of diffusion-weighted (DWI) MRI for predicting complete tumour response (T0N0) in rectal cancer treated with neo-adjuvant chemoradiation therapy (CRT)
S. Sassen, M. de Booij, M.N. Sosef, G. Lammering, C.M.M. Bakker, R. Clarijs, R.C.M. Berendsen, J. Wals, R.F.A. Vliegen | Sunday, March 10, 10:30 – 12:00 / Room A
Purpose: Patients with complete response (CR) after CRT might be considered for less aggressive treatment like a wait-and-see strategy. Few studies investigated the value of DWI-MRI for predicting CR after CRT, but none included lymph nodes in the analysis (ypT0N0). The aim of the present study was to retrospectively determine the additional value of DWI-MRI to conventional (T2-weighted) MRI for predicting CR after CRT.
Methods and Materials: Eighty locally advanced rectal cancer patients underwent CRT followed by restaging MRI and operation. MRI consisted of conventional sequences and DWI. Two readers with different levels of experience independently scored conventional images for CR and, in a second reading, combined conventional and DWI-MRI images. A 5-point confidence level score was used to generate ROC curves. Differences in performance were calculated by comparing areas under the ROC curves (AUC). Interobserver agreement, sensitivity, specificity and positive predictive values (PPV) were calculated. Histology served as reference standard.
Results: Ten of 80 patients (13%) had a pathologic complete response (ypT0N0). Comparison of the ROC curves showed significant improvement of the AUC only for the experienced reader 1 from 0,77 to 0,88 (p=0,009). Sensitivity improved from 20-30% to 40-70%. Specificity and PPV improved only for reader 1 from 87 to 93 %, resp., 25 to 58 %. Interobserver agreement improved from 0,14 to 0,27.
Conclusion: Adding DWI to conventional MRI improves diagnostic performance of experienced readers and increases interobserver agreement for identification of CR. Sensitivity and PPV remain low, with a considerable risk of over- and undertreatment.
A-425 Scrotal tumours
P.S. Sidhu | Sunday, March 10, 14:00 – 15:30 / Room C
Ultrasound remains the imaging modality of choice for the assessment of any form of scrotal pathology. The resolution capabilities of the technique and the superficial nature of the scrotal contents allow ultrasound examination to deliver optimal imaging. Testicular tumours maybe imaged and characterised with ease, without need for further imaging techniques. The addition of colour Doppler ultrasound allows for the interrogation of the vascularity of any lesion seen, and the addition of newer techniques such as contrast-enhanced ultrasound and tissue elastography has beneficial effects to aid interpretation and diagnosis. Nearly all focal abnormalities of the testis in the adult patient are malignant lesions, with primary germ cell tumours a frequent abnormality in the younger patient, and lymphoma or a secondary malignancy common in the older patient. However, benign abnormalities such as a focal infarction, haematoma or an epidermoid cyst may mimic malignancy. It is important to be able differentiate benign from malignant causes, with testis sparing the ultimate goal. Non-germ cell tumours present a specific conundrum, with the newer imaging techniques likely to be of benefit in distinguishing these tumours from germ cell tumours. Extra-testicular tumours are nearly always benign and include lipoma and adenomatoid lesions. Inflammatory disease may also simulate a tumour and presents an unexpected pitfall. A carful scrotal ultrasound examination, using all the available ultrasound techniques should allow the examiner to make a confident assessment of any scrotal tumour, and allow for the correct management without need for further imaging.
B-0158 Initial clinical results of simultaneous PET/MRI in comparison with PET/CT in patients with head and neck cancer
P. Stumpp, K. Kubiessa, S. Purz, M. Gawlitza, A. Kühn, K.G. Steinhoff, A. Boehm, R. Kluge, T. Kahn | Thursday, March 7, 14:00 – 15:30 / Room C
Purpose: Describing diagnostic capability of simultaneous PET/MRI in comparison with PET/CT and their single components CT, MRI and PET in an initial prospective study based on 17 patients with head-and-neck cancer.
Methods and Materials: 17 patients with head-and-neck cancer received an 18F-FDG-PET/CT for staging or follow-up and an additional simultaneous PET/MRI scan with a whole body imaging part and a dedicated examination of the neck. Sole MRI, CT and PET components of the multimodal acquisitions plus the PET/MRI and PET/CT examinations were evaluated independently, blinded and in a randomised order by two readers. Results were compared with the reference standard, and sensitivity, specificity, positive (PPV) and negative predictive value (NPV) were calculated.
Results: 23 malignant tumours and 55 benign changes were found with the reference standard. For PET/CT the two reader groups showed a sensitivity of 78.3% and 87 %, a specificity of 85.5% and 89.1%, a PPV of 71.4% and 75 % and a NPV of 90.7% and 94 %. For PET/MRI sensitivity was 78.3% and 82.6%, specificity 81.8% and 94.5%, PPV 65.5% and 85.7% and NPV 91.2% and 93.8%. Evaluation of the single PET part from PET/CT revealed highest sensitivity of 95.7%, whereas evaluation of the sole MRI component from PET/MRI showed best specificity of 96.4%. There was a high interrater agreement in all modalities (Cohen’s kappa coefficient: 0.61 – 0.82).
Conclusion: PET/MRI of patients with head and neck cancer yielded good diagnostic capability, similar to PET/CT. Further studies on larger cohorts to prove these first results seem justified.
