L. Lestrade

Choline-PET in prostate cancer management: The point of view of the radiation oncologist

Among PET radiotracers, FDG seems to be quite accepted as an accurate oncology diagnostic tool, frequently helpful also in the evaluation of treatment response and in radiation therapy treatment planning for several cancer sites. To the contrary, the reliability of Choline as a tracer for prostate cancer (PC) still remains an object of debate for clinicians, including radiation oncologists. This review focuses on the available data about the potential impact of Choline-PET in the daily clinical practice of radiation oncologists managing PC patients. In summary, routine Choline-PET is not indicated for initial local T staging, but it seems better than conventional imaging for nodal staging and for all patients with suspected metastases. In these settings, Choline-PET showed the potential to change patient management. A critical limit remains spatial resolution, limiting the accuracy and reliability for small lesions. After a PSA rise, the problem of the trigger PSA value remains crucial. Indeed, the overall detection rate of Choline-PET is significantly increased when the trigger PSA, or the doubling time, increases, but higher PSA levels are often a sign of metastatic spread, a contraindication for potentially curable local treatments such as radiation therapy. Even if several published data seem to be promising, the current role of PET in treatment planning in PC patients to be irradiated still remains under investigation. Based on available literature data, all these issues are addressed and discussed in this review.

Impact of hydrogel spacer injections on interfraction prostate motion during prostate cancer radiotherapy

Abstract Background The dosimetric advantage of prostate-rectum spacers to displace the anterior rectal wall outside of the high-dose radiation regions has been clearly established in prostate cancer radiotherapy (RT). The aim of this study was to assess the impact of hydrogel spacer (HS) in the interfraction prostate motion in patients undergoing RT for prostate cancer. Material and methods Twenty prostate cancer patients implanted with three fiducial markers (FM) with (n = 10) or without (n = 10) HS were analyzed. Displacements between the prostate isocenter based on the FM’s position and the bony anatomy were quantified in the left-right (LR), anterior-posterior (AP), superior-inferior (SI) axes by offline analyses of 122 cone beam computed tomography scans. Group systematic (M), systematic (Σ) and random (σ) setup errors were determined. Results In patients with or without HS, the overall mean interfraction prostate displacements were 0.4 versus −0.4 mm (p = 0.0001), 0.6 versus 0.6 mm (p = 0.85), and −0.6 mm versus −0.3 mm (p = 0.48) for the LR, AP, and SI axes, respectively. Prostate displacements >5 mm in the AP and SI directions were similar for both groups. No differences in M, Σ and σ setup errors were observed in the three axes between HS + or HS- patients. Conclusions HS implantation does not significantly influence the interfraction prostate motion in patients treated with RT for prostate cancer. The major expected benefit of HS is a reduction of the high-dose levels to the rectal wall without influence in prostate immobilization.

Early-stage Favourable Anal Cancer: A Retrospective Analysis of Clinical Outcomes of a Moderately Low Dose Elective Nodal Intensity-modulated Radiotherapy Schedule

In this retrospective study we evaluated the long-term results of 35 early-stage favourable T1-2 N0 M0 anal cancer patients treated with intensity-modulated radiotherapy techniques combining low dose prophylactic inguinal-pelvic irradiation with dose-escalated boost. Optimal locoregional control and good tolerance makes this treatment a valuable alternative to brachytherapy boost and involved-field radiotherapy plans.

Could Concomitant Radio-Chemotherapy Improve the Outcomes of Early-Stage Node Negative Anal Canal Cancer Patients? A Retrospective Analysis of 122 Patients

One hundred twenty-two early-stage anal canal cancer patients (median age: 69 years) were treated with curative radiotherapy with (70 patients) or without (52 patients) concomitant chemotherapy. Median follow-up was 65 months (range: 4–238). At multivariate analysis, concomitant chemotherapy significantly improved local control (p = .007). Local control significantly influenced all considered endpoints, except the metastases free survival. The global rates of G3–G4 acute and late toxicity were 13.1% and 8.2%, respectively, and they were not increased by concomitant chemotherapy. Finally, concomitant chemotherapy is efficacious and safe in the treatment of T1-2N0 anal canal cancer patients and should be prospectively studied.

Development and validation of a machine learning-based predictive model to improve the prediction of inguinal status of anal cancer patients: A preliminary report

Introduction The role of prophylactic inguinal irradiation (PII) in the treatment of anal cancer patients is controversial. We developped an innovative algorithm based on the Machine Learning (ML) allowing the tailoring of the prescription of PII. Results Once verified on the independent testing set, J48 showed the better performances, with specificity, sensitivity, and accuracy rates in predicting relapsing patients of 86.4%, 50.0% and 83.1% respectively (vs 36.5%, 90.4% and 80.25%, respectively, for LR). Methods We classified 194 anal cancer patients with Logistic Regression (LR) and other 3 ML techniques based on decision trees (J48, Random Tree and Random Forest), using a large set of clinical and therapeutic variables. We tested obtained ML algorithms on an independent testing set of 65 anal cancer patients. TRIPOD (Transparent Reporting of a multivariable prediction model for Individual Prognosis or Diagnosis) methodology was used for the development, the Quality Assurance and the description of the experimental procedures. Conclusion In an internationally approved quality assurance framework, ML seems promising in predicting the outcome of patients that would benefit or not of the PII. Once confirmed in larger and/or multi-centric databases, ML could support the physician in tailoring the treatment and in deciding if deliver or not the PII.

The Pocketable Electronic Devices in Radiation Oncology (PEDRO) Project

Purpose: To analyze the impact of mobile electronic devices (MEDs) and apps in the daily clinical activity of young radiation or clinical oncologists in 5 Western European countries (Italy, Germany, Spain, Portugal, and Denmark). Methods: A web-based questionnaire was sent to 462 young (≤40 years) members of the national radiation or clinical oncology associations of the countries involved in the study. The 15 items investigated diffusion of MEDs (smartphones and/or tablets), their impact on daily clinical activity, and the differences perceived by participants along time. Results: A total of 386 (83.5%) of the 462 correctly filled questionnaires were statistically evaluated. Up to 65% of respondents declared to use an electronic device during their clinical activity. Conversely, 72% considered low to moderate impact of smartphones/tables on their daily practice. The daily use significantly increased from 2009 to 2012: users reporting a use ≥6 times/d raised from 5% to 39.9%. Professional needs fulfillment was declared by less than 68% of respondents and compliance to apps indications by 66%. Significant differences were seen among the countries, in particular concerning the feeling of usefulness of MEDs in the daily clinical life. The perception of the need of a comprehensive Web site containing a variety of applications (apps) for clinical use significantly differed among countries in 2009, while it was comparable in 2012. Conclusions: This survey showed a large diffusion of MEDs in young professionals working in radiation oncology. Looking at these data, it is important to verify the consistency of information found within apps, in order to avoid potential errors eventually detrimental for patients. “Quality assurance” criteria should be specifically developed for medical apps and a comprehensive Web site gathering all reliable applications and tools might be useful for daily clinical practice.

The Pocketable Electronic Devices in Radiation Oncology (PEDRO) Project: How the Use of Tools in Medical Decision Making is Changing?

Purpose: To analyze the impact of mobile electronic devices (MEDs) and apps in the daily clinical activity of young radiation or clinical oncologists in 5 Western European countries (Italy, Germany, Spain, Portugal, and Denmark). Methods: A web-based questionnaire was sent to 462 young (≤40 years) members of the national radiation or clinical oncology associations of the countries involved in the study. The 15 items investigated diffusion of MEDs (smartphones and/or tablets), their impact on daily clinical activity, and the differences perceived by participants along time. Results: A total of 386 (83.5%) of the 462 correctly filled questionnaires were statistically evaluated. Up to 65% of respondents declared to use an electronic device during their clinical activity. Conversely, 72% considered low to moderate impact of smartphones/tables on their daily practice. The daily use significantly increased from 2009 to 2012: users reporting a use ≥6 times/d raised from 5% to 39.9%. Professional needs fulfillment was declared by less than 68% of respondents and compliance to apps indications by 66%. Significant differences were seen among the countries, in particular concerning the feeling of usefulness of MEDs in the daily clinical life. The perception of the need of a comprehensive Web site containing a variety of applications (apps) for clinical use significantly differed among countries in 2009, while it was comparable in 2012. Conclusions: This survey showed a large diffusion of MEDs in young professionals working in radiation oncology. Looking at these data, it is important to verify the consistency of information found within apps, in order to avoid potential errors eventually detrimental for patients. “Quality assurance” criteria should be specifically developed for medical apps and a comprehensive Web site gathering all reliable applications and tools might be useful for daily clinical practice.

PO-0703: Safety and efficacy of image guided intensity-modulated radiation therapy in the treatment of anal canal cancer

Conclusions: We describe a method to extract data from multiple sources, and to apply a prediction model on routine clinical patient data. Although the free text extraction was not perfect and the number of patients in our validation was low (N=38), we have successfully shown a method for automatically (nightly) applying prediction models in clinical practice, and thus enabling use of prediction results for treatment decisions. Unfortunately, there is still a need to enhance data collection at the source. For example, the availability of pCR was our most limiting factor (only 4% of patients). Furthermore, the extraction of tumor length from free text reports remains necessary until available in a structured format. Based on this method, future work consists of adding more data sources and routine clinical validation of prediction models.

PO-0698: Radiotherapy±chemotherapy in the treatment of anal canal cancer: A single-institute long-term experience

PO-0696 Adaptive strategy in preoperative RT for rectal cancer with Tomotherapy: boosting the dose to the shrinking tumor N. Slim, C. Fiorino, P. Passoni, M. Ronzoni, V. Ricci, S. Di Palo, A. Tamburini, N.A. Iacovelli, R. Calandrino, N. Di Muzio San Raffaele Scientific Institute, Radiotherapy, Milan, Italy San Raffaele Scientific Institute, Medical Physics, Milan, Italy San Raffaele Scientific Institute, Medical Oncology, Milan, Italy San Raffaele Scientific Institute, Surgery, Milan, Italy

Setup margins and geometric uncertainties in intensity-modulated radiation therapy in treating pituitary adenomas: the experience of Lyon Sud Hospital

PurposeThe authors retrospectively evaluated the setup uncertainties in Intensity-Modulated Radiation Therapy (IMRT) for pituitary adenomas and verified the margins used in daily practice (3 mm).Materials and methodsCraniocaudal (CC), anteroposterior (AP) and laterolateral (LL) displacements were measured during the first 3 days of treatment and then weekly by comparing two orthogonal images obtained by an electronic system of portal imaging with Digitally Reconstructed Radiographs (DRRs). Setup Margins (SM) were defined according to the International Commission on Radiation Units (ICRU)-62 formula, the Stroom equation and the van Herk equation. The systematic (Σ) and random (σ) errors of the population were calculated as standard deviation (SD) of the population mean and the mean of SDs for every patient, respectively.ResultsTwenty patients were treated by IMRT for pituitary adenomas, and a total of 231 measurements were obtained. Σ and σ were 0.6 and 1.3 mm, 0.8 and 1 mm, 1.2 and 1.5 mm in the AP, LL and CC direction, respectively. Larger setup margin was 2.4, 2.7 and 4 mm in the AP, LL and CC direction, respectively (van Herk formula).ConclusionsIMRT is a highly sophisticated treatment technique that requires precise definition and optimisation of local setup errors and, finally, of the irradiated volumes. The role of image-guided RT in these kinds of treatments should be prospectively evaluated.RiassuntoObiettivoScopo del presente lavoro è stato valutare retrospettivamente le incertezze di setup nella Radioterapia ad Intensità Modulata (IMRT) degli adenomi ipofisiari e verificare i margini usati nella nostra pratica quotidiana (3 mm).Materiali e metodiGli spostamenti cranio-caudali (CC), antero-posteriori (AP) e latero-laterali (LL) sono stati misurati durante i primi 3 giorni di trattamento e poi settimanalmente comparando due immagini ortogonali ottenute da un sistema elettronico di portal imaging e le Digitally Reconstructed Radiographs (DRRs). I margini di setup sono stati definiti secondo la formula dell’International Commission on Radiation Units (ICRU)-62, l’equazione di Stroom e l’equazione di Van-Herk. L’errore sistematico (Σ) e random (σ) della popolazione sono stati calcolati rispettivamente come deviazione standard della media della popolazione e come media delle deviazioni standard per ogni paziente.RisultatiVenti pazienti sono stati trattati con IMRT per adenoma ipofisiario ed un totale di 231 misure sono state ottenute. L’errore sistematico (Σ) e random (σ) sono stati rispettivamente di 0,6 e 1,3 mm, 0,8 e 1 mm, 1,2 e 1,5 mm, rispettivamente nelle direzioni AP, LL e CC. Il maggiore setup margin calcolato è stato di 2,4, 2,7 e 4 mm rispettivamente nella direzione AP, LL and CC (formula di van Herk).ConclusioniLa IMRT è una tecnica di trattamento altamente sofisticata che necessita di una definizione precisa ed ottimizzata degli errori di setup locali e, quindi, dei volumi da irradiare. Il ruolo dell’image guided radiation therapy in questo tipo di trattamenti deve essere valutato prospetticamente.