Nadia Rondi

Intensity-Modulated Radiation Therapy with Simultaneous Integrated Boost Combined with Concurrent Chemotherapy for the Treatment of Anal Cancer Patients: 4-Year Results of a Consecutive Case Series

ABSTRACT Purpose: To report the 4-year outcomes of a consecutive series of anal cancer patients treated with concurrent chemo-radiation delivered with intensity-modulated radiotherapy (IMRT), employing a simultaneous integrated boost (SIB) approach. Methods: A consecutive series of 54 patients was enrolled between 2007 and 2013. Treatment schedule consisted of 50.4 Gy/28 fractions (1.8 Gy daily) to the gross tumor volume, while the elective nodal volumes were prescribed 42 Gy/28 fractions (1.5 Gy/daily) for patients having a cT2N0 disease. Patients with cT3-T4/N0-N3 tumors were prescribed 54 (T3) or 60 (T4) Gy/30 fractions (1.8–2 Gy daily) to the gross tumor volume; gross nodal volumes were prescribed 50.4 Gy/30 fr (1.68 Gy daily) if sized ≤ 3 cm or 54 Gy/30 fr (1.8 Gy daily) if > 3 cm; elective nodal regions were given 45 Gy/30 fractions (1.5 Gy daily). Chemotherapy was administered concurrently according to the Nigros regimen. Primary endpoint was colostomy-free survival (CFS). Secondary endpoints were local control (LC), disease-free survival (DFS), cancer-specific survival (CSS), overall survival (OS), and toxicity profile. Results: Median follow up was 32.6 months (range 12–84). The actuarial probability of being alive at 4 years without a colostomy (CFS) was 68.9% (95% CI: 50.3%–84.7%). Actuarial 4-year OS, CSS, DFS, and LC were 77.7% (95% CI: 60.7–88.1%), 81.5% (95% CI: 64%–91%), 65.5% (95% CI: 47.7%–78.5%), and 84.6% (95% CI: 71.6%–92%). Actuarial 4-year metastasis-free survival was 74.4% (95% CI: 55.5%–86.2%). Maximum detected acute toxicities were as follows: dermatologic –G3: 13%; GI-G3: 8%; GU-G3: 2%; anemia-G3: 2%; neutropenia-G3:11%; G4: 2%; thrombocytopenia- G3:2%. Four-year G2 chronic toxicity rates were 2.5% (95% CI: 3.6–16.4) for GU, 14.4% (95% CI: 7.1–28) for GI, 3.9% (95% CI: 1%–14.5%) for skin, and 4.2% (95% CI: 1.1–15.9) for genitalia. Conclusions: Our study shows the feasibility of IMRT in the combined modality treatment of anal cancer, with comparable results to the literature with respect to LC, sphincter preservation and survival. Acute toxicity is lower if compared to series employing standard techniques. Our results support the use of IMRT on a routine basis for the treatment of anal cancer.

Efficacy and Safety of Tadalafil 20 mg on Demand vs. Tadalafil 5 mg Once-a-Day in the Treatment of Post-Radiotherapy Erectile Dysfunction in Prostate Cancer Men: A Randomized Phase II Trial

INTRODUCTION The role of phosphodiesterase type 5 inhibitors in the treatment of post-radiotherapy erectile dysfunction (ED) has not been extensively investigated. AIM To compare the efficacy and safety of on-demand 20-mg tadalafil (arm A) with the newly released tadalafil 5-mg once-a-day dosing (arm B) in patients with ED following radiotherapy for prostate cancer (PC). METHODS Randomized study to receive on-demand 20-mg or once-a-day 5-mg tadalafil for 12 weeks. Main Outcome Measures.  Changes in the International Index of Erectile Function (IIEF) domain scores and Sexual Encounter Profile (SEP) question 2 and 3 positive response rates. RESULTS Fifty-two out of 86 screened patients were randomized. Forty-four patients were evaluable for efficacy. A significant improvement in all domains of the IIEF was observed in both arms (P = 0.0001) with mean erectile function domain scores values of 25 and 27.1 for the 20-mg and 5-mg tadalafil, respectively (P = 0.19). SEP 2 and 3 positive response rates increased from 0% in both arms at baseline to 81% and 70% in the 20-mg arm and 90% and 73% in the 5-mg arm, respectively, at the end of treatment (P = 0.27). End of treatment global efficacy question positive answers were 86% in the 20-mg arm and 95% in the 5-mg arm (P = 0.27). Higher treatment compliance was shown in arm B (100%) as compared with arm A (86%). There was a nonstatistically significant trend toward fewer side effects in favor of the 5-mg daily dose arm. CONCLUSIONS In the study population, both tadalafil formulations generated significantly high response rates according to the outcome measures and were well tolerated. The once-a-day 5-mg dosing showed higher compliance and marginally reduced side effects, thus making it an attractive alternative to on-demand therapy for ED in post-radiotherapy PC patients.

Volumetric modulated arc therapy (VMAT) in the combined modality treatment of anal cancer patients

OBJECTIVE To report clinical and dosimetric outcomes of a consecutive series of patients with anal cancer treated with volumetric-modulated arc therapy (VMAT) concomitant to chemotherapy (CT). METHODS A cohort of 39 patients underwent VMAT employing a schedule consisting of 50.4 Gy/28 fractions to the gross tumour volume (GTV) and 42 Gy/28 fractions to the elective nodal volumes for patients with cT2N0 disease. Patients with cT3-T4/N0-N3 tumours were prescribed 54 Gy/30 fractions to the GTV and 50.4 Gy/30 fractions to the gross nodal volumes if sized ≤3 cm or 54 Gy/30 fractions if > 3 cm. Elective nodal regions were given 45 Gy/30 fractions. CT was administered concurrently following Nigros regimen. The primary end point was acute toxicity. Secondary end points were colostomy-free survival (CFS), disease-free survival (DFS), cancer-specific survival (CSS) and overall survival (OS). Dosimetric data are also provided. RESULTS Median follow-up was 21 months. Maximum acute toxicities were: dermatologic-G3: 18%; gastrointestinal-G3: 5%; genitourinary-G3: 2%; anaemia-G2: 7%; leukopenia-G3: 28%; G4: 8%; neutropenia-G3: 13%; G4: 18%; thrombocytopenia-G3: 11%; and G4: 2%. The actuarial 2-year CFS was 77.9% [95% confidence interval (CI): 54-90.4%]. Actuarial 2-year OS and CSS were 85.2% (95% CI: 60.1-95.1%), while DFS was 75.1% (95% CI: 52.4.7-88.1%). CONCLUSION Our clinical results support the use of VMAT as a safe and effective intensity-modulated radiotherapy (IMRT) option in the combined modality treatment of anal cancer, with consistent dosimetry, mild toxicity and promising sphincter preservation and survival rates. ADVANCES IN KNOWLEDGE IMRT is a standard of care for patients with anal cancer, and VMAT is a robust technical solution in this setting.

Tracking target position variability using intraprostatic fiducial markers and electronic portal imaging in prostate cancer radiotherapy

PurposeModern radiotherapy has achieved substantial improvement in tumour control and toxicity rates by escalating the total dose to the target volume while sparing surrounding normal tissues. It has therefore become necessary to precisely track tumour position in order to minimise geometrical uncertainties due to setup errors and organ motion. We conducted this prospective evaluation of prostate cancer patients treated with image-guided conformal radiation therapy at our institution. We implanted three fiducial markers (gold seeds) within the prostatic gland in order to quantify daily target displacements and to generate specific margins around the clinical target volume (CTV) to create an appropriate planned target volume (PTV).Materials and methodsBetween April and December 2009, ten patients affected with localised prostate cancer were transrectally implanted with three radio-opaque markers. Each patient underwent a computed tomography (CT) scan for planning purposes following proper bladder and rectum preparation. During treatment two orthogonal images were acquired daily and compared with previously generated digitally reconstructed radiographs. After manual localisation, comparison between the position of the gold seeds on the portal and reference images was carried out, and a set of extrapolated lateral-lateral (LL), anterior-posterior (AP) and cranial-caudal (CC) shift corrections was calculated and recorded. Couch corrections were applied with a threshold of 3 mm displacement.ResultsSystematic and random errors for each direction were calculated either as measured according to displacement of the gold seeds prior to any couch movement and after couch position correction according to the radio-opaque markers. For skin marks, mean systematic and random errors were 0.12+2.94 mm for LL, 1.04+3.37 mm for AP, −1.14+2.71 mm for CC, whereas for seed markers, mean and systematic errors were 0.6+1.5 mm for LL, 0.51+2.45 mm for AP and −0.25+2.51 mm for CC. A scatter plot generated on all measurements after couch repositioning according to gold-seed displacement suggested a confidence range of shift distributions within 5 mm for LL, 8 mm for CC, and 7 mm for AP. The total systematic and random components were then used to calculate proper PTV in patients receiving conventional treatment (7 mm for LL and 9 mm for both AP and CC).ConclusionsProstate positional variability during a course of radiation treatment is strongly influenced by setup and organ motion. Organ tracking through fiducial markers and electronic portal imaging is able to reduce the spread of displacements, significantly contributing to improve the ballistic precision of radiation delivery.RiassuntoObiettivoLa moderna radioterapia ha raggiunto traguardi considerevoli in termini di controllo tumorale e riduzione dei tassi di tossicità associati al trattamento, con la possibilità di erogare dosi importanti al volume bersaglio, risparmiando contemporaneamente i tessuti sani. Risulta, pertanto, focale la caratterizzazione precisa della posizione della lesione neoplastica per minimizzare le incertezze geometriche dovute agli errori di posizionamento ed al movimento d’organo. Abbiamo intrapreso una valutazione prospettica dei pazienti trattati mediante radioterapia conformazionale guidata dalle immagini per carcinoma prostatico, utilizzando tre reperi fiduciali (semi d’oro) impiantati all’interno della prostata per quantificare gli scostamenti giornalieri del volume bersaglio e generare margini specifici attorno al volume bersaglio clinico (CTV) creando un appropriato volume bersaglio di pianificazione (PTV).Materiali e metodiTra aprile e dicembre 2009, 10 pazienti affetti da adenocarcinoma prostatico organo-confinato sono stati sottoposti ad impianto trans-rettale sotto guida ecografica di 3 reperi fiduciali radio-opachi. Ogni paziente è stato sottoposto a tomografia computerizzata (CT) di pianificazione con una adeguata preparazione vescicale e rettale; ad ogni seduta di trattamento, sono state acquisite 2 immagini ortogonali e poi confrontate con immagini radiografiche a ricostruzione digitale. è stata effettuata una localizzazione manuale confrontando la posizione dei reperi fiduciali nelle immagini portali con quella nelle immagini di riferimento. Sono stati estrapolati e registrati gli scostamenti nelle direzioni latero-laterale (LL), anteroposteriore (AP) e cranio-caudale (CC). La correzione della posizione del lettino di trattamento è stata effettuata con una soglia di 3 mm.RisultatiSono stati calcolati l’errore standard e sistematico per ogni direzione, misurando gli scostamenti dei semi d’oro prima del movimento del lettino di trattamento e dopo aver applicato gli spostamenti secondo i reperi fiduciali. Per i reperi cutanei, l’errore sistematico e casuale medio sono stati 0,12±2,94 mm per la direzione LL, 1,04±3,37 mm per la direzione AP e −1,14±2,71 mm per la direzione CC; per i reperi fiduciali, l’errore sistematico e casuale medio sono stati 0,6±1,5 mm per la direzione LL, 0,51±2,45 mm per la direzione AP e −0,25±2,51 mm per la direzione CC. è stato creato un diagramma di distribuzione di tutte le misure ottenute dopo il riposizionamento del lettino in funzione degli scostamenti registrati mediante i reperi fiduciali; l’ambito di confidenza della distribuzione degli spostamenti si trova entro i 5 mm per la direzione LL, entro i 6 mm per la direzione CC ed entro i 7 mm per la direzione AP. L’errore sistematico e l’errore casuale totale sono stati utilizzati per generare margini per ottenere il PTV nei pazienti trattati convenzionalmente (7 mm per la direzione LL; 9 mm sia per la direzione AP che per la direzione CC).ConclusioniLa variabilità della posizione della ghiandola prostatica durante un trattamento radiante è influenzata in modo importante dal posizionamento e dal movimento d’organo. Il monitoraggio della posizione della prostata mediante reperi fiduciali ed immagini portali è in grado di ridurre la dispersione degli scostamenti rispetto all’atteso, contribuendo in maniera significativa al miglioramento della precisione balistica della radioterapia.

Value of staging squamous cell carcinoma of the anal margin and canal using the sentinel lymph node procedure: an update of the series and a review of the literature

Background:Inguinal metastases in patients affected by anal cancer are an independent prognostic factor for local failure and overall mortality. Since 2001, sentinel lymph node biopsy was applied in these patients. This original study reports an update of personal and previous published series, which were compared with Literature to value the incidence of inguinal metastases T-stage related and the overall incidence of false negative inguinal metastases at sentinel node.Methods:In all, 63 patients diagnosed with anal cancer submitted to inguinal sentinel node. Furthermore a research in the Pub Med database was performed to find papers regarding this technique.Results:In our series, detection rate was 98.4%. Inguinal metastases were evidentiated in 13 patients (20.6%). Our median follow-up was 35 months. In our series, no false negative nodes were observed.Conclusion:Sentinel node technique in the detection of inguinal metastases in patients affected by anal cancer should be considered as a standard of care. It is indicated for all T stages in order to select patients to be submitted to inguinal radiotherapy, avoiding related morbidity in negative ones. An overall 3.7% rate of false negative must be considered acceptable.

Image-guided IMRT with simultaneous integrated boost as per RTOG 0529 for the treatment of anal cancer

To report on clinical outcomes of simultaneous integrated boost intensity‐modulated radiation therapy (IMRT) and concurrent chemotherapy as per Radiation Therapy Oncology Group (RTOG) 0529 protocol in anal cancer patients.

Dose to Pelvic Bone Marrow Defined with FDG-PET Predicts for Hematologic Nadirs in Anal Cancer Patients Treated with Concurrent Chemo-radiation

Abstract Purpose: To investigate whether irradiated volume of pelvic active bone marrow (ACTBM) may predict decreased blood cells nadirs in anal cancer patients undergoing concurrent chemo-radiation. Methods: Forty-four patients were analyzed and pelvic active bone marrow (ACTBM) was characterized employing 18FDG-PET. Dosimetric parameters on dose–volume histograms were correlated to nadirs with generalized linear modeling. Results: ACTBM mean dose was significantly correlated to white blood cell (β = −1.338; 95%CI: −2.455/−0.221; p = 0.020), absolute neutrophil count (β = −1.651; 95%CI: −3.284/−0.183; p = 0.048), and platelets (β = −0.031; 95%CI: −0.057/−0.004; p = 0.024) nadirs. Other dosimetric parameters were found to be correlated (ACTBM-V10,-V20,-V30and-V40). Conclusions: 18FDG-PET is able to define active bone marrow and may predict for decreased blood cells count nadirs.

Variabilità della posizione del volume bersaglio utilizzando reperi fiduciali intra-prostatici ed immagini portali nella radioterapia del tumore della prostata

PurposeModern radiotherapy has achieved substantial improvement in tumour control and toxicity rates by escalating the total dose to the target volume while sparing surrounding normal tissues. It has therefore become necessary to precisely track tumour position in order to minimise geometrical uncertainties due to setup errors and organ motion. We conducted this prospective evaluation of prostate cancer patients treated with image-guided conformal radiation therapy at our institution. We implanted three fiducial markers (gold seeds) within the prostatic gland in order to quantify daily target displacements and to generate specific margins around the clinical target volume (CTV) to create an appropriate planned target volume (PTV).Materials and methodsBetween April and December 2009, ten patients affected with localised prostate cancer were transrectally implanted with three radio-opaque markers. Each patient underwent a computed tomography (CT) scan for planning purposes following proper bladder and rectum preparation. During treatment two orthogonal images were acquired daily and compared with previously generated digitally reconstructed radiographs. After manual localisation, comparison between the position of the gold seeds on the portal and reference images was carried out, and a set of extrapolated lateral-lateral (LL), anterior-posterior (AP) and cranial-caudal (CC) shift corrections was calculated and recorded. Couch corrections were applied with a threshold of 3 mm displacement.ResultsSystematic and random errors for each direction were calculated either as measured according to displacement of the gold seeds prior to any couch movement and after couch position correction according to the radio-opaque markers. For skin marks, mean systematic and random errors were 0.12+2.94 mm for LL, 1.04+3.37 mm for AP, −1.14+2.71 mm for CC, whereas for seed markers, mean and systematic errors were 0.6+1.5 mm for LL, 0.51+2.45 mm for AP and −0.25+2.51 mm for CC. A scatter plot generated on all measurements after couch repositioning according to gold-seed displacement suggested a confidence range of shift distributions within 5 mm for LL, 8 mm for CC, and 7 mm for AP. The total systematic and random components were then used to calculate proper PTV in patients receiving conventional treatment (7 mm for LL and 9 mm for both AP and CC).ConclusionsProstate positional variability during a course of radiation treatment is strongly influenced by setup and organ motion. Organ tracking through fiducial markers and electronic portal imaging is able to reduce the spread of displacements, significantly contributing to improve the ballistic precision of radiation delivery.RiassuntoObiettivoLa moderna radioterapia ha raggiunto traguardi considerevoli in termini di controllo tumorale e riduzione dei tassi di tossicità associati al trattamento, con la possibilità di erogare dosi importanti al volume bersaglio, risparmiando contemporaneamente i tessuti sani. Risulta, pertanto, focale la caratterizzazione precisa della posizione della lesione neoplastica per minimizzare le incertezze geometriche dovute agli errori di posizionamento ed al movimento d’organo. Abbiamo intrapreso una valutazione prospettica dei pazienti trattati mediante radioterapia conformazionale guidata dalle immagini per carcinoma prostatico, utilizzando tre reperi fiduciali (semi d’oro) impiantati all’interno della prostata per quantificare gli scostamenti giornalieri del volume bersaglio e generare margini specifici attorno al volume bersaglio clinico (CTV) creando un appropriato volume bersaglio di pianificazione (PTV).Materiali e metodiTra aprile e dicembre 2009, 10 pazienti affetti da adenocarcinoma prostatico organo-confinato sono stati sottoposti ad impianto trans-rettale sotto guida ecografica di 3 reperi fiduciali radio-opachi. Ogni paziente è stato sottoposto a tomografia computerizzata (CT) di pianificazione con una adeguata preparazione vescicale e rettale; ad ogni seduta di trattamento, sono state acquisite 2 immagini ortogonali e poi confrontate con immagini radiografiche a ricostruzione digitale. è stata effettuata una localizzazione manuale confrontando la posizione dei reperi fiduciali nelle immagini portali con quella nelle immagini di riferimento. Sono stati estrapolati e registrati gli scostamenti nelle direzioni latero-laterale (LL), anteroposteriore (AP) e cranio-caudale (CC). La correzione della posizione del lettino di trattamento è stata effettuata con una soglia di 3 mm.RisultatiSono stati calcolati l’errore standard e sistematico per ogni direzione, misurando gli scostamenti dei semi d’oro prima del movimento del lettino di trattamento e dopo aver applicato gli spostamenti secondo i reperi fiduciali. Per i reperi cutanei, l’errore sistematico e casuale medio sono stati 0,12±2,94 mm per la direzione LL, 1,04±3,37 mm per la direzione AP e −1,14±2,71 mm per la direzione CC; per i reperi fiduciali, l’errore sistematico e casuale medio sono stati 0,6±1,5 mm per la direzione LL, 0,51±2,45 mm per la direzione AP e −0,25±2,51 mm per la direzione CC. è stato creato un diagramma di distribuzione di tutte le misure ottenute dopo il riposizionamento del lettino in funzione degli scostamenti registrati mediante i reperi fiduciali; l’ambito di confidenza della distribuzione degli spostamenti si trova entro i 5 mm per la direzione LL, entro i 6 mm per la direzione CC ed entro i 7 mm per la direzione AP. L’errore sistematico e l’errore casuale totale sono stati utilizzati per generare margini per ottenere il PTV nei pazienti trattati convenzionalmente (7 mm per la direzione LL; 9 mm sia per la direzione AP che per la direzione CC).ConclusioniLa variabilità della posizione della ghiandola prostatica durante un trattamento radiante è influenzata in modo importante dal posizionamento e dal movimento d’organo. Il monitoraggio della posizione della prostata mediante reperi fiduciali ed immagini portali è in grado di ridurre la dispersione degli scostamenti rispetto all’atteso, contribuendo in maniera significativa al miglioramento della precisione balistica della radioterapia.

Tracking target position variability using intraprostatic fiducial markers and electronic portal imaging in prostate cancer radiotherapy@@@Variabilità della posizione del volume bersaglio utilizzando reperi fiduciali intra-prostatici ed immagini portali nella radioterapia del tumore della prostata

PurposeModern radiotherapy has achieved substantial improvement in tumour control and toxicity rates by escalating the total dose to the target volume while sparing surrounding normal tissues. It has therefore become necessary to precisely track tumour position in order to minimise geometrical uncertainties due to setup errors and organ motion. We conducted this prospective evaluation of prostate cancer patients treated with image-guided conformal radiation therapy at our institution. We implanted three fiducial markers (gold seeds) within the prostatic gland in order to quantify daily target displacements and to generate specific margins around the clinical target volume (CTV) to create an appropriate planned target volume (PTV).Materials and methodsBetween April and December 2009, ten patients affected with localised prostate cancer were transrectally implanted with three radio-opaque markers. Each patient underwent a computed tomography (CT) scan for planning purposes following proper bladder and rectum preparation. During treatment two orthogonal images were acquired daily and compared with previously generated digitally reconstructed radiographs. After manual localisation, comparison between the position of the gold seeds on the portal and reference images was carried out, and a set of extrapolated lateral-lateral (LL), anterior-posterior (AP) and cranial-caudal (CC) shift corrections was calculated and recorded. Couch corrections were applied with a threshold of 3 mm displacement.ResultsSystematic and random errors for each direction were calculated either as measured according to displacement of the gold seeds prior to any couch movement and after couch position correction according to the radio-opaque markers. For skin marks, mean systematic and random errors were 0.12+2.94 mm for LL, 1.04+3.37 mm for AP, −1.14+2.71 mm for CC, whereas for seed markers, mean and systematic errors were 0.6+1.5 mm for LL, 0.51+2.45 mm for AP and −0.25+2.51 mm for CC. A scatter plot generated on all measurements after couch repositioning according to gold-seed displacement suggested a confidence range of shift distributions within 5 mm for LL, 8 mm for CC, and 7 mm for AP. The total systematic and random components were then used to calculate proper PTV in patients receiving conventional treatment (7 mm for LL and 9 mm for both AP and CC).ConclusionsProstate positional variability during a course of radiation treatment is strongly influenced by setup and organ motion. Organ tracking through fiducial markers and electronic portal imaging is able to reduce the spread of displacements, significantly contributing to improve the ballistic precision of radiation delivery.RiassuntoObiettivoLa moderna radioterapia ha raggiunto traguardi considerevoli in termini di controllo tumorale e riduzione dei tassi di tossicità associati al trattamento, con la possibilità di erogare dosi importanti al volume bersaglio, risparmiando contemporaneamente i tessuti sani. Risulta, pertanto, focale la caratterizzazione precisa della posizione della lesione neoplastica per minimizzare le incertezze geometriche dovute agli errori di posizionamento ed al movimento d’organo. Abbiamo intrapreso una valutazione prospettica dei pazienti trattati mediante radioterapia conformazionale guidata dalle immagini per carcinoma prostatico, utilizzando tre reperi fiduciali (semi d’oro) impiantati all’interno della prostata per quantificare gli scostamenti giornalieri del volume bersaglio e generare margini specifici attorno al volume bersaglio clinico (CTV) creando un appropriato volume bersaglio di pianificazione (PTV).Materiali e metodiTra aprile e dicembre 2009, 10 pazienti affetti da adenocarcinoma prostatico organo-confinato sono stati sottoposti ad impianto trans-rettale sotto guida ecografica di 3 reperi fiduciali radio-opachi. Ogni paziente è stato sottoposto a tomografia computerizzata (CT) di pianificazione con una adeguata preparazione vescicale e rettale; ad ogni seduta di trattamento, sono state acquisite 2 immagini ortogonali e poi confrontate con immagini radiografiche a ricostruzione digitale. è stata effettuata una localizzazione manuale confrontando la posizione dei reperi fiduciali nelle immagini portali con quella nelle immagini di riferimento. Sono stati estrapolati e registrati gli scostamenti nelle direzioni latero-laterale (LL), anteroposteriore (AP) e cranio-caudale (CC). La correzione della posizione del lettino di trattamento è stata effettuata con una soglia di 3 mm.RisultatiSono stati calcolati l’errore standard e sistematico per ogni direzione, misurando gli scostamenti dei semi d’oro prima del movimento del lettino di trattamento e dopo aver applicato gli spostamenti secondo i reperi fiduciali. Per i reperi cutanei, l’errore sistematico e casuale medio sono stati 0,12±2,94 mm per la direzione LL, 1,04±3,37 mm per la direzione AP e −1,14±2,71 mm per la direzione CC; per i reperi fiduciali, l’errore sistematico e casuale medio sono stati 0,6±1,5 mm per la direzione LL, 0,51±2,45 mm per la direzione AP e −0,25±2,51 mm per la direzione CC. è stato creato un diagramma di distribuzione di tutte le misure ottenute dopo il riposizionamento del lettino in funzione degli scostamenti registrati mediante i reperi fiduciali; l’ambito di confidenza della distribuzione degli spostamenti si trova entro i 5 mm per la direzione LL, entro i 6 mm per la direzione CC ed entro i 7 mm per la direzione AP. L’errore sistematico e l’errore casuale totale sono stati utilizzati per generare margini per ottenere il PTV nei pazienti trattati convenzionalmente (7 mm per la direzione LL; 9 mm sia per la direzione AP che per la direzione CC).ConclusioniLa variabilità della posizione della ghiandola prostatica durante un trattamento radiante è influenzata in modo importante dal posizionamento e dal movimento d’organo. Il monitoraggio della posizione della prostata mediante reperi fiduciali ed immagini portali è in grado di ridurre la dispersione degli scostamenti rispetto all’atteso, contribuendo in maniera significativa al miglioramento della precisione balistica della radioterapia.