Introduction: Our department commonly uses a planning target volume (PTV) expansion of 6 mm posterior and 1 cm in all other directions when treating prostate cancer patients with image-guided radiotherapy (IGRT). This study aimed to test the adequacy of this PTV expansion by assessing geographical miss of the prostate on post-treatment cone-beam CT (CBCT) and identify those at risk of geographical miss. Methods: Twenty-two prostate cancer patients receiving IGRT with implanted fiducial markers underwent daily pre-treatment orthogonal kV imaging followed by a post-treatment CBCT for a total of 432 fractions. The prostate was outlined on all CBCTs. For each imaging set, the volume of geographic miss was measured by subtracting the PTV from the planning CT and prostate volume on the post-treatment CBCT. Results: The prostate volume moved outside the PTV by >0.01 cc in 9% of fractions (39/432). This occurred in 13 (59%) of 22 patients. Large prostates >40 cc and >50 cc had significantly more geographical miss events (both P < 0.001). Changes in rectal filling appear to be responsible for prostate motion/deformation in 82% (32/39) of fractions. Conclusions: Our analysis suggests that, despite IGRT, prostate PTV margins are not adequate in some patients, particularly those with large prostates. PTV margins may be reduced in some other patients. Prostate rotation and deformation play an important role in setting margins and may not always be represented accurately by fiducial marker displacements. Individualised and adaptive margins for prostate cancer patients should be a priority for future research.

This study investigated a relationship between rectum diameter and prostate motion during treatment with a view to reducing planning target volume (PTV) margins for an adaptive protocol. One hundred and ninety-four cone-beam computed tomography (CBCT) images of 10 patients were used to relate rectum diameter on CBCT to prostate intrafraction displacement. A threshold rectum diameter was used to model the impact of an adaptive PTV margin on rectum and bladder dose. Potential dose escalation with a 6 mm uniform margin adaptive protocol was compared to a PTV margin of 10 mm expansion of the clinical target volume (CTV) except 6 mm posterior. Of 194 fractions, 104 had a maximum rectal diameter of ≤3.5 cm. The prostate displaced ≤4 mm in 102 of those fractions. Changing from a standard to an adaptive PTV margin reduced the volume of rectum receiving 25, 50, 60, and 70 Gy by around 12, 9, 10, and 16%, respectively and bladder by approximately 21, 27, 29, and 35%, respectively. An average dose escalation of 4.2 Gy may be possible with an adaptive prostate radiotherapy protocol. In conclusion, a relationship between the prostate motion and the diameter of the rectum on CBCT potentially could enable daily adaptive radiotherapy which can be implemented from the first fraction.

To the Editor,Treatment outcomes for prostate cancer radiotherapy improve with increased dose delivered to the prostate [1]. To enable dose escalation to the prostate without increasing treatment t...

BACKGROUND:The Royal Australian and New Zealand College of Radiologists (RANZCR) initiated a unique instrument to audit the quality of patient notes and radiotherapy prescriptions. We present our experience collected over ten years from the use of the RANZCR audit instrument.METHODS:In this study, the results of data collected prospectively from January 1999 to June 2009 through the audit instrument were assessed. Radiotherapy chart rounds were held weekly in the uro-oncology tumour stream and real time feedback was provided. Electronic medical records were retrospectively assessed in September 2009 to see if any omissions were subsequently corrected.RESULTS:In total 2597 patients were audited. One hundred and thirty seven (5%) patients had one hundred and ninety nine omissions in documentation or radiotherapy prescription. In 79% of chart rounds no omissions were found at all, in 12% of chart rounds one omission was found and in 9% of chart rounds two or more omissions were found. Out of 199 omissions, 95% were of record keeping and 2% were omissions in the treatment prescription. Of omissions, 152 (76%) were unfiled investigation results of which 77 (51%) were subsequently corrected.CONCLUSIONS:Real-time audit with feedback is an effective tool in assessing the standards of radiotherapy documentation in our department, and also probably contributed to the high level of attentiveness. A large proportion of omissions were investigation results, which highlights the need for an improved system of retrieval of investigation results in the radiation oncology department.

Purpose To assess the correlation of 18F-FDG-PET (PET) response to pathological response after neoadjuvant chemoradiation (CRT) for locally advanced rectal cancer. Methods and materials Twenty patients with locally advanced rectal cancer were identified between 2001 and 2005. The median age was 57 years (range 37–72) with 14 males and 6 females. All patients were staged with endorectal ultrasound and/or MRI, CT, and PET. The clinical staging was T3N0M0 (16), T3N1M0 (2), and T3N0M1 (2). Restaging PET was performed after CRT, and prior to definitive surgery. The response on PET and pathology was assessed and correlated. Patient outcome according to PET response was also assessed. Results Following CRT, a complete PET response occurred in 7 patients, incomplete response in 10, and no response in 3 patients. At surgery, complete pathological response was recorded in 7 patients, incomplete response in 10 and no response in 3. There was a good correlation of PET and pathological responses in complete responders (5/7 cases) and non-responders (3/3 cases). After a median follow-up of 62 months (range 7–73), twelve patients were alive with no evidence of disease. All patients achieving complete metabolic response were alive with no evidence of disease, while as those who had no metabolic response, all died as a result of metastatic disease. Conclusions PET is a promising complementary assessment tool for assessing tumor response after CRT if there is a complete or no response. PET response may also predict for outcome.

PurposeTo assess the accuracy and implications on workflow of an online correction electronic portal imaging (EPI) protocol utilising bony anatomy in the online environment and an assessment of three implanted gold seed fiducial markers in the offline environment. This paper summarises an initial trial to establish the range of systematic and random errors present in patient set-up for both bony anatomy and fiducial markers, and to calculate optimal clinical target volume (CTV) to planning target volume (PTV) margins. The impact of the introduction of such a technique was also assessed in terms of impact on workflow and resource management in a single machine unit (SMU).Methods and materialsPre treatment electronic portal images (EPIs) were acquired and bony anatomy was matched with CT derived digitally reconstructed radiographs (DRRs). Intervention in field placement was made if field placement fell outside the range of 4mm on any of the orthogonal axes. In the offline environment the position of the implanted gold seed fiducials was aligned with that of the DRRs. An analysis of set-up error, total error and internal organ motion was then undertaken, with full statistical analysis of systematic and random errors.ResultsEleven patients completed treatment as specified, with 1006 EPIs available for analysis. Treatment times were in the order of 10.4min. Set-up errors were in the order of 2.7mm right–left, 2.4mm sup–inf and 1.6mm ant–pst. These were reduced to 1.2mm, 0.7mm and 0.9mm respectively utilising an online correction protocol. However there was minimal impact on total error and internal organ motion. Using the data obtained in both the online and offline environments optimal CTV–PTV margins were calculated for correcting to bone, correcting to gold seed fiducials and also the possibility of EPI malfunction.ConclusionsDaily targeting of the prostate is both technically feasible and can be carried out in an efficient and accurate manner. An online correction protocol using gold seeds as the matching mechanism provides the ability to significantly reduce treatment margins for most prostate patients, and importantly does not impact on a busy clinical workflow.

Purpose: To assess the utility of FDG-PET in anal cancer for staging and impact on radiotherapy planning (RTP), response and detection of recurrent disease.Methods and materials: Fifty histopathological anal cancer patients were reviewed between 1996 and 2006. The median age was 58 years (range 36-85) with 19 males: 3 1 females. Clinical assessment with CT was compared to PET. Impact on management, disease response, recurrence and metastases was evaluated.Results: The non-PET staging was Stage I(8), Stage II(18), Stage III(22), and Stage IV(2)s. The primary was strongly FDG avid in 98% with non-excised tumors compared to CT (58%). PET upstaged 17% with unsuspected pelvic/inguinal nodal disease. Pre-treatment PET identified 11 additional by involved nodal groups in 48 patients causing RTP amendments in 19%. Post-treatment PETs at median 17 weeks (range 9-28) showed complete responses in 20 (80%) and 5 (20%) partial responses (PR). PRs were biopsy positive in 2 and negative in 3. Fifteen had follow-up scans of which all nine PETs detected recurrences were pathologically confirmed.Conclusions: Anal cancer is FDG-PET avid. PET upstages 17% and changes the RTP in 19%. PET can aid in anal cancer staging and identification of residual disease, recurrent/metastaitic disease but warrants further prospective studies. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

AbstractGiven the onset of dose escalation and increased planning target volume (PTV) conformity, the requirement of accurate field placement has also increased. This study examines the role of online corrections (OC) to increase the accuracy of field placement. This study explores the role of radiation therapists in the process of achieving an online correction.Method Field placement data were collected on patients receiving radical radiotherapy to the prostate. Both intra‐ and inter field data was collected with OC being carried out within the confines of the Ballarat Austin Radiation Oncology Centre (BAROC) prostate Electronic Portal Imaging (EPI) policy.Results Statistical analysis of 740 portal images from 10 patients was carried out, illustrating that without OC field placement will fall at ± 7 mm on a daily basis. This evidence was further supported by a case study of computer dosimetry presenting the worst‐case possible impact upon a patient's total course of treatment if OC were not performed. Discussion The use of OC can prove to be of enormous benefit to both patient and practitioner. For centres with the available technology, it places the responsibility of field placement upon the radiation therapist. This responsibility, and the development of relevant protocols, in turn impacts on the education, training and empowerment of the radiation therapy group. These are issues of the utmost importance to centres considering the use of OC.Conclusions Without the use of OC there is a serious risk of underdosing both CTV and PTV. In this instance the CTV received only 60% of the prescribed dose, while the PTV received only 80% of the expected dose. OC are an important consideration for those looking to dose escalate.

Given the onset of dose escalation and increased planning target volume (PTV) conformity, the requirement of accurate field placement has also increased. This study compares and contrasts a combination offline/online electronic portal imaging (EPI) device correction with a complete online correction protocol and assesses their relative effectiveness in managing set-up error. Field placement data was collected on patients receiving radical radiotherapy to the prostate. Ten patients were on an initial combination offline/online correction protocol, followed by another 10 patients on a complete online correction protocol. Analysis of 1480 portal images from 20 patients was carried out, illustrating that a combination offline/online approach can be very effective in dealing with the systematic component of set-up error, but it is only when a complete online correction protocol is employed that both systematic and random set-up errors can be managed. Now, EPI protocols have evolved considerably and online corrections are a highly effective tool in the quest for more accurate field placement. This study discusses the clinical workload impact issues that need to be addressed in order for an online correction protocol to be employed, and addresses many of the practical issues that need to be resolved. Management of set-up error is paramount when seeking to dose escalate and only an online correction protocol can manage both components of set-up error. Both systematic and random errors are important and can be effectively and efficiently managed. (author abstract)

Interferon-alpha2b (IFNalpha2b) is the only form of systemic adjuvant therapy for stage III melanoma with documented survival benefit. Radiotherapy can also be utilized in the adjuvant setting in patients at high risk of nodal basin recurrence. As IFNalpha2b is associated with substantial toxicity, we sought to determine both the systemic and radiation-related toxicities in patients treated with combined adjuvant IFNalpha2b and regional adjuvant radiotherapy delivered in the setting of a single institution. Eighteen consecutive patients who commenced adjuvant IFNalpha2b between November 1997 and August 2002 were analysed retrospectively for toxicities associated with the combination of IFNalpha2b and adjuvant radiotherapy (40-50 Gy in 15-25 fractions) to nodal basins delivered during the maintenance phase of IFNalpha2b therapy (median dose during radiotherapy of 6.5 MU/m three times per week). Seven out of 18 patients who received concurrent radiotherapy and IFNalpha2b displayed grade 3 skin reactions. Severe radiation-induced toxicity was seen in three further patients, one who developed radiation pneumonitis, one who developed severe oral mucositis, and one who developed wound dehiscence that took 10 months to resolve. Non-radiation-related toxicity to IFNalpha2b therapy was typical for this dose and schedule. We conclude that concurrent use of adjuvant radiotherapy and IFNalpha2b may enhance radiation-induced toxicity. However, overall we found concurrent radiation and IFNalpha2b could be safely delivered with appropriate clinical monitoring.