Samantha Cipressi

Impact of plan parameters on the dosimetric accuracy of volumetric modulated arc therapy

PURPOSE To evaluate the effect of plan parameters on volumetric modulated arc therapy (VMAT) dosimetric accuracy, together with the possibility of scoring plan complexity. METHODS 142 clinical VMAT plans initially optimized using a 4° control point (CP) separation were evaluated. All plans were delivered by a 6 MV Linac to a biplanar diode array for patient-specific quality assurance (QA). Local Γ index analysis (3%, 3 mm and 2%, 2 mm) enabled the comparison between delivered and calculated dose. The following parameters were considered for each plan: average leaf travel (LT), modulation complexity score applied to VMAT (MCSv), MU value, and a multiplicative combination of LT and MCSv (LTMCS). Pearsons correlation analysis was performed between Γ passing rates and each parameter. The effects of CP angular separation on VMAT dosimetric accuracy were also analyzed by focusing on plans with high LT values. Forty out of 142 plans with LT above 350 mm were further optimized using a finer angle spacing (3° or 2°) and Γ analysis was performed. The average Γ passing rates obtained at 4° and at 3°∕2° sampling were compared. A further correlation analysis between all parameters and the Γ pass-rates was performed on 142 plans, but including the newly optimized 40 plans (CP every 3° or 2°) in place of the old ones (CP every 4°). RESULTS A moderate significant (p < 0.05) correlation between each examined parameter and Γ passing rates was observed for the original 142 plans at 4° CP discretization. A negative correlation was found for LT with Pearsons r absolute values above 0.6, suggesting that a lower dosimetric accuracy may be expected for higher LT values when a 4° CP sampling is used. A positive correlation was observed for MCSv and LTMCS with r values above 0.5. In order to score plan complexity, threshold values of LTMCS were defined. The average Γ passing rates were significantly higher for the plans created using the finer CP spacing (3°∕2°) compared to the plans optimized using the standard 4° spacing (Student t-test p < 0.05). The correlation between LT and passing rates was strongly diminished when plans with finer angular separations were considered, yielding Pearsons r absolute values below 0.45. CONCLUSIONS At 4° CP sampling, LT, MCSv, and LTMCS were found to be significantly correlated with VMAT dosimetric accuracy, expressed as Γ pass-rates. These parameters were found to be possible candidates for scoring plan complexity using threshold values. A finer CP separation (3°∕2°) led to a significant increase in dosimetric accuracy for plans with high leaf travel values, and to a decrease in correlation between LT and Γ passing rates. These results indicated that the influence of LT on VMAT dosimetric accuracy can be controlled by reducing CP separation. CP spacing for all plans requiring large leaf motion should not exceed 3°. The reported data were integrated to optimize our clinical workflow for plan creation, optimization, selection among rival plans, and patient-specific QA of VMAT treatments.

Patterns of care and survival in a retrospective analysis of 1059 patients with glioblastoma multiforme treated between 2002 and 2007: a multicenter study by the Central Nervous System Study Group of Airo (italian Association of Radiation Oncology).

OBJECTIVETo investigate the pattern of care and outcomes for newly diagnosed glioblastoma in Italy and compare our results with the previous Italian Patterns of Care study to determine whether significant changes occurred in clinical practice during the past 10 years. METHODSClinical, pathological, therapeutic, and survival data regarding 1059 patients treated in 18 radiotherapy centers between 2002 and 2007 were collected and retrospectively reviewed. RESULTSMost patients underwent both computed tomography and magnetic resonance imaging either preoperatively (62.7%) or postoperatively (35.5%). Only 123 patients (11.6%) underwent a biopsy. Radiochemotherapy with temozolomide was the most frequent adjuvant treatment (70.7%). Most patients (88.2%) received 3-dimensional conformal radiotherapy. Median survival was 9.5 months. Two- and 5-year survival rates were 24.8% and 3.9%, respectively. Multivariate analysis showed the statistical significance of age, postoperative Karnofsky Performance Status scale score, surgical extent, use of 3-dimensional conformal radiotherapy, and use of chemotherapy. Use of a more aggressive approach was associated with longer survival in elderly patients. Comparing our results with those of the subgroup of patients included in our previous study who were treated between 1997 and 2001, relevant differences were found: more frequent use of magnetic resonance imaging, surgical removal more common than biopsy, and widespread use of 3-dimensional conformal radiotherapy + temozolomide. Furthermore, a significant improvement in terms of survival was noted (P < .001). CONCLUSIONChanges in the care of glioblastoma over the past few years are documented. Prognosis of glioblastoma patients has slightly but significantly improved with a small but noteworthy number of relatively long-term survivors.

Changes in neurocognitive functioning and quality of life in adult patients with brain tumors treated with radiotherapy

This review aims to summarize what is currently known about neurocognitive outcome and quality of life in patients with brain tumors treated with radiotherapy. Whether potential tumor-controlling benefits of radiotherapy outweigh its potential toxicity in the natural history of brain tumors is a matter of debate. This review focuses on some of the adult main brain tumors, for which the issue of neurocognitive decline has been thoroughly studied: low-grade gliomas, brain metastases, and primary central nervous system lymphomas. The aims of this review are: (1) the analysis of existing data regarding the relationship between radiotherapy and neurocognitive outcome; (2) the identification of strategies to minimize radiotherapy-related neurotoxicity by reducing the dose or the volume; (3) the evidence-based data concerning radiotherapy withdrawal; and (4) the definition of patients subgroups that could benefit from immediate radiotherapy. For high grade gliomas, the main findings from literature are summarized and some strategies to reduce the neurotoxicity of the treatment are presented. Although further prospective studies with adequate neuropsychological follow-up are needed, this article suggests that cognitive deficits in patients with brain tumor have a multifactorial genesis: radiotherapy may contribute to the neurocognitive deterioration, but the causes of this decline include the tumor itself, disease progression, other treatment modalities and comorbidities. Treatment variables, such as total and fractional dose, target volume, and irradiation technique can dramatically affect the safety of radiotherapy: optimizing radiation parameters could be an excellent approach to improve outcome and to reduce neurotoxicity. At the same time, delayed radiotherapy could be a valid option for highly selected patients.

Post-operative radiotherapy in N2 non-small cell lung cancer: A retrospective analysis of 175 patients

BACKGROUND AND PURPOSE Post-operative radiotherapy (PORT) in radically resected non-small cell lung cancer (NSCLC) has the aim to reduce loco regional recurrence and to improve overall survival. PORT has been evaluated in several trials but indication to post-operative treatment in N2 patients is still debated. MATERIAL AND METHODS We retrospectively analyzed 175 patients treated at University of Florence between 1988 and 2004 with completely resected NSCLC stages IIIA-IIIB, N2 disease. Surgery consisted in a lobectomy in 58.9% and in a bi-lobectomy or in a pneumonectomy in 41.1% of patients. One hundred and nineteen patients underwent PORT and 56 patients did not receive PORT (no-PORT). RESULTS At a median follow-up of 27.6 months (range 4-233 months), we found a significant reduction in local recurrence (LR) in PORT group (log-rank test p=0.015; HR: 0.45; 95%CI: 0.24-0.87). No statistical difference were found in terms of overall survival (OS) (log-rank test p=0.92). Concerning other prognostic factors, male sex emerged as statistically significant (HR:4.33;1.04-18.02) on local progression free survival (LPFS) at univariate analysis. Acute and long-term toxicity was mild. CONCLUSION Our retrospective analysis showed that PORT may improve local disease control in N2 NSCLC patients with an acceptable treatment-related toxicity.

Radiotherapy and temozolomide in anaplastic astrocytoma: a retrospective multicenter study by the Central Nervous System Study Group of AIRO (Italian Association of Radiation Oncology).

Although the evidence for the benefit of adding temozolomide (TMZ) to radiotherapy (RT) is limited to glioblastoma patients, there is currently a trend toward treating anaplastic astrocytomas (AAs) with combined RT + TMZ. The aim of the present study was to describe the patterns of care of patients affected by AA and, particularly, to compare the outcome of patients treated exclusively with RT with those treated with RT + TMZ. Data of 295 newly diagnosed AAs treated with postoperative RT ± TMZ in the period from 2002 to 2007 were reviewed. More than 75% of patients underwent a surgical removal. All the patients had postoperative RT; 86.1% of them were treated with 3D-conformal RT (3D-CRT). Sixty-seven percent of the entire group received postoperative chemotherapy with TMZ (n = 198). One-hundred sixty-six patients received both concomitant and sequential TMZ. Prescription of postoperative TMZ increased in the most recent period (2005-2007). One- and 4-year survival rates were 70.2% and 28.6%, respectively. No statistically significant improvement in survival was observed with the addition of TMZ to RT (P = .59). Multivariate analysis showed the statistical significance of age, presence of seizures, Recursive Partitioning Analysis classes I-III, extent of surgical removal, and 3D-CRT. Changes in the care of AA over the past years are documented. Currently there is not evidence to justify the addition of TMZ to postoperative RT for patients with newly diagnosed AA outside a clinical trial. Results of prospective and randomized trials are needed.

Pediatric primary anaplastic ganglioglioma: a case report and review of the literature.

Gangliogliomas with anaplastic features are classified as grade III tumors by the World Health Organization. The clinical course and optimal treatment of anaplastic gangliogliomas have not been well understood to date. We report a case of a primary pure anaplastic ganglioglioma in a 14-year-old male treated with surgery and radiotherapy, who is disease-free 6 years after the diagnosis. A review of primary pure anaplastic gangliogliomas in children (between 3 and 21 years of age) is presented. Gross total removal and focal radiotherapy with a total dose of 54 Gy are recommended. The addition of chemotherapy should be evaluated. Prospective studies are needed to identify an appropriate chemotherapy schedule and to define biological factors in order to select those patients with a poor prognosis, who are to be treated with a more aggressive therapy.

Clinical outcome of stereotactic body radiotherapy for abdominal lymph node metastases.

Aims and background. To report the clinical outcome of linac-based or robotic, image-guided stereotactic body radiotherapy in patients affected by abdominal lymph node metastases from different primary cancers. Methods and methods. Twenty-six patients with 32 abdominal lymph node metastases were consecutively treated at the University of Florence between April 2011 and May 2012. The mean follow-up was 4.6 months (SD, 3.9; range, 0.3-13). The dose prescription ranged between 24 Gy and 36 Gy delivered in 1-5 fractions. Results. In terms of local control, complete response to stereotactic body radiotherapy was obtained in 18 cases (66.7%), partial response in 7 (25.9%), and stable disease in 2 (7.4%). At the Cox univariate regression analysis, an increased risk of partial response or absence of local response to radiotherapy was found for subjects of the female sex (P = 0.036), age less than 50 years (P = 0.022), primary tumor of the genital tract (P = 0.007), and previous chemotherapy (P = 0.057). An excellent local control rate (90.9%) was obtained in patients affected by abdominal lymph node metastases of prostatic origin. Conclusions. Stereotactic body radiotherapy for abdominal lymph node metastases is a safe and effective treatment in terms of high rates of local control, especially in a subset of patients affected by prostate cancer.

Adjuvant radiotherapy for a prostate cancer after renal transplantation and review of the literature.

Renal transplant recipients are a population usually considered at a higher risk of malignancies, mostly skin cancer and lymphoproliferative disorder. In recent years, prostate cancer in renal transplant recipients has been becoming more frequent. This is probably due to the growing age and the longer survival of the transplanted patients. We report the case of a 50-year-old man with prostate cancer and renal allograft, who received radiotherapy after prostatectomy at the Institute of Radiotherapy of the University of Florence. Radiotherapy is part of the standard treatment for many cases of prostate cancer. According to the few series reported in the literature and also to our experience, radiation therapy is feasible also in renal transplant recipients with accurate treatment planning.

Cyberknife Treatment for Low and Intermediate Risk Prostate Cancer

Cyberknife is an emerging treatment for early stage prostate cancer. Between October 2012 and January 2014, 32 patients were treated in our institution. Prescribed dose was 35–36.25 Gy in five fractions. Biochemical response was observed in 22 patients. Four patients experienced G2 acute genitourinary toxicity and in two cases we recorded G3 acute GU toxicity. 5 patients experienced G2 acute proctitis. At last follow up visit, all patients were still alive. 29 remained free of disease at last follow up appointment, while three developed a biochemical recurrence. Our experience confirms the efficacy and safety of Cyberknife for localized prostate cancer.

Salvage stereotactic re-irradiation with CyberKnife for locally recurrent head and neck cancer: a single center experience.

Aims and Background We report the toxicity and preliminary clinical outcome in patients affected by locally recurrent head and neck cancer treated with stereotactic reirradiation. Methods Between February 2012 and August 2013, 17 patients were treated with CyberKnife as stereotactic re-irradiation for locally recurrent head and neck cancer. All patients had previously received a full dose radiation treatment with radical intent, with a median total dose of 66 Gy (range, 50–70) delivered with standard fractionation. The median interval between the primary radiotherapy and re-irradiation was 24 months (range, 10–168). Results All patients completed the prescribed treatment, which was delivered in 5 fractions. The median tumor dose administered was 30 Gy (range, 25–35) prescribed to the 80% isodose line. Treatment sites were as follows: neck lymph nodes in 5 patients, paranasal sinuses in 5, oropharynx in 2, nasopharynx, and larynx, oral cavity, nasal fossa and parotid gland each in 1 patient. The median target volume treated was 58.7 cm3 (range, 8.5–211.3). Sixteen patients (94%) were evaluated for response. At a median follow-up of 7.5 months (range, 2–17), 4 patients achieved complete response (25%), 5 had partial response (31%) and 7 showed stable disease (44%). No patient showed in-field progression after re-irradiation. Grade 3 acute toxicity was noted in one patient only; no late side effect was observed during the follow-up. Conclusions Stereotactic re-irradiation with CyberKnife is an appealing non-surgical salvage treatment for selected patients with local-regionally recurrent head and neck cancer.