Uncertainty-aware MR-based CT synthesis for robust proton therapy planning of brain tumour

BACKGROUND AND PURPOSE

Deep learning techniques excel in MR-based CT synthesis, but missing uncertainty prediction limits its clinical use in proton therapy. We developed an uncertainty-aware framework and evaluated its efficiency in robust proton planning.

MATERIALS AND METHODS

A conditional generative-adversarial network was trained on 64 brain tumour patients with paired MR-CT images to generate synthetic CTs (sCT) from combined T1-T2 MRs of three orthogonal planes. A Bayesian neural network predicts Laplacian distributions for all voxels with parameters (μ, b). A robust proton plan was optimized using three sCTs of μ and μ±b. The dosimetric differences between the plan from sCT (sPlan) and the recalculated plan (rPlan) on planning CT (pCT) were quantified for each patient. The uncertainty-aware robust plan was compared to conventional robust (global ± 3 %) and non-robust plans.

RESULTS

In 8-fold cross-validation, sCT-pCT image differences (Mean-Absolute-Error) were 80.84 ± 9.84HU (body), 35.78 ± 6.07HU (soft tissues) and 221.88 ± 31.69HU (bones), with Dice scores of 90.33 ± 2.43 %, 95.13 ± 0.80 %, and 85.53 ± 4.16 %, respectively. The uncertainty distribution positively correlated with absolute prediction error (Correlation Coefficient: 0.62 ± 0.01). The uncertainty-conditioned robust optimisation improved the rPlan-sPlan agreement, e.g., D95 absolute difference (CTV) was 1.10 ± 1.24 % compared to conventional (1.64 ± 2.71 %) and non-robust (2.08 ± 2.96 %) optimisation. This trend was consistent across all target and organs-at-risk indexes.

CONCLUSION

The enhanced framework incorporates 3D uncertainty prediction and generates high-quality sCTs from MR images. The framework also facilitates conditioned robust optimisation, bolstering proton plan robustness against network prediction errors. The innovative feature of uncertainty visualisation and robust analyses contribute to evaluating sCT clinical utility for individual patients.

Retrospective reconstruction of four-dimensional magnetic resonance from interleaved cine imaging - A comparative study with four-dimensional computed tomography in the lung

Background and purpose

Imaging of respiration-induced anatomical changes is essential to ensure high accuracy in radiotherapy of lung cancer. We expanded here on methods for retrospective reconstruction of time-resolved volumetric magnetic resonance (4DMR) of the thoracic region and benchmarked the results against 4D computed tomography (4DCT).

Materials and method

MR data of six lung cancer patients were collected by interleaving cine-navigator images with 2D data frame images, acquired across the thorax. The data frame images have been stacked in volumes based on a similarity metric that considers the anatomical deformation of lungs, while addressing ambiguities in respiratory phase detection and interpolation of missing data. The resulting images were validated against cine-navigator images and compared to paired 4DCTs in terms of amplitude and period of motion, assessing differences in internal target volume (ITV) margin definition.

Results

4DMR-based motion amplitude was on average within 1.8 mm of that measured in the corresponding 2D cine-navigator images. In our dataset, the 4DCT motion and the 4DMR median amplitude were always within 3.8 mm. The median period was generally close to CT references, although deviations up to 24 % have been observed. These changes were reflected in the ITV, which was generally larger for MRI than for 4DCT (up to 39.7 %).

Conclusions

The proposed algorithm for retrospective reconstruction of time-resolved volumetric MR provided quality anatomical images with high temporal resolution for motion modelling and treatment planning. The potential for imaging organ motion variability makes 4DMR a valuable complement to standard 4DCT imaging.

Treatment planning comparison for head and neck cancer between photon, proton, and combined proton-photon therapy - From a fixed beam line to an arc

BACKGROUND AND PURPOSE

This study investigates whether combined proton-photon therapy (CPPT) improves treatment plan quality compared to single-modality intensity-modulated radiation therapy (IMRT) or intensity-modulated proton therapy (IMPT) for head and neck cancer (HNC) patients. Different proton beam arrangements for CPPT and IMPT are compared, which could be of specific interest concerning potential future upright-positioned treatments. Furthermore, it is evaluated if CPPT benefits remain under inter-fractional anatomical changes for HNC treatments.

MATERIAL AND METHODS

Five HNC patients with a planning CT and multiple (4-7) repeated CTs were studied. CPPT with simultaneously optimized photon and proton fluence, single-modality IMPT, and IMRT treatment plans were optimized on the planning CT and then recalculated and reoptimized on each repeated CT. For CPPT and IMPT, plans with different degrees of freedom for the proton beams were optimized. Fixed horizontal proton beam line (FHB), gantry-like, and arc-like plans were compared.

RESULTS

The target coverage for CPPT without adaptation is insufficient (average V95%=88.4 %), while adapted plans can recover the initial treatment plan quality for target (average V95%=95.5 %) and organs-at-risk. CPPT with increased proton beam flexibility increases plan quality and reduces normal tissue complication probability of Xerostomia and Dysphagia. On average, Xerostomia NTCP reductions compared to IMRT are -2.7 %/-3.4 %/-5.0 % for CPPT FHB/CPPT Gantry/CPPT Arc. The differences for IMPT FHB/IMPT Gantry/IMPT Arc are + 0.8 %/-0.9 %/-4.3 %.

CONCLUSION

CPPT for HNC needs adaptive treatments. Increasing proton beam flexibility in CPPT, either by using a gantry or an upright-positioned patient, improves treatment plan quality. However, the photon component is substantially reduced, therefore, the balance between improved plan quality and costs must be further determined.

Quality-of-life evaluations in children and adolescents with Ewing sarcoma treated with pencil-beam-scanning proton therapy

BACKGROUND

With improved survival rates for children with cancer, quality-of-life (QoL) issues have increasingly become the focus of attention. We report the QoL of children with Ewing sarcoma (EWS) treated with pencil-beam-scanning proton therapy (PT).

METHODS

A PEDQOL (QoL questionnaire for children 4-18 years) self/proxy questionnaire was used to prospectively assess the QoL of 23 children <18 years with EWS treated with PT. This questionnaire evaluates eight different domains. Children (self-rating) and parents (proxy-rating) filled out the questionnaire at the start of PT (E1), 2 months after treatment (E2), and thereafter once yearly (E≥3).

RESULTS

Compared with healthy controls, parents rated the QoL of their children at E1 significantly worse in all but two (cognition and social functioning-family) domains. At E4, significant differences between the two groups only remained in three of eight domains. At E1, children self-rated their QoL significantly worse in the domain Physical functioning (p = .004) and significantly better in the domain Body image (p = .044) compared to healthy controls, whereas no significant differences were observed at E4. For the longitudinal comparison E1 versus E4, according to parents, Emotional functioning, Cognition and Social functioning-peers were slightly decreased 2 years after PT. The children rated Emotional functioning and Body image poorly 2 years after PT.

CONCLUSIONS

Children with EWS usually recovered seemingly well to normal QoL levels 2 years after the end of PT. They tended to rate their QoL substantially higher than their parents. However, in the longitudinal analysis at 2 years, children rated their Emotional functioning and Body image scores poorly.

Hearing Loss in Cancer Patients with Skull Base Tumors Undergoing Pencil Beam Scanning Proton Therapy: A Retrospective Cohort Study

To assess the incidence and severity of changes in hearing threshold in patients undergoing high-dose pencil-beam-scanning proton therapy (PBS-PT). This retrospective cohort study included fifty-one patients (median 50 years (range, 13–68)) treated with PBS-PT for skull base tumors. No chemotherapy was delivered. Pure tone averages (PTAs)were determined before (baseline) and after PBS-PT as the average hearing thresholds at frequencies of 0.5, 1, 2, and 4 kHz. Hearing changes were calculated as PTA differences between pre-and post-PBS-PT. A linear mixed-effects model was used to assess the relationship between the PTA at the follow-up and the baseline, the cochlea radiation dose intensity, the increased age, and the years after PBS-PT. Included patients were treated for chordoma (n = 24), chondrosarcoma (n = 9), head and neck tumors (n = 9), or meningioma (n = 3), with a mean tumor dose of 71.1 Gy (RBE) (range, 52.0–77.8), and a mean dose of 37 Gy (RBE) (range, 0.0–72.7) was delivered to the cochleas. The median time to the first follow-up was 11 months (IQR, 5.5–33.7). The PTA increased from a median of 15 dB (IQR 10.0–25) at the baseline to 23.8 (IQR 11.3–46.3) at the first follow-up. In the linear mixed-effect model, the baseline PTA (estimate 0.80, 95%CI 0.64 to 0.96, p ≤ 0.001), patient’s age (0.30, 0.03 to 0.57, p = 0.029), follow-up time (2.07, 0.92 to 3.23, p ≤ 0.001), and mean cochlear dose in Gy (RBE) (0.34, 0.21 to 0.46, p ≤ 0.001) were all significantly associated with an increase in PTA at follow-up. The applied cochlear dose and baseline PTA, age, and time after treatment were significantly associated with hearing loss after proton therapy.

Clinical Outcome After Pencil Beam Scanning Proton Therapy of Patients With Non-Metastatic Malignant and Benign Peripheral Nerve Sheath Tumors

Objective

Peripheral nerve sheath tumors (PNSTs) commonly arise from peripheral nerve roots and grow locally invasive. Malignant PNSTs (mPNSTs) represent aggressive sarcomas of neural origin that can originate from PNSTs. Radiation therapy is commonly used as part of the required multimodal treatment. However, both entities tend to occur early in life and are associated with the genetic disorder neurofibromatosis type 1 (NF-1), which is known to cause increased radiosensitivity. Pencil beam scanning proton therapy (PBSPT) allows for a minimization of the dose delivered to organs at risk and the integral dose and, thus, potentially also a reduction of radiation-induced adverse events. We report the clinical outcome and toxicity rates of patients with (m)PNSTs treated with PBSPT.

Methods

We retrospectively reviewed 36 patients who received PBSPT (median dose, 64 GyRBE) with curative intent for (m)PNSTs between 1999 and 2020 at our institute. Twenty-eight (78%) and 8 (22%) patients were treated at diagnosis and for tumor recurrence/progression, respectively. The median age was 32 years (range, 3–75), and 25 (69%) patients were male. mPNST and PNST were diagnosed in 31 (86%) and 5 (14%) patients, respectively. Underlying NF-1 disease was found in 8 (22%) patients. Acute and late toxicities were recorded according to Common Terminology Criteria for Adverse Events, version 4.1 (CTCAE v4.1). Overall survival (OS), local control (LC), and distant control (DC) were estimated using the Kaplan–Meier method.

Results

With a median follow-up time of 31 months (range, 4–194), 13 (36%) patients died from a progressive disease, 8 (22%) experienced local failure, and 14 (39%) experienced distant failure after PBSPT. Estimated 2-year OS, LC, and DC were 75.5%, 73.5%, and 61.2%, respectively. Acute grade 3 toxicity (dermatitis, mucositis, and pain) was observed in 5 (14%) patients. Late grade 3 cataract and osteonecrosis were both observed in 1 (3%) patient at 34 and 194 months after PBSPT, respectively. There was no late grade &gt;3 toxicity or radiation-induced secondary cancer.

Conclusion

To our knowledge, this is the first study to analyze the outcome of (m)PNSTs treated with proton therapy using a PBS delivery paradigm. In our cohort, consisting mainly of patients with mPNSTs, we report reasonable oncological outcomes and low toxicity rates after PBSPT.

[Malignant tumors of the oral cavity]

Klinisches/methodisches Problem

Mundhöhlenmalignome stellen weltweit die häufigsten Tumoren im Bereich der Hals-Nasen-Ohrenheilkunde bzw. Otorhinolaryngologie dar. Es handelt sich um eine heterogene Gruppe an Tumoren, deren Kenntnis erforderlich ist, um den unterschiedlichen Anforderungen an Diagnostik und Therapie gerecht zu werden.

Radiologische Standardverfahren

Computertomographie (CT), Magnetresonanztomographie (MRT), Sonographie, nuklearmedizinische Verfahren (NUK).

Leistungsfähigkeit

Die o. g. Diagnostika werden komplementär eingesetzt.

Bewertung

Eine frühzeitigere Diagnose des Tumors verbessert das Staging und somit die Therapie und Prognose des Patienten.

Schlussfolgerung

Dem Radiologen kommt bei der interdisziplinären Behandlung von Malignomen der Mundhöhle eine bedeutende Rolle zu. Trotz großer Fortschritte in der Radiotherapie, Onkologie und Immuntherapie spielt die Chirurgie weiterhin eine wichtige Rolle in der Behandlung maligner Erkrankungen der Mundhöhle.

RONC-15. OUTCOMES OF BRAIN AND SKULL-BASE TUMOURS IN ADOLESCENTS AND YOUNG ADULTS TREATED WITH PENCIL BEAM SCANNING PROTON THERAPY

BACKGROUND

The use of highly conformal proton therapy in adolescents and young adults (AYAs) for management of brain/skull-base tumours is becoming increasingly common. This study aims to assess the long-term clinical outcomes, prognostic factors and employment status of AYAs (15–39 years) treated with pencil-beam-scanning proton-therapy (PT).

METHODS

Between 1997–2018, 176 AYAs were treated with PT at the Paul Scherrer Institute. Median age was 30 years (range, 15–39) and the male/female ratio was 0.8.

RESULTS

After a median follow-up of 66 months (range, 12–236), 24 (13.6%) local failures and 1 (0.6%) distant failure were observed between 6 and 152 months after PT. The most common histologies treated were chordomas/chondrosarcomas (61.4%), followed by meningiomas (14.2%) and gliomas (15.3%). The 6-year local-control (LC), distant-progression-free survival and overall-survival (OS) rate was 83.2%, 97.4% and 90.2% respectively. On univariate analysis, age ≥24 years was a negative prognostic factor for LC. Recurrent disease, infratentorial tumours and low-grade-glioma histology were poor prognostic factors for both LC and OS. The 6-year ≥G3 PT-related late toxicity-free survival was 88.5%. The moderate-high grade late toxicity crude rates were 37.8% G2, 12.2% G3, 0.6% G4 and 0.6% G5. No secondary malignancies were observed. The unemployment rate was 7.3% at PT, rising to 25.3% at survivorship. High-grade(≥G3) toxicity rate in the unemployed vs employed group was 21% vs 8.5%.

CONCLUSION

PT is an effective treatment for AYAs with brain/skull-base tumours with good tumour control and acceptable long-term toxicity. Despite having satisfactory clinical outcomes, around 1 in 4 AYAs surviving brain/skull base tumours are unemployed.

Outcomes of adolescents and young adults treated for brain and skull base tumors with pencil beam scanning proton therapy

BACKGROUND

The use of proton therapy (PT) in adolescents and young adults (AYAs) is becoming increasingly popular. This study aims to assess the outcomes and late toxicity consequences in AYAs (15-39 years) with brain/skull base tumors treated with pencil beam scanning proton therapy.

METHODS

One hundred seventy six AYAs treated curatively at the Paul Scherrer Institute (PSI) were identified. Median age was 30 years (range 15-39) and median prescribed dose was 70.0 Gy (relative biological effectiveness [RBE]) (range 50.4-76.0). The most common tumors treated were chordomas/chondrosarcomas (61.4%), followed by gliomas (15.3%), and meningiomas (14.2%).

RESULTS

After a median follow up of 66 months (range 12-236), 24 (13.6%) local only failures and one (0.6%) central nervous system (CNS) distant only failure were observed. The 6-year local control, distant progression-free survival, and overall survival were 83.2%, 97.4%, and 90.2%, respectively. The 6-year high-grade (≥grade [G] 3) PT-related late toxicity-free survival was 88.5%. Crude late toxicity rates were 26.2% G1, 37.8% G2, 12.2% G3, 0.6% G4, and 0.6% G5. The one G4 toxicity was a retinopathy and one G5 toxicity was a brainstem hemorrhage. The 6-year cumulative incidences for any late PT-related pituitary, ototoxicity, and neurotoxicity were 36.3%, 18.3%, and 25.6%; whilst high-grade (≥G3) ototoxicity and neurotoxicity were 3.4% and 2.9%, respectively. No secondary malignancies were observed. The rate of unemployment was 9.5% pre-PT, increasing to 23.8% post-PT. Sixty-two percent of survivors were working whilst 12.7% were in education post-PT.

CONCLUSIONS

PT is an effective treatment for brain/skull base tumors in the AYA population with a reasonable late toxicity profile. Despite good clinical outcomes, around one in four AYA survivors are unemployed after treatment.

Clinical outcomes of head and neck adenoid cystic carcinoma patients treated with pencil beam-scanning proton therapy

OBJECTIVE

The aim of this study was to evaluate the outcome of patients with head and neck adenoid cystic carcinoma (ACC) treated using pencil beam scanning proton therapy (PBS PT) at our institution.

MATERIALS AND METHODS

Thirty-five patients who underwent treatment with PBS PT for ACC between 2001 and 2017 were included. Local control (LC), distant control (DC), progression-free survival (PFS), overall survival (OS) and their prognostic factors were evaluated. Adverse effects were prospectively assessed.

RESULTS

The median patient follow-up was 30 months. Prior to PT, 26 patients (74.3%) underwent surgery with R0/R1/R2 outcome in 5, 13 and 8 cases, respectively. Nine patients (25.7%) presented with inoperable disease. The 2-year LC, DC, PFS and OS was 92.2%, 77.8%, 74.3% and 88.8%, respectively. LC was influenced by patient age (p = 0.002) with a significant difference between local and distant failure (median 61.3 vs. 42.3 years, p = 0.005). Tumor T stage was a significant risk factor for PFS (p = 0.045) and tumor prognostic group affected OS (p = 0.049). No significant survival advantage for operable vs. inoperable disease could be identified. The acute and late grade 3 toxicity rates were 14.3% and 6.1%, respectively. No acute or late grade 4/5 toxicities were observed.

CONCLUSIONS

PBS PT is an effective and safe treatment for patients with head & neck ACC in both definitive and adjuvant setting. Distant metastases are the main pattern of failure. Age, tumor stage and clinical stage had a significant negative impact on LC, OS and PFS.

Prognostic impact of the "Sekhar grading system for cranial Chordomas" in patients treated with pencil beam scanning proton therapy: an institutional analysis

BACKGROUND

Skull base chordomas are rare and heterogeneously behaving tumors. Though still classified as benign they can grow rapidly, are locally aggressive, and have the potential to metastasize. To adapt the treatment to the specific needs of patients at higher risk of recurrence, a pre-proton therapy prognostic grading system would be useful. The aim of this retrospective analysis is to assess prognostic factors and the "Sekhar Grading System for Cranial Chordomas" (SGSCC) by evaluating the larger cohort of patients treated at our institution as to determine its reproducibility and ultimately to ensure more risk adapted local treatments for these challenging tumors.

METHODS

We analyzed 142 patients treated for skull base chordomas between 2004 and 2016. We focused the analysis on the 5 criteria proposed for the SGSCC (tumor size, number of anatomic regions and vessels involved, intradural invasion, as well as recurrence after prior treatment) and classified our patients according to their score (based on the above mentioned criteria) into three prognostic groups, low-risk, intermediate-risk and high-risk. The three groups were then analyzed in regards of local control, local recurrence-free survival and overall survival.

RESULTS

The median follow up was 52 months (range, 3-152). We observed 34 (24%) patients with a local recurrence, resulting in a local control of 75% at 5 years. Overall survival was 83% at 5 years, 12 (9%) patients had died due to local progression. When split into the three prognostic groups according to the SGSCC the observed local control was 90, 72 and 64% (p = 0.07) in the low-, intermediate- and high-risk group, respectively. A similar correlation was observed for local recurrence-free survival with 93, 89 and 66% (p = 0.05) and for overall survival with 89, 83 and 76% (p = 0.65) for the same prognostic groups.

CONCLUSIONS

After splitting our patient cohort into the three SGSCC risk groups, we found a trend towards better outcome for those patients with lower as opposed to higher scores. These results suggest that this prognostic grading system published by Sekhar et al. could be integrated in the management decision-tree for patients with skull base chordoma.

Outcomes, Prognostic Factors and Salvage Treatment for Recurrent Chordoma After Pencil Beam Scanning Proton Therapy at the Paul Scherrer Institute

AIMS

The outcome of chordoma patients with local or distant failure after proton therapy is not well established. We assessed the disease-specific (DSS) and overall survival of patients recurring after proton therapy and evaluated the prognostic factors affecting DSS.

MATERIALS AND METHODS

A retrospective analysis was carried out of 71 recurring skull base (n = 36) and extracranial (n = 35) chordoma patients who received adjuvant proton therapy at initial presentation (n = 42; 59%) or after post-surgical recurrence (n = 29; 41%). The median proton therapy dose delivered was 74 GyRBE (range 62-76). The mean age was 55 ± 14.2 years and the male/female ratio was about one.

RESULTS

The median time to first failure after proton therapy was 30.8 months (range 3-152). Most patients (n = 59; 83%) presented with locoregional failure only. There were only 12 (17%) distant failures, either with (n = 5) or without (n = 7) synchronous local failure. Eight patients (11%) received no salvage therapy for their treatment failure after proton therapy. Salvage treatments after proton therapy failure included surgery, systemic therapy and additional radiotherapy in 45 (63%), 20 (28%) and eight (11%) patients, respectively. Fifty-three patients (75%) died, most often from disease progression (47 of 53 patients; 89%). The median DSS and overall survival after failure was 3.9 (95% confidence interval 3.1-5.1) and 3.4 (95% confidence interval 2.5-4.4) years, respectively. On multivariate analysis, extracranial location and late failure (≥31 months after proton therapy) were independent favourable prognostic factors for DSS.

CONCLUSION

The survival of chordoma patients after a treatment failure following proton therapy is poor, particularly for patients who relapse early or recur in the skull base. Although salvage treatment is administered to most patients with uncontrolled disease, they will ultimately die as a result of disease progression in most cases.

Early results and volumetric analysis after spot-scanning proton therapy with concomitant hyperthermia in large inoperable sacral chordomas

OBJECTIVE

Large inoperable sacral chordomas show unsatisfactory local control rates even when treated with high dose proton therapy (PT). The aim of this study is assessing feasibility and reporting early results of patients treated with PT and concomitant hyperthermia (HT).

METHODS:

Patients had histologically proven unresectable sacral chordomas and received 70 Gy (relative biological effectiveness) in 2.5 Gy fractions with concomitant weekly HT. Toxicity was assessed according to CTCAE_v4. A volumetric tumor response analysis was performed.

RESULTS:

Five patients were treated with the combined approach. Median baseline tumor volume was 735 cc (range, 369-1142). All patients completed PT and received a median of 5 HT sessions (range, 2-6). Median follow-up was 18 months (range, 9-26). The volumetric analysis showed an objective response of all tumors (median shrinkage 46%; range, 9-72). All patients experienced acute Grade 2-3 local pain. One patient presented with a late Grade 3 iliac fracture.

CONCLUSION

Combining PT and HT in large inoperable sacral chordomas is feasible and causes acceptable toxicity. Volumetric analysis shows promising early results, warranting confirmation in the framework of a prospective trial.

ADVANCES IN KNOWLEDGE:

This is an encouraging first report of the feasibility and early results of concomitant HT and PT in treating inoperable sacral chordoma.

Radiation-induced optic neuropathy after pencil beam scanning proton therapy for skull-base and head and neck tumours

OBJECTIVE

To assess the radiation-induced optic neuropathy (RION) prevalence, following high dose pencil beam scanning proton therapy (PBSPT) to skull base and head and neck (H&N) tumours.

METHODS

Between 1999 and 2014, 216 adult patients, median age 47 years (range, 18-77), were treated with PBS PT for skull base or H&N malignancies, delivering ≥45 Gy_RBE to the optic nerve(s) (ON) and/or optic chiasma (OC). The median administered dose to the planning target volume was 74.0 Gy_RBE (range, 54.0-77.4). The median follow-up was 5.3 years (range, 0.8-15.9).

RESULTS

RION was observed in 14 (6.5%) patients at a median time of 13.2 months (range, 4.8-42.6) following PBSPT. Most (92.9%) of RION were symptomatic. Most affected patients (11/14; 79%) developed unilateral toxicity. Grade 4, 3, 2 and 1 toxicity was observed in 10, 2, 1 and 1 patients, respectively. On univariate analyses, age (<70 vs ≥70 years; p < 0.0001), hypertension (p = 0.0007) and tumour abutting the optic apparatus (p = 0.012) were associated with RION. OC's V60 Gy_RBE was of border line significance (p = 0.06). None of the other evaluated OC-ON dose/volume metrics (Dmax, Dmean, V40-60) were significantly associated with this complication.

CONCLUSION

These data suggest that high-dose PBS PT for skull base and H&N tumours is associated with a low prevalence of RION. Caution should be however exercised when treating elderly/hypertensive patients with tumours abutting the optic apparatus.

ADVANCES IN KNOWLEDGE

This is the first study reporting the risk of developing RION following proton therapy with PBS technique, demonstrating the safety of this treatment.

Proton therapy for brain tumours in the area of evidence-based medicine

ADVANCES IN KNOWLEDGE

This review details the indication of brain tumors for proton therapy and give a list of the open prospective trials for these challenging tumors.

Pencil beam scanned protons for the treatment of patients with Ewing sarcoma

BACKGROUND

Few data exist regarding the clinical outcome of patients with Ewing sarcoma (EWS) treated with pencil beam scanning proton therapy (PT). We report the outcome of children, adolescents and young adults (AYA) treated with PT at the Paul Scherrer Institute.

MATERIALS

Thirty-eight patients (median age, 9.9 years) received a median dose of 54.9 Gy(RBE) (where RBE is relative biologic effectiveness). Size of the tumor ranged from 1.7 to 24 cm. Most common primary site was axial/pelvic (n = 27; 71%). Four patients (11%) presented with metastases at diagnosis. Twenty (53%) patients had chemo-PT only. Median follow-up was 49.6 months (range, 9.2-131.7).

RESULTS

The 5-year actuarial rate of local control (LC), distant metastasis-free survival (DMFS), and overall survival (OS) were 81.5%, 76.4%, and 83.0%, respectively. All local recurrences occurred in field and in patients with nonextremity primaries. Six patients died, all of tumor progression. Age < 10 years was a favorable factor of borderline significance for LC (P = 0.05) and OS (P = 0.05), but was significant for DMFS (P = 0.003). Tumor volume <200 ml was a significant prognostic factors for DMFS (P = 0.03), but not for OS (P = 0.07). Metastasis at diagnosis was a strong predictor of local failure (P = 0.003). Only two grade 3 late toxicities were observed. The 5-year actuarial rate of grade 3 toxicity-free survival was 90.9%.

CONCLUSIONS

These preliminary data suggest that the outcomes of children and AYA with EWS are good and PT was well tolerated with few late adverse events. The local and distant tumor control for older patients with large pre-PT tumor volumes remains problematic.

Induction chemotherapy with docetaxel, cisplatin and 5-fluorouracil followed by radiotherapy with cetuximab for locally advanced squamous cell carcinoma of the head and neck

PURPOSE

To determine the efficacy and feasibility of induction chemotherapy (ICT) with docetaxel, cisplatin and 5-fluorouracil followed by radiotherapy and cetuximab (C) in patients with locally advanced head and neck cancer.

PATIENTS AND METHODS

Forty-nine previously untreated patients with local advanced stage III and IV squamous cell carcinoma of the head and neck (SCCHN) received three courses of ICT consisting of docetaxel 75mg/m(2) day 1, cisplatin 75mg/m(2) day 1 and infusional 5-fluorouracil 750mg/m(2)/day on days 1-5 followed by radiotherapy plus C at 250mg/m(2)/week (after an initial loading dose of 400mg/m(2)).

RESULTS

After completion of ICT 44 of 49 patients received radiotherapy plus C. Three months after therapy completion tumour response was observed in 33 patients and after two years, 25 patients were in complete remission (CR). The most common grade 4 toxicity during the whole treatment period was dermatitis (30%), followed by mucositis (27%) and neutropenia (17%) without fever. One toxic related death was observed during ICT. Two-year progression-free survival (PFS) rate was 59% and two-year overall survival (OS) rate was 63%, respectively.

CONCLUSION

Concurrent radiotherapy plus C after three courses of ICT was feasible and was associated with promising CR, PFS and OS rates. Further optimisation of dose and sequence is warranted.

Evaluating repetitive 18F-fluoroazomycin-arabinoside (18FAZA) PET in the setting of MRI guided adaptive radiotherapy in cervical cancer

BACKGROUND

The aim of this pilot study was to assess tumour hypoxia in patients with cervical cancer before, during and after combined radio-chemotherapy and Magnetic Resonance Imaging (MRI) guided brachytherapy (BT) by use of the hypoxia Positron Emission Tomography (PET) tracer (18)F-fluoroazomycin-arabinoside ((18)FAZA ).

MATERIAL AND METHODS

Fifteen consecutive patients with locally advanced cervical cancer referred for definitive radiotherapy (RT) were included in an approved clinical protocol. Stage distribution was 3 IB1, 1 IB2, 10 IIB, 1 IIIB, tumour volume was 55 cm(3) (+/- 67, SD). Dynamic and static (18)FAZA -PET scans were performed before, during and after external beam therapy (EBRT) and image guided BT +/- concomitant cisplatin. Dose was prescribed to the individual High Risk Clinical Target Volume (HR CTV) taking into account the dose volume constraints for adjacent organs at risk.

RESULTS

Five patients had visually identifiable tumours on (18)FAZA -PET scans performed prior to radio-chemotherapy and four patients before brachytherapy. One of five (18)FAZA PET positive patients had incomplete remission three months after RT, one had regional recurrence. Four of ten (18)FAZA-PET negative patients developed distant metastases. The one patient with incomplete remission received 69 Gy (D90) in the HR CTV, whereas all other patients received mean 99 Gy (+/-12, SD).

CONCLUSION

PET imaging with (18)FAZA is feasible in patients with cancer of the uterine cervix. However, its predictive and prognostic value remains to be clarified. This applies in particular for the additional value of (18)FAZA-PET compared to morphologic repetitive MRI within the setting of image guided high dose radiotherapy which may contribute to overcome hypoxia related radioresistance.

Dose volume parameter D2cc does not correlate with vaginal side effects in individual patients with cervical cancer treated within a defined treatment protocol with very high brachytherapy doses

The study aimed to determine whether post-radiation vaginal side effects in cervical cancer patients can be correlated with DVH parameter D(2cc). The result was negative in that no correlation could be demonstrated between D(2cc) and the presence and grade of side effects in this patients' subset treated with high brachytherapy doses.

Gene expression profiling in cervical cancer: an exploration of intratumor heterogeneity

PURPOSE

To explore intratumor heterogeneity in gene expression profiles from patients with cervical cancer.

EXPERIMENTAL DESIGN

A total of 33 biopsies were obtained from 11 patients, sampling between two and five different areas for each tumor. The extracted RNA was hybridized onto the Affymetrix U133 Plus 2.0 oligonucleotide chip. The variance of expression within a patient (W), between patients (B) and the total variance (T = W + B) were calculated for each ProbeSet, and the ratio W/T was used as a measure of intratumor heterogeneity. Gene Ontology functional analysis was done to assess the function of genes that had high W/T (top 10%) and low W/T (bottom 10%) values.

RESULTS

In total, 448 ProbeSets (2.2% of the total) had W/T < 0.10, indicating low intratumor heterogeneity, and 537 ProbeSets (2.7% of the total) had W/T > 0.90, indicating high intratumor heterogeneity. In total 14,473 ProbeSets (72.4%) had higher intertumor than intratumor heterogeneity (W/T < 0.5). Genes with low intratumor heterogeneity were characterized by a statistically significant enrichment of immune-related functions (P < 0.0001). Genes with high intratumor heterogeneity were characterized by a significant tendency towards nuclear localization and nucleic acid binding (both P < 0.0001). For genes with W/T > 0.5, more than six biopsies would be required to minimize the intratumoral heterogeneity to <0.15; if W/T is 0.3 to 0.4, four biopsies are required; and for low W/T of 0.16 to 0.3, only two to three biopsies would be needed.

CONCLUSION

Although the intratumor heterogeneity was low for the majority of the tested ProbeSets, for many genes, multiple biopsies are required to obtain a reliable estimate of gene expression.

3D conformal HDR-brachy- and external beam therapy plus simultaneous cisplatin for high-risk cervical cancer: clinical experience with 3 year follow-up

BACKGROUND AND PURPOSE

To assess feasibility, safety and effectiveness of CT-based 3D conformal external beam radiotherapy (EBRT) plus concurrent cisplatin and MRI-based 3D conformal HDR-brachytherapy (HDR-BT) in the treatment of advanced cervical cancer.

PATIENTS AND METHODS

A total of 48 patients with advanced cervical cancer, treated with CT-based EBRT plus simultaneous cisplatin chemotherapy (40mg/m(2) of body surface per week for 5 weeks) and MRI-based HDR-BT, were included for analysis.

RESULTS

All patients completed radiotherapy as planned and 90% received at least four cycles chemotherapy. Frequencies of CTC grade 3 anaemia, grade 3-4 leucopenia and grade 3 thrombocytopenia were 4, 23 and 10%, respectively. Two patients developed deep vein thrombosis and one non-fatal pulmonary embolism. Grade 4 genitourinary late side effects (bladder) occurred in 2 patients. No grade 3-4 gastrointestinal side effects were observed. Complete response (CR) was obtained in 45 patients (94%). After a median follow-up of 33 months, 27 patients were disease free. Actuarial overall survival at 3 years was 61%, progression free survival 51% and continuous complete remission for true pelvis 85%.

CONCLUSIONS

MRI-based 3D HDR-BT and 3D EBRT plus cisplatin appears to be safe and effective, although acute haematological toxicity is increased. Gastrointestinal morbidity is minimal when prospectively applying 3D dose volume constraints and MRI-based 3D dose volume adaptation.

Impact of radiotherapy with and without concurrent cisplatin on lymphocyte subpopulations in cervical cancer patients

BACKGROUND

The impact of radiotherapy alone (RT-alone) and radiotherapy plus concurrent chemotherapy with cisplatin (RT-CHT) was determined for lymphocyte subpopulations in cervical cancer patients.

MATERIALS AND METHODS

Thirty-four women were treated either with RT-alone (n=14) or RT-CHT (n=20). Peripheral lymphocytes were collected before, immediately after and 6, 12 and 24 weeks after completion of treatment. Flow cytometric analysis included total T-cells, T-helper-cells, T-suppressor-cells, T-cytotoxic-cells, NK-cells, B-cells and the CD4+/CD8+ratio.

RESULTS

Twenty-four weeks after treatment, B-cells had recovered to pretreatment levels whereas total lymphocyte counts, T-helper and T-cytotoxic-cells were still significantly reduced in both groups. In contrast, T-suppressor-cells and NK-cells had recovered to pretreatment levels only in patients who received RT-alone and were still significantly reduced in patients who received RT-CHT.

CONCLUSION

RT-alone and RT-CHT induce a significant and prolonged suppression of all lymphocyte subpopulations. RT-CHT, but not RT-alone, causes a prolonged suppression of NK-cells and T-suppressor cells.

Comparison of late toxicity between continuous low-dose-rate and pulsed-dose-rate brachytherapy in cervical cancer patients

PURPOSE

To compare survival and severe late radiation toxicity between patients who received continuous low-dose-rate (LDR) brachytherapy (BT) and pulsed-dose-rate (PDR) BT for cervical cancer.

METHODS AND MATERIALS

A retrospective review of cervical cancer patients who underwent primary radiotherapy with or without concurrent cisplatin was performed. Late Grade 3 or worse toxicities were assessed using the National Cancer Institute Common Toxicity Criteria. The study endpoints were overall and disease-free survival and the probability of severe late toxicity.

RESULTS

A total of 109 patients (65.7%) received LDR BT and 57 (34.3%) received PDR BT. Seventy patients received concurrent chemotherapy with cisplatin. The 3-year overall survival and disease-free survival rate was 70% and 57% for the LDR group and 82% and 70% for the PDR group, respectively (p = 0.25 and p = 0.19). The 3-year probability rate for late Grade 3 or worse toxicity was 7.4% for LDR BT patients and 7.6% for PDR BT patients, respectively (p = 0.69) and 6.9% and 7.6%, respectively, for concurrent chemotherapy vs. none (p = 0.69).

CONCLUSION

No difference was found in severe late toxicity, overall survival, or disease-free survival between the LDR and PDR groups.

Overexpression of hypoxia-inducible factor 1alpha indicates diminished response to radiotherapy and unfavorable prognosis in patients receiving radical radiotherapy for cervical cancer

PURPOSE

The purpose is to investigate the impact of hypoxia-inducible factor (HIF)-1alpha expression on response to radiotherapy and prognosis of patients with primary irradiated cervical cancer. Because human papillomavirus (HPV) oncoprotein E6 might interact with HIF-1alpha in various pathways, we also investigated the relation of HIF-1alpha and HPV status.

EXPERIMENTAL DESIGN

Expression of HIF-1alpha was investigated by immunohistochemistry in 67 specimens of patients who had received radical radiotherapy for cervical cancer stages IB-IIIB. HPV analysis was performed using type-specific PCR, cloning, and sequencing. Survival analysis was performed using univariate and multivariate analysis.

RESULTS

Immunohistochemistry revealed expression of HIF-1alpha in 72.1% of the tumor samples. In 16 (23.9%) cases, there was a weak expression, in 25 (37.3%) a moderate expression, and in 7 cases (10.4%) a strong expression of HIF-1alpha. Nineteen samples (28.4%) were considered negative for HIF-1alpha expression. Strong/moderate expression of HIF-1alpha was associated with only partial response to radiotherapy (P = 0.037, chi(2) test). Strong/moderate expression of HIF-1alpha was also an independent prognostic factor for shorter progression-free survival (P = 0.036, Cox regression) and cervical cancer-specific survival (P = 0.04, Cox regression). No association between HIF-1alpha expression and infection with different HPV types could be found.

CONCLUSIONS

Overexpression of HIF-1alpha has predictive and prognostic significance in cervical cancer patients receiving curative radiation therapy. Possibly, expression of HIF-1alpha could serve as intrinsic marker of hypoxia in cervical cancer.

Impact of multiple HPV infection on response to treatment and survival in patients receiving radical radiotherapy for cervical cancer

To obtain information on the incidence and the clinical significance of infection with various types of the human papillomavirus (HPV) in cancer of the uterine cervix, we retrospectively examined the HPV status of 106 patients who had received radical radiotherapy for cervical cancer stages IB to IIIB. DNA was extracted from formalin-fixed, paraffin-embedded biopsies and PCR was carried out to identify HPV types 16, 18, 31, 35, 33 and 45. To detect additional HPV types, consensus PCR products were cloned and sequenced. A catalyzed signal-amplified colorimetric in situ hybridization was carried out in 84 of 106 specimens as a positive control. Response to therapy, progression-free survival (PFS) and cervical cancer-specific survival (CCSS) were the statistical endpoints. Survival analysis was carried out using univariate and multivariate analysis (Cox regression). Ninety-six patients (90.6%) were HPV-positive and 42/96 (43.7%) were positive for multiple HPV types. Eight patients had persistent disease after radiotherapy. From these 8 patients, 7 were infected with multiple HPV types and only 1 patient had an infection with a single HPV type. After a median follow up period of 50 months, patients with multiple HPV infection had a significantly shorter PFS and CCSS compared to those with single HPV infection (24.8% and 34.9% vs. 64% and 60.8%, Log rank, p < 0.01 and 0.04). In multivariate analysis, the presence of multiple HPV types (RR 1.9), node status (RR 2.3), tumor size (RR 3.2) and histologic type (RR 4.8) were independent prognostic factors of CCSS. Our results demonstrate that the presence of multiple HPV types is associated with poor response and with reduced survival in cervical cancer patients who receive radiotherapy as the primary treatment.

Serum VEGF levels in patients undergoing primary radiotherapy for cervical cancer: impact on progression-free survival

Vascular endothelial growth factor (VEGF) plays an important role in the regulation of tumour growth and metastasis. It was the aim of this study to examine the impact of serum VEGF levels on the likelihood of response to radiotherapy and on the disease-free survival in patients with cervical cancer. Blood was taken before commencing treatment and serum VEGF was assessed by quantitative ELISA in 23 patients with cervical cancer stage IB-IVA undergoing primary radiotherapy. Serum VEGF levels were correlated with clinical and histopathologic factors as well as with response to radiotherapy and time to progression. Nineteen of the 23 patients had a complete response and four patients had persistent disease at 3 months. The median follow-up was 25 months (95% confidence interval: 23.5-26.5 months). At the time of analysis, eight patients were tumour-free and 15 patients had tumour progression; 12 of these 15 patients died of disease. Overall, the median serum VEGF level was 244 pg/ml (range 31.9-817.6 pg/ml). All four patients with local failure had VEGF levels >244 pg/ml, whereas 11 of the 19 patients with complete response had serum VEGF of < or =244 pg/ml (P=0.035). The median time to progression was 5 months in patients with VEGF of >244 pg/ml compared to 19 months in patients with VEGF of < or = 244 pg/ml (log rank, P=0.003). In multivariate analysis, serum VEGF, tumour size and histological type, but not the patient's age, stage and grade of histological differentiation influenced the progression-free survival. Elevated pre-therapeutic serum VEGF levels are associated with poor response and a shorter time to progression in patients with cervical cancer undergoing primary radiotherapy.

Impact of hemoglobin levels before and during concurrent chemoradiotherapy on the response of treatment in patients with cervical carcinoma: preliminary results

BACKGROUND

In patients undergoing radiation for cervical carcinoma, there is evidence that anemia is associated with an impaired outcome. For patients undergoing chemoradiation, there are no data available. The objective of this retrospective study was to examine the impact of anemia before and during chemoradiation in patients with cervical carcinoma.

METHODS

The authors collected data on hemoglobin (Hb) levels before and during treatment from 57 patients with cervical carcinoma. The stage of disease ranged between Stage IB and Stage IVA. All patients were treated with concurrent chemoradiation. Response to chemoradiation was evaluated by univariate and multivariate analyses.

RESULTS

The mean Hb level at the time of presentation was 12.9 +/- 1.6 g/dL in patients with a complete clinical response (CCR) and 12.1 +/- 1.4 g/dL in those with persistent disease (P = 0.126). In patients with a CCR, the mean nadir Hb level was 11.1 +/- 1.3 g/dL, and in patients with treatment failure, it was 9.8 +/- 1.8 g/dL (P = 0.008). A univariate logistic regression model demonstrated that the nadir Hb level was the most predictive factor for treatment failure (relative risk, 1.92; P = 0.015) followed by disease stage (relative risk, 0.51; P = 0.074). In a multivariate model, the nadir Hb level remained the only prognostically relevant factor predicting the response to chemoradiation. Only patients with nadir Hb values > 11 g/dL throughout chemoradiation had a more than 90% chance of achieving a CCR.

CONCLUSIONS

In patients undergoing chemoradiation for cervical carcinoma, the nadir Hb level is highly predictive of response to treatment, whereas the Hb level at the time of presentation is prognostically not significant.

Signal-amplified colorimetric in situ hybridization for assessment of human papillomavirus infection in cervical lesions

Detection and typing of human papillomavirus (HPV) infection may have a major impact in cervical-screening and follow-up. In this study various commercially available techniques for the detection of HPV were evaluated. HPV-status was determined in 86 samples of cervical cancer by PCR and direct sequencing, catalyzed signal amplified colorimetric DNA in situ hybridization (CSAC- ISH) (GenPoint system, DAKO), immunohistochemistry (IHC) and in 12 selected cases also by conventional, non-amplified ISH. Twenty-one samples of cervical intraepithelial neoplasias grade III (CIN III) were investigated by CSAC-ISH, conventional ISH and by IHC, in corresponding PAP smears HPV-detection and typing was performed by CSAC-ISH and Hybrid Capture test II (HC). In additional 20 PAP smears HPV typing was performed using HC and a novel immunocytochemical system for HPV detection and-typing. CSAC-ISH showed good correlation with PCR analysis in cervical cancers: In 87% of PCR positive cases, HPV infection was also detected by CSAC- ISH (66/76). HPV 16 was detected in 75% of PCR-positive cases (44/59), HPV 18 in 71% of PCR positive cases (5/7). CSAC-ISH detected HPV 31 in only 29% of PCR positive cases (2/7), and HPV 33 in 64% of PCR-positive cases (23/36). Nevertheless, CSAC-ISH- false negative cases for HPV 31 or 33 were nearly always combined infections with other HPV types, which were detectable by CSAC-ISH in most cases. CSAC-ISH revealed HPV infection in 20 of 21 HC-positive cervical smears, while in corresponding biopsies (CIN III) CSAC-ISH detected 100% of HPV infections. Conventional, non-amplified ISH showed significantly lower sensitivity compared with CSAC-ISH, and immunocyto- and -histochemistry were of very low sensitivity for detection of HPV. CSAC-ISH is an easy-to-handle method for detection and typing of cervical HPV infection, and shows sufficient sensitivity for clinical practice.

Impact of human papillomavirus infection on the expression of the KAI1 metastasis suppressor protein in invasive cervical cancer

Downregulation of KAI1 metastasis suppressor protein is associated with dismal prognosis in a variety of cancers. Mutation of p53 was suggested to be involved in KAI1-downregulation. In cervical cancer, p53 is inactivated by human papillomavirus (HPV) oncoprotein E6 with the grade of inactivation depending on the HPV type. KAI1-expression was immunohistochemically determined in 67 specimens of cervical cancer, HPV-typing was performed using polymerase chain reaction (PCR), cloning, and sequencing. KAI1-downregulation was found in 68.1% of patients, HPV-infection in 91%. There was no association of KAI1-downregulation and infection with a particular HPV type. KAI1-downregulation in cervical cancer seems independent of HPV-E6 induced p53 inactivation.

The impact of expression of the metastasis suppressor protein KAI1 on prognosis in invasive squamous cell cervical cancer

OBJECTIVES

Loss of KAI1 protein is a frequent event in various types of cancer and has been reported to be associated with increased rate of metastasis and shorter survival time.

METHODS

Expression of KAI1 and p53 was immunohistochemically determined in 75 biopsy specimens from patients with primary irradiated, invasive squamous cell cervical cancer and 30 cases with CIN I-III.

RESULTS

In invasive cancer, 22 cases showed strong expression, 42 cases down-regulation, and 11 cases no expression of KAI1. All specimens with CIN I showed strong KAI1 expression, while in CIN II and III down-regulation was observed in 45% of cases. There was no significant correlation of KAI1 expression with clinical and histopathological parameters. No influence of KAI1 expression on prognosis was observed.

CONCLUSIONS

KAI1-down-regulation is a frequent event in cervical cancer occurring early in carcinogenesis. KAI1 expression did not influence the prognosis of patients with primary irradiated cervical cancer.