[From bunker construction to patient treatment: quality controls applied to modern radiotherapy techniques]. / De la construction du bunker à la prise en charge du patient : contrôles qualité des techniques modernes de radiothérapie.

Installation and use of a new radiotherapy device require an adequate quality and safety policy. The process leading to the commissioning of an accelerator following the construction of a bunker includes, among other tasks, the installation of the accelerator, the verification of compliance with the specifications, the signature of the acceptance specification as well as the process of characterization and modeling of the accelerator before its clinical use. The emergence of modern radiotherapy techniques, such as intensity modulated conformational radiotherapy and stereotactic radiotherapy, has resulted in more complex quality controls. The purpose of this article is to explain the different stages of the implementation of innovative radiotherapy techniques and to specify their features.

Contouring workload in adjuvant breast cancer radiotherapy.

PURPOSE: To measure the impact of contouring on worktime in the adjuvant radiation treatment of breast cancer, and to identify factors that might affect the measurements. MATERIAL AND METHODS: The dates and times of contouring clinical target volumes and organs at risk were recorded by a senior and by two junior radiation oncologists. Outcome measurements were contour times and the time from start to approval. The factors evaluated were patient age, type of surgery, radiation targets and setup, operator, planning station, part of the day and day of the week on which the contouring started. The Welch test was used to comparatively assess the measurements. RESULTS: Two hundred and three cases were included in the analysis. The mean contour time per patient was 34minutes for a mean of 4.72 structures, with a mean of 7.1minutes per structure. The clinical target volume and organs at risk times did not differ significantly. The mean time from start to approval per patient was 29.4hours. Factors significantly associated with longer contour times were breast-conserving surgery (P=0.026), prone setup (P=0.002), junior operator (P<0.0001), Pinnacle planning station (P=0.026), contouring start in the morning (P=0.001), and contouring start by the end of the week (P<0.0001). Factors significantly associated with time from start to approval were age (P=0.038), junior operator (P<0.0001), planning station (P=0.016), and contouring start by the end of the week (P=0.004). CONCLUSION: Contouring is a time-consuming process. Each delineated structure influences worktime, and many factors may be targeted for optimization of the workflow. These preliminary data will serve as basis for future prospective studies to determine how to establish a cost-effective solution.

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

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

Pattern of Progression after Stereotactic Body Radiotherapy for Oligometastatic Prostate Cancer Nodal Recurrences.

AIMS: To report the relapse pattern of stereotactic body radiotherapy (SBRT) for oligorecurrent nodal prostate cancer (PCa). MATERIALS AND METHODS: PCa patients with ≤3 lymph nodes (N1/M1a) at the time of recurrence were treated with SBRT. SBRT was defined as a radiotherapy dose of at least 5 Gy per fraction to a biological effective dose of at least 80 Gy to all metastatic sites. Distant progression-free survival was defined as the time interval between the first day of SBRT and appearance of new metastatic lesions, outside the high-dose region. Relapses after SBRT were recorded and compared with the initially treated site. Secondary end points were local control, time to palliative androgen deprivation therapy and toxicity scored using the Common Terminology Criteria for Adverse Events v4.0. RESULTS: Overall, 89 metastases were treated in 72 patients. The median distant progression-free survival was 21 months (95% confidence interval 16-25 months) with 88% of patients having ≤3 metastases at the time of progression. The median time from first SBRT to the start of palliative androgen deprivation therapy was 44 months (95% confidence interval 17-70 months). Most relapses (68%) occurred in nodal regions. Relapses after pelvic nodal SBRT (n = 36) were located in the pelvis (n = 14), retroperitoneum (n = 1), pelvis and retroperitoneum (n = 8) or in non-nodal regions (n = 13). Relapses after SBRT for extrapelvic nodes (n = 5) were located in the pelvis (n = 1) or the pelvis and retroperitoneum (n = 4). Late grade 1 and 2 toxicity was observed in 17% (n = 12) and 4% of patients (n = 3). CONCLUSION: SBRT for oligometastatic PCa nodal recurrences is safe. Most subsequent relapses are again nodal and oligometastatic.

Significance of 18F-fluorocholine PET/CT positive pulmonary lesions in prostate cancer patients.

AIM: To assess the frequency and the significance of incidental pulmonary lesions with 18F-fluorocholine (18F-FCH) PET/CT in prostate cancer (PCa) patients. PATIENTS, METHODS: 225 consecutive PCa patients referred for 18F-FCH PET/CT (median age 68 years) were retrospectively evaluated for the presence of lesions in the lungs: 173 referred for restaging and 52 for initial staging regarding their high risk of extra prostatic extension. The final diagnosis was based on histopathological or on clinical and radiological follow-up. RESULTS: 13 patients had 18F-FCH positive pulmonary and 8 patients malignant lesions: 5 patients (38%) had a primary lung cancer (2 squamous cell carcinomas, 1 papillary adenocarcinoma, 1 typical pulmonary carcinoid, 1 bronchioloalveolar carcinoma) and 3 patients (23%) PCa metastases. Benign lesions were found in 5 subjects (38%). SUVmax and maximum diameter were neither significantly different in primary and metastatic tumors nor between malignant and benign lesions. CONCLUSIONS: Although our results suggest that incidental uptake in the lungs in PCa patients are nonspecific, their detection may have a significant impact on patient management knowing that more than 60% represent malignant disease.

11C-Choline PET/CT in the primary diagnosis of prostate cancer: impact on treatment planning.

AIM: Aim of the present study was to evaluate the usefulness of 11C-choline PET/CT for detecting lymphatic or haematogenous spread and for planning radiotherapy in patients with medium-to-high risk prostate cancer. METHODS: We have included 61 consecutive patients recently diagnosed with cancer prostate by biopsy. All patients were classified as medium-to-high risk: Gleason: 7-9; PSA: 6.3-30.4 ng/mL; stage T2c (N.=20) or stage T3 (N.=41). Image acquisition began 5 min after intravenous injection of 11C-choline (656+119 MBq), starting at the pelvis and continuing craniocaudally. Images were interpreted visually to evaluate uptake by the prostate gland. Lymph nodes with 11C-choline uptake were considered invaded, regardless of their size. Bone lesions were considered positive when they showed greater focal uptake than the surrounding bone. In patients with evidence of lymph-node invasion or bone metastases (15 patients), disease was classified as locoregional, oligometastatic, or multimetastatic. RESULTS: All patients had prostate gland uptake (20 focal, 8 bifocal, and 33 multifocal). Extraprostatic disease was present in 15 patients (24.6%), as follows: 9 (60%) in a single location: in an infradiaphragmatic lymph node (N.=6), in a supradiaphragmatic lymph node (N.=1), and in bone (M1) (N.=2). Six (40%) as multifocal invasion: with both infra- and supradiaphragmatic lymph node involvement (N.=2); with infradiaphragmatic lymph node involvement and M1 bone metastases (N.=3); and infra- and supradiaphragmatic lymph node involvement plus M1 bone metastases (N.=1). Disease was classified as locoregional (N.=6), oligometastatic (N.=5), and multimetastatic (N.=4). The 11 (73.3%) patients with locoregional and oligometastatic disease were selected to undergo intensity-modulated radiation therapy with dose escalation based on the PET findings. CONCLUSION: Our results suggest that 11C-choline PET/CT is a useful one-stop diagnostic procedure for evaluating patients with medium/high risk prostate cancer scheduled for radical treatment. 11C-choline PET/CT can reliably rule out lymph node involvement and remote metastases, allowing to select candidates for radiotherapy and to plan their treatment.

[Prostate-rectum spacers: optimization of prostate cancer irradiation]. / Spacers entre prostate et rectum : optimisation des techniques d'irradiation du cancer de la prostate.

In the curative radiotherapy of localized prostate cancer, improvements in biochemical control observed with dose escalation have been counterbalanced by an increase in radiation-induced toxicity. The injection of biodegradable spacers between prostate and rectum represents a new frontier in the optimization of radiotherapy treatments for patients with localized disease. Transperineal injection of different types of spacers under transrectal ultrasound guidance allows creating a 7-to-20 mm additional space between the prostate and the anterior rectal wall lasting 3 to 12 months. Dosimetrically, a relative reduction in the rectal volume receiving at least 70 Gy (V70) in the order of 43% to 84% is observed with all types of spacers, regardless of the radiotherapy technique used. Preliminary clinical results show for all spacers a good tolerance and a possible reduction in the acute side effects rate. The aim of the present systematic review of the literature is to report on indications as well as dosimetric and clinical advantages of the different types of prostate-rectum spacers commercially available (hydrogel, hyaluronic acid, collagen, biodegradable balloon).

Hypofractionated external beam radiotherapy to boost the prostate with ≥85 Gy/equivalent dose for patients with localised disease at high risk of lymph node involvement: feasibility, tolerance and outcome.

AIMS: To evaluate the tolerance and preliminary outcome of prostate cancer patients at high risk of lymph node involvement treated with normofractionated whole pelvic radiotherapy (WPRT) followed by a hypofractionated boost to the prostate with an intensity-modulated radiotherapy (IMRT) technique. MATERIALS AND METHODS: Between 2004 and 2011, 78 T1-4N0M0 prostate cancer patients at high risk of lymph node involvement (70 patients with a Roach index ≥ 15%; 57 with T-stage ≥ 3a; 40 with Gleason score ≥ 8) underwent WPRT to a median normofractionated dose of 50.4 Gy (range 48.0-50.4 Gy) with conformal three-dimensional techniques for most patients. A 24 Gy boost (4 Gy/six fractions, twice weekly) was delivered to the prostate with IMRT. The total median delivered dose was 74.4 Gy, equivalent to 85.2 Gy in 2 Gy/fractions (α/ß = 1.5 Gy). All patients underwent androgen deprivation for a total median time of 10.8 months. The maximum gastrointestinal and genitourinary acute and late toxicity scores were recorded according to the Radiation Therapy Oncology Group scoring system. RESULTS: All patients completed treatment as planned. Only 1% of patients presented with grade 3 genitourinary or gastrointestinal acute toxicity and none scored ≥ grade 4. With a median follow-up of 57 months, the 5 year probability of late grade ≥2 genitourinary and gastrointestinal toxicity-free survival was 79.1 ± 4.8% and 84.1 ± 4.5%, respectively. The 5 year biochemical disease-free survival, local relapse-free survival and distant metastasis-free survival were 84.5 ± 4.5%, 96.0 ± 2.8% and 86.4 ± 4.4%, respectively. A pre-radiotherapy prostate-specific antigen ≤0.3 ng/ml was associated with a better 5 year biochemical disease-free survival (P = 0.036) and distant metastasis-free survival (P = 0.049). CONCLUSIONS: The use of a hypofractionated IMRT boost after WPRT may allow a minimally invasive dose escalation to successfully treat patients with non-metastatic prostate cancer at high risk of lymph node involvement. Higher prostate-specific antigen values before radiotherapy may require alternative adjuvant treatments to further optimise the outcome of this high-risk group of patients.

[Prostate cancer and androgen deprivation: benefits of psychological counseling]. / Cancer de la prostate et déprivation androgénique: bénéfices d'un accompagnement psychologique.

Androgen deprivation is a therapeutic option for patients with prostate cancer, however with a range of side effects that negatively affects their physical and psychological condition. A multidisciplinary care program, ADAPP ("Androgenic deprivation in prostate cancer patients"), has been created with a special focus on managing these side effects. This article describes the intervention of the liaison psychiatry within this program, with care options ranging from psychological support to intensive psychotherapy to address patients' intrapsychic dynamics throughout this care program. Clinical cases are reported to illustrate the relevance and the necessity of this specialized counselling.

Excess of cardiovascular mortality among node-negative breast cancer patients irradiated for inner-quadrant tumors.

BACKGROUND: Radiotherapy of the left breast is associated with higher cardiovascular mortality linked to cardiotoxic effect of irradiation. Radiotherapy of inner quadrants can be associated with greater heart irradiation, but no study has evaluated the effect of inner-quadrant irradiation on cardiovascular mortality. PATIENTS AND METHODS: We identified 1245 women, the majority with breast-conserving surgery, irradiated for primary node-negative breast cancer from 1980 to 2004 registered at the Geneva Cancer Registry. We compared breast cancer-specific and cardiovascular mortality between inner-quadrant (n = 393) versus outer-quadrant tumors (n = 852) by multivariate Cox regression analysis. RESULTS: After a mean follow-up of 7.7 years, 28 women died of cardiovascular disease and 91 of breast cancer. Patients with inner-quadrant tumors had a more than doubled risk of cardiovascular mortality compared with patients with outer-quadrant tumors (adjusted hazard ratio 2.5; 95% confidence interval 1.1-5.4). Risk was particularly increased in the period with higher boost irradiation. Patients with left-sided breast cancer had no excess of cardiovascular mortality compared with patients with right-sided tumors. CONCLUSIONS: Radiotherapy of inner-quadrant breast cancer is associated with an important increase of cardiovascular mortality, a possible result of higher irradiation of the heart. For patients with inner-quadrant tumors, the heart should be radioprotected.

[Total body irradiation: present and future]. / Irradiation corporelle totale : présent et avenir.

Total body irradiation (TBI) has an established role as preparative regimen for bone-marrow transplantation in the treatment of hematological malignancies. Many randomized trials demonstrated that the clinical outcomes obtained from the association of TBI and cyclophosphamide are equivalent, or, sometimes, better than those based on chemotherapeutic agents. Despite the therapeutic progress of the last years, and the consequent improvement in the overall survival, this preparative regimen remains always associated with a relatively high rate of acute and late toxicity. In this article, we review the actual indications of TBI in clinical practice, and analyze the technological progress in this domain. We focus on the hypothesis that a selective irradiation of the hematopoietic or lymphoid organs is actually possible with intensity-modulated radiotherapy. Technical limits and preliminary results in terms of acute and late toxicities of intensity-modulated TBI are analyzed. With these new technologies, treatment-related toxicity is not anymore a major limiting factor in the preparative regimens for bone-marrow transplantation, allowing for a larger spectrum of TBI indications, a possible extension to patients older than 50 years, or a dose escalation. Preliminary results warrant, however, further evaluation in clinical trials to better assess the impact of this new approach on disease control and the long-term toxicity.

Estimated dose to the rectum and colon in prostate cancer patients treated with exclusive radiation therapy presenting a secondary colorectal malignancy.

AIMS: To estimate the dose to colorectal structures after external beam radiation therapy (EBRT) delivered to prostate cancer patients who developed secondary colorectal cancers (sCRC). MATERIALS AND METHODS: Using data from a population-based cancer registry of 1134 prostate cancer patients, 11/264 (4.2%) patients treated with EBRT presented a sCRC. To evaluate the dose delivered to the colon and rectum, each individual index patient was matched with a study case and, using the index case treatment characteristics, dose calculations were carried out on the latter. RESULTS: The median maximum, mean and minimum doses delivered to the colon or rectum affected by the sCRC were 39.3 (range 0.2-66.0), 5.4 (range 0.2-41.3) and 0.6 (range 0.2-7.8) Gy, respectively. All but three sCRCs occurred outside the treatment fields. The estimated rectal doses after prostate radiation therapy were substantially higher than those delivered to non-rectal colic structures (mean dose 47.2+/-16.6 vs 9.4+/-6.4 Gy), but only one (9%) patient presented a rectal cancer. The differential mean doses given to the rectosigmoid junction and sigmoid colon, with or without sCRC, were not different. CONCLUSIONS: These data suggest that the administered dose after EBRT for prostate cancer to the colon, excluding the rectum, may be below the Gy unit in sCRC patients.

Characteristics and outcome of prostate cancer with PSA <4 ng/ml at diagnosis: a population-based study.

This population-based study aims to assess prognosis of prostate cancer diagnosed with prostate-specific antigen (PSA) levels <4 ng/ml in routine care. Materials and methods We compared prostate cancer patients with low PSA values (n=59) with other prostate cancer patients (n=1330) by logistic regression and the Cox model using data from the Geneva Cancer Registry. Results Patients with low PSA values more frequently had early-stage and well differentiated tumours. Nevertheless, 35% presented with aggressive tumour characteristics or metastases. After adjustment for other prognostic factors, prostate cancer-specific mortality was similar for both groups (hazard ratio: 1.1; 95%CI: 0.6-2.2). Conclusion We conclude that cancer with low PSA values at diagnosis is not indolent.

Three-phase 18F-fluorocholine PET/CT in the evaluation of prostate cancer recurrence.

AIM: Contribution of 3-phase 18F-fluorocholine PET/CT in suspected prostate cancer recurrence at early rise of PSA. PATIENTS, METHODS: Retrospective analysis was performed in 47 patients after initial treatment with radiotherapy (n=30) or surgery (n=17). Following CT, 10 minutes list-mode PET acquisition was done over the prostate bed after injection of 300 MBq of 18F-fluorocholine. Three timeframes of 3 minutes each were reconstructed for analysis. All patients underwent subsequent whole body PET/CT. Delayed pelvic PET/CT was obtained in 36 patients. PET/CT was interpreted visually by two observers and SUVmax determined for suspicious lesions. Biopsies were obtained from 13 patients. RESULTS: Biopsies confirmed the presence of cancer in 11 of 13 patients with positive PET for a total of 15 local recurrences in which average SUVmax increased during 14 minutes post injection and marginally decreased in delayed scanning. Conversely inguinal lymph nodes with mild to moderate metabolic activity on PET showed a clearly different pattern with decreasing SUVmax on dynamic images. Three-phase PET/CT contributed to the diagnostic assessment of 10 of 47 patients with biological evidence of recurrence of cancer. It notably allowed the discrimination of confounding blood pool or urinary activity from suspicious hyperactivities. PET/CT was positive in all patients with PSA>or=2 ng/ml (n=34) and in 4/13 patients presenting PSA values<2 ng/ml. CONCLUSION: 18F-fluorocholine 3-phase PET/CT showed a progressively increasing SUVmax in biopsy confirmed cancer lesions up to 14 minutes post injection while decreasing in inguinal lymph nodes interpreted as benign. Furthermore, it was very useful in differentiating local recurrences from confounding blood pool and urinary activity.

Quality of life and social integration after allogeneic hematopoietic SCT.

In total, 124 adult patients in remission after allogeneic hematopoietic SCT (HSCT) participated in a cross-sectional study to assess health-related quality of life (HRQL). Assessment of HRQL was carried out using two questionnaires: the (EORTC QLQ-C30) and the Functional Assessment of Cancer Therapy (FACT) with specific modules for BMT (FACT-BMT). Transplanted patients differed from healthy controls in many HRQL-related dimensions in the EORTC QLQ-C30: social functioning 73.4 versus 85.8, P<0.0001; role functioning 74.6 versus 83.3, P<0.004; physical functioning 83.9 versus 89.9, P<0.001; emotional functioning 72.2 versus 82.8, P<0.0001 but were not significant for global HRQL 71.2 versus 75.3, P<0.03. In total, 60% of the patients returned to work after HSCT; 31% part time and 29% full time. Age at HSCT and employment status were significantly associated with HRQL. Other factors such as disease and disease stage and especially the occurrence of late complications did not impact the perception of HRQL. This study suggests that the perception of HRQL after HSCT differs from the general population. Issues to increase work-related capabilities and improve social support need to be addressed.

Longitudinal follow-up of body composition in hematopoietic stem cell transplant patients.

Patients with hematological malignancies are well nourished prior to allogeneic hematopoietic stem cell transplantation (HSCT). HSCT and associated complications can affect body composition. The study evaluated cross-sectionally the prevalence and longitudinally the changes in lean body mass index (LBMI) in HSCT patients. Patients (n=82) were classified as normal or low LBMI. Logistic regression analyses were used to estimate odds ratios (OR) for low vs normal LBMI, between healthy volunteers and patients; for limited or extensive vs no chronic graft-versus-host-disease (GVHD); and for decreased (Karnofsky <80) vs normal functional status (>80). Patients were significantly more likely to have low LBMI at 6, 12 months, 2-3, 4-6 and >6 years than volunteers. In all, 38% of patients were below pre-HSCT LBMI at 4-6 years post-HSCT. Low LBMI was significantly associated with steroid treatment (OR 2.6, confidence intervals (CI) 1.3-5.2, P=0.008); limited (OR 5.5, CI 1.7-18.5, P=0.005) or extensive chronic GVHD (OR 20.3, CI 5.7-71.6, P<0.001); and decreased performance status (Karnofsky scores of < or =80) (OR 2.7, CI 1.3-5.9, P=0.01). Patients were more likely to have low LBMI than volunteers. Chronic GVHD and low performance status were associated with low LBMI; thus, complications and/or treatment increase the likelihood of low LBMI.

Invasive bladder carcinoma: a pilot study of conservative treatment with accelerated radiotherapy and concomitant cisplatin.

From November 1992 to December 1997, 25 patients (inoperable or refusing cystectomy) were included in a prospective study to assess the feasibility, tolerance, and curative potential of accelerated radiotherapy (RT) and concomitant cisplatin. Median age was 74 years (range 49-86). Stage distribution was as follows: 1 T1, 10 T2, 8 T3, and 6 T4. Two patients had clinically positive pelvic nodes. The goal was to deliver a total dose of 40 Gy to the whole pelvis and bladder in 4 weeks using a concomitant boost of 20 Gy to the tumor or to the whole bladder during the third and fourth weeks (total dose 60 Gy), with daily cisplatin (6 mg/m(2)) before RT for patients with creatinine clearance > 50 ml/min. All but one patient completed the RT protocol. Daily cisplatin was successfully delivered in 18 patients. One patient presented with grade III ototoxicity. Diarrhea was scored grade III in two and grade IV in two patients. Acute urinary toxicity was scored grade III in one patient. Posttreatment late effects included bladder grade II and grade III in two patients and one patient, respectively; large bowel grade III in one; urethral grade III in one; and femoral head radionecrosis in one. Four-year overall and disease-specific survival rates were 23% and 35%, respectively. The latter was 60% for patients with T2 tumors. The 4-year actuarial locoregional control rate for all patients was 61%. In summary, accelerated RT and concomitant cisplatin is feasible with acceptable tolerance even in relatively old patients. Although outcome was better for patients with low-stage tumors, local control and survival rates appeared similar to those of standard RT schedules for a similar patient population.

Bladder opacification does not significantly influence dose distribution in conformal radiotherapy of prostate cancer.

PURPOSE: To compare the results of treatment planning with or without bladder contrast during simulation of three dimensional conformal radiotherapy (3D-CRT) for prostate cancer (18 MV X-rays, six field arrangement), and to assess the potential changes in dose distribution in the target and rectal volumes. METHODS AND MATERIALS: Based on CT-simulation using intravenous contrast media, 3-D conformal treatment planning was performed in five patients. To simulate a non-opacified bladder, the electron matrix density of the opacified bladder was virtually changed to water density. Two treatment plans were carried out, with and without bladder opacification. In each patient dose distributions were formally compared for both plans, and the increment in monitor units (MU) needed to compensate for the presence of contrast media was assessed. RESULTS: A mean dose variation of -0.03% (range, -0.03-0.14%) and -1.13% (range, -1.85-0%) was observed for the prostate and the rectum, respectively. The average mean MU increment without bladder contrast normalized to the case with bladder contrast was 0.31% +/- 0.52. CONCLUSIONS: Bladder opacification used during simulation does not significantly influence prostate or rectal dose distributions in prostate patients treated with 3D-CRT, 18 MV X-rays, and a six-beam arrangement.

Total body irradiation before allogeneic bone marrow transplantation: is more dose better?

PURPOSE: This study was performed to retrospectively assess the potential influence of total-body irradiation (TBI) dose on overall survival in patients undergoing allogeneic bone-marrow transplants (BMT) for hematologic malignancies. METHODS AND MATERIALS: Between October 1984 and December 1996, 116 patients were conditioned with high-dose chemotherapy and fractionated TBI before allogeneic BMT. The median age was 34 years (range 3-60). The TBI dose was given in 6 fractions, twice-a-day, over 3 days before BMT. The total dose was 10 Gy in 24 patients, 12 Gy in 66 patients, and 13.5 Gy in 26 patients. RESULTS: TBI dose was inversely correlated with overall survival. Five-year survival was 62% for patients conditioned with 10 Gy, 55% for patients conditioned with 12 Gy, and 46% for patients conditioned with 13.5 Gy. Age at BMT was also independently correlated with survival, with the best outcome for patients < 40 years old. CONCLUSION: A TBI dose (fractionated) > 10 Gy may not necessarily be associated with a better outcome in patients undergoing allogeneic bone-marrow transplant for hematologic malignancies.

Potential role of intensity modulated proton beams in prostate cancer radiotherapy.

PURPOSE: The present study was undertaken to assess the potential benefit of intensity modulated (IM) proton beams in optimizing the dose distribution to safely escalate the tumor dose in prostate cancer radiotherapy. METHODS AND MATERIALS: Four treatment plans were compared in a prostate cancer patient aiming to deliver 81 Gy to the target: 1) conformal 18 MV X-rays, 6-fields; 2) 214 MeV protons, 2-fields; 3) IM 15 MV X-rays, 5-fields; and 4) 177-200 Mev IM protons, 5-fields as in Plan 3. In addition, IM methods were used to further escalate the tumor dose to 99 Gy. Dose-volume histograms (DVH) were used to physically compare the treatment plans. DVH data were also used to obtain normal tissue complication probabilities (NTCP) for the rectum, bladder, femoral heads, and tumor control probabilities. RESULTS: Although the planning target volume dose distribution was satisfactory with the four treatment plans, the homogeneity was slightly reduced in both X-ray plans (IM and standard) and the low-to-medium doses delivered to all organs at risk, and other normal tissues were significantly reduced by both proton plans. For a prescribed dose of 81 Gy, only the IM X-ray and IM proton plans both succeeded in predicting an acceptably low NTCP for the rectum (<5%, Grade 3). The integral nontarget dose was significantly reduced with IM proton beams (i.e., 3.1, 1.3, and 1.7 times less than Plans 1, 2, and 3, respectively). When escalating the dose to 99 Gy, no additional improvement between IM protons and IM X-ray beams was observed. CONCLUSION: Both IM X-ray and proton beams were able to optimize the dose distribution and comply with the goal of delivering the highest dose to the target while reducing the risk of severe morbidity to acceptable levels. The main advantage compared to IM X-rays was that IM protons succeeded in significantly reducing the low-to-medium dose to the nontarget tissues and achieved a small improvement in planning target volume (PTV) dose heterogeneity.