Planning target volume margin in head and neck cancer patients undergoing radiation therapy: Estimations derived from own data and literature.

Planning target volume (PTV) to deliver the desired dose to the clinical target volume (CTV) accounts for systematic (∑) and random (σ) errors during the planning and execution of intensity modulated radiation therapy (IMRT). As these errors vary at different departments, this study was conducted to determine the 3-dimensional PTV (PTV3D) margins for head and neck cancer (HNC) at our center. The same was also estimated from reported studies for a comparative assessment. A total of 77 patients with HNCs undergoing IMRT were included. Of these, 39 patients received radical RT and 38 received postoperative IMRT. An extended no action level protocol was implemented using on-board imaging. Shifts in the mediolateral (ML), anteroposterior (AP), and superoinferior (SI) directions of each patient were recorded for every fraction. PTV margins in each direction (ML, AP, SI) and PTV3D were calculated using van Herk's equation. Weighted PTV3D was also computed from the ∑ and σ errors in each direction published in the literature for HNC. Our patients were staged T2-4 (66/77) and N0 (39/77). In all, 2280 on-board images were acquired, and daily shifts in each direction were recorded. The PTV margins in the ML, AP, and SI directions were computed as 3.2 mm, 2.9 mm, and 2.6 mm, respectively. The PTV3D margin was estimated to be 6.5 mm. This compared well with the weighted median PTV3D of 7.2 mm (range: 3.2 to 9.9) computed from the 16 studies reported in the literature. To ensure ≥95% CTV dose coverage in 90% of HNC patients, PTV3D margin for our department was estimated as 6.5 mm. This agrees with the weighted median PTV3D margin of 7.2 mm computed from the 16 published studies in HNCs. Site-specific PTV3D margin estimations should be an integral component of the quality assurance protocol of each department to ensure adequate coverage of dose to CTV during IMRT.

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.

Hyperthermia with photon radiotherapy is thermoradiobiologically analogous to neutrons for tumors without enhanced normal tissue toxicity.

The depth dose profiles of photons mirror those of fast neutrons. However, in contrast to the high linear energy transfer (LET) characteristics of neutrons; photons exhibit low LET features. Hyperthermia (HT) inhibits the repair of radiation-induced DNA damage and is cytotoxic to the radioresistant hypoxic tumor cells. Thus, thermoradiobiologically, HT simulates high LET radiation with photons. At temperatures of 39-45 °C, the physiological vasodilation allows rapid heat dissipation from normal tissues. On the contrary, the chaotic and relatively rigid tumor vasculature results in heat retention leading to higher intratumoural temperatures. Consequently, the high LET attributes of HT with photon radiations are mostly limited to the confines of the heated tumor while the normothermic normal tissues would be irradiated with low LET photons. HT thereby augments photon therapy by conferring therapeutic advantages of high LET radiations to the tumors akin to neutrons, while the 'heat-sink' effect spares the normal tissues from thermal radiosensitization. Thus, photon thermoradiotherapy imparts radiobiological advantages selectively to tumors analogous to neutrons without exaggerating normal tissue morbidities. The later has been the major concern with clinical fast neutron beam therapy. Outcomes reported from several clinical trials in diverse tumor sites add testimony to the enhanced therapeutic efficacy of photon thermoradiotherapy.

A Pilot Study of Radiotherapy and Local Hyperthermia in Elderly Patients With Muscle-Invasive Bladder Cancers Unfit for Definitive Surgery or Chemoradiotherapy.

Purpose: To present the outcomes of a pilot study with hyperthermia (HT) and radiotherapy (RT) in elderly patients of muscle-invasive bladder cancers (MIBC) unfit for surgery or chemoradiotherapy (CTRT). Methods: Sixteen elderly patients with unifocal or multifocal MIBCs received a total dose of 48 Gy/16 fractions/4 weeks or 50 Gy/20 fractions/4 weeks, respectively. HT with a radiofrequency HT unit was delivered once weekly for 60 min before RT and a mean temperature of 41.3°C was attained (maximum temperature 41.1-43.5°C). Local control was assessed using RECIST criteria at 3-monthly intervals by cystoscopy with or without biopsy. Results: The median age, KPS and age-adjusted Charlson comorbidity index were 81 years, 70 and 5, respectively. At median follow-up of 18.5 months (range: 4-65), bladder preservation was 100% with satisfactory function. 11/16 patients (68.7%) had no local and/or distant failure, while isolated local, distant and combined local and distant failures were evident in 2, 2, and 1 patient, respectively. Two local failures were salvaged by TUR-BT resulting in a local control rate of 93.7%. The 5-year cause-specific (CS) local disease free survival (LDFS), disease free survival (DFS), and overall survival (OS) were 64.3, 51.6, and 67.5%, respectively while 5-year non-cause-specific (NCS)-LDFS, NCS-DFS, and NCS-OS were 26.5, 23.2, and 38%, respectively. None of the patients had acute or late grade 3/4 gastrointestinal or genitourinary toxicities. Conclusions: The outcomes from this pilot study indicate that thermoradiotherapy is a feasible therapeutic modality in elderly MIBC patients unfit for surgery or CTRT. HTRT is well-tolerated, allows bladder preservation and function, achieves long-term satisfactory locoregional control and is devoid of significant treatment-related morbidity. This therapeutic approach deserves further evaluation in randomized studies.

An in silico comparative dosimetric study of postmastectomy locoregional irradiation using intensity-modulated vs 3-dimensional conventional radiotherapy.

An in silico dosimetric evaluation of intensity-modulated radiation therapy (IMRT) vs 3-dimensional conventional radiation therapy (3D-CRT) treatment plans in postmastectomy radiation therapy (PMRT) to the chest wall and regional lymphatics was conducted. Twenty-five consecutive patients with breast cancer referred for locoregional PMRT, stages T2-4 with N1-3, were planned to receive 50 Gy in 25 fractions with IMRT. Additionally, a 3D-CRT plan was generated using identical contours for the clinical target volumes (CTV), planning target volumes (PTV), and organs at risk (OAR). Treatment plans were assessed using dose-volume histogram (DVH) parameters of D98, D95, D50, D2, and homogeneity index for individual CTVs and PTVs. OARs evaluated were ipsilateral and contralateral lungs, heart, spinal cord, and opposite breast. Most DVH parameters pertaining to CTVs and PTVs significantly favored IMRT. V20 for ipsilateral and contralateral lungs, D33 of heart and maximum dose to spinal cord favored IMRT (all p < 0.001). The mean dose to the opposite breast was significantly lesser with 3D-CRT (5.8 ± 1.8 Gy vs 2.0 ± 1.0 Gy, p < 0.001). Thus, except for the mean dose to the opposite breast, the compliance to DVH constraints applied to PTV and OARs were significantly better with IMRT. At a median follow-up of 76 months (7-91), none had locoregional failure or pulmonary or cardiac morbidity. For PMRT, requiring comprehensive irradiation to both chest wall and regional lymphatics, IMRT offers superior dosimetric advantages over 3D-CRT. This was also corroborated by long-term outcomes in these patients treated with IMRT.

"HEATPAC" - a phase II randomized study of concurrent thermochemoradiotherapy versus chemoradiotherapy alone in locally advanced pancreatic cancer.

BACKGROUND: Pancreatic cancer has a dismal prognosis with 5-year overall survival rate of around 5%. Although surgery is still the best option in operable cases, majority of the patients who present in locally advanced stages are deemed inoperable. Novel approaches are therefore needed for the management of around 80% of these inoperable locally advanced pancreatic cancers (LAPC). Hyperthermia (39-43 °C) is a potent radiosensitizer and further enhances the action of gemcitabine, also a known radiosensitizer. Thus through triple sensitization, a combination of hyperthermia, radiotherapy and gemcitabine could be expected to improve the therapeutic outcomes in LAPC. METHODS: This phase II randomized trial, HEATPAC in unresectable LAPC, explores the feasibility and efficacy of concurrent thermochemoradiotherapy (HTCTRT) over chemoradiotherapy (CTRT) alone with pre- and post-intervention FOLFIRINOX at standard dosage and schedule. Following 4 cycles of neoadjuvant FOLFIRINOX, patients with no metastasis and absence of gross peritoneal carcinomatosis would be randomized to either (a) control arm: concurrent CTRT with gemcitabine (400 mg/m2, weekly ×6) or (b) study arm: locoregional hyperthermia (weekly ×6 during radiotherapy) with concurrent CTRT (same as in control arm). All patients would receive simultaneous-integrated boost intensity-modulated radiation therapy to doses of 56Gy and 50.4Gy to the gross and clinical target volumes respectively delivered in 28 fractions over 5.5 weeks. Deep locoregional hyperthermia would be administered weekly and monitored with real-time intraduodenal multisensor thermometry probe. A temperature of 40-43 °C for 60 min would be aimed for each hyperthermia session. On completion of CTRT/HTCTRT, patients of both groups would receive an additional 8 cycles of FOLFIRINOX. DISCUSSION: The expected 1-year baseline overall survival with CTRT alone is considered as 40%. With HTCTRT, a survival advantage of +20% is expected. Considering α = 0.05 and ß = 0.80 for sample size computation, a total of 86 patients would be equally randomized into the two treatment groups. This phase II study if found to be safe and effective, would form the basis of a future phase III randomized study. TRIAL REGISTRATION: The trial has been registered with the ClinicalTrials.gov ( NCT02439593 ). The study has been approved by the Ethical Commissions of Basel and Zurich and is open for patient recruitment.

Concurrent chemoradiotherapy vs. radiotherapy alone in locally advanced cervix cancer: A systematic review and meta-analysis.

The efficacy of concurrent chemoradiotherapy (CTRT) in locally advanced cervix cancer (LACC, stages IIB-IVA) is contentious. This is due to the variable extent of therapeutic benefit reported in different randomized clinical trials and meta-analyses that usually include all stages of cervix cancer. A systematic review and meta-analysis was therefore conducted to evaluate the efficacy of concurrent CTRT over radiotherapy (RT) alone, predominantly in LACC for the key endpoints; complete response (CR), long-term loco-regional control (LRC), overall survival (OS), grade III/IV acute and late toxicities. Six databases namely - PubMed, EMBASE, SCOPUS, Web of Science, Google Scholar and Cochrane library were explored and supplemented by hand-searching. Only prospective randomized trials conducted in LACC between concurrent CTRT and RT alone with no surgical interventions were included. Fourteen English language articles from 1788 citations were shortlisted for the final analysis. Of the 2445 patients evaluated (CTRT: n=1217; RT: n=1228), 95.7% had LACC and 96% had a squamous cell histology. Eight studies used cisplatin alone, 4 had cisplatin-based combination chemotherapy (CT) while 2 used mitomycin-C, either alone or in combination. CTRT improved the CR (+10.2%, p=0.027), LRC (+8.4%, p<0.001) and OS (+7.5%, p<0.001) over RT alone. However a 10.4% higher incidence of grade III/IV acute toxicities (p<0.001) was also evident with CTRT. Late toxicities in both groups were equivalent. Subgroup analysis and meta-regression did not reveal any significant advantage in outcomes between the 3 CTRT regimens. Thus, although concurrent CTRT provides conclusive therapeutic benefit over RT alone in LACC, the choice of CT agents should be based on their cost-effectiveness and the anticipated expenses for the management of any associated acute toxicities. This assumes importance particularly in resource-constrained low-middle-income countries with the highest burden of LACC, where majority of the patients meet the treatment costs as out-of-pocket expenses.

Radiotherapy infrastructure and human resources in Switzerland : Present status and projected computations for 2020.

PURPOSE: The purpose of this study was to evaluate the present status of radiotherapy infrastructure and human resources in Switzerland and compute projections for 2020. MATERIALS AND METHODS: The European Society of Therapeutic Radiation Oncology "Quantification of Radiation Therapy Infrastructure and Staffing" guidelines (ESTRO-QUARTS) and those of the International Atomic Energy Agency (IAEA) were applied to estimate the requirements for teleradiotherapy (TRT) units, radiation oncologists (RO), medical physicists (MP) and radiotherapy technologists (RTT). The databases used for computation of the present gap and additional requirements are (a) Global Cancer Incidence, Mortality and Prevalence (GLOBOCAN) for cancer incidence (b) the Directory of Radiotherapy Centres (DIRAC) of the IAEA for existing TRT units (c) human resources from the recent ESTRO "Health Economics in Radiation Oncology" (HERO) survey and (d) radiotherapy utilization (RTU) rates for each tumour site, published by the Ingham Institute for Applied Medical Research (IIAMR). RESULTS: In 2015, 30,999 of 45,903 cancer patients would have required radiotherapy. By 2020, this will have increased to 34,041 of 50,427 cancer patients. Switzerland presently has an adequate number of TRTs, but a deficit of 57 ROs, 14 MPs and 36 RTTs. By 2020, an additional 7 TRTs, 72 ROs, 22 MPs and 66 RTTs will be required. In addition, a realistic dynamic model for calculation of staff requirements due to anticipated changes in future radiotherapy practices has been proposed. This model could be tailor-made and individualized for any radiotherapy centre. CONCLUSION: A 9.8 % increase in radiotherapy requirements is expected for cancer patients over the next 5 years. The present study should assist the stakeholders and health planners in designing an appropriate strategy for meeting future radiotherapy needs for Switzerland.

Hyperthermia and radiotherapy in bladder cancer.

Hyperthermia represents a unique, safe, and advantageous methodology for improving therapeutic strategies in the management of bladder cancer. This modality has shown promise in contributing to treatment regimens for both superficial and muscle-invasive disease. Especially in conjunction with intravesical chemotherapy, systemic therapy, and radiotherapy, hyperthermia shows particular synergistic benefit. As such, it should be explored further through clinical use and clinical trial in conjunction with currently available techniques and emerging technologies. However, to conceptualise the way forward, it is particularly important to understand the current challenges to widespread use of non-invasive, bladder-sparing approaches and the current state of bladder cancer care. As such, in the following article, we have focused on not only the rationale for concurrent radiotherapy and hyperthermia, but also the clinical landscape in bladder cancer as a whole.

Human papillomavirus confers radiosensitivity in cancer cervix: a hypothesis toward a possible restoration of apoptotic pathways based on clinical outcomes.

AIM: To evaluate if high baseline local human papillomavirus (HPV) titer confers radiosensitivity in cancer cervix. A hypothesis is proposed to explain the clinical outcomes. MATERIALS & METHODS: 121 serial HPV titers from cervical smears of 21 patients were estimated during radiotherapy (RT) and correlated with RT dose-response curves, local response and local disease-free survival (LDFS). RESULTS: Local response (p = 0.04) and LDFS (p = 0.06) were better in high HPV than low HPV baseline group. On multivariate analysis, RT doses for 50% tumor regression and baseline HPV titer were the only predictors for LDFS. CONCLUSION: Serial reductions of HPV titers following RT could restore the HPV induced temporarily downregulated p53 and pRb apoptotic pathways resulting in radiosensitivity of these tumors.

Teleradiotherapy Network: Applications and Feasibility for Providing Cost-Effective Comprehensive Radiotherapy Care in Low- and Middle-Income Group Countries for Cancer Patients.

Globally, new cancer cases will rise by 57% within the next two decades, with the majority in the low- and middle-income countries (LMICs). Consequently, a steep increase of about 40% in cancer deaths is expected there, mainly because of lack of treatment facilities, especially radiotherapy. Radiotherapy is required for more than 50% of patients, but the capital cost for equipment often deters establishment of such facilities in LMICs. Presently, of the 139 LMICs, 55 do not even have a radiotherapy facility, whereas the remaining 84 have a deficit of 61.4% of their required radiotherapy units. Networking between centers could enhance the effectiveness and reach of existing radiotherapy in LMICs. A teleradiotherapy network could enable centers to share and optimally utilize their resources, both infrastructure and staffing. This could be in the form of a three-tier radiotherapy service consisting of primary, secondary, and tertiary radiotherapy centers interlinked through a network. The concept has been adopted in some LMICs and could also be used as a "service provider model," thereby reducing the investments to set up such a network. Teleradiotherapy networks could be a part of the multipronged approach to address the enormous gap in radiotherapy services in a cost-effective manner and to support better accessibility to radiotherapy facilities, especially for LMICs.

Brachytherapy in cancer cervix: Time to move ahead from point A?

Brachytherapy forms an integral part of the radiation therapy in cancer cervix. The dose prescription for intracavitary brachytherapy (ICBT) in cancer cervix is based on Tod and Meredith's point A and has been in practice since 1938. This was proposed at a time when accessibility to imaging technology and dose computation facilities was limited. The concept has been in practice worldwide for more than half a century and has been the fulcrum of all ICBT treatments, strategies and outcome measures. The method is simple and can be adapted by all centres practicing ICBT in cancer cervix. However, with the widespread availability of imaging techniques, clinical use of different dose-rates, availability of a host of applicators fabricated with image compatible materials, radiobiological implications of dose equivalence and its impact on tumour and organs at risk; more and more weight is being laid down on individualised image based brachytherapy. Thus, computed tomography, magnetic-resonance imaging and even positron emission computerized tomography along with brachytherapy treatment planning system are being increasingly adopted with promising outcomes. The present article reviews the evolution of dose prescription concepts in ICBT in cancer cervix and brings forward the need for image based brachytherapy to evaluate clinical outcomes. As is evident, a gradual transition from "point" based brachytherapy to "profile" based image guided brachytherapy is gaining widespread acceptance for dose prescription, reporting and outcome evaluation in the clinical practice of ICBT in cancer cervix.

Radiotherapy infrastructure and human resources in Europe - present status and its implications for 2020.

Radiotherapy (RT) is required for nearly half of the newly diagnosed cancer patients. To optimise the quality and availability of RT, guidelines have been proposed by European Society for Radiotherapy and Oncology-QUAntification of Radiation Therapy Infrastructure And Staffing Needs (ESTRO-QUARTS) and the International Atomic Energy Agency (IAEA). This study evaluates the present status of RT capacity in Europe and the projected needs by 2020 as per these recommendations. Thirty-nine of the 53 countries, listed in Europe by the UN Statistical Division, whose cancer incidences, teletherapy and human resources were available in the Global Cancer Incidence, Mortality and Prevalence (GLOBOCAN), International Agency for Research on Cancer (IARC) and DIrectory of RAdiotherapy Centres (DIRAC) (IAEA) databases were evaluated. A total of 3550 teletherapy units (TRT), 7017 radiation oncologists (RO), 3685 medical physicists (MP) and 12,788 radiotherapy technologists (RTT) are presently available for the 3.44 million new cancer cases reported annually in these countries. The present infrastructure and human resources in RT are estimated to provide RT access to 74.3% of the patients requiring RT. The current capacity in TRT, RO, MP and RTT when compared with recommended guidelines has a deficit of 25.6%, 18.3%, 22.7% and 10.6%, respectively. Thus, to respond to requirements by 2020, the existing capacity needs to be augmented by an additional 1698 TRTs, 2429 ROs, 1563 MPs and 2956 RTTs. With an imminent rise in cancer incidence, multifaceted strategic planning at national and international levels within a coordinated comprehensive cancer control programme is highly desirable to give adequate access to all patients who require radiotherapy across Europe. Specific steps to address this issue at national and continental levels involving all major stakeholders are proposed.

Coordinating care and treatment for cancer patients.

Survival following a diagnosis of cancer is contingent upon an interplay of factors, some non-modifiable (e.g., age, sex, genetics) and some modifiable (e.g., volitional choices) but the majority determined by circumstance (personal, social, health system context and capacity, and health policy). Accordingly, mortality and survival rates vary considerably as a function of geography, opportunity, wealth and development. Quality of life is impacted similarly, such that aspects of care related to coordination and integration of care across primary, community and specialist environments; symptom control, palliative and end-of-life care for those who will die of cancer; and survivorship challenges for those who will survive cancer, differs greatly across low, middle and high-income resource settings. Session 3 of the 4th International Cancer Control Congress (ICCC-4) focused on cancer care and treatment through three plenary presentations and five interactive workshop discussions: 1) establishing, implementing, operating and sustaining the capacity for quality cancer care; 2) the role of primary, community, and specialist care in cancer care and treatment; 3) the economics of affordable and sustainable cancer care; 4) issues around symptom control, support, and palliative/end-of-life care; and 5) issues around survivorship. A number of recommendations were proposed relating to capacity-building (standards and guidelines, protocols, new technologies and training and deployment) for safe, appropriate evidence-informed care; mapping and analysis of variations in primary, community and specialist care across countries with identification of models for effective, integrated clinical practice; the importance of considering the introduction, or expansion, of evidence-supported clinical practices from the perspectives of health economic impact, the value for health resources expended, and sustainability; capacity-building for palliative, end-of-life care and symptom control and integration of these services into national cancer control plans; the need for public education to reduce the fear and stigma associated with cancer so that patients are better able to make informed decisions regarding follow-up care and treatment; and the need to recognize the challenges and needs of survivors, their increasing number, the necessity to integrate survivorship into cancer control plans and the economic and societal value of functional survival after cancer. Discussions highlighted that coordinated care and treatment for cancer patients is both a ' systems'challenge and solution, requiring the consideration of patient and family circumstances, societal values and priorities, the functioning of the health system (access, capacity, resources, etc.) and the importance assigned to health and illness management within public policy.

Malignant peripheral nerve sheath tumor of the occipital region: case report.

OBJECTIVE: A rare case of a malignant peripheral nerve sheath tumor of the occipital region is presented. The role of postoperative radiotherapy in such cases is reviewed. CLINICAL PRESENTATION: A 36-year-old man presented with a small spongy swelling in the posterior aspect of the cranium since childhood. The swelling gradually increased for 2 years and then rapidly over the next 7 months. There were no associated symptoms of headache, vomiting, vertigo, focal weakness, or visual impairment. INTERVENTION: A small occipital craniectomy for total excision of the tumor was attempted. However, as a result of intracranial extension to the transverse sinus, the tumor could not be completely excised. Local radiotherapy to a dose of 59.4 Gy in 33 fractions over 6.5 weeks was delivered to the residual microscopic disease in the posterior part of the cranium. The patient has been followed up regularly for the past 28 months and continues to remain asymptomatic. CONCLUSION: An aggressive malignant peripheral nerve sheath tumor of an atypical site such as the scalp, in which complete surgery may not always be possible, could benefit from postoperative radiotherapy. A dose of approximately 60 Gy could be effectively delivered with a satisfactory outcome.

Comparative assessment of doses to tumor, rectum, and bladder as evaluated by orthogonal radiographs vs. computer enhanced computed tomography-based intracavitary brachytherapy in cervical cancer.

PURPOSE: To carry out a comparative assessment of intracavitary brachytherapy (ICBT) doses to tumor, bladder, and rectum based on orthogonal films and contrast enhanced computed tomography (CECT). METHODS AND MATERIALS: Fifty-five ICBT procedures with CT/MRI compatible applicator and CECT scans were evaluated. Doses to Point A, International Commission on Radiation Units and Measurement (ICRU) reference points for maximum bladder (B max(ICRU)) and rectum (R max(ICRU)) localized from orthogonal films were compared with CECT delineated tumor, bladder (B max(CECT)), and rectum (R max(CECT)) doses, respectively. The 95th and 90th percentile bladder (B 95(CECT) and B 90(CECT)) and rectal (R 95(CECT) and R 90(CECT)) doses based on CECT were also estimated. RESULTS: Mean percentage tumor volume encompassed within the prescribed dose of 600 cGy to Point A was 88.8%. Mean B max(ICRU), B max(CECT), R max(ICRU), and R max(CECT) were 631.3 cGy, 1221.4 cGy, 454.8 cGy, and 526.9 cGy, respectively. Paired mean differences were significant between B max(ICRU) and B max(CECT) or B 95(CECT) (both p < 0.001); R max(ICRU) and R max(CECT) (p = 0.005) or R 90(CECT) (p < 0.001), whereas insignificant for B max(ICRU) and B 90(CECT) (p = 0.281), and R max(ICRU) and R 95(CECT) (p = 0.372). CONCLUSIONS: Prescription based on Point A ICBT doses could lead to uncertainty and underdosage in tumor. ICRU 38 maximum bladder and rectal doses significantly underestimate the maximum doses to these organs and represent the 90th and 95th percentile of the maximum doses to these organs, respectively.

From 'points' to 'profiles' in intracavitary brachytherapy of cervical cancer.

PURPOSE OF REVIEW: This article reviews some recent developments that have occurred with the widespread use of imaging modalities during intracavitary brachytherapy in cervical cancer. RECENT FINDINGS: The practice of dose prescription with intracavitary brachytherapy continues to be largely based on the traditional hypothetical point - point A. Recent studies have indicated that significant uncertainties could result with such point dose prescriptions. Gradually a shift is perceived towards the incorporation of target and normal structure outlines for dose prescription and treatment planning during intracavitary brachytherapy. SUMMARY: Dose prescriptions during brachytherapy could be framed with certainty if various imaging modalities are integrated during the intracavitary procedure. With the availability of computerized tomography/magnetic resonance imaging-compatible applicators, dose prescriptions and distributions could be based on either anatomical images of the diseased and normal organs obtained from computerized tomography or magnetic resonance imaging studies or on anatometabolic images after co-registration of the anatomical and functional images obtained from computerized tomography/magnetic resonance imaging and positron emission tomography. A shift from traditional two-dimensional 'points' to three-dimensional 'profiles' for targets and normal tissue doses could be expected in the near future with the use of image-guided intracavitary brachytherapy in cervical cancer.

Improvement of radiotherapy facilities in developing countries: a three-tier system with a teleradiotherapy network.

Incidence of cancer has been projected to rise worldwide by around 50% in the next 20 years, most of which will be in developing countries. To face this unprecedented global health problem, it is essential to plan effective health-care strategies. Radiotherapy-a main component of the multidisciplinary therapeutic approach for cancer-involves a huge capital investment that can pose difficulties for developing countries. Limited resources should therefore be used effectively to meet the projected requirements and to find ways to offer quality-assured radiotherapy to patients. Taking advantage of the global explosion of telecommunication technology, we present a proposal for creation of an integrated three-tier radiotherapy service, which consists of primary, secondary, and tertiary radiotherapy centres in developing countries-coordinated through a teleradiotherapy network. Such a network could be cost effective, help to bridge the gap, and give all patients access to the state-of-the-art technology in radiotherapy.