Whole abdominopelvic radiotherapy in the palliative treatment of pseudomyxoma peritonei.

BACKGROUND: Pseudomyxoma peritonei (PMP) is a rare clinical syndrome characterized by mucinous peritoneal disease arising from disseminated peritoneal adenomucinosis. Primary treatment involves a combination of cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC). There is no consensus on the proper treatment of recurrent PMP. In selected patients, repeated cytoreductive surgery with or without HIPEC might improve outcome. However, every repeated debulking procedure becomes less effective with increased morbidity. CASE REPORT: We present a case of a patient with intestinal obstruction caused by recurrent pseudomyxoma peritonei. We treated the patient with whole abdominopelvic radiotherapy (WAPRT) using intensity-modulated arc therapy (IMAT) to a total dose of 33 Gy, delivered in 22 daily fractions. The treatment was well tolerated and resulted in resolution of the obstruction for a period of 24 months. CONCLUSION: To the best of our knowledge, we present the first case report showing the possibility of resolving intestinal obstruction with WAPRT in a patient with recurrent PMP. It is our opinion that WAPRT delivered by IMAT, in analogy with ovarian cancer, should be considered as a palliative treatment option in managing patients with recurrent PMP especially in case of obstruction.

Moderate hypofractionated radiotherapy for prostate cancer: 3-year toxicity results of a multicentre randomized phase 3, non-inferiority trial.

BACKGROUND AND PURPOSE: Moderate hypofractionated radiotherapy (HFRT) is a standard treatment for prostate cancer patients. We compared 2 moderate HFRT regimens, with a biologically equivalent dose of 80 Gy in 2 Gy fractions, with a modest simultaneous integrated boost to the dominant intraprostatic lesion. MATERIAL AND METHODS: This is a multicenter, non-inferiority, randomized phase 3 trial with acute toxicity as the primary endpoint, comparing: 56 Gy in 4 weeks (16x3.5 Gy, 4 days/week, Arm A) with 67 Gy in 5 weeks (25x2.68 Gy, 5 days/week, Arm B). The H0 hypothesis is that both regimens are equivalent in terms of acute grade ≥ 2 gastro-intestinal toxicity, defined as a difference in acute grade ≥ 2 gastro-intestinal toxicity of ≤ 10 %. Here we report on acute and late toxicity. RESULTS: We included 170 patients in Arm A and 172 patients in Arm B. The median follow-up time for all patients was 42 months. Acute grade ≥ 2 gastrointestinal toxicity was reported by 24 % of patients in both groups. Acute grade 2 and 3 urinary toxicity was observed in 52 % and 9 % of patients in Arm A and 53 % and 7 % in Arm B. Late grade 2 and grade ≥ 3 gastrointestinal toxicity occurred in 19 % and 4 % of patients in Arm A compared with 15 % and 4 % in Arm B. Late grade 2 and grade ≥ 3 urinary toxicity was observed in 37 % and 10 % of patients in Arm A and 36 % and 6 % in Arm B. CONCLUSION: This analysis confirms that both HFRT regimens are safe and equivalent in terms of acute grade ≥ 2 gastrointestinal toxicity.

Imaging treated prostate cancer.

In patients with a clinical suspicion of recurrence after treatment for prostate cancer, imaging can be used to distinguish between local recurrence and metastatic disease. Multiparametric magnetic resonance imaging (mpMRI) of the prostate may be a valuable imaging modality for the detection and localization of local recurrence in patients treated for prostate cancer. In mpMRI, morphological T2-weighted images are combined with functional MRI techniques including diffusion-weighted imaging, dynamic contrast-enhanced imaging, and magnetic resonance spectroscopic imaging to improve accuracy. In this paper, the current status of imaging techniques used to detect and to localize tumor recurrence in patients treated for prostate cancer will be reviewed, with emphasis on mpMRI for local prostate cancer recurrence.

Intensity-modulated arc therapy with cisplatin as neo-adjuvant treatment for primary irresectable cervical cancer. Toxicity, tumour response and outcome.

PURPOSE: The goal of this work was to evaluate the feasibility and outcome of intensity-modulated arc therapy ± cisplatin (IMAT ± C) followed by hysterectomy for locally advanced cervical cancer. PATIENTS AND METHODS: A total of 30 patients were included in the study. The primary tumour and PET-positive lymph node(s) received a simultaneous integrated boost. Four weeks after IMAT ± C treatment, response was evaluated. Resection consisted of hysterectomy with or without lymphadenectomy. Tumour response, acute and late radiation toxicity, postoperative morbidity and outcome were evaluated. RESULTS: All hysterectomy specimens were macroscopically tumour-free with negative resection margins; pathological complete response was 40%. In 2 patients, one resected lymph node was positive. There was no excess in postoperative morbidity. Apart from two grade 3 hematologic toxicities, no grade 3 or 4 acute radiation toxicity was observed. No grade 3, 1 grade 4 (4%) intestinal, and 4 grade 3 (14%) urinary late toxicities were observed. The 2-year local and regional control rates were 96% and 100%, respectively. The 2-year distant control rate was 92%. Actuarial 2-year progression free survival rate was 89%. Actuarial 1- and 2-year overall survival rates were 96% and 91%, while 3-year overall survival was 84%. CONCLUSION: Surgery after IMAT ± C is feasible with low postoperative morbidity and radiation toxicity. Local, regional, distant control and survival rates are promising.

Adjuvant Radiotherapy After Radical Cystectomy for Patients with High-risk Muscle-invasive Bladder Cancer: Results of a Multicentric Phase II Trial.

BACKGROUND: High-risk muscle-invasive bladder cancer (MIBC) has a poor prognosis. Old trials showed that external beam radiotherapy (EBRT) after radical cystectomy (RC) decreases the incidence of local recurrences but induces severe toxicity. OBJECTIVE: To evaluate the toxicity and local control rate after adjuvant EBRT after RC delivered with volumetric arc radiotherapy. DESIGN, SETTING, AND PARTICIPANTS: This is a multicentric phase 2 trial. From August 2014 till October 2020, we treated 72 high-risk MIBC patients with adjuvant EBRT after RC. High-risk MIBC is defined as ≥pT3-MIBC ± lymphovascular invasion, fewer than ten lymph nodes removed, pathological positive lymph nodes, or positive surgical margins. INTERVENTION: Patients received 50 Gy in 25 fractions with intensity-modulated radiotherapy to the pelvic lymph nodes ± cystectomy bed. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome is acute toxicity. We report on local relapse-free rate (LRFR), clinical relapse-free survival (CRFS), overall survival (OS), and bladder cancer-specific survival (BCSS). RESULTS AND LIMITATIONS: The median follow-up is 18 mo. Forty-two patients (61%) developed acute grade 2 gastrointestinal (GI) toxicity. Four patients (6%) had acute grade 3 GI toxicity. One patient had grade 5 diarrhea and vomiting due to obstruction at 1 mo. Two-year probabilities of developing grade ≥3 and ≥2 GI toxicity were 17% and 76%, respectively. Urinary toxicity, assessed in 17 patients with a neobladder, was acceptable with acute grade 2 and 3 urinary toxicity reported in 53% (N = 9) and 18% (N = 3) of the patients, respectively. The 2-yr LRFR is 83% ± 5% and the 2-yr CRFS rate is 43% with a median CRFS time of 12 mo (95% confidence interval: 3-21 mo). Two-year OS and BCSS are 52% ± 7% and 62% ± 7%, respectively. Shortcomings are the nonrandomized study design and limited follow-up. CONCLUSIONS: Adjuvant EBRT after RC can be administered without excessive severe toxicity. PATIENT SUMMARY: In this report, we looked at the incidence of toxicity and local control after adjuvant external beam radiotherapy (EBRT) following radical cystectomy (RC) in high-risk muscle-invasive bladder cancer patients. We found that adjuvant EBRT was feasible and resulted in good local control. We conclude that these data support further enrollment of patients in ongoing trials to evaluate the place of adjuvant EBRT after RC.

Salvage Radiotherapy for Prostate Cancer.

For patients experiencing biochemical recurrence in the absence of distant metastasis, salvage radiotherapy (SRT) with or without androgen deprivation therapy (ADT) is currently the only possible curative treatment option. Prostate-specific antigen (PSA) monitoring and the selected use of SRT has some advantages when compared with adjuvant radiotherapy. The most important one is avoidance of a potential overtreatment of patients who would never have disease progression, even in the presence of high-risk pathological features. The identification of a specific PSA cut-off seems to be incorrect. In patients with more adverse pathological features, early SRT administered at the very first sign of a PSA rise granted better disease control. Dose-intensified SRT is feasible and well tolerated with no significant difference in grade 2 or more acute and late toxicity. At least 66 Gy must be given in the salvage setting. ADT has a radio-sensitising effect on the radiotherapy by inhibiting the repair of DNA double-strand breaks. The use of ADT in the salvage setting results in a better oncological outcome. Hormonal therapy is associated with a decrease in quality of life and side-effects depending on the duration of hormone therapy. The oncological benefit of hormone therapy duration depends on their clinical and pathological characteristics. 68-Ga-prostate-specific membrane antigen positron emission tomography-computed tomography is the gold standard in staging prostate cancer patients with biochemical persistence or recurrence after radical prostatectomy. The implementation of 18F-labelled PSMA tracers can provide a further improvement.

The survival impact of neoadjuvant hormonal therapy before radical prostatectomy for treatment of high-risk prostate cancer.

BACKGROUND: Several randomized controlled trials assessed the outcomes of patients treated with neoadjuvant hormonal therapy (NHT) before radical prostatectomy (RP). The majority of them included mainly low and intermediate risk prostate cancer (PCa) without specifically assessing PCa-related death (PCRD). Thus, there is a lack of knowledge regarding a possible effect of NHT on PCRD in the high-risk PCa population. We aimed to analyze the effect of NHT on PCRD in a multicenter high-risk PCa population treated with RP, using a propensity-score adjustment. METHODS: This is a retrospective multi-institutional study including patients with high-risk PCa defined as: clinical stage T3-4, PSA >20 ng ml-1 or biopsy Gleason score 8-10. We compared PCRD between RP and NHT+RP using competing risks analysis. Correction for group differences was performed by propensity-score adjustment. RESULTS: After application of the inclusion/exclusion criteria, 1573 patients remained for analysis; 1170 patients received RP and 403 NHT+RP. Median follow-up was 56 months (interquartile range 29-88). Eighty-six patients died of PCa and 106 of other causes. NHT decreased the risk of PCRD (hazard ratio (HR) 0.5; 95% confidence interval (CI) 0.32-0.80; P=0.0014). An interaction effect between NHT and radiotherapy (RT) was observed (HR 0.3; 95% CI 0.21-0.43; P<0.0008). More specifically, of patients who received adjuvant RT, those who underwent NHT+RP had decreased PCRD rates (2.3% at 5 year) compared to RP (7.5% at 5 year). The retrospective design and lack of specific information about NHT are possible limitations. CONCLUSIONS: In this propensity-score adjusted analysis from a large high-risk PCa population, NHT before surgery significantly decreased PCRD. This effect appeared to be mainly driven by the early addition of RT post-surgery. The specific sequence of NHT+RP and adjuvant RT merits further study in the high-risk PCa population.

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.

Cognitive factors influencing treatment decision-making in patients with localised prostate cancer: development of a standardised questionnaire.

BACKGROUND: Men diagnosed with localised prostate cancer have to make a well-informed treatment choice between (robot-assisted) radical prostatectomy, external beam radiotherapy and, in selected cases, brachytherapy and active surveillance. We developed and validated a questionnaire to determine the cognitive reasons motivating this choice. MATERIALS AND METHODS: The Prostate Cancer Decision-Making Questionnaire (PC-DMQ) was designed in-house and validated through the Delphi method. Finally, we tested the questionnaire in a cohort of 24 men, recently diagnosed with localised PC, before undergoing RARP (n = 16), EBRT (n = 6), brachytherapy (n = 1) or active surveillance (n = 1). RESULTS: The experts reached consensus after three rounds. In the patient cohort, 75% of men undergoing RARP chose this treatment because 'it provides the best chance of cure'. Reasons to choose EBRT were not as explicit: 33.3% chose this treatment because 'it provides the best chance of cure' and 33.3% because 'the maintenance of potency is important to them'. CONCLUSIONS: The PC-DMQ is a comprehensive and standardised tool that allows further research into cognitive factors that influence treatment decision-making in patients with localised PC.

Collagen vascular diseases and radiation therapy: a critical review.

PURPOSE: Although many oncologists have the impression that patients with collagen vascular disease tolerate radiotherapy less well than other patients, until now this was never described in a review article. METHODS AND RESULTS: The principal objective was to determine whether patients with collagen vascular diseases have a greater risk of severe radiation therapy complications, than those without a collagen vascular disease. However, most of the publications found on this topic are short anecdotal case reports of patients with increased toxicity after radiation. Consequently, the true incidence of these side effects is unknown. CONCLUSIONS: Unless further studies on this subject are reported, each radiation oncologist should be cautious in treating these patients.

Radiotherapy of prostate cancer with or without intensity modulated beams: a planning comparison.

PURPOSE: To evaluate whether intensity modulated radiotherapy (IMRT) by static segmented beams allows the dose to the main portion of the prostate target to escalate while keeping the maximal dose at the anterior rectal wall at 72 Gy. The value of such IMRT plans was analyzed by comparison with non-IMRT plans using the same beam incidences. METHODS AND MATERIALS: We performed a planning study on the CT data of 32 consecutive patients with localized adenocarcinoma of the prostate. Three fields in the transverse plane with gantry angles of 0 degrees, 116 degrees, and 244 degrees were isocentered at the center of gravity of the target volume (prostate and seminal vesicles). The geometry of the beams was determined by beam's eye view autocontouring of the target volume with a margin of 1.5 cm. In study 1, the beam weights were determined by a human planner (3D-man) or by computer optimization using a biological objective function with (3D-optim-lim) or without (3D-optim-unlim) a physical term to limit target dose inhomogeneity. In study 2, the 3 beam incidences mentioned above were used and in-field uniform segments were added to allow IMRT. Plans with (IMRT-lim) or without (IMRT-unlim) constraints on target dose inhomogeneity were compared. In the IMRT-lim plan, target dose inhomogeneity was constrained between 15% and 20%. After optimization, plans in both studies were normalized to a maximal rectal dose of 72 Gy. Biological (tumor control probability [TCP], normal tissue complication probability [NTCP]) and physical indices for tumor control and normal tissue complication probabilities were computed, as well as the probability of the uncomplicated local control (P+). RESULTS: The IMRT-lim plan was superior to all other plans concerning TCP (p < 0.0001). The IMRT-unlim plan had the worst TCP. Within the 3D plans, the 3D-optim-unlim had the best TCP, which was significantly different from the 3D-optim-lim plan (p = 0.0003). For rectal NTCP, both IMRT plans were superior to all other plans (p < 0.0001). The IMRT-unlim plan was significantly better than the IMRT-lim plan (p < 0.0001). Again, 3D-optim-unlim was superior to the other 3D plans (p < 0. 0007). Physical endpoints for target showed the mean minimal target dose to be the lowest in the IMRT-unlim plan, caused by a large target dose inhomogeneity (TDI). Medial target dose, 90th percentile, and maximal target dose were significantly higher in both IMRT plans. Physical endpoints for the rectum showed the IMRT-unlim plan to be superior compared to all other plans. There was a strong correlation between the 65th percentile (Rp65) and rectal NTCP (correlation coefficient > or =89%). For bladder, maximal bladder dose was significantly higher in the IMRT-unlim plan compared to all other plans (p < or = 0.0001).P+ was significantly higher in both IMRT-plans than in all other plans. The 3D-optim-unlim plan was significantly better than the two other 3D plans (p < 0.0001). CONCLUSION: IMRT significantly increases the ratio of TCP over NTCP of the rectum in the treatment of prostate cancer. However, constraints for TDI are needed, because a high degree of TDI reduced minimal target dose. IMRT improved uncomplicated local control probability. In our department, IMRT by static segmented beams is planned and delivered in a cost-effective way. IMRT-lim has replaced non-modulated conformal radiotherapy as the standard treatment for prostate cancer.

Execution of a single-isocenter three-field technique, using a multileaf collimator or tray-mounted cerrobend blocks: effect on treatment time.

PURPOSE: In this article, we studied the total treatment time of a single-isocenter three-field irradiation of breast and axilla, using either tray-mounted cerrobend blocks, or a multileaf collimator (MLC) for field shaping. METHODS AND MATERIALS: A total of 20 female, unselected patients were given 50 Gy (2 Gy/fraction) on breast and 46 Gy on axilla and supraclavicular region (2 Gy/fraction). Patients were randomized between two different treatment groups. The first group (n = 10) was treated on a Philips SL-75 linear accelerator (SL-75), using 5 MV photons with tray-mounted cerrobend blocks. The second group (n = 10) was treated on a Philips SL-25 linear accelerator, using 6 MV photons and a MLC (SL-25-MLC). RESULTS: Although the beam-on time on the SL-25-MLC was significantly higher (p < 0.0001) compared to the SL-75, overall treatment time was significantly shorter using a MLC instead of tray-mounted cerrobend blocks (p < 0.0001). The difference in total treatment time was in the range of 100 s per patient per day. The main difference between the two accelerators was observed when setup of the second and third field was done using the automatic setup facility of the SL-25-MLC (avoids entering the treatment room). A mean time gain of 124 s per treatment session was observed using automatic setup. Considering the yearly number of patients receiving this treatment, a total time gain equivalent to 16.15 8-h workdays was calculated. CONCLUSIONS: Compared to a technique using tray-mounted cerrobend blocks in the single-isocenter three-field irradiation of a breast and axilla, a MLC combined with automatic field setup provides a significant time advantage, by reducing the number of manipulations inside the treatment room.

High-dose preoperative radiotherapy does not alter the strength of unilaterally irradiated colon anastomoses in rats.

PURPOSE: We studied the influence of preoperative radiotherapy on the strength of colon anastomoses in rats. We compared a conventional (2 Gy/fraction; 1 fraction/day; 5 days/week; cumulative doses of 40.0, 60.0, and 80.0 Gy) and a hyperfractionated schedule (1.6 Gy/fraction, 2 fractions/day, 5 days/week, cumulative doses of 41.6, 60.8, and 80.0 Gy). We compared unilaterally with bilaterally irradiated anastomoses for two conventional radiation schedules. METHODS AND MATERIALS: The rectosigmoid was always irradiated. Depending on the experiment, the cecum was irradiated or not. A side-to-side anastomosis between rectosigmoid and cecum was constructed the day following the last irradiation. The strength of the anastomosis was evaluated by means of a bursting pressure (BP) measurement after 10 days. A control group and a sham-treated group were carried out. RESULTS: Compared to controls, the strength of unilaterally irradiated anastomoses was not altered and BP values were independent of the radiation schedule and of the cumulative dose. In case of bilaterally irradiated colon anastomoses, anastomotic strength was significantly reduced at 80 Gy, but not at 40 Gy. CONCLUSIONS: After high doses of preoperative radiotherapy, colon anastomoses in rats can be safely constructed if only one anastomotic segment is irradiated. The strength of bilaterally irradiated colon anastomoses is dose-dependent.

Influence of preoperative combined radiochemotherapy on surgical outcome and colonic anastomotic healing: experimental study in the rat.

PURPOSE: To study the influence of combined preoperative hyperfractionated irradiation with intraperitoneal 5-fluorouracil (5-FU) on surgical outcome and colonic anastomotic healing in a rat model. METHODS: Male Wistar rats were given 41.6 Gy of preoperative radiotherapy (RT) or sham irradiation, with intraperitoneal 5-FU at low dose (10 mg/kg) or high dose (20 mg/kg). Animals were arranged in 6 groups: RT + low-dose 5-FU (RCT-L), RT + high-dose 5-FU (RCT-H), sham RT + low-dose 5-FU (CT-L), sham RT + high-dose 5-FU (CT-H), RT alone (R), and a control group (sham RT + intraperitoneal saline). Side-to-side colonic anastomoses were constructed from one irradiated and one nonirradiated limb 4 days after radiochemotherapy. Animals were sacrificed 10 days after surgery. RESULTS: Compared to controls, more complications occurred in group RCT-H (50% versus 0%, p = 0.01). Adhesion formation was more intense in groups RCT-H and CT-H (p < 0.001 and p = 0.001, respectively). After therapy, white blood cell counts dropped significantly in all irradiated animals (p < 0.01), and platelet counts decreased significantly in group RCT-H (p = 0.01). No significant differences were noticed in anastomotic bursting pressure when the treated groups were compared to each other or to the control group. CONCLUSIONS: Neoadjuvant radiochemotherapy has no adverse effect on the strength of colonic anastomosis in this rat model. However, the combined RT with high-dose 5-FU does increase operative morbidity and adhesion formation.

Clinical delivery of intensity modulated conformal radiotherapy for relapsed or second-primary head and neck cancer using a multileaf collimator with dynamic control.

BACKGROUND AND PURPOSE: Concave dose distributions generated by intensity modulated radiotherapy (IMRT) were applied to re-irradiate three patients with pharyngeal cancer. PATIENTS, MATERIALS AND METHODS: Conventional radiotherapy for oropharyngeal (patients 1 and 3) or nasopharyngeal (patient 2) cancers was followed by relapsing or new tumors in the nasopharynx (patients 1 and 2) and hypopharynx (patient 3). Six non-opposed coplanar intensity modulated beams were generated by combining non-modulated beamparts with intensities (weights) obtained by minimizing a biophysical objective function. Beamparts were delivered by a dynamic MLC (Elekta Oncology Systems, Crawley, UK) forced in step and shoot mode. RESULTS AND CONCLUSIONS: Median PTV-doses (and ranges) for the three patients were 73 (65-78), 67 (59-72) and 63 (48-68) Gy. Maximum point doses to brain stem and spinal cord were, respectively, 67 Gy (60% of volume below 30 Gy) and 32 Gy (97% below 10 Gy) for patient 1; 60 Gy (69% below 30 Gy) and 34 Gy (92% below 10 Gy) for patient 2 and 21 Gy (96% below 10 Gy) at spinal cord for patient 3. Maximum point doses to the mandible were 69 Gy for patient 1 and 64 Gy for patient 2 with, respectively, 66 and 92% of the volume below 20 Gy. A treatment session, using the dynamic MLC, was finished within a 15-min time slot.

Primary sinonasal mucosal melanoma: three different therapeutic approaches to inoperable local disease or recurrence and a review of the literature.

Sinonasal melanoma is an uncommon disease with a bad prognosis and a high local recurrence rate. The use of radiotherapy in such conditions remains controversial. A review of the literature is presented in an attempt to answer some of the questions regarding therapeutic options. Data on incidence, aetiology, pathology and prognosis are also provided. Case studies are reported of three patients with sinonasal melanoma referred to our department in a relatively short time period and needing radiotherapy as a single treatment modality, using a conformal three-dimensional treatment technique. One patient was also treated with temporary 1251 seeds, while another was treated using intensity modulation. Both intensity modulation and temporary 1251 seeds are feasible techniques, providing satisfactory dose distributions encompassing the tumour volume while sparing critical structures. Surgery remains the treatment of choice for sinonasal melanoma. Radiotherapy should be used postoperatively and is a good alternative in cases of inoperable disease. Adjacent critical structures limit the radiation dose to the tumour area, especially when high fraction doses are used. Therefore, beam intensity modulation and 1251 seeds can be used to increase the tumour dose without exceeding the radiation tolerance of the surrounding structures.

Dose conformation in IMRT for head and neck tumors: which solution to apply?

At Ghent University Hospital, IMRT for head and neck cancer is routinely performed. The desired dose distribution is defined upfront as a range of acceptable doses assigned to each voxel of volumes of interest. It was found important to specify the range of acceptable doses separately to areas of the PTV either in or outside the buildup zone as well as to areas which do or do not intersect with PTV-dose limiting organs at risk (OAR). To avoid high doses at distance from the PTV, the creation of a "surrounding" OAR which is the whole scanned volume minus the PTV was found efficient, especially if inside this OAR, subvolumes were created at increasing distance from the PTV. By specifying inside these subvolumes maximum dose constraints which decreased with distance from the PTV, conformality is secured. The creation of these additional PTV and OAR subvolumes allows comprehensive and unambiguous definition of the range of acceptable doses and thereby avoids user-interactive assignment of weights to the terms of the objective function during optimization. The efficiency of inverse planning is highly improved. Its outcome is predictable, plan evaluation is objective as the plan either does or does not comply with the predefined range of acceptable doses. Accurate reporting of the planned dose distribution is facilitated by description of the dose range to all volumes. The expense of this procedure is modest and lays mostly 1) in the creation of the subvolumes, which can be done semi-automatically by modern image segmentation tools and 2) in the inclusion of constraints to all subvolumes into the objective function.

The single-isocentre treatment of head and neck cancer: time gain using MLC and automatic set-up.

PURPOSE: In this manuscript, we studied the difference in the treatment time required to execute a single-isocentre three-field irradiation of the head and neck, using either tray-mounted cerrobend blocks or a multileaf collimator (MLC) for field shaping and automatic set-up. MATERIALS AND METHODS: A total of twenty consecutive, unselected patients (16 males, four females), were eligible for this study because the dose they were to received was 44 Gy (2 Gy/fraction) to the head, neck and supraclavicular regions. Patients were randomly allocated to one of two treatment groups. The first group (n = 11) was treated on a Philips SL-75 linear accelerator (SL-75), using 5 MV photons and tray-mounted cerrobend blocks. The second group (n = 9) was treated on a Philips SL-25 linear accelerator (SL-25-MLC), using 6 MV photons and a MLC. Patients of the second group were treated using the automatic set-up facility of the SL-25-MLC, without entering the treatment room between consecutive fields. RESULTS: Overall treatment time was significantly shorter on the SL-25-MLC than on the SL-75 (P < 0.0001). The difference in total treatment-execution time was in the range of 157 s per treatment session. The largest difference was observed in the set-up time. There was an average of a 125 s time gain per treatment day (P < 0.0001) in favour of the SL-25-MLC. CONCLUSIONS: Compared to tray-mounted cerrobend blocks, a MLC and automatic set-up results in a significant time advantage when a single isocentre technique is used to treat head and neck cancer.

Screening and early diagnosis of prostate cancer: an update.

Screening for prostate cancer has become a main controversial topic. First the currently used screening tools, PSA (Prostate Specific Antigen) and DRE (Digital Rectal Examination) have a low accuracy in the prediction of prostate cancer. Second, the benefit of screening in reducing the prostate cancer related mortality was not uniformly shown in older screening studies and there was concern about the risk of overdiagnosis and over-treatment of insignificant prostate cancers. Very recently, 3 major prospective, randomized screening studies have been published. This paper aims to provide an overview how the performance of the current screening tools can be ameliorated and evaluates the recently published screening studies with practical considerations for future screening protocols.