Dose distribution of the brain tissue associated with cognitive functions in high-grade glioma patients

PurposeThe purpose of this prospective dosimetric study was to assess the dose distribution regarding the brain areas implied in cognitive functions using two approaches: volumetric modulated arc therapy (VMAT) and helical tomotherapy (HT).Patients and methodsThirty-seven patients were treated using a dual-arc VMAT approach for supratentorial glioblastoma between 2016 and 2018. The total dose of 60 Gy in 30 daily fractions was administered to the planning target volume (PTV). The brain structures that play an important role in cognitive physiology, such as the hippocampi, corpus callosum, cerebellum, subventricular zones (SVZ), were delineated. For each patient, a new treatment plan in HT was determined by a second medical physicist in a blindly fashion according to the same dose constraints and priorities. Statistical analyses were performed using the Wilcoxon-signed rank test.ResultsConformity indexes remained similar with both techniques. The mean values were 0.96 (0.19–1.00) for VMAT and 0.98 (range, 0.84–1.00) for HT, respectively (P = 0.73). Significant D_50% reductions were observed with VMAT compared to HT: 14.6 Gy (3.8–28.0) versus 17.4 Gy (12.1–25.0) for the normal brain (P = 0.014); 32.5 Gy (10.3–60.0) versus 35.6 Gy (17.1–58.0) for the corpus callosum (P = 0.038); 8.1 Gy (0.4–34.0) versus 12.8 Gy (0.8–27.0) for the cerebellum (P < 0.001), respectively.ConclusionThe VMAT approach seemed to improve the sparing of the key brain areas implied in cognitive functions without jeopardizing PTV coverage.     

Irradiation axillaire prophylactique « de diffusion » dans le cancer du sein — revue de la littérature

PurposeIn breast cancer, radiotherapy is an essential component of the treatment. However, indications of irradiation of the internal mammary chain and axillary area are debatables. Axillary recurrence in patients with invasive breast carcinoma remains an issue. Currently, the substitution of axillary lymph node dissection by sentinel node biopsy leads to revisit the role of axillary irradiation. Breast irradiation including level I, II and III might decrease the risk of axillary recurrence.Material and methodsA literature search was performed in PubMed and the Cochrane library to identify articles publishing data regarding dose-volume analysis of axillary levels in breast irradiation aiming to determine the potential therapeutic implications.ResultsEleven articles were retained. A total of 375 treatment plans were analyzed. The results concerning the irradiation technique, initial dose prescribed to breast, delineated volumes and dose received at axillary levels were heterogeneous. The average dose delivered to axilla levels I–III with 3D-conformal radiotherapy using standard fields were between 24 Gy and 43.5 Gy, 3 Gy and 32.5 Gy and between 1.0 Gy and 20.5 Gy respectively. The average doses delivered to axilla levels I–III with 3D-conformal radiotherapy using high tangential fields were between 38 Gy and 49.7 Gy, 11 Gy and 47.1 Gy and 5 Gy 38.7 Gy, 32.1 Gy and 5 Gy (result available for only one study) respectively. Finally, the average doses delivered to axilla levels I–III with intensity modulated radiation therapy were between 14.5 Gy and 42.6 Gy, 3.4 Gy and 35 Gy and between 1.2 Gy and 25.5 Gy respectively.ConclusionsIncidental axillary dose seems insufficient to be therapeutic regardless of the irradiation technique. There are meaningful differences between intensity modulated radiation therapy and 3D-conformal radiotherapy.     

Radiothérapie postopératoire des carcinomes médullaires de la thyroïde à haut risque de rechute locorégionale

PurposeTo assess the outcome of locally advanced medullary thyroid carcinoma treated with surgery and adjuvant external beam radiotherapy.Patients and methodsTwenty-nine consecutive patients with non-metastatic medullary thyroid carcinoma treated in our institution between January 1995 and December 2012 were retrospectively evaluated. All underwent curative-intended optimal surgery, followed by external beam radiotherapy because of high risk of locoregional relapse. Twelve patients were stage III, 16 IVa and 1 IVb. Positive surgical margins were present in 11 cases (10 R1 and 1 R2). Median and average preradiotherapy serum calcitonin were 141 pg/mL and 699 pg/mL, respectively. Fourteen patients received 3D-conformal radiotherapy and 15 received intensity-modulated radiotherapy. Median prescribed dose was 63 Gy to the high-risk volumes and 54 Gy to the low-risk volumes. Treatment was delivered in 30 fractions. The median gap between surgery and radiotherapy was 1.9 months. Median follow-up was 76.4 months.ResultsKaplan-Meier estimates of 5-year locoregional relapse-free survival and overall survival were 79 and 96 %, respectively. Among the five locoregional relapses, two were related to a macroscopic metastatic cervical lymph node that was unfortunately not removed during the lymphadenectomy. Eight of ten patients with microscopic positive margins (R1) were controlled regarding the thyroidectomy bed. Eight patients had normal serum calcitonin after external beam radiotherapy, of whom only one developed a locoregional relapse during follow-up. Regarding the 21 patients with persistent positive serum calcitonin after treatment, only ten developed a macroscopic locoregional or distant relapse. One grade III and no grade IV acute morbidity were reported. Fifteen patients reported grade II chronic morbidity and no grade III/IV.ConclusionMaximal surgery followed by adjuvant external beam radiotherapy as a treatment for locally advanced medullary thyroid carcinoma provides a high rate of long-term locoregional control and overall survival with limited toxicity. Postoperative external beam radiotherapy should be considered when patients present features indicating a high risk of locoregional relapse.     

Irradiation mammaire locorégionale gauche avec modulation d’intensité rotationnelle et inspiration profonde : comparaison dosimétrique

PurposeAdjuvant left-sided breast cancer locoregional radiotherapy can be accounted for long-term cardiac toxicity. The deep inspiration breath hold techniques can reduce cardiac doses. Only a few studies have investigated rotational intensity-modulated radiotherapy with deep inspiration breath hold.Material and methodsWe conducted a dosimetric study comparing rotational intensity-modulated radiotherapy in free breathing with deep inspiration breath hold for irradiation of left breast cancer and locoregional lymph nodes. Doses to organs at risk were compared, as well as doses to coronary arteries, left anterior descending coronary artery region, and aortic valve.ResultsThe data from nine patients were included in the study. Treatment plans were comparable for target volumes. The deep inspiration breath hold delivery technique, compared with free breathing, reduced radiation dose to the heart (mean dose 4.8 Gy vs. 6.6 Gy, p = 0.008; dose in 2% of the volume 16.8 Gy vs. 23.3 Gy, p = 0.008; volume receiving 25 Gy 0.8% vs. 2,2%, p = 0.008; volume receiving 30 Gy 0.4% vs. 1.2%, p = 0.009), as well as to the right coronary artery (mean dose 6 Gy vs. 8.9 Gy, p = 0.028), to the left anterior descending artery (mean dose 9.6 Gy vs. 14.6 Gy, p = 0.021), to the left anterior descending coronary artery region (dose in 2% of the volume 17.4 Gy vs. 24.6 Gy, p = 0.021), and to the aortic valve (mean dose 4.8 Gy vs. 7 Gy, p = 0.028). Other doses to organs at risk were similar.ConclusionRotational intensity-modulated radiotherapy with deep inspiration breath hold is associated with better sparing of the heart, on the right and left anterior descending coronary arteries, and on the aortic valve, compared with free breathing techniques, for adjuvant left breast cancer locoregional irradiation.     

The efficacy of hypofractionated radiotherapy (HFRT) with concurrent and adjuvant temozolomide in newly diagnosed glioblastoma: A meta-analysis

PurposeThe efficacy of hypofractionated radiotherapy (HFRT) in glioblastoma (GBM) without age restrictions remains unclear. The aim of this meta-analysis is to access the survival outcomes of HFRT in these patients.MethodsA comprehensive electronic literature search of PubMed, Web of Science and Cochrane Library was conducted up to June 1, 2020. The main evaluation data were the overall survival (OS) rate at 12 months and 24 months and the progression-free survival (PFS) rate at 6 and 12 months. The secondary evaluation data was the incidence of radionecrosis and adverse events. The study was performed using R “meta” package.ResultsEleven studies met the inclusion criteria, which totally contained 484 participants. The 12-month OS and 24-month OS rate of HFRT in GBM were 71.3% and 34.8%, while the 6-month PFS and 12-month rate were 74.0% and 40.8%. Compared to low-BED (biological equivalent dose) schedules (< 78 Gy), high-BED schedules may increase survival benefit both in PFS-6 (P = 0.003) and PFS-12 (P = 0.011), while the difference did not show on OS. Different dose per fraction had no significant effect on both OS and PFS. Incidence of radionecrosis was 14.2%. Although the overall incidence of adverse reactions cannot be quantified, the toxicity of HFRT was acceptable.ConclusionsCompared with survival data for standard treatment, HFRT seemed to improve overall survival and progression-free survival, while high BED schedules may future increase benefit on PFS. Meanwhile, the toxicity of HFRT was tolerable. Further randomised controlled clinical studies are needed to confirm these findings.     

Toxicity and early clinical outcomes in cervical cancer following extended field helical tomotherapy to para-aortic lymph nodes

PurposeTo evaluate toxicity and early disease outcome among patients treated for cervical cancer with extended-field helical tomotherapy to the para-aortic nodes.Patients and methodsThirty-eight patients (International Federation of Gynecology and Obstetrics [FIGO] stage IB2–IVA) from four institutions received extended-field helical tomotherapy and were retrospectively evaluated. All had nodal disease. Para-aortic lymph nodes were involved in 31 patients. Patients were assessed for toxicity using version 4 of the National Cancer Institute's common terminology criteria for adverse events. Survival curves were plotted using Kaplan-Meier estimates.ResultsAll patients underwent radiation to the tumor region (median dose: 45 Gy; range: 44–66 Gy), pelvic lymph nodes and para-aortic lymph nodes (median dose: 45 Gy; range: 44–60 Gy). The median dose to positive lymph nodes was 55 Gy (range: 45–65 Gy). All received platinum-based chemotherapy (31 concurrently). The median follow-up was 15 months. Acute toxicity events observed included one patient with grade 5 febrile neutropenia, 11 patients (29%) with grade 3 hematologic complications. Grades 3–4 gastrointestinal and genitourinary toxicities occurred in six (16%) and four (11%) patients, respectively. Three patients had grade 3 pelvic pain (8%). The 6- and 18-month overall survival rates were 94.7 and 63.9%, respectively. The 18-month locoregional control, disease-free survival, and late grade 3 toxicity rates were 60.2, 43.3 and 7.3%, respectively.ConclusionExtended-field helical tomotherapy was associated with low rates of acute gastrointestinal and genitourinary toxicities with early survival and locoregional control similar to other published series.     

Intensity-modulated radiotherapy prolongs the survival of patients with nasopharyngeal carcinoma compared with conventional two-dimensional radiotherapy: A 10-year experience with a large cohort and long follow-up

BackgroundTo evaluate the survival benefit of intensity-modulated radiotherapy (IMRT) compared with conventional two-dimensional radiotherapy (2D-CRT) in nasopharyngeal carcinoma (NPC) using a large cohort with long follow-up.MethodsWe retrospectively analysed 7081 non-metastatic NPC patients who received curative IMRT or 2D-CRT from February 2002 to December 2011.ResultsOf the 7081 patients, 2245 (31.7%) were administered IMRT, while 4836 (68.3%) were administered 2D-CRT. At 5 years, the patients administered IMRT had significantly higher local relapse-free survival (LRFS), loco-regional relapse-free survival (LRRFS), progression-free survival (PFS) and overall survival (OS) (95.6%, 92.5%, 82.1% and 87.4%, respectively) than those administered 2D-CRT (90.8%, 88.5%, 76.7% and 84.5%, respectively; p < 0.001). The distant metastasis-free survival (DMFS) was higher for IMRT than 2D-CRT, with borderline significance (87.6% and 85.7%, respectively; p = 0.056). However, no difference was observed between IMRT and 2D-CRT in nodal relapse-free survival (NRFS; 96.3% and 97.4%, respectively; p = 0.217). Multivariate analyses showed that IMRT was an independent protective prognostic factor for LRFS, LRRFS and PFS, but not NRFS, DMFS or OS.ConclusionsIMRT provided an improved LRFS, LRRFS and PFS in both the early and advanced T classifications and overall stage for non-disseminated NPC compared with 2D-CRT. However, no significant advantage was observed in NRFS, DMFS or OS when IMRT was used.     

Dosimetric comparison of four high performance techniques for irradiation of breast cancer patients

PurposeThe use of IMRT for the treatment of breast cancer has been growing considerably in our institution since 2009. Alternatively, helical tomotherapy (HT) using a field width of 2.5 and 5 cm (HT_FW_5), volumetric-modulated arc therapy (VMAT), or proton therapy with pencil-beam scanning (PT-PBS) have also been used to reduce treatment duration or optimize organ-at-risk (OAR) sparing. The purpose of this study was to compare the 4 treatment modalities available at our site.Patients and methodsWe studied 10 patients treated for breast cancer with lymph node involvement. The prescribed dose was 51.8 Gy to the breast with a simultaneous integrated boost up to 63 Gy, and 50.4 Gy to lymph nodes in 28 fractions. The CTV was delineated according to ESTRO Guidelines. Dosimetric planning in routine clinical practice was performed using HT_FW_2.5. The approved clinical plan was compared to the 3 other plans. Dosimetric goals for PTV coverage were D95% ≥ 95% and D2% ≤ 107% of the prescribed dose. Mean and maximum doses to OAR were recorded.ResultsHT_FW_5 and VMAT plans ensure equivalent or even better PTV coverage compared to the initial clinically approved plan but at the cost of poorer OAR sparing. PT_PBS plans showed that an excellent PTV coverage can be maintained with significantly lower doses to OAR.ConclusionHT_FW_5 and VMAT plans allow a significant reduction of treatment duration and can be a good alternative to HT_FW_2.5 for specific populations. HT_FW_2.5 could be chosen for patients at higher risk of side effects. In addition, PT_PBS should be considered in the near future as it has been shown to have a major potential benefit to lower the risk of side effects with the same level of PTV coverage.     

Cancer du sein traité exclusivement par l’association d’une irradiation externe et d’une curiethérapie exclusive : résultats à long terme

PurposeTo report retrospective long-term results of historical experience of breast radiotherapy (RT) including external beam radiotherapy (EBRT) followed by low dose rate (LDR) brachytherapy.Patients and methodsBetween 1971 and 1983, at our service 474 breast cancer patients underwent exclusive conserving radiotherapy treatment. The RT included an initial external irradiation followed by interstitial LDR brachytherapy (37 Gy) to the residual tumour. The local regional nodes received 47.5 Gy followed by a 15 Gy boost delivered to the mammary nodes internal (IMN) and 25 Gy axilla.ResultsMedian follow-up was 139 months (8–342). There were 40 T1, 356 T2, and 78 T3. Local recurrences (LR) were observed in 20% of cases. The rate of recurrences free at 5, 10, 15 and 20 years were 86%, 77%, 73% and 67% respectively. At 5, 10, 15 and 20-year, the disease-free survival rates were 63%, 42%, 32% and 24%. Overall survival rates at 5, 10, 15 and 20-years were 75%, 53%, 34% and 25% respectively.ConclusionAlthough the historical retrospective character of these series, it is interesting to have this experience and to analyse it according to our new knowledge and advances. The described technique was a standard for many years and could be still used in some cases.     

Chimioradiothérapie exclusive pour cancer de l’œsophage : comparaison entre 66 Gy et 50 Gy,une étude rétrospective

PurposeTo compare the influence of radiation dose, high dose versus standard dose, on survival for patients with esophageal carcinomas treated with definitive radiochemotherapy.Patients and methodsBetween 2003 and 2006, 143 consecutive patients with squamous-cell carcinoma and adenocarcinoma, clinical stage I to IVA, treated in two different institutions were retrospectively reviewed, 83 patients had received more than 50.4 Gy, median dose 66 Gy (50.7–72 Gy) and 60 less than or equal to 50.4 Gy, median dose 50 Gy (38–50.4 Gy).ResultsMedian age was higher in high dose group (67.6 versus 61.7 years). Nutritional status and stage were better in high dose group with a lower weight loss (5.1 versus 7.9%), a higher body mass index (25.7 versus 22.9), more N0 patients (60.2 versus 31.7%) and less stage III (27.7 versus 63.3%). Median follow up was 20.8 months (2.8–92.4 months), and 64.9 months (4.2–92.4 months) for the 33 surviving patients. No statistically significant difference was shown for local/locoregional control, disease-free survival. Overall survival at 2-, 3- and 5-year and median survival was respectively 44.7%, 36.8%, 19.1% and 21.2 months in high dose group and 50.8%, 31.6%, 20.7% and 24.6 months in standard dose group (P = 0.9).ConclusionNo difference was found between the two groups in terms of local/distant control and overall survival. A prospective randomised study is needed.     

Tolerance and efficacy of dose escalation using IMRT combined with chemotherapy for unresectable esophageal carcinoma: Long-term results of 51 patients

PurposeThe optimal dose in esophageal cancer patients treated with definitive chemoradiation (CRT) remains debated. We herein report on the dosimetric results, treatment-related toxicities and long-term outcomes of escalated dose up to 60 Gy delivered with intensity-modulated radiotherapy (IMRT).Materials and methodsAll consecutive patients that received a definitive CRT > 50 Gy for an unresectable esophageal carcinoma between 2010 and 2015 were retrospectively evaluated for this study. Methodology included data base search, delayed toxicity grading, statistical testing including frequency analysis and survival analysis.ResultsA total of 51 patients were irradiated for a squamous cell carcinoma (86.3%) or an adenocarcinoma (13.7%). The median age at diagnosis was 62 years. Seven patients were simultaneously irradiated for another synchronous primary tumor. Forty-six patients (90.2%) received concurrent platin-based chemotherapy. The median prescribed doses were 60 Gy (54–66) and 48 Gy (44.8–56) delivered in 30 (27–35) fractions to the high and the low risks PTV respectively. The mean dose delivered to the lungs was 11.4 Gy (IC 95%: 4.8–19.8), the median volumes receiving up to 20 Gy (V20) and 30 Gy (V30) were 13.5% (3.0–46.0) and 4.6% (0.7–19.8) respectively. The mean dose delivered to the heart was 13.9 Gy (IC 95%:0.3–31.3) with a median V40 of 3.3% (0.0–25.0). One treatment-related death occurred within days after RT completion (neutropenic aplasia). After a median follow-up of 2.7 years (95% CI: 1.9–4.3), the 2-year overall survival, disease free survival and loco-regional control rates were 53.6%, 42.0% and 72.8% respectively. Delayed treatment related-toxicities ≤ grade 3 occurred among 25 patients (62.5%) mostly esophageal stricture (79.2%).ConclusionWe demonstrated in this study that dose escalation using IMRT in combination with platin-based chemotherapy as a definitive treatment for esophageal carcinoma is safe and results in higher loco-regional and control survival when compared to previously reported data.     

Salivary glands radiotherapy to reduce sialorrhea in amyotrophic lateral sclerosis: Dose and energy

PurposeThis retrospective study evaluated the effectiveness of salivary gland radiotherapy for reducing sialorrhea in patients with amyotrophic lateral sclerosis (ALS).Patients and methodsFrom August 2001 to February 2008, 21 patients with amyotrophic lateral sclerosis (six men, 15 women; mean age 61.2 years, range 39–81) received external beam radiotherapy for sialorrhea (evaluation by the ALS Functional Rating Scale). All patients had previously received pharmacological treatments with unsatisfactory results or side effects. The mean dose was 19.1 Gy (range 3–48), delivered in five fractions (range 1–16) on 17 days (range 1–77). Eight patients received 3D-conformal and 13 received 2D-conformal radiotherapy. Clinical target volumes included the parotids and submandibular glands (18 patients), submandibular glands and one parotid (one patient), or parotids (two patients). Thirteen patients were treated with 5.5–6 MV photons and eight were treated with 6–15 MeV electrons. A satisfactory salivary response was defined as complete or partial improvement. The median follow up was 10.4 months (range 0.4–26). One patient was lost to follow up.ResultsA positive response was observed in 65% of patients during a mean of 7 months (range 1–23). Four patients (20%) treated with photons and no patients treated with electrons experienced acute toxicity. Half (50%) the patients treated with photons and 87.5% of patients treated with electrons responded positively (P = 0.09). Positive responses were more common with a high total dose (≥ 16 Gy; 78.6%) than a low total dose (< 16 Gy; 33%; P = 0.07). No differences were observed in tolerance (P = 0.27). Age and sex did not impact the response.ConclusionSalivary gland radiotherapy effectively reduced sialorrhea in patients with amyotrophic lateral sclerosis. An adequate compromise between toxicity and efficiency was achieved with 3D-conformal radiotherapy delivered with electrons to parotids and submandibular glands in a total dose of 16 Gy or more (mean: 20 Gy in five fractions).     

Évolution des cancers de l’œsophage : impact de la stratégie thérapeutique

PurposeTo assess the outcome of esophageal cancer according to therapeutic strategy.Patients and methodsOne-hundred and twenty patients with esophageal cancer treated by an association of radiotherapy and chemotherapy and possibly surgery, between 2004 and 2010, were retrospectively studied. The first site of relapse was classified as follows: local (tumour), locoregional (tumour and/or nodal: celiac, mediastinal, sus-clavicular) or metastatic.ResultsWith a 15.7-months (1.4–62) median follow-up, there were 89 deaths and 79 recurrences. Three types of treatments were performed: 50 Gy exclusive chemoradiotherapy (47 patients) or 50 to 65 Gy exclusive chemoradiotherapy (44 patients) or chemoradiotherapy followed by surgery (27 patients). The local first relapse was as much frequent as distant relapse (50 patients). With a-5 cm margin up and down to the tumour, there was only one nodal relapse. Two-year survival was 39.5% (95% confidence interval [IC]: 30.5–40.8) and relapse-free survival was 26.5% (CI: 18.6–35). Multivariate analysis revealed that treatment type and disease stage had a significant impact on survival, relapse-free survival and locoregional control. Compared to exclusive chemoradiotherapy, surgery improved locoregional control (40.2 versus 8.7 months, P = 0.0004) but in a younger population. Despite postoperative mortality, the gain was maintained for distance relapse-free survival (40.2 versus 10 months, P = 0.0147) and overall survival (29.3 versus 14.2 months, P = 0.0088). Compared to 50 Gy chemoradiotherapy, local control was improved if high dose chemoradiotherapy was performed (13.8 versus 7.5 months, P = 0.05) but not overall survival (14.0 versus 15.4 months, P = 0.24).ConclusionMore than one-third relapse is local. Locoregional control is better with high dose chemoradiotherapy. In this study, surgery performed in selected patients only, improved locoregional control, relapse-free disease and overall survival.     

Lumbosacral spine and marrow cavity modeling of acute hematologic toxicity in patients treated with intensity modulated radiation therapy for squamous cell carcinoma of the anal canal

PurposeTo identify various dosimetric parameters of bone marrow cavity that correlate with acute hematologic toxicity (HT) in patients with anal squamous cell carcinoma treated with definitive chemoradiation therapy (CRT).Methods and materialsWe analyzed 32 patients receiving CRT. The whole pelvic bone marrow (PBM) and the lumbosacral spine (LSS) subregion were contoured for each patient. Marrow cavities were contoured using the Hounsfield units (HUs) of 100, 150, 200, and 250 as maximum density threshold levels. The volume of each region receiving at least 5, 10, 15, 20, 30, and 40 Gy was calculated. The endpoint was grade ≥ 3 HT (HT3 +). Normal-tissue complication probability (NTCP) was evaluated with the Lyman-Kutcher-Burman (LKB) model. Maximal likelihood estimate was used to compare the parameter set. Logistic regression was used to test associations between HT and both dosimetric and clinical parameters.ResultsTen patients (31%) experienced HT3 +. While dose to both LSS and PBM significantly predicted for HT3 +, LSS was superior to PBM by logistic regression and LKB modeling. Constrained optimization of the LKB model for HT3 + yielded the parameters m = 0.21, n = 1, and TD₅₀ = 32 Gy for LSS. The NTCP fits were better with the whole bone than with marrow cavity using any HU threshold. Mean LSS doses of 21 Gy and 23.5 Gy result in a 5% and 10% risk of HT3 +, respectively. Mean dose and low-dose radiation parameters (V5, V10, V15, V20) of whole bone or bone cavities of LSS were correlated most significantly with HT3 +.ConclusionsFor predicting the risk of HT3 +, whole-bone contours were superior to marrow cavity and LSS was superior to PBM by LKB modeling. The results confirm PBM and LSS as parallel organs when predicting hematologic toxicity. Recommended dose constraints to the LSS are V10 ≤80%. An LSS mean dose of 23.5 Gy is associated with a 10% risk of HT.     

Bénéfice attendu du curage ganglionnaire et de l’exérèse des vésicules séminales pour diminuer la toxicité de la radiothérapie des tumeurs prostatiques de haut risque

PurposeIn case of pelvic lymph node and seminal vesicle dissection followed by prostate cancer intensity-modulated radiotherapy, the objective of the study was to evaluate the dosimetric benefit of reducing the target volume.Patients and methodsA total of 25 patients with high-risk prostate cancer had surgery first followed by intensity-modulated radiotherapy and androgen deprivation. Four treatment planning were simulated for each patient, based on two CT scans performed before and after surgery. The target volumes were: prostate–seminal vesicles–lymph nodes, prostate–lymph nodes, prostate–seminal vesicles and prostate only. The total dose was 46 Gy in the seminal vesicles and lymph nodes, and 80 Gy in the prostate.ResultsCompared to prostate target volume only, the addition of seminal vesicles and lymph nodes multiplied by a factor of 1.6 and 6.5 the target volume, respectively. Decreasing the target volume from prostate–seminal vesicles–lymph nodes to prostate–seminal vesicles, to prostate only decreased the rectal wall mean dose from 49 Gy to 42 Gy, to 36 Gy, and the risk of late rectal bleeding from 4.4% to 3.2%, to 2.4% (P < 0.05), respectively. The bladder wall mean dose decreased from 51 Gy to 40 Gy, to 35 Gy (P < 0,05), respectively. Not irradiating the lymph nodes decreased the absolute risk of diarrhea by 11%.ConclusionLymph node and seminal vesicle dissection before prostate cancer intensity-modulated radiotherapy allows decreasing moderately the risk of digestive toxicity.     

Dose escalation of three-dimensional conformal radiotherapy for locally recurrent nasopharyngeal carcinoma: a prospective randomised study

AimsTo investigate prospectively the feasibility and efficacy of dose escalation using three-dimensional conformal radiotherapy (3D-CRT) boost technique for locally recurrent nasopharyngeal carcinoma (NPC) in a randomised study.Materials and methodsThirty-six patients with locally recurrent NPC (>6 months interval from previous radical radiotherapy, no cervical lymph-node involvement and no distant metastasis) were enrolled. Treatment included conventional external-beam radiotherapy to 54 Gy, followed by a 3D-CRT boost to the gross tumour region. Patients were randomised to three boost dose levels: 16 Gy, 20 Gy and 24 Gy for groups I, II and III, respectively, with 12 patients in each group. All boost doses were delivered in 4-Gy fractions and 3 fractions per week. Median follow-up was 27 months (range 14–44 months).ResultsThree-year, local-recurrence-free survival rate was significantly higher (72%) for the high-dose group III than for groups I and II (37% and 28%, respectively, P = 0.047). No significant difference was found in the 3-year overall survival rate among the three groups (72%, 59% and 82% for groups I, II and III, respectively). Three-year distant metastases rates were 17%, 0% and 18%, respectively. Skull-base invasion (P = 0.017) and pathology (P = 0.0006) correlated with overall survival. Treatment was well tolerated and no significant difference was observed among the three groups in acute and late toxicities (grade III toxicity is minimal: 17%, 17%, 0% of oral mucositis and 25%, 17%, 17% of nasopharyngeal mucositis in groups I, II, III, respectively, and 8% leukocytopenia only in group II; no grade IV toxicity occurred in any of the groups except for a fatal bleeding in group III).ConclusionsRe-irradiation with high-dose 3D-CRT boost technique results in high local control rate and acceptable toxicity in patients with recurrent NPC. Dose escalation to the boost volume to 78 Gy (54 Gy + 24 Gy boost) results in improved recurrence-free survival compared with lower doses.