Dataset Information

Modeling early haematologic adverse events in conformal and intensity-modulated pelvic radiotherapy in anal cancer.

ABSTRACT:

Background and purpose

To determine if there are differences between dose to pelvic bone marrow (PBM) using intensity modulated radiotherapy (IMRT) under UK guidance versus conformal radiotherapy (CRT) per ACT II protocol and if differences translate to rates of early haematological adverse events grade 3 or greater (HT3+).

Methods and materials

Two groups of 20+ patients, treated under IMRT and CRT regimes respectively, were identified. All patients underwent weekly blood cell count: haemoglobin (HgB), white cell count (WCC), absolute neutrophil count (ANC) and platelets (plats). Percent volume of PBM and sub structures receiving 5-25 Gy were tested for statistical significance. Regression models were used to test for correlation to blood counts. NTCP modeling was also performed.

Results

PMB dose metrics showed a significant increase in the IMRT group. Regression analysis showed iliac and lumbosacral PBM dose metrics to associate with reduced nadir ANC and WCC. NTCP at HT3+ was 0.13 using IMRT relative to 0.07 using CRT (p<0.05).

Conclusion

Whilst this is a relatively small retrospective study and lacks information on the distribution of active PBM, IMRT treatment has been shown to significantly increase PMB irradiation. PBM dose metrics have been shown to be predictive of WCC and ANC suppression. NTCP modeling predicts much high risk of HT3+. Paradoxically, actual rates of HT3+ were comparable suggesting that differences in the distributions of dose metrics maybe a significant factor and/or that there are insufficiency in the NTCP modeling.

SUBMITTER: Robinson M

PROVIDER: S-EPMC4678285 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature

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Publications

Modeling early haematologic adverse events in conformal and intensity-modulated pelvic radiotherapy in anal cancer.

Robinson Maxwell M Sabbagh Ahmed A Muirhead Rebecca R Durrant Lisa L Van den Heuvel Frank F Hawkins Maria M

Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology 20150922 2

<h4>Background and purpose</h4>To determine if there are differences between dose to pelvic bone marrow (PBM) using intensity modulated radiotherapy (IMRT) under UK guidance versus conformal radiotherapy (CRT) per ACT II protocol and if differences translate to rates of early haematological adverse events grade 3 or greater (HT3+).<h4>Methods and materials</h4>Two groups of 20+ patients, treated under IMRT and CRT regimes respectively, were identified. All patients underwent weekly blood cell co ...[more]

PMID: 26409831

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Project description:PurposeAlthough 3-dimensional conformal radiotherapy (3D-CRT) is the worldwide standard for the treatment of esophageal cancer, intensity modulated radiotherapy (IMRT) improves dose conformality and reduces the radiation exposure to normal tissues. We hypothesized that the dosimetric advantages of IMRT should translate to substantive benefits in clinical outcomes compared with 3D-CRT.Methods and materialsAn analysis was performed of 676 nonrandomized patients (3D-CRT, n=413; IMRT, n=263) with stage Ib-IVa (American Joint Committee on Cancer 2002) esophageal cancers treated with chemoradiotherapy at a single institution from 1998-2008. An inverse probability of treatment weighting and inclusion of propensity score (treatment probability) as a covariate were used to compare overall survival time, interval to local failure, and interval to distant metastasis, while accounting for the effects of other clinically relevant covariates. The propensity scores were estimated using logistic regression analysis.ResultsA fitted multivariate inverse probability weighted-adjusted Cox model showed that the overall survival time was significantly associated with several well-known prognostic factors, along with the treatment modality (IMRT vs 3D-CRT, hazard ratio 0.72, P<.001). Compared with IMRT, 3D-CRT patients had a significantly greater risk of dying (72.6% vs 52.9%, inverse probability of treatment weighting, log-rank test, P<.0001) and of locoregional recurrence (P=.0038). No difference was seen in cancer-specific mortality (Gray's test, P=.86) or distant metastasis (P=.99) between the 2 groups. An increased cumulative incidence of cardiac death was seen in the 3D-CRT group (P=.049), but most deaths were undocumented (5-year estimate, 11.7% in 3D-CRT vs 5.4% in IMRT group, Gray's test, P=.0029).ConclusionsOverall survival, locoregional control, and noncancer-related death were significantly better after IMRT than after 3D-CRT. Although these results need confirmation, IMRT should be considered for the treatment of esophageal cancer.

Project description:Although a large number of influential studies that have been conducted worldwide on locally advanced esophageal cancer (EC) have employed the treatment modality of three-dimensional conformal radiotherapy (3D-CRT), an advanced as well as highly conformal technology known as intensity-modulated radiotherapy (IMRT) has attracted increasing attention from the radiotherapy research community. This is because of the clear advantages of IMRT, including decrease in radiation dose that reaches critical cardiopulmonary organs. These two treatment modalities need to be investigated with regard to their effect on local control rate and patient survival. In addition, related clinical factors also need to be explored. Data from a total of 431 patients with locally advanced EC, who underwent radiation therapy between January 1, 2010 and December 31, 2013, were included in the present study. Two hundred and ninety-three patients received 3D-CRT, while 138 patients received IMRT. We constructed propensity score matches to make the two groups be comparable (136 patients in 3D-CRT group and 138 patients in IMRT group. Kaplan-Meier analysis was conducted to evaluate the endpoint of overall survival (OS). A Cox proportional hazards model was employed to analyze the relationship between the associated factors and the outcomes via univariate and multivariate approaches. The mean follow-up period was 36.2 months, and the median follow-up period was 23 months. For the IMRT group, the median OS was 31 months, and the 1-, 3-, and 5-year OS rates were 70.3%, 50.0%, and 42.8%, respectively, while for the 3D-CRT group, the median OS was 22 months, and the 1-, 3-, and 5-year OS rates were 63.2%, 41.0%, and 35.4%, respectively (p < 0.05). The univariate analysis revealed that quit drinking, chemotherapy, and concurrent chemotherapy were significant risk factors for the prognosis of EC (p < 0.05), as well as the radiation therapy technique used (p=0.052). The multivariate analysis indicated that chemotherapy and quit drinking were independent predictive factors for OS. OS is found to be significantly better in the IMRT group, compared with that of the 3D-CRT group. Even though these outcomes need further validation, IMRT should be considered preferentially as a therapeutic option for EC, in combination with chemotherapy and persuading patients to quit drinking.

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Project description:AimsNode-positive bladder cancer (NPBC) carries a poor prognosis and has traditionally been treated palliatively. However, surgical series suggest that a subset of NPBC patients can achieve long-term control after cystectomy and lymph node dissection. There is little published data regarding the use of radiotherapy to treat NPBC patients. This is in part due to concerns regarding the toxicity of whole-pelvis radiotherapy using conventional techniques. We hypothesised that, using intensity-modulated radiotherapy (IMRT), the pelvic nodes and bladder could be treated within a radical treatment volume with acceptable toxicity profiles.Materials and methodsThe Intensity-modulated Pelvic Node and Bladder Radiotherapy (IMPART) trial was a phase II single-centre prospective study designed to assess the feasibility of delivering IMRT to treat the bladder and pelvic nodes in patients with node-positive or high-risk node-negative bladder cancer (NNBC). The primary end point was meeting predetermined dose constraints. Secondary end points included acute and late toxicity, pelvic relapse-free survival and overall survival.ResultsIn total, 38 patients were recruited and treated between June 2009 and November 2012; 22/38 (58%) had NPBC; 31/38 (81.6%) received neoadjuvant chemotherapy; 18/38 (47%) received concurrent chemotherapy; 37/38 (97%) patients had radiotherapy planned as per protocol. Grade 3 gastrointestinal and genitourinary acute toxicity rates were 5.4 and 20.6%, respectively. At 1 year, the grade 3 late toxicity rate was 5%; 1-, 2- and 5-year pelvic relapse-free survival rates were 55, 37 and 26%, respectively. The median overall survival was 1.9 years (95% confidence interval 1.1-3.8) with 1-, 2- and 5-year overall survival rates of 68, 50 and 34%, respectively.ConclusionDelivering IMRT to the bladder and pelvic nodes in NPBC and high-risk NNBC is feasible, with low toxicity and low pelvic nodal recurrence rates. Long-term control seems to be achievable in a subset of patients. However, relapse patterns suggest that strategies targeting both local recurrence and the development of distant metastases are required to improve patient outcomes.

Dataset Information

Modeling early haematologic adverse events in conformal and intensity-modulated pelvic radiotherapy in anal cancer.

Background and purpose

Methods and materials

Results

Conclusion

Publications

Modeling early haematologic adverse events in conformal and intensity-modulated pelvic radiotherapy in anal cancer.

Similar Datasets

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