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Objective:To comprehensively evaluate the effects of different bolus usages in postmastectomy intensity-modulated radiotherapy (PM-IMRT) on doses.Methods:Fifty patients receiving PM-IMRT at Fudan University Shanghai Cancer Center from April to October 2021 were retrospectively studied. The planning target volume (PTV) was divided into four parts, namely chest wall (CW), internal mammary node, retained axillary lymph node, and supraclavicular node. The prescription dose was 50 Gy/25 fractions. Three PM-IMRT plans applying boluses with different thicknesses (3, 5 and 10 mm) were designed for each patient. The effects of different thicknesses and usage frequencies of boluses on PTV coverage, high dose volume of the CW skin, and dose to surrounding normal tissues were comprehensively evaluated.Results:When boluses were applied throughout the PM-IMRT, the PTV V95% of plans applying 10 mm-thick boluses was lower than that of plans applying 3 and 5 mm-thick boluses ( F=3.340, P < 0.05), the CI of plans applying 3 mm-thick boluses was higher than that of plans applying 5 and 10 mm-thick boluses ( F = 50.05, P < 0.05), and there was no statistically significant differences in the skin V105% and V110% of three plans( P > 0.05). Both PTV V95% and skin V105% were reduced with a decrease in the usage frequency of boluses. At a frequency of 20, PTV V95% decreased slightly (< 1%), while skin V105% decreased sharply to nearly half of the original values. At a frequency of 15, the PTV V95%, CI, and HI in the three plans showed no statistically significant dosimetric differences ( P > 0.05). The PTV Dmax of plans applying 3 mm-thick boluses was lower than that of plans applying 5 and 10 mm-thick boluses ( F = 9.21, P < 0.05). As for the dose to surrounding normal tissues, different bolus thicknesses and frequencies had negligible effects on doses to heart and lung, causing little different biological effects. Conclusions:For PM-IMRT, different bolus thicknesses have similar effects on doses to the PTV, skin, heart, and lung. Bolus usage frequency, rather than thickness, was the major factor determining the PTV coverage and the dose to CW skin.
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Objective To explore the importance of head fixation in chest wall field combined with supraclavicular field radiotherapy for breast cancer by comparing the displacement error and dosimetric differences caused by multi-functional body board and breast bracket.Methods Thirty patients with breast cancer were randomly divided into groups A and B.In group A,patients were fixed with multi-functional body board and head thermoplastic film.In group B,patients were fixed with traditional breast brackets.Each patient received CBCT scan before and after radiotherapy.Both setup errors and intra-fractional displacements in the x-,y-and z-axis,V100 and V95 were calculated.Statistical analyses were performed using the independent sample t-test.Results The displacement errors in groups A and B before and after radiotherapy were (1.24± 0.42),(1.71± 0.61) and (2.25± 1.04) mm vs.(3.67± 2.05),(3.78± 1.74),(4.65±2.66) mm in the x-,y-and z-axis,respectively (P=0.033,0.027,0.020).The intra-fractional displacements in groups A and B were (1.10±0.66),(1.13±0.59),(1.11 ±0.62) mm vs.(2.48±0.88),(2.21 ±0.98),(3.53±2.01) mm in the x-,y-and z-axis,respectively (P=0.030,0.021,0.013).The V100 in groups A and B were (94.27± 3.20) ％ and (99.08± 0.60) ％ (P =0.065),and (89.48± 4.70) ％ and (96.53± 2.50) ％ for V95 (P =0.002),respectively.Conclusion The risk of displacement error is significantly reduced using multi-functional body board,which enhances the accuracy of radiation dose in chest wall and supraclavicular fields of breast cancer patients.
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Objective To investigate the treatment outcome of patients with localized soft tissue sarcoma (STS) and related prognostic factors,with a focus of the role of postoperative radiotherapy in the treatment of STS.Methods A retrospective analysis was performed for the clinical data of 203 STS patients who underwent organ preservation surgery in Fudan University Shanghai Cancer Center from July 2000 to July 2010.Of all the patients,76(37.4％) received adjuvant radiotherapy,which was delivered via anterior-posterior parallel opposed fields at a dose of 45-70 Gy.The Kaplan-Meier method was used to calculate survival rates,the log-rank test was used for survival difference analysis,and the Cox proportional hazards model was used for multivariate analysis.Results The follow-up rate was 100％.The 5-year overall survival (OS) rate,local failure-free survival rate,and distant metastasis-free survival rate were 69.1％,69.2％,and 68.0％,respectively.The multivariate analysis showed that pathological subtype,tumor size,resection margin status,and postoperative radiotherapy were influencing factors for OS.Among these factors,postoperative radiotherapy was associated with a significantly reduced risk of local recurrence in STS patients (HR=0.327,95％ CI 0.177-0.605,P=0.000) and a significantly increased OS rate (HR=0.489,95％ CI 0.266-0.897,P=0.021).Conclusions Postoperative radiotherapy can reduce local recurrence and improve OS in patients with localized STS,and further studies are needed to clarify its role.
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Objective The frequency and the anatomic distribution of involved regional nodes in recurrent and locally advanced breast cancer were analyzed, in order to evaluate the rational of conventional regional node radiation technique and provide evidence for target definition of breast cancer . Methods Patients with recurrent or locally advanced breast cancer who were treated in our hospital from August 2003 to December 2009 were included in this study. 111 patients had contrast enhanced chest CT images of the whole regional nodes before treatment. The regional nodes were categorized into 8 anatomical substructures including medial and lateral supraclavicular nodes ( SC-M, SC-L), axilla nodes ( ALN )- Ⅰ , Ⅱ , Ⅲ,infraclavicular nodes (IFN), Rotter's nodes (RN) and internal mammary nodes (IMN). The frequency of involvement and anatomical distribution of the involved nodes on CT images were analyzed. Results A total of 111 patients were enrolled this study and 199 anatomical substructures with involved nodes were identified. The frequency of involvement were :SC-M 33, SC-L 21, ALN- Ⅰ 30, ALN-Ⅱ 25, ALN-Ⅲ + IFN 35, RN 27, IMN 28. Supraclavicular region and axilla were the most frequently involved area (72. 3% ).The average depth of the SC-M and SC-L nodes was 33.48 mm ± 10. 57 mm and 45.62 mm ±20. 45 mm,and 51.5% and 71.4% of the SC-M and SC-L nodes were located more than 3 cm deep from the skin. The axilla nodes were located cranial and caudal to the axillary vein in 5 and 20 locally advanced breast cancer patients and in 64 and 28 patients who received prior axillary dissection. The majority of involved IMN was located within the first 3 intercostal spaces (26/28). The average distance between the center of involved IMN and chest skin was 24. 23 mm ± 10. 28 mm. The average distance between the center of involved IMN and midline of the body was 29. 38 mm ±6. 7 mm. The center of involved IMN was 6.19 mm ±5.73 mm lateral and 5.73 mm ± 4. 56 mm posterior to the internal mammary vessels. Conclusions Conventional field design is unlikely to provide sufficient dose to the entire risk region because of individual differences.Individualized treatment planning based on CT would become feasible with increasing knowledge of natural risk of nodal involvement.
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Objective To determine the change of tumor bed volume during whole breast irradiation by repeated computed tomography scanning and to analyze the dosimetric impact of boost-planning on different CT images. Methods From July 2008 to Jan 2009, sixteen patients with early-stage breast cancer underwent breast conservative surgery (BCS) were enrolled in the study. All patients received whole breast irradiation and tumor bed boost, no adjuvant chemotherapy was given. Two additional CT scans were acquired in addition to the planning CT ( CT1 ), one in the course of radiotherapy ( CT2 ) and the other before the boost (CT3). Tumor beds were contoured in all CT images. Three-dimensional conformal radiotherapy planning for tumor bed boost was done on CT1 and CT3 respectively. Results The mean tumor bed volume on CT1, CT2 and CT3 were 49.5 cm3, 25.6 cm3 and 22. 2 cm3 ( F = 5. 63, P = 0. 007 ),respectively. Further analysis found statistically significant difference between CT1 and CT2 ( q = 0. 03, P =0. 010), CT1 and CT3 ( q = 0. 01, P = 0. 004), but not between CT2 and CT3 ( q = 1.00, P = 0. 333 ). The average reduction of tumor bed volume from CT1 to CT3 was 43.4%. A reduction of 20% or above was found in 88% of the patients ( n = 14), 50% or above in 38% of the patients (n = 6). In the boost-planning, the volume of the ipsilateral breast receiving 100% prescribed dose (V100%) on CT1 and CT3 was 183.5 cm3 and 144. 5 cm3, respectively ( t = 3.06, P = 0. 008 ). Conclusions Volume of tumor bed is dynamically reduced in the course of whole breast irradiation after BCS, with more important reduction in the early weeks after the beginning of irradiation. A second CT scan before tumor bed boost is warranted.
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Radiotherapy plays an important role in breast cancer management after mastectomy, breast reconstruction was much more accepted by patients after mastectomy. The impact of radiotherapy on breast reconstruction are commonly concerns by radiation oncologist, breast surgeon and plastic surgeon. This article reviewed the timing and method of reconstruction in patents who underwent breast reconstruction after mastectomy,and the negative impact of radiotherapy on cosmetic result. We also analysed the impact of reconstruction on radiation design and the most appropriate timing and method of reconstruction in different settings of radiotherapy.