soft tissue sarcomas ( stss ) of the extremities are not commonly seen , and usually occurs in less than 1% of all adult tumors , but make up nearly half of all soft tissue sarcomas . symptoms like local pain , neuralgias , or restriction of motor function can result later due to the involvement of nerve bundles , bone , or significant muscular compartment . radiotherapy and surgery have been the standard modalities in the treatment of extremity soft tissue sarcomas . low - grade tumors predominantly have the risk of local recurrence , requiring only adjuvant radiotherapy . on the other hand , most patients with intermediate or high - grade tumors larger than 5 cm in size , develop distant metastases compared to less than 10% in low - grade lesions or less than 5 cm in size [ 3 , 4 ] . adjuvant radiotherapy either used as interstitial brachytherapy or external beam radiotherapy ( ebrt ) has been found to improve local control rates ( lc ) in patients who have undergone limb - sparing resections with level 1 evidence available [ 5 , 6 ] . for completely resected high - grade sarcomas of the extremities , brachytherapy can be used as the sole therapy if the target volume is localized and accessible , as it gives high doses to the tumor bed and extremely low doses to tissues outside the treated volume . data also suggests improved outcome with a combination of brachytherapy ( interstitial ) and ebrt for patients with positive margins [ 8 , 9 , 10 ] . a 48-year - old female patient was referred to the radiotherapy department for post - operative radiotherapy for a soft tissue sarcoma of the right shoulder . she presented with a history of a swelling developed over a six - month period ( size and surgery details are not available ) , for which she subsequently underwent excision but no adjuvant therapy . a year later , the patient developed a 10 cm x 6 cm recurrence , at the same site for which she presented to our institute . a biopsy was done and it reported a low - grade fibrosarcoma , and metastatic workup was negative . the patient was advised surgery followed by adjuvant radiotherapy or surgery , and intra - operative interstitial brachytherapy as either single radiation modality or with external beam therapy . however , because of extensive horizontal spread of tumor and the proximity of humeral head with fears of graft rejection of post - interstitial brachytherapy , the patient was planned for surgery and post - operative radiotherapy . the patient then underwent wide local excision of the tumor and the histopathological review reported dermatofibrosarcoma with an involvement of the deep resected margin . patient has been treated by external beam photon irradiation with 6 mv photons , using ap - pa portals , with mlc blocking for lung shielding and use of bolus over surgical scar to a dose of 40 gy in 20 fractions . after ebrt , a boost with surface mould brachytherapy using a base of thermoplastic immobilizer with wax mould was given ( figures 1 and 2 ) . the patient received brachytherapy boost with dose of 3.5 gy per fraction , twice daily , for seven fractions . patient characteristics upper torso mould used in the first patient with extensive involvement of right shoulder tissue a ) site of mould in the first patient . b ) computed tomography image with mould in place in the first patient a 45-year - old female patient was referred to the radiotherapy department for post - operative radiotherapy for soft tissue sarcoma of left chest wall . she presented with a swelling over the left upper part of the chest in the infra - clavicular region developing over three years , and was operated at another hospital in january 2014 ( size and surgery details are not available ) . a post - surgery histopathological review reported dermatofibrosarcoma protuberans with deep resected margin involved by tumor . the patient was subsequently treated by external beam photon irradiation with 6 mv photons , using conventional ap - pa portals with lung shielding and use of bolus ( of 0.5 cm thickness ) over the surgical scar to a prescribed dose of 40 gy in 20 fractions . this was followed by a boost , with surface mould brachytherapy to a dose of 3.5 gy per fraction , twice daily for 7 fractions ( figure 3 ) . a ) dose color wash and b ) 3d dose reconstruction of treated area in the second patient a 36-year - old male patient has been referred to the radiotherapy department for post - operative radiotherapy of soft tissue sarcoma of the anterior shoulder at left side . he had presented in another hospital with a swelling of the left anterior shoulder over ten months . local examination reported an 8 x 6 cm mass lesion with no nodes or restriction of mobility . the post - surgery histopathological review reported the mass as a low - grade sarcoma with fibro sarcomatous pattern and with involved deep margin . the patient then received external beam radiotherapy with 6 mv , using ap - pa portals with the use of bolus of 0.5 cm over surgical scar to a dose of 44 gy in 22 fractions , followed by a boost with surface mould brachytherapy to a dose of 3.5 gy per fraction twice daily for six fractions . each mould was prepared from a framework of thermoplastic sheet molded to the patient s anatomy , and then covered by thin layer of dental wax . after marking of target volume by the oncologist , the physicist helped to make an initial cut - out with thermoplastic sheet . then the wax was heated in a water heater , and cast in the required shape over the thermoplastic and molded according to local anatomy . the shaped wax mould was approximated to the lesion in the treatment position , matched with lesion surface and local anatomy , edges were trimmed and smoothened . catheters were fixed to the mould , which was then placed on the patient to check the feasibility of placement and target volume coverage ( figure 1 ) . the lesion was then marked with lead wires and computed tomography ( ct)-simulation of the patient in the treatment position was done with mould in place . after ct - simulation , image reconstruction , target volume contouring , and treatment planning was carried out on eclipse ( varian medical systems , palo alto , ca , usa ) tps version 10.0 , and treatment delivery was done on gammamedplusix ( varian medical systems , palo alto , ca , usa ) . the target volume was defined as the volume encompassing the tumor bed with lateral margins of 2 - 2.5 cm and depth of 1 - 1.5 cm . the tumor bed has been identified by comparing pre - operative and post - operative ct / magnetic resonance ( mr ) films , as well as taking into account the surgical scar . the dose was prescribed to 80% , 85% , and 90% isodose lines , respectively , in the three cases in order to cover the depth of 1 - 1.5 cm ( figures 2 , 3 and 4 ) . treatments were delivered twice daily , six hours interval , and review of reactions was done every third day and at the completion . all patients tolerated the mould boost well with skin darkening as observed towards the end of treatment , and grade 2 skin changes seen in the second and third patients . brachytherapy dose ranged from 21 - 24.5 gy in fraction sizes of 3.5 gy , delivered twice daily . brachytherapy part eqd2 of these patients were 24 and 28.6 gy , while total eqd2 of these patients was 68.5 gy in the three cases . biologically equivalent dose for 3 and 10 gy has been also calculated ( table 2 and figure 6 ) in all cases , and the total bed3 dose ( including external beam component ) has been between 119 - 129 gy in all cases . selecting an isodose of 85 - 100% ( figure 7 ) helped in achieving maximal tumor volume coverage , while at the same time , keeping volume of tissue receiving more than 150% ( v150 ) to below 2% and volume of tissue receiving more than 200% ( v200 ) of prescribed dose to below 0.001% . this meant that areas receiving more than 200% of the prescribed dose were limited to the substance of the mould ( table 3 and figure 7 ) . maximum dose to oar was assessed as dose to 2 cc of oar and ranged between 55 - 87% of the prescribed dose with a median dose being 80% ( figure 8) . equivalent dose at 2 gy per fraction , bed3gy / bed10gy  biologically equivalent dose for late effects ( bed3gy ) and for early effects ( bed10gy ) fraction , ebrt  external beam radiation therapy dose volume comparisons ptv  planning target volume , v200%  volume receiving 200% of prescribed dose , v150%  volume receiving 150% of prescribed dose immediate post - radiotherapy skin changes in the third patient biologically equivalent dose ( bed ) of treated cases tissue volume and dose received dose to organ at risk ( head of humerus ) there were no severe skin reactions like ulcers or necrosis ( table 4 ) . at six months of follow - up , none of the patients showed any local or distal recurrence both clinically as well by imaging ( ct thorax and local mri ) . all the cases again reported for follow - up in march 2015 , in august 2015 , in january 2016 , july 2016 , october 2016 , and january 2017 ( figures 9 and 10 ) . by then , patients had completed 36 , 34 , and 32 months uneventful follow - up , respectively . local examination and imaging showed no local recurrence or distant metastases or even no local site late treatment sequelae ( figure 11 , table 4 ) . skin reactions and survival skin changes in the first patient , photograph taken 3 months post - radiotherapy magnetic resonance imaging in the third patient , photograph taken at 27 months post - radiotherapy showing no local recurrence disease free survival ( dfs ) of treated cases a 48-year - old female patient was referred to the radiotherapy department for post - operative radiotherapy for a soft tissue sarcoma of the right shoulder . she presented with a history of a swelling developed over a six - month period ( size and surgery details are not available ) , for which she subsequently underwent excision but no adjuvant therapy . a year later , the patient developed a 10 cm x 6 cm recurrence , at the same site for which she presented to our institute . a biopsy was done and it reported a low - grade fibrosarcoma , and metastatic workup was negative . the patient was advised surgery followed by adjuvant radiotherapy or surgery , and intra - operative interstitial brachytherapy as either single radiation modality or with external beam therapy . however , because of extensive horizontal spread of tumor and the proximity of humeral head with fears of graft rejection of post - interstitial brachytherapy , the patient was planned for surgery and post - operative radiotherapy . the patient then underwent wide local excision of the tumor and the histopathological review reported dermatofibrosarcoma with an involvement of the deep resected margin . patient has been treated by external beam photon irradiation with 6 mv photons , using ap - pa portals , with mlc blocking for lung shielding and use of bolus over surgical scar to a dose of 40 gy in 20 fractions . after ebrt , a boost with surface mould brachytherapy using a base of thermoplastic immobilizer with wax mould was given ( figures 1 and 2 ) . the patient received brachytherapy boost with dose of 3.5 gy per fraction , twice daily , for seven fractions . patient characteristics upper torso mould used in the first patient with extensive involvement of right shoulder tissue a ) site of mould in the first patient . b ) computed tomography image with mould in place in the first patient a 45-year - old female patient was referred to the radiotherapy department for post - operative radiotherapy for soft tissue sarcoma of left chest wall . she presented with a swelling over the left upper part of the chest in the infra - clavicular region developing over three years , and was operated at another hospital in january 2014 ( size and surgery details are not available ) . a post - surgery histopathological review reported dermatofibrosarcoma protuberans with deep resected margin involved by tumor . the patient was subsequently treated by external beam photon irradiation with 6 mv photons , using conventional ap - pa portals with lung shielding and use of bolus ( of 0.5 cm thickness ) over the surgical scar to a prescribed dose of 40 gy in 20 fractions . this was followed by a boost , with surface mould brachytherapy to a dose of 3.5 gy per fraction , twice daily for 7 fractions ( figure 3 ) . a ) dose color wash and b ) 3d dose reconstruction of treated area in the second patient a 36-year - old male patient has been referred to the radiotherapy department for post - operative radiotherapy of soft tissue sarcoma of the anterior shoulder at left side . he had presented in another hospital with a swelling of the left anterior shoulder over ten months . local examination reported an 8 x 6 cm mass lesion with no nodes or restriction of mobility . the post - surgery histopathological review reported the mass as a low - grade sarcoma with fibro sarcomatous pattern and with involved deep margin . the patient then received external beam radiotherapy with 6 mv , using ap - pa portals with the use of bolus of 0.5 cm over surgical scar to a dose of 44 gy in 22 fractions , followed by a boost with surface mould brachytherapy to a dose of 3.5 gy per fraction twice daily for six fractions . a 48-year - old female patient was referred to the radiotherapy department for post - operative radiotherapy for a soft tissue sarcoma of the right shoulder . she presented with a history of a swelling developed over a six - month period ( size and surgery details are not available ) , for which she subsequently underwent excision but no adjuvant therapy . a year later , the patient developed a 10 cm x 6 cm recurrence , at the same site for which she presented to our institute . a biopsy was done and it reported a low - grade fibrosarcoma , and metastatic workup was negative . the patient was advised surgery followed by adjuvant radiotherapy or surgery , and intra - operative interstitial brachytherapy as either single radiation modality or with external beam therapy . however , because of extensive horizontal spread of tumor and the proximity of humeral head with fears of graft rejection of post - interstitial brachytherapy , the patient was planned for surgery and post - operative radiotherapy . the patient then underwent wide local excision of the tumor and the histopathological review reported dermatofibrosarcoma with an involvement of the deep resected margin . patient has been treated by external beam photon irradiation with 6 mv photons , using ap - pa portals , with mlc blocking for lung shielding and use of bolus over surgical scar to a dose of 40 gy in 20 fractions . after ebrt , a boost with surface mould brachytherapy using a base of thermoplastic immobilizer with wax mould was given ( figures 1 and 2 ) . the patient received brachytherapy boost with dose of 3.5 gy per fraction , twice daily , for seven fractions . patient characteristics upper torso mould used in the first patient with extensive involvement of right shoulder tissue a ) site of mould in the first patient . a 45-year - old female patient was referred to the radiotherapy department for post - operative radiotherapy for soft tissue sarcoma of left chest wall . she presented with a swelling over the left upper part of the chest in the infra - clavicular region developing over three years , and was operated at another hospital in january 2014 ( size and surgery details are not available ) . a post - surgery histopathological review reported dermatofibrosarcoma protuberans with deep resected margin involved by tumor . the patient was subsequently treated by external beam photon irradiation with 6 mv photons , using conventional ap - pa portals with lung shielding and use of bolus ( of 0.5 cm thickness ) over the surgical scar to a prescribed dose of 40 gy in 20 fractions . this was followed by a boost , with surface mould brachytherapy to a dose of 3.5 gy per fraction , twice daily for 7 fractions ( figure 3 ) . a ) dose color wash and b ) 3d dose reconstruction of treated area in the second patient a 36-year - old male patient has been referred to the radiotherapy department for post - operative radiotherapy of soft tissue sarcoma of the anterior shoulder at left side . he had presented in another hospital with a swelling of the left anterior shoulder over ten months . local examination reported an 8 x 6 cm mass lesion with no nodes or restriction of mobility . the post - surgery histopathological review reported the mass as a low - grade sarcoma with fibro sarcomatous pattern and with involved deep margin . the patient then received external beam radiotherapy with 6 mv , using ap - pa portals with the use of bolus of 0.5 cm over surgical scar to a dose of 44 gy in 22 fractions , followed by a boost with surface mould brachytherapy to a dose of 3.5 gy per fraction twice daily for six fractions . each mould was prepared from a framework of thermoplastic sheet molded to the patient s anatomy , and then covered by thin layer of dental wax . after marking of target volume by the oncologist , the physicist helped to make an initial cut - out with thermoplastic sheet . then the wax was heated in a water heater , and cast in the required shape over the thermoplastic and molded according to local anatomy . the shaped wax mould was approximated to the lesion in the treatment position , matched with lesion surface and local anatomy , edges were trimmed and smoothened . catheters were fixed to the mould , which was then placed on the patient to check the feasibility of placement and target volume coverage ( figure 1 ) . the lesion was then marked with lead wires and computed tomography ( ct)-simulation of the patient in the treatment position was done with mould in place . after ct - simulation , image reconstruction , target volume contouring , and treatment planning was carried out on eclipse ( varian medical systems , palo alto , ca , usa ) tps version 10.0 , and treatment delivery was done on gammamedplusix ( varian medical systems , palo alto , ca , usa ) . the target volume was defined as the volume encompassing the tumor bed with lateral margins of 2 - 2.5 cm and depth of 1 - 1.5 cm . the tumor bed has been identified by comparing pre - operative and post - operative ct / magnetic resonance ( mr ) films , as well as taking into account the surgical scar . the dose was prescribed to 80% , 85% , and 90% isodose lines , respectively , in the three cases in order to cover the depth of 1 - 1.5 cm ( figures 2 , 3 and 4 ) . treatments were delivered twice daily , six hours interval , and review of reactions was done every third day and at the completion . all patients tolerated the mould boost well with skin darkening as observed towards the end of treatment , and grade 2 skin changes seen in the second and third patients . brachytherapy dose ranged from 21 - 24.5 gy in fraction sizes of 3.5 gy , delivered twice daily . brachytherapy part eqd2 of these patients were 24 and 28.6 gy , while total eqd2 of these patients was 68.5 gy in the three cases . biologically equivalent dose for 3 and 10 gy has been also calculated ( table 2 and figure 6 ) in all cases , and the total bed3 dose ( including external beam component ) has been between 119 - 129 gy in all cases . selecting an isodose of 85 - 100% ( figure 7 ) helped in achieving maximal tumor volume coverage , while at the same time , keeping volume of tissue receiving more than 150% ( v150 ) to below 2% and volume of tissue receiving more than 200% ( v200 ) of prescribed dose to below 0.001% . this meant that areas receiving more than 200% of the prescribed dose were limited to the substance of the mould ( table 3 and figure 7 ) . maximum dose to oar was assessed as dose to 2 cc of oar and ranged between 55 - 87% of the prescribed dose with a median dose being 80% ( figure 8) . equivalent dose at 2 gy per fraction , bed3gy / bed10gy  biologically equivalent dose for late effects ( bed3gy ) and for early effects ( bed10gy ) fraction , ebrt  external beam radiation therapy dose volume comparisons ptv  planning target volume , v200%  volume receiving 200% of prescribed dose , v150%  volume receiving 150% of prescribed dose immediate post - radiotherapy skin changes in the third patient biologically equivalent dose ( bed ) of treated cases tissue volume and dose received dose to organ at risk ( head of humerus ) there were no severe skin reactions like ulcers or necrosis ( table 4 ) . at six months of follow - up , none of the patients showed any local or distal recurrence both clinically as well by imaging ( ct thorax and local mri ) . all the cases again reported for follow - up in march 2015 , in august 2015 , in january 2016 , july 2016 , october 2016 , and january 2017 ( figures 9 and 10 ) . by then , patients had completed 36 , 34 , and 32 months uneventful follow - up , respectively . local examination and imaging showed no local recurrence or distant metastases or even no local site late treatment sequelae ( figure 11 , table 4 ) . skin reactions and survival skin changes in the first patient , photograph taken 3 months post - radiotherapy magnetic resonance imaging in the third patient , photograph taken at 27 months post - radiotherapy showing no local recurrence disease free survival ( dfs ) of treated cases post - operative or adjuvant radiotherapy in soft tissue sarcomas are indicated in situations with increased risk of local recurrence after surgery . these include cases with narrow or positive surgical margins , local recurrence after prior surgery , tumor size of more than 5 cm , as well as lesions deep to or invading the superficial fascia , high grade , or age of patient younger than 50 years . interstitial brachytherapy has been more commonly used and can achieve good dose distribution especially in limited target volumes , and helps to achieve good control rates [ 11 , 12 ] . early results from memorial sloan - kettering cancer center ( mskcc ) have shown better results when the brachytherapy is added to radiotherapy as adjuvant therapy , especially in cases with positive margins   as well as in recurrent disease [ 9 , 13 ] . in france , the gustav roussy institute reported 80% local control rates with interstitial brachytherapy , but 30% margin failures and a 35% necrosis rate . however , the use of interstitial brachytherapy in the treatment of sarcomas is associated with certain constraints . these include difficulty in covering a larger target volume , limits in catheter patterns , achieving good geometry because of the presence of bone or visceral organs or difficult anatomic sites such as around the shoulder , and risk of radiation injury to nerves that are in direct contact with the bt catheters . the mskcc group noticed that shoulder location was an independent prognostic factor for poor local control with interstitial brachytherapy . therefore , in many of these situations , particularly when the target volume is superficially located , a customized mould using acrylic or thermoplastic casts can be used for catheter placement , geometry , and even the immobilization . the brachytherapy catheters are laid directly onto the mould or can be used with a spacer such as in freiburg flap to ensure uniform catheter distribution . compared to interstitial brachytherapy , surface mould brachytherapy though extensively studied in skin cancers , head and neck , scalp , or even intra - ocular regions , has not been widely used for treating extremity soft tissue sarcomas , and dose guidelines have to be extrapolated from interstitial brachytherapy . these custom - made external molds can result in dose distribution with a sharp gradient in the edges of the applicator , especially over curved or irregular surfaces , and are easy to use with highly accurate daily treatment reproduction . they enable one to obtain excellent local control with minimum treatment - related sequelae or late complications . in our case series , the position of the tumor bed in all the three cases was very close to the head of humerus and with deep involved margins , and the need was not only to adequate cover the area at risk , but also to achieve sharp dose fall - off to avoid the joint or bone . it is better to prescribe to isodose of 85 - 100% to obtain an acceptable coverage of the target volume to limit the amount of tissue irradiated by 150% isodose . any attempt to pull the isodose outward to cover a bigger target volume altogether could result in more tissue receiving doses above 200% and cause severe skin reactions . in all our cases , the authors managed to keep the area receiving dose of 200% and above to within the substance of the mould , while area receiving above 150% thus , the use of surface moulds can result in dose distributions more homogeneous than even electron beam therapy , and may even rival imrt with the added benefits of minimal surrounding tissue dose and much less integral body dose . in our series , we noticed grade 1 skin changes in all cases and grade 2 reactions in 2 cases . furthermore , all reactions healed within six weeks . brachytherapy , usually interstitial , plays an useful role in the treatment of soft tissue sarcomas of the extremities helping achieve improved local control with both organ and function preservation . surface mould brachytherapy can be a valuable alternative to interstitial brachytherapy , especially in cases where the target volume is extensively superficial , underlying critical structures , and where catheter placement may be difficult , such as the shoulder , with excellent medium term local control and mild toxicity .
purposesoft tissue sarcomas of the extremities account for half of all soft tissue sarcomas . 
 radiotherapy and surgery have been the standard modalities in the treatment of this type of cancer . 
 brachytherapy can be used as the sole therapy , if the target volume is localized and easily accessible . 
 this work reports three cases of shoulder soft tissue sarcomas with positive deep resected margins , treated with a combination of external beam radiotherapy and surface mould brachytherapy boost technique.material and methodsbetween january and june 2014 , three patients received brachytherapy with sites close to the shoulder , and post - surgery involved deep resected margins . 
 each mould was made on a base of thermoplastic , over which dental wax was coated and catheters implanted . 
 the target volume was defined as the tissue covering the tumor bed with lateral margins of 2 - 2.5 cm and depth of 1 - 1.5 cm . 
 treatment planning was computed tomography - based and dose prescribed was 85 - 100% isodose . 
 treatments has been delivered twice daily , six hours interval , and a review of reactions evaluated.resultsvolume receiving more than 150% of the prescribed dose has been limited to less than 2% , and that above 200% to be inside the mould . 
 brachytherapy equivalent dose at 2 gy per fraction ( eqd2 ) of these patients was 24 and 28.6 gy . 
 maximum dose to organ at risk ( oar ) ( 2 cc of oar ) ranged between 55 - 87% of prescribed dose , with a median dose being 80% . 
 all cases had only grade 1 post - radiotherapy skin immediate reactions , which resolved within four weeks . in all patients 
 , no treatment failures were noted at nearly 2-years post-irradiation.conclusionssurface mould brachytherapy in soft tissue sarcomas could be a useful alternative to interstitial brachytherapy , especially where the target volume is superficially extensive with underlying critical structures , and where catheter placement may be difficult , such as the shoulder .