despite continuous progress in cancer treatment , lung cancer remains the most common cause of cancer - related deaths in korea   as well as worldwide . although the overall survival ( os ) rate has gradually improved , lung cancer still has a high mortality rate because local and distant failures are common . non - small cell lung cancer ( nsclc ) is a heterogeneous group of diseases that accounts for about 80%of lung cancer cases . although surgery can be curative at the early stages of nsclc , the majority of patients with nsclc may already be in a locally advanced stage that is not amenable to curative resection at diagnosis . historically , thoracic radiotherapy has played a major role in the management of locally advanced nsclc , and many prospective clinical trials [ 3 - 5 ] have established the benefits of incorporating chemotherapy with radiotherapy over radiotherapy alone . in recent years , the improvement in survival rates has been attributed to the development of modern chemotherapeutic agents and advances in radiation therapy techniques which improved local tumor control without significantly increasing radiation - related morbidity there are some variations in the standard of care for patients with locally advanced disease . while surgery can be the treatment of choice for selected n2 positive patients , a neoadjuvant treatment scheme   may be used for potentially resectable diseases . other treatment options , such as induction chemotherapy followed by chemoradiation , chemoradiation followed by consolidation chemotherapy   or preoperative chemoradiation followed by surgery   can be used , but outcomes have not been established . there are frequently encountered problems such as gross residual diseases after surgical resection , especially in stage iii patients , or locally recurrent disease . in patients with a good performance status , aggressive treatment , such as concurrent chemoradiation , some reports have shown that the survival of patients with locally recurrent nsclc is comparable to that of patients initially diagnosed with locally advanced nsclc . furthermore , there has been a study reporting that patients with locally recurrent nsclc who were treated with curative intent survived much longer than those who were treated with palliative intent . in the current study , we retrospectively analyzed treatment results , clinical responses , toxicities , and prognostic factors associated with the os of patients who received concurrent chemoradiation for locally advanced stage iii nsclc , postoperative gross residual diseases , and locally recurrent nsclc . mary 's hospital lung cancer multidisciplinary treatment team enrolled 55 patients who were histologically confirmed as having nsclc . this included locally advanced stage iii nsclc , postoperative gross residual diseases , and locally recurrent nsclc . among these 55 patients all patients had pathologically confirmed measurable disease , an eastern cooperative oncology group performance status ( ecog ps ) of 0 - 2 , and acceptable pulmonary , bone marrow , liver and renal functions . for stage evaluation , patients underwent a chest x - ray , computed tomography ( ct ) scans of the chest including upper abdomen , bronchoscopy , and positron emission tomography / computed tomography ( pet / ct ) . tc-99 m whole body bone scans , whole abdominal ct scans , and magnetic resonance imaging of the brain were selectively performed when clinically indicated . mediastinoscopy was not routinely done ; it was performed in 6 of 28 patients in the definitive chemoradiation group to discriminate between n2 and n3 diseases . all patients underwent ct simulation for three - dimensional conformal radiotherapy planning , and radiation was delivered with 6 mv to 15 mv of photon beam energy by linac - based radiation units . the total radiation dose was 16 - 66.4 gy ( median , 59.4 gy ) , and the fractional size of 1.8 or 2 gy was prescribed 5 times a week . the gross tumor volume ( gtv ) was defined as the primary tumor mass plus the involved lymph nodes . the clinical target volume ( ctv ) was defined as the gtv plus a 3-d expansion of 0.5 - 1 cm including the ipsilateral hilum . the planning target volume ( ptv ) was defined as the ctv plus a 1 cm expansion circumferentially and a 1 - 2 cm expansion in the superior - inferior directions . dose limits for normal tissue were as follows : spinal cord received45 - 49 gy ( at any point ) , the lung volume received20 gy ( v20)25 - 30% , and a mean lung dose ( mld)18 - 20 gy . beam arrangement was planned to minimize the irradiated lung volume usually using 3 to 5 coplanar oblique beams . some patients having a bulky tumor were treated with an anteroposterior - posteroanterior field to include the ctv for the first 30 - 40 gy , followed by off - cord oblique beams usually composed of 3 - 5 beams . boost field to gtv with reduced margin was routinely used after 46 - 50 gy . chemotherapy was administered weekly using one of the following regimens : cisplatin ( 30 mg / m ) , paclitaxel ( 60 mg / m ) , docetaxel ( 20 mg / m ) plus cisplatin ( 20 mg / m ) . when hematologic toxicity was severe during treatment , chemotherapy administration was delayed based on the medical oncologist 's decision . consolidation chemotherapy was administered 4 weeks after the finish of the chemoradiation course by the following regimens : 2 - 4 cycles of docetaxel and cisplatin in 8 patients , 4 cycles of paclitaxel and cisplatin in 4 patients , and 1 cycle of gemcitabine and carboplatin in 1 patient . blood chemistry and a complete blood count were obtained weekly , or more frequently , if needed during the treatment periods . we performed chest ct and/or pet / ct for the evaluation of treatment responses between 4 and 12 weeks after the end of the chemoradiation treatment course . the world health organization ( who ) criteria were used for response evaluations . these consisted of complete response ( cr ) , partial response ( pr ) , stable disease ( sd ) or progressive disease ( pd ) . acute toxicity was assessed using the national cancer institute common toxicity criteria ( nci ctcae ) ver . os was defined as the time from the histologically confirmed date to the date of death or to the patient 's last visit . progression free survival ( pfs ) was defined as the time from the histologically confirmed date to the date of disease progression or the date of the patient 's last visit . in case of locally recurrent disease , a starting point for the calculation of os or pfs was the date on which recurrence was confirmed by serial radiologic findings , or histologically if specimens were available . for statistical analysis , spss ver.12.0 ( spss inc . , chicago , il ) was used . a log - rank test was used to compare survival differences between treatment groups , and the cox proportional hazards regression model was used to identify independent prognostic factors and to determine the impact of factors on os . mary 's hospital lung cancer multidisciplinary treatment team enrolled 55 patients who were histologically confirmed as having nsclc . this included locally advanced stage iii nsclc , postoperative gross residual diseases , and locally recurrent nsclc . among these 55 patients all patients had pathologically confirmed measurable disease , an eastern cooperative oncology group performance status ( ecog ps ) of 0 - 2 , and acceptable pulmonary , bone marrow , liver and renal functions . for stage evaluation , patients underwent a chest x - ray , computed tomography ( ct ) scans of the chest including upper abdomen , bronchoscopy , and positron emission tomography / computed tomography ( pet / ct ) . tc-99 m whole body bone scans , whole abdominal ct scans , and magnetic resonance imaging of the brain were selectively performed when clinically indicated . mediastinoscopy was not routinely done ; it was performed in 6 of 28 patients in the definitive chemoradiation group to discriminate between n2 and n3 diseases . all patients underwent ct simulation for three - dimensional conformal radiotherapy planning , and radiation was delivered with 6 mv to 15 mv of photon beam energy by linac - based radiation units . the total radiation dose was 16 - 66.4 gy ( median , 59.4 gy ) , and the fractional size of 1.8 or 2 gy was prescribed 5 times a week . the gross tumor volume ( gtv ) was defined as the primary tumor mass plus the involved lymph nodes . the clinical target volume ( ctv ) was defined as the gtv plus a 3-d expansion of 0.5 - 1 cm including the ipsilateral hilum . the planning target volume ( ptv ) was defined as the ctv plus a 1 cm expansion circumferentially and a 1 - 2 cm expansion in the superior - inferior directions . dose limits for normal tissue were as follows : spinal cord received45 - 49 gy ( at any point ) , the lung volume received20 gy ( v20)25 - 30% , and a mean lung dose ( mld)18 - 20 gy . beam arrangement was planned to minimize the irradiated lung volume usually using 3 to 5 coplanar oblique beams . some patients having a bulky tumor were treated with an anteroposterior - posteroanterior field to include the ctv for the first 30 - 40 gy , followed by off - cord oblique beams usually composed of 3 - 5 beams . boost field to gtv with reduced margin was routinely used after 46 - 50 gy . chemotherapy was administered weekly using one of the following regimens : cisplatin ( 30 mg / m ) , paclitaxel ( 60 mg / m ) , docetaxel ( 20 mg / m ) plus cisplatin ( 20 mg / m ) . when hematologic toxicity was severe during treatment , chemotherapy administration was delayed based on the medical oncologist 's decision . consolidation chemotherapy was administered 4 weeks after the finish of the chemoradiation course by the following regimens : 2 - 4 cycles of docetaxel and cisplatin in 8 patients , 4 cycles of paclitaxel and cisplatin in 4 patients , and 1 cycle of gemcitabine and carboplatin in 1 patient . blood chemistry and a complete blood count were obtained weekly , or more frequently , if needed during the treatment periods . we performed chest ct and/or pet / ct for the evaluation of treatment responses between 4 and 12 weeks after the end of the chemoradiation treatment course . the world health organization ( who ) criteria were used for response evaluations . these consisted of complete response ( cr ) , partial response ( pr ) , stable disease ( sd ) or progressive disease ( pd ) . acute toxicity was assessed using the national cancer institute common toxicity criteria ( nci ctcae ) ver . os was defined as the time from the histologically confirmed date to the date of death or to the patient 's last visit . progression free survival ( pfs ) was defined as the time from the histologically confirmed date to the date of disease progression or the date of the patient 's last visit . in case of locally recurrent disease , a starting point for the calculation of os or pfs was the date on which recurrence was confirmed by serial radiologic findings , or histologically if specimens were available . for statistical analysis , spss ver.12.0 ( spss inc . , chicago , il ) was used . a log - rank test was used to compare survival differences between treatment groups , and the cox proportional hazards regression model was used to identify independent prognostic factors and to determine the impact of factors on os . the number of patients in each treatment group was as follows : 28 in locally advanced stage iii nsclc , 11 in postoperative gross residual disease , and 12 in locally recurrent nsclc . the median age was 63 years ( range , 40 to 79 years ) , and 82.4% of patients were male . the majority of patients had an ecog ps score of 0 - 1 ( 92.1% ) , and the distribution of histology findings were squamous cell carcinoma ( 54.9% ) and adenocarcinoma ( 33.3% ) . stage was determined by the 6th edition of the american joint committee on cancer ( ajcc ) staging system . if pathologic specimens were available , we used pathologic stages for tumor - node - metastasis ( tnm ) staging . the distribution of clinical stages was as follows : iiia ( 37.3% ) , iiib ( 56.9% ) . four patients were treated with radiation doses of less than 50 gy , which was inappropriate for achieving an optimal radiation effect . in one patient , treatment was discontinued after 16 gy of radiotherapy because acute dyspnea developed after 2 cycles of concurrent chemoradiation . these symptoms were probably due to a hypersensitivity reaction to the chemotherapeutic agent . in another patient , treatment was discontinued after 42 gy of radiotherapy because abrupt pneumothorax developed during treatment . in the remaining 2 patients , treatment - related toxicities were not severe , but the treatment was discontinued after their respective radiation doses of 32.4 gy and 46.8 gy by patient decision because of poor general conditions or other reasons . the median number of chemotherapy cycles during the concurrent chemoradiation treatment was 6 ( range , 2 - 8 ) . forty - five patients ( 88.2% ) were treated with at least 6 cycles of chemotherapy . response evaluation was done by chest ct with or without pet / ct . the number of patients with a response evaluation at 1 month after the end of chemoradiation was 8 . the overall response rate ( cr+pr ) was 84.3% ( n=43 ) , including 23 cr ( 45.1% ) . the postoperative gross residual group showed a relatively high cr rate ( 81.8% ) , probably due to the reduced tumor burden after surgical resection . there was no difference in the overall response rates among different chemotherapeutic regimens ( p=0.194 ) . at the time of this analysis tumors recurred in the following sites : locoregional sites ( 23.6% ) and distant organs ( 27.5% ) . all of the patients with recurrent disease received palliative treatments including chemotherapy , molecular targeted therapy or localized radiotherapy . the median follow - up duration in the entire population was 40.8 months ( range , 3 to 69.9 months ) . the median pfs in the entire population was 12.5 months , and the 1-year and 2-year pfs rates were 51% and 23% , respectively . there was no statistically significant difference between treatment groups ( p=0.583 ) ( figs . 2 and 3 ) . the median os in the entire population was 17.6 months , and the 2-year and 3-year os rates were 42% and 17.8% , respectively . median survival was different between treatment groups but not statistically significant ( p=0.638 ) ( figs . 2 and 3 ) . the results of univariate and multivariate analysis affecting os in the entire population are shown in table 3 . the covariables were gender , age , histologic type , ecog ps score , number of chemotherapeutic agents , chemotherapeutic regimen , clinical tumor response , t stage , n stage , clinical stage and tumor size . in the univariate analysis , a better ecog ps score ( 0 vs. 1 - 2 , p=0.042 ) and higher clinical tumor response ( cr+pr vs. sd+pd , p=0.002 ) were significantly associated with improved os , and a trend was detected that patients with<65 years had better survival than those with65 years ( p=0.062 ) . among these factors , clinical tumor response ( p=0.002 ) was the only independent factor associated with improved os in the multivariate analysis . kaplan - meier os curves stratified by clinical tumor response in the overall patients group is shown in fig . 4 . we performed subgroup analysis of the definitive chemoradiation arm to evaluate prognostic factors . this analysis included age , gender , histologic type , ecog ps score , number of chemotherapeutic agents , chemotherapeutic regimen , t stage , n stage , clinical stage , tumor size , use of consolidation chemotherapy , total radiation dose , which was converted into biologically equivalent dose ( bed ) , and clinical tumor response . among these factors , the use of consolidation chemotherapy ( p=0.042 ) , bed1070 ( p=0.011 ) and higher clinical response ( p=0.0049 ) were significantly associated with improved os in the univariate analysis . in the multivariate analysis , the use of consolidation chemotherapy ( p=0.022 ) , bed1070 ( p=0.007 ) , and higher clinical tumor response ( p=0.030 ) were the independent prognostic factors associated with improved os . the results of univariate and multivariate analyses of the definitive chemoradiation arm are shown in table 4 and kaplan - meier os curves stratified by clinical tumor response , bed10 and use of consolidation chemotherapy are shown in fig . the incidence of neutropenia ( grade 3 ) and esophagitis ( grade 3 ) were 31.4% and 27.5% , respectively . the volume of lung that received 20 gy ( v20 ) were 31% and 41% , and 30 gy ( v30 ) were 24% and 32% , respectively . one death was caused by viral pneumonia superimposed on acute radiation pneumonitis during hospitalization around 1 month after the end of the treatment . another patient died of acute respiratory distress syndrome during hospitalization 3 months after the end of treatment . chronic esophageal toxicities were observed in 2 patients who presented with esophageal stricture and fistula , respectively . the number of patients in each treatment group was as follows : 28 in locally advanced stage iii nsclc , 11 in postoperative gross residual disease , and 12 in locally recurrent nsclc . the median age was 63 years ( range , 40 to 79 years ) , and 82.4% of patients were male . the majority of patients had an ecog ps score of 0 - 1 ( 92.1% ) , and the distribution of histology findings were squamous cell carcinoma ( 54.9% ) and adenocarcinoma ( 33.3% ) . stage was determined by the 6th edition of the american joint committee on cancer ( ajcc ) staging system . if pathologic specimens were available , we used pathologic stages for tumor - node - metastasis ( tnm ) staging . the distribution of clinical stages was as follows : iiia ( 37.3% ) , iiib ( 56.9% ) . four patients were treated with radiation doses of less than 50 gy , which was inappropriate for achieving an optimal radiation effect . in one patient , treatment was discontinued after 16 gy of radiotherapy because acute dyspnea developed after 2 cycles of concurrent chemoradiation . these symptoms were probably due to a hypersensitivity reaction to the chemotherapeutic agent . in another patient , treatment was discontinued after 42 gy of radiotherapy because abrupt pneumothorax developed during treatment . in the remaining 2 patients , treatment - related toxicities were not severe , but the treatment was discontinued after their respective radiation doses of 32.4 gy and 46.8 gy by patient decision because of poor general conditions or other reasons . the median number of chemotherapy cycles during the concurrent chemoradiation treatment was 6 ( range , 2 - 8 ) . forty - five patients ( 88.2% ) were treated with at least 6 cycles of chemotherapy . response evaluation was done by chest ct with or without pet / ct . the number of patients with a response evaluation at 1 month after the end of chemoradiation was 8 . the overall response rate ( cr+pr ) was 84.3% ( n=43 ) , including 23 cr ( 45.1% ) . the postoperative gross residual group showed a relatively high cr rate ( 81.8% ) , probably due to the reduced tumor burden after surgical resection . there was no difference in the overall response rates among different chemotherapeutic regimens ( p=0.194 ) . at the time of this analysis , recurrence has been observed in 21 patients ( 41% ) . the distribution of the first site of recurrence is shown in fig . tumors recurred in the following sites : locoregional sites ( 23.6% ) and distant organs ( 27.5% ) . all of the patients with recurrent disease received palliative treatments including chemotherapy , molecular targeted therapy or localized radiotherapy . the median follow - up duration in the entire population was 40.8 months ( range , 3 to 69.9 months ) . the median pfs in the entire population was 12.5 months , and the 1-year and 2-year pfs rates were 51% and 23% , respectively . there was no statistically significant difference between treatment groups ( p=0.583 ) ( figs . 2 and 3 ) . the median os in the entire population was 17.6 months , and the 2-year and 3-year os rates were 42% and 17.8% , respectively . median survival was different between treatment groups but not statistically significant ( p=0.638 ) ( figs . 2 and 3 ) . the results of univariate and multivariate analysis affecting os in the entire population are shown in table 3 . the covariables were gender , age , histologic type , ecog ps score , number of chemotherapeutic agents , chemotherapeutic regimen , clinical tumor response , t stage , n stage , clinical stage and tumor size . in the univariate analysis , a better ecog ps score ( 0 vs. 1 - 2 , p=0.042 ) and higher clinical tumor response ( cr+pr vs. sd+pd , p=0.002 ) were significantly associated with improved os , and a trend was detected that patients with<65 years had better survival than those with65 years ( p=0.062 ) . among these factors , clinical tumor response ( p=0.002 ) was the only independent factor associated with improved os in the multivariate analysis . kaplan - meier os curves stratified by clinical tumor response in the overall patients group is shown in fig . 4 . we performed subgroup analysis of the definitive chemoradiation arm to evaluate prognostic factors . this analysis included age , gender , histologic type , ecog ps score , number of chemotherapeutic agents , chemotherapeutic regimen , t stage , n stage , clinical stage , tumor size , use of consolidation chemotherapy , total radiation dose , which was converted into biologically equivalent dose ( bed ) , and clinical tumor response . among these factors , the use of consolidation chemotherapy ( p=0.042 ) , bed1070 ( p=0.011 ) and higher clinical response ( p=0.0049 ) were significantly associated with improved os in the univariate analysis . in the multivariate analysis , the use of consolidation chemotherapy ( p=0.022 ) , bed1070 ( p=0.007 ) , and higher clinical tumor response ( p=0.030 ) were the independent prognostic factors associated with improved os . the results of univariate and multivariate analyses of the definitive chemoradiation arm are shown in table 4 and kaplan - meier os curves stratified by clinical tumor response , bed10 and use of consolidation chemotherapy are shown in fig . hematologic and esophageal toxicity were major acute toxicities . the incidence of neutropenia ( grade 3 ) and esophagitis ( grade 3 ) were 31.4% and 27.5% , respectively . the volume of lung that received 20 gy ( v20 ) were 31% and 41% , and 30 gy ( v30 ) were 24% and 32% , respectively . one death was caused by viral pneumonia superimposed on acute radiation pneumonitis during hospitalization around 1 month after the end of the treatment . another patient died of acute respiratory distress syndrome during hospitalization 3 months after the end of treatment . chronic esophageal toxicities were observed in 2 patients who presented with esophageal stricture and fistula , respectively . after many randomized trials revealed that the integration of systemic chemotherapy with radiotherapy would be more beneficial than radiotherapy alone [ 3 - 5 ] , combination chemoradiation , especially concurrent chemoradiation rather than sequential chemoradiation , has become one of the standard treatments . recently , the intergroup 0139   study showed improved survival with preoperative chemoradiation followed by surgery over definitive chemoradiation in iiia - n2 nsclc when lobectomy was possible . this neoadjuvant chemoradiation protocol can be used to treat selected minimal n2 nsclc patients who become resectable . however , additional trials with more population - based studies would be required to show conclusive results . in the current study , we analyzed the treatment results of 3 different groups : locally advanced stage iii nsclc , postoperative gross residual disease , and locally recurrent nsclc . the median os time for all patients was 17.6 months , and the 2-year and 3-year os rates were 42% and 17.8% , respectively . those treatment outcomes are comparable with previous reports [ 7 - 11,18 ] . among the different groups , the clinical development of third generation chemotherapy showed potent radiosensitization effects , and those chemotherapeutic agents are commonly used with radiotherapy in the definitive chemoradiation setting . the proportion of patients in our study receiving combined taxane chemotherapy ( paclitaxel or decetaxel ) was 82.4% , which was a very high frequency . however , differences in a number or regimen of chemotherapeutic agent ( single vs. double , taxane vs. non - taxane , platinum vs. non - platinum ) did not affect os significantly ( table 3 ) . our study showed different median survival durations between treatment groups : 17.6 months in full analysis patients , 13.2 months in the definitive chemoradiation group , 26.4 months in the locally recurrent group , and 23.9 months in the postoperative gross residual group . in the definitive chemoradiation group , this was probably due to the fact that most of the patients enrolled in our study were in stage iiib ( 71.4% ) , and a few of those patients had shorter follow up periods . we compared the effect of the total radiation dose on os between two groups of patients-9 patients who received 66 gy and another 12 patients who were treated with 59 - 60 gy . however , we found that there was no significant difference in os between the two groups . this lack of significance might be due to the small sample size of the group or the narrow range of total radiation dose differences between the two groups . therefore , re - evaluation with longer follow up of larger sample sizes will be required for more definitive conclusions . in the locally recurrent group , we noted reliably longer os with a non - inferior outcome when compared with the initially diagnosed locally advanced nsclc group . this was supported by the several previous studies , which implies that aggressive treatment such as concurrent chemoradiation or dose escalation radiotherapy would result in improved survival in locally recurrent cases . among 12 locally recurrent patients in our study , two had only bronchial stump recurrence and ten had mediastinal lymph node recurrence with or without bronchial stump recurrence . there have been a few studies reporting that bronchial stump recurrence has better prognosis than cases combined with mediastinal lymph node recurrence or chest wall invasion . the median survival was 26 months in the radical intent group and 10.5 months in the palliative intent group . although we included the majority of mediastinal lymph node recurrences , our patients had relatively long os durations . our concurrent chemoradiation scheme might contribute to this outcome , and this scheme could be justified for locally recurrent cases , especially those with mediastinal lymph node recurrences . further studies are now required to define the beneficial role of combining chemotherapy with radiotherapy in loco - regionally recurrent nsclc . however , there were 2 toxic deaths associated with radiation pneumonitis , 1 - 3 months after completion of chemoirradiation in 2 elderly patients , which suggests that a careful evaluation of pulmonary function and close follow up will be needed after treatment in an immune - suppressed host . in the analysis of prognostic factors , the clinical tumor response was significantly associated with os not only in the entire patient cohort , but also in the definitive chemoradiation group . however , we could not find any significant factors associated with good responses such as total radiation dose , chemotherapeutic regimen , tnm stage or histologic type . from the fact that the reduced tumor burden after surgery resulted in a relatively high cr rate ( 81.8% ) , we can only infer that the tumor burden ( tumor volume ) could be a significant factor . in our study , the t or n stage was not associated with the response rate , and this may be due to a small sample size . there have been significant advances in molecular biology , and these will help pinpoint the factors associated with responses to therapy . there are several known pre - treatment prognostic factors associated with os in nsclc such as weight loss , tumor stage , performance status and pulmonary function . we could n't examine all of these factors due to the limitations of a retrospective study . however , among the pre - treatment factors , ecog ps was the most strongly associated with os . in subgroup analysis of the definitive chemoradiation group , the use of consolidation chemotherapy , bed1070 , and higher clinical tumor response were the independent prognostic factors that improved os . furthermore , our subgroup analysis of locally recurrent and postoperative gross residual diseases indicated that clinical tumor response and ps are significant prognostic factors affecting os ( data not shown ) . this means that more radical tumor control will eventually be connected to improved survival in nsclc . in the swog 9504   trial , concurrent chemoradiation with etoposide - cisplatin followed by consolidation docetaxel were administered to stage iiib patients . the result was encouraging with a median survival time of 26 months , and 3-year and 5-year survival rate were 37% and 29% , respectively . after the swog 9504 trial , several phase iii randomized trials   were conducted to define the role of consolidation chemotherapy in locally advanced nsclc . however , different results were shown among the studies , and some studies showed a relatively high frequency of high - grade hematologic and esophageal toxicities . in the most recently reported interim analysis of a multinational phase iii randomized trial ( cchein ) , consolidation chemotherapy with docetaxel plus cisplatin ( dp ) after concurrent chemoradiation ( ccrt ) with weekly dp was shown to be feasible and tolerable , but there were no statistically significant differences in time to progression and median os between observation and consolidation arms . as a result , further investigations are needed to precisely define the role of consolidation chemotherapy after ccrt in locally advanced nsclc . we would cautiously infer that stage iiib patients with good ps will benefit mostly from the consolidation chemotherapy . in the same context , our study showed that the benefit of consolidation chemotherapy was probably due to the high proportion of iiib patients in the definitive chemoradiation arm . to further evaluate the radiation dose effect , we calculated bed using an /ratio of 10 because the fractional size was different . however , some patients treated with a less than optimal radiation dose were included in the study , and we did not apply a time factor in calculating bed . thus , a follow up study including a larger cohort should be performed . in our study , patients treated with bed1070 showed a better os when compared to those with bed1070 , and this was the independent prognostic factor associated with improved os in the multivariate analysis ( hazard ratio , 6.184 ; 95% confidence interval , 1.644 to 23.259 ; p=0.007 ) . this result needs careful interpretation : it should be interpreted as the optimal minimum dose to get the radiation effect attributed to improving overall survival , not the appropriate radiation dose in the ccrt setting . many clinical trials have been performed with a radiation dose of 60 - 74 gy , and the optimal radiation dose in concurrent chemoradiation setting remains unclear . although some studies showed that a higher radiation dose may be correlated with improved local control and os , the results of the ongoing phase iii intergroup study ( rtog 0617 ) ( 60 gy vs. 74 gy ) will more definitively identify the additional role of a higher radiation dose in the chemoradiation setting . the current study demonstrated that ecog ps and clinical tumor response were the independent prognostic factors despite heterogeneous composition of the subgroups . in subgroup analysis of the definitive chemoradiation group , the use of consolidation chemotherapy , bed1070 and higher clinical tumor responses were the independent prognostic factors correlated with the improved os . in locally recurrent nsclc , however , our study needs a longer follow up with more population group for more precise outcomes . further investigations would be required to define the factors associated with improving tumor response , the role of optimal radiation dose in definitive chemoradiation setting , and the optimal treatment scheme in locally recurrent nsclc .