Objective To explore prognostic factors and recurrence patterns in patients with gallbladder cancer after radical surgery, guiding for delineation of clinical target volumethe of postoperative adjuvant radiotherapy.

Methods 102 patients are from Zhongshan Hospital, Fudan University, with gallbladder cancer who underwent radical surgery between 2008 to 2018. Locoregional failure was defined as tumor bed recurrence or celiac lymph node recurrence.102 cases were included in the criteria and fully followed up.37 cases received postoperative adjuvant chemotherapy and 65 did not receive chemotherapy.

Results The mean time of locoregional recurrence was 12.4 months after radical surgery.Univariate analysis:stage pT, stage pN, mucinous adenocarcinoma, tumor differentiation are related to locoregional recurrence(P < 0.05). Multivariate analysis:pT and pN are independent predictors(P < 0.05).The mean time of tumor bed recurrence was 12.5 months (95% CI 8.4-16.5).The mean time of celiac lymph node recurrence was 10.9 months (95% CI 8.1-13.7).Univariate analysis:pT, pN, tumor differentiation are related to tumor bed recurrence(P < 0.05); pT, pN, neurovascular invasion are related to celiac lymph node recurrence (P < 0.05).Multivariate analysis:pT/pN are independent predictors of tumor bed recurrence and celiac lymph node recurrence (P < 0.05).Recurrence map of abdominal lymph nodes:group 8, 12a, 16b1 are high risk of recurrence (>40%); group 9, 12p, 13, 16a2 are intermediate risk of recurrence(20%-30%); group 3, 5, 6, 7, 14, 16b2, 17, 18 are fewer recurrent (< 10%).

Conclusions The locoregional failure rate of gallbladder cancer after radical resection is high.pT/pN are independent predictors affecting recurrence.Even after n1 site dissection, celiac lymph nodes recurrence is still more often.Clinical target volume of adjuvant radiotherapy can include tumor beds and some celiac lymph nodes:group 8, 9, 12a, 12p, 13, 16a2, 16b1.