ObjectiveTo study the correlation of lymph node metastasis and recurrence with body mass index (BMI) and estrogen receptor (ER) in papillary thyroid carcinoma (PTC).MethodThe relevant literatures were retrieved in the past six years through the CNKI, VIP, Wanfang, CBM, PubMed, Medline, Embase, Cochrane Library, etc. databases for meta-analysis of relationship of lymph node metastasis and recurrence of PTC with BMI or ER and its subtypes.ResultsThe meta-analysis showed that the lymph node metastasis of PTC was associated with the BMI and ERα [OR=1.27, 95% CI (1.12, 1.42), P<0.000 1; OR=2.68, 95% CI (1.86, 3.86), P<0.000 01, respectively ], and which not associated with the ER and ERβ [OR=0.87, 95% CI (0.56, 1.35), P=0.53; OR=1.22, 95% CI (0.78,1.89), P=0.39, respectively ]. The ERα was associated with the PTC recurrence [OR=1.87, 95% CI (1.04, 3.35), P=0.04 ], but the BMI was not the risk factor for the recurrence of PTC [OR=1.187 1, 95% CI (0.930 0, 1.515 3), P=0.17 ].ConclusionsAlthough BMI was not found to be associated with PTC recurrence, high BMI promotes PTC metastasis, so lymph node dissection in obese patients should be more careful and comprehensive. Positive ERα increases risk of lymph node metastasis and recurrence of PTC, which can be used as a negative factor in evaluating prognosis of PTC and provide a new idea for endocrine therapy of PTC.