Effects of central neck dissection on complications in differentiated thyroid cancer

Abstract

Objective: It is still controversial whether performing central neck dissection (CND) in addition to total thyroidectomy (TT) increases the risk of complications. In the present study, we aimed to evaluate the effect of CND on the development of complications in differentiated thyroid cancer (DTC) compared to TT. Material and Methods: The data of 186 patients (136 females and 50 males) with a mean age of 48.73 ± 14.78 (range, 17–82) whom were operated for DTC were evaluated retrospectively. The patients were divided into two groups; TT (Group 1) and CND±TT/Completion thyroidectomy±lateral neck dissection (Group 2). Results: There were 117 (91 F, 26 M) patients in Group 1 and 69 (45 F, 24 M) patients in Group 2. Parathyroid auto transplantation (PA) was significantly higher in Group 2 compared to Group 1 (42% vs. 6%) ( p =0.000). Total (58% vs. 21.4%, respectively; p =0.000) and transient hypoparathyroidism (52.2% vs. 20.5%, respectively; p =0.000) were significantly higher in Group 2 than in Group 1, but permanent hypoparathyroidism rates were statistically not significant (5.8% vs. 0.9%, respectively; p =0.064). In the multinomial logistic regression analysis, CND alone was determined as an independent risk factor for increased both total and transient hypoparathyroidism. The relative risk (RR) of CND for total hypoparathyroidism was 5.2 times increased (odds ratio [OR]: 0.192) ( p =0.007), while the RR for transient hypoparathyroidism was 3.5 times increased (OR: 0.285) ( p =0.036). According to the number of nerves at risk, CND was performed in 119 neck side and only thyroidectomy was performed in 253 neck side. Total vocal cord paralysis (VCP) rate (9 [7.6%] vs. 6 [2.4%], respectively) ( p =0.017) and transient VCP rate (7 [6%] vs. 4 [1.6%], respectively) ( p =0.021) in patients who underwent CND were significantly higher compared to those who underwent only thyroidectomy. In multinomial logistic regression analysis performing only CND was an independent risk factor for total VCP, and increased the total VCP RR approximately 5.34 times (OR:0.184; p =0.007). Conclusion: Although CND can be applied without increasing the rates of permanent hypoparathyroidism and VCP compared to TT, it increases the risk of total and transient hypoparathyroidism, total, and transient VCP. Patients undergoing CND should be followed carefully in terms of transient hypoparathyroidism.

Genetic Changes in Thyroid Cancers and the Importance of Their Preoperative Detection in Relation to the General Treatment and Determination of the Extent of Surgical Intervention—A Review

“…Nowadays, the findings of genetic research on thyroid cancer are beginning to be applied to clinical practice [ 12 ]. In preoperative molecular FNAC diagnostics, the aggressiveness of cancers with the most frequently occurring mutations ( BRAF , RAS , RET / PTC , TERT , PAX8 / PPAR-γ , RET proto-oncogene ) is correlated with the extent of the planned surgical treatment [ 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. However, there are no established guidelines for most genetic alterations, and their use in the preoperative and postoperative periods is still debated.…”

“…However, preoperative detection of genetic changes may also lead to an extension of surgical treatment to the lymph node catchment area [ 7 , 8 , 9 ]. Because of the relatively high incidence of occult metastases in PTC (20–40%) and the associated higher risk of disease recurrence and mortality, the indication of elective block neck dissection of region VI in cN0 patients is still a matter of debate [ 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ].…”

“…The detection of BRAF mutation as a possible predictive factor of occult metastasis could lead to the indication of elective neck dissection of region VI, which in the case of positive metastatic lymph nodes would lead to a reduction of recurrence and refinement of the extent of the disease (staging—conversion from cN0 to pN1a) [ 15 , 41 , 42 , 43 , 44 , 45 , 46 ]. However, the change in surgical treatment intensification (neck dissection routinely indicated) based on the identification of mutations in the preoperative period in cN0 PTC is still controversial because of the potential increased risk of surgical complications (recurrent laryngeal nerve injury, hypoparathyroidism) and its relation to the overall treatment benefit (persistence, recurrence of disease) [ 33 , 34 , 35 , 41 , 42 ].…”

“…In the following section, we present the results of recently published studies that address the general risks (temporary/permanent recurrent laryngeal nerve involvement, temporary/permanent hypoparathyroidism) and benefits (reduced incidence of persistence/recurrence of disease, reduced incidence of lymph node metastasis) of elective neck dissection of region VI in patients with thyroid carcinomas (especially PTC) [ 33 , 34 , 35 , 36 , 37 , 40 ]. We also present the results of studies focusing on performing neck dissections of region VI specifically in patients with BRAF V600E -positive mutation, where BRAF V600E mutation in PTC is correlated with a higher risk of occult metastasis, and it is discussed whether it should be a determining factor for indicating elective neck dissection of region VI under the assumption of improved survival and reduced risk of recurrence of the primary disease [ 15 , 41 , 42 , 43 , 44 , 45 , 46 ].…”

“…The results of studies comparing the benefits of elective neck dissection and the increased risk of postoperative complications in patients with PTC are different, with many authors pointing out the inappropriateness of routinely performed elective neck dissection [ 33 , 34 , 35 ] in contrast to authors who recommend extended surgical treatment [ 36 , 37 , 38 , 39 , 40 ]. Publications suggesting that routine elective neck dissection is not recommended show a statistically significantly higher incidence of postoperative surgical complications in terms of temporary damage of the recurrent laryngeal nerve, temporary hypoparathyroidism, and permanent hypoparathyroidism, while finding no statistically significant difference in the overall survival and recurrence rate (including metastasis) of the disease in the group of patients operated by total thyroidectomy and neck dissection of region VI compared with the group of patients operated by total thyroidectomy only [ 33 , 34 , 35 ]. However, ipsilateral neck dissection of region VI could be an interesting option due to the lower rate of hypocalcemia [ 34 ].…”