Risk factors of dysphagia after surgery in patients with oral cancer identified in new study

This prospective study by Hasegawa et al investigated the change of swallowing ability using SASS and swallowing-related QOL by Performance Status Scale for Head and Neck Cancer patients (PSS-H&N). This study also investigated the risk factors for postoperative dysphagia in patients who received reconstructive surgery for oral cancer.

This study included 64 patients (33 men and 31 women) who underwent radical surgery with neck dissection and reconstructive surgery for oral cancers between July 2014 and February 2018. Authors evaluated risk factors for poor swallowing ability after treatment, including demographic factors, preoperative factors and perioperative factors, with univariate and multivariate analyses. The change of swallowing ability by the SASS and swallowing-related QOL by PSS-H&N were evaluated prospectively prior to the initiation of surgery within 1 week and at 1 and 3 months after treatment.

Advanced T stage (P < 0.001), advanced N stage (P = 0.013), bilateral neck dissection (P = 0.005), modified radical neck dissection (MRND) (P = 0.019), the resection of unilateral or bilateral suprahyoid muscles (P = 0.010) and longer operation time (P = 0.035) were significantly associated with poor swallowing ability. The scores of all groups at 3 months after treatment were significantly lower than the scores before surgery (P < 0.05).

With regard to the operative factors according to T stage, there was no significant difference between advanced T stage and extensive neck dissection, extensive resection of suprahyoid muscle, and adjacent organs. However, there were many cases of resection of mandible among cases with advanced T stage (P = 0.021).

In overall patients group and good group showed significantly higher scores at 3 months after treatment than at 1 month (P = 0.016, P = 0.006). The poor group showed a decreased Eating in Public score at 3 months after treatment compared with at 1 month. However, there was no significant difference.

Oral and oropharyngeal cancer patients are reported to suffer a higher risk of posttreatment dysphagia with less than half oral intake achieved compared with patients with cancers in other sites of the head and neck. The postoperative swallowing ability can be influenced by many factors, including additional treatments such as RT and chemoradiotherapy, operative factors and patient-related factors such as wound healing, rehabilitation and personal motivation.

Early posttreatment dysphagia is mainly related to reduced tongue base retraction and laryngeal elevation. In contrast, late posttreatment dysphagia is related to delayed pharyngeal swallowing and incomplete cricopharyngeal opening. In particular, suprahyoid muscles play important roles in hyoid and laryngeal elevation and are related to early posttreatment dysphagia.

Laryngeal penetration and aspiration are caused by poor hyoid/laryngeal elevation and poor opening of the entry into esophagus. The suprahyoid muscles are involved with depression of the mandible and subsequent opening of the mouth, movement of the tongue as secondary muscles of mastication.

Surgical resection of tumors can damage structures, such as the muscles that control swallowing. Furthermore, extensive surgery and RT can lead to tissue fibrosis and edema. In this study, advanced T stage (T3, 4) (P = 0.001) and the resection of unilateral or bilateral suprahyoid muscles (P = 0.012) were significantly associated with poor swallowing ability. These results of T stage were consistent with other reports. In the analyses of operative factors according to T stage, there was no significant difference between advanced T stage and extensive neck dissection, extensive resection of suprahyoid muscle, and adjacent organs. Instead, there were many cases of resection of mandible in cases with advance T stage (P = 0.021).

Therefore, tooth loss, trismus, and extensive resection of suprahyoid muscle with resection of mandible may affect postoperative dysphagia.

In this study, MRND in univariate analysis and bilateral neck dissection (P = 0.010) in multivariate analysis were significantly associated with poor swallowing ability. One reason may be the disturbance of laryngeal elevation by neck dissection and the resection of suprahyoid muscles. Therefore, authors tried to preserve suprahyoid muscles intraoperatively without increasing the risk of recurrence. In addition, they performed surgery such as laryngeal suspension to improve swallowing function for high risk patients with postoperative dysphagia (the resection of bilateral suprahyoid muscles). In case of bilateral neck dissection and the resection of bilateral suprahyoid muscles, decrease of swallowing ability cannot be completely prevented, although laryngeal suspension has a certain effect to swallowing ability.

The treatment of oral cancer inhibits this social function causing marked deterioration in QOL. In this study, in the good group, the F scores at 3 months after treatment were significantly higher than those at 1 month after treatment (P = 0.022). Regarding the Normalcy of Diet of PSS-H&N score, the overall patient group and good group showed significantly higher scores at 3 months after treatment than at 1 month (P = 0.016, P = 0.006, respectively). These results suggested that postoperative swallowing ability decreased the most at the early postoperative phase (1 month postoperatively) and then increased. In contrast, in the poor group of this study, the T score at 3 months after treatment was significantly decreased compared with 1 month after treatment (P = 0.013). These results suggest that if patients with risk factors are managed more intensively between 1 month and 3 months after treatment, postoperative dysphagia at 3 months after treatment may possibly be improved in the poor group.

In this study, the scores for time for food intake and Eating in Public were associated with decrease of QOL (Eating in Public) in the poor group. The patients in the poor group might have challenges to adjust the form of food intake because of insufficient support from the social environment such as from the medical staff or the patients' family members after discharge from a hospital. Thus, psychological factors caused by longer time for food intake may negatively impact eating in public.

In conclusion, study successfully demonstrated the change of swallowing ability by SASS and swallowing related QOL by PSS-H&N and the risk factors for postoperative dysphagia in patients who received reconstructive surgery for oral cancer. The scores for time for food intake and Eating in Public were associated with decrease of QOL in the poor group. Advanced T stage (T3, 4), bilateral neck dissection and the resection of unilateral or bilateral suprahyoid muscles were significantly associated with poor swallowing ability. Authors propose that clinicians consider these risk factors and pay close attention to the management of oral cancer patients with reconstructive surgery. Suprahyoid muscles may have to be preserved intraoperatively as much as possible, if the risk of recurrence do not increases.

Source: Hasegawa et al. Journal of Otolaryngology - Head and Neck Surgery (2021) 50:4 https://doi.org/10.1186/s40463-020-00479-6