Unilateral radiation therapy for well-lateralized tonsillar cancer with multiple ipsilateral neck nodes: should we encourage patients take risks and pursue quality of life or not?
Article information
The life expectancy of patients with oropharyngeal squamous cell carcinoma (OPSCC) is expected to improve, largely due to the rising incidence of human papillomavirus-associated OPSCC globally, which generally carries a favorable prognosis. While achieving optimal treatment outcomes remains paramount, there is a growing focus on mitigating post-treatment complications and enhancing the quality of life for these patients. Efforts to reduce the dose or volume of radiation therapy have shown promise in alleviating treatment-related morbidities especially from bilateral neck radiation therapy (BNRT) to unilateral neck radiation therapy (UNRT), may decrease treatment-related morbidities. In a multi-institutional retrospective review of gastrostomy tube use, the replacement rate dropped from 55% in patients with clinical stages III–IV to 28% in those with clinical stages I–II, with most patients receiving BNRT [1]. Furthermore, a recent study reported a notable reduction in lower gastric tube replacement rate to (9%) during the treatment period, and no patient required feeding tube 6 months post-treatment [2].
Studies of UNRT in OPSCC have reported contralateral neck recurrence rates (CNR) ranging from 0% to 14.3% [3-6]. These studies include a small number of N2b patients, as seen in the article entitled “Unilateral radiotherapy for tonsillar cancer with multiple ipsilateral neck lymph nodes” by Kim et al. [4] in the Radiation Oncology Journal. While some researchers are concerned that concluding UNRT is sufficient for tonsil cancer with N2b disease may be overly reassuring [5-7], other studies, including those by Kim et al. [4], have demonstrated that UNRT can achieve low CNR rates with minimal toxicity for these patients [2,8]. Thus, it is reasonable to conclude that the N2b category should not be treated as a single group, as sufficiently distinct subgroups exist within it when considering UNRT. There is currently a consensus that BNRT is not necessary for all patients with OPSCC. Factors such as midline tumors, high T stage, advanced ipsilateral nodal disease, multiple lymph node involvement (N2b), and extracapsular extension are associated with CNR [9]. The key challenges is selecting patients to receive UNRT. As some evidence suggests that N2b disease may carry an elevated risk of CNR, guidelines from the American College of Radiology and American Radium Society recommend definitive or adjuvant UNRT to the ipsilateral neck for well-lateralized tonsil-confined tumors with minimal lymph node involvement, suggesting that a subset of N2b patients may be appropriate candidates for UNRT [10,11].
Should We Encourage the Most of These N2b Patients Take Risks and Pursue Quality of Life or Not?
Before opting for UNRT in patients with N2b disease, several factors must be carefully considered, the most critical being a thorough evaluation of the contralateral neck. Advances in imaging diagnostics have improved accuracy in assessing the extent of the primary tumor and status of lymph node metastasis in head and neck cancer. If 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) is routinely performed for diagnostic purposes in all patients with head and neck cancer, as in the case of Kim et al. [4], the validity of UNRT is more likely to be supported than in situations where it is not used. If FDG PET-CT is not performed or if a diagnostic evaluation of the contralateral neck, such as ultrasound with fine needle aspiration or sentinel node biopsy, is not performed, BNRT should be prioritized. In addition, proper evaluation of tumor laterality is very important, for which a multidisciplinary approach, including the examination opinion of an experienced specialist, is essential rather than relying on imaging.
However, the choice of UNRT for patients with N2b OPSCC might be reasonable if salvage surgery is possible. Most studies report a high success rate of salvage surgery, even in cases of CNR after UNRT [2,5]; however, there are conflicting results that do not agree with this [3,7]. This seems to be related to factors such as patient age, preferences, medical condition, and resectability of the recurrent disease. Therefore, when considering UNRT for patients with well-lateralized N2b, it is crucial to take into account the various factors mentioned above. The optimal frequency of CT or magnetic resonance (MR) imaging after treatment in patients with head and neck cancer remains debatable; however, more frequent imaging may be beneficial in select cases. Follow-up guidelines typically recommend short-term CT or MR imaging at 3- to 4-month intervals after treatment [12]. However, shorter intervals may be considered if the treatment response is uncertain or based on the patient's specific clinical situation.
The decision to perform UNRT or BNRT in N2b well-lateralized tonsillar cancer is not straightforward. Instead, it is important to determine the balance between the risk of CNR and the toxicity associated with BNRT.
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Conflict of Interest
No potential conflict of interest relevant to this article was reported.