Freedom from local and regional failure of contralateral neck with ipsilateral neck radiotherapy for node-positive tonsil cancer: Updated results of an institutional clinical management approach

Histopathologic predictors of recurrence and survival in early T stage oral tongue squamous cell carcinoma

Objectives

Recurrence and survival in early T-stage oral tongue squamous cell carcinoma (OTSCC) may be impacted by histopathologic risk factors. This study aims to examine which of these factors predict long-term outcomes of T1 and T2 OTSCC.

Methods

A retrospective review of T1 and T2 OTSCC patients treated with surgery at a single tertiary care center was conducted. Multivariate regression and Kaplan-Meier survival plots were used to identify predictors of recurrence and compare disease-free survival respectively.

Results

100 consecutive patients were studied. Of these, 51 were staged pT1, 49 pT2, 69 pN0, 10 pN1, and 21 pN2. Multivariate regression analysis revealed that >4 nodes was the strongest predictor of overall recurrence [odds ratio 1.68 (1.23-2.28), p = 0.001], while >4 nodes [odds ratio 1.14 (1.09-1.85), p = 0.008] and pT2 [odds ratio 1.15 (1.01-1.30), p = 0.033] were predictors of local recurrence (R2 = 0.112). Five-year disease-free survival was not significantly impacted by any risk factors except for the number of positive nodes-86% for ≤4 nodes vs. 20% for >4 nodes (p < 0.001)-and pathologic T-stage-90% for pT1 vs. 75% for pT2 (p = 0.035) regardless of adjuvant radiation and/or chemotherapy use.

Conclusions

Patients who underwent adjuvant radiation and/or chemotherapy had similar survival to those who did not despite having worse overall tumor prognostic factors. Adding adjuvant therapy may equalize some high-risk histopathologic factors. In the highest risk patients-specifically those with pathologic >4 nodes and pT2 staging-adjuvant therapy should be considered.

Association of Unilateral Radiotherapy With Contralateral Lymph Node Failure Among Patients With Squamous Cell Carcinoma of the Tonsil: A Systematic Review and Meta-analysis

Importance

Ipsilateral neck radiotherapy (RT) is controversial in some patients with tonsil cancer due to concern for nodal failure within the contralateral nonirradiated neck (hereinafter referred to as contralateral neck failure [CNF]).

Objective

To determine the rate of CNF following ipsilateral neck RT in patients with tonsil cancer.

Data Sources

Databases including PubMed, Embase, Web of Science, and Cochrane Library were queried for peer-reviewed, English language articles published between January 1, 1980, and December 31, 2021.

Study Selection

Studies reporting rates of CNF from at least 20 patients treated with ipsilateral neck RT. Studies were excluded if they lacked full text, reported results from databases or systematic reviews, or did not provide RT details.

Data Extraction and Synthesis

Data were extracted following the PRISMA reporting guideline. Study quality was assessed using criteria from a methodological index for nonrandomized studies. Pooled outcomes were estimated using random-effects models.

Main Outcomes and Measures

Primary outcome was the pooled rate of CNF following ipsilateral neck RT. Secondary outcomes were the pooled rates of CNF by tumor and nodal staging categories from the 7th edition of the AJCC Cancer Staging Manual and rates of toxic effects.

Results

A total of 17 studies (16 retrospective and 1 prospective) including 1487 unique patients were identified. The pooled risk of CNF was 1.9% (95% CI, 1.2%-2.6%). The rate of CNF by tumor (T) category was as follows: 1.3% (95% CI, 0.3%-2.3%) for T1; 3.0% (95% CI, 1.6%-4.4%) for T2; 11.3% (95% CI, 3.3%-19.2%) for T3; and 16.0% (95% CI, -7.8% to 39.8%) for T4. Patients with T3 to T4 tumors had a significantly higher rate of CNF than those with T1 to T2 tumors (11.5% [95% CI, 3.9%-19.1%] vs 1.8% [95% CI, 1.0%-2.6%]; P < .001). The rate of CNF by nodal (N) category was 1.2% (95% CI, 0.1%-2.2%) for N0; 4.8% (95% CI, 2.4%-7.2%) for N1; 3.1% (95% CI, 0.4%-5.8%) for N2a; 3.1% (95% CI, 1.2%-4.9%) for N2b; and 0 (95% CI, not applicable) for N3. Rates of CNF were similar for patients with N2b to N3 and N0 to N2a disease (3.0% [95% CI, 1.2%-4.7%] vs 1.7% [95% CI, 0.6%-2.8%], respectively; P = .07). Compared with bilateral RT, ipsilateral RT was associated with increased risk of CNF (log odds ratio, 1.29 [95% CI, 0.09-2.48]; P = .04). The crude rates of xerostomia of grade 3 or greater and feeding tube use were 0.9% (95% CI, -0.2% to 1.9%) and 13.3% (95% CI, 8.3%-18.3%), respectively.

Conclusions and Relevance

In this systematic review and meta-analysis, ipsilateral neck RT was associated with a low rate of CNF in patients with small, lateralized tonsil cancers. Bilateral neck RT was associated with lower risk of CNF compared with ipsilateral neck RT. Patients with tumors of a higher T category were at increased risk for CNF following ipsilateral neck RT, and advanced nodal stage was not associated with CNF. Rates of toxic effects appeared favorable in patients treated with ipsilateral neck RT.

Patient- and Clinician-Reported Outcomes in Human Papillomavirus-Associated Tonsillar Carcinoma Treated With Unilateral and Bilateral Intensity Modulated Radiation Therapy-A Substudy From TROG 12.01

PURPOSE

The aim of this TROG 12.01 substudy was to report longitudinal variations in patient- (PRO) and clinician-reported outcomes based on receipt of unilateral (URT) or bilateral radiation therapy (BRT).

METHODS AND MATERIALS

Patients with lateralized T1-2 N1-2b human papillomavirus-associated tonsillar carcinoma (AJCC7) enrolled on TROG 12.01 were eligible. The primary endpoint was patient-reported radiation symptom severity score (MDASI-RSS) at 2 years, a composite of 9 MDASI-Head and Neck (HN) symptom items. Secondary endpoints included patient-reported symptom burden and interference (MDASI-HN), quality of life (FACT-HN), emotional distress (HADS), return to work (RTW), clinician-reported performance status scale (PSS-HN), and late adverse events (CTCAE). Mean MDASI-RSS, symptom severity (MDASI-SS), symptom interference (MDASI-SI) and selected single items were compared 1 week, 3 months, and 2 years post-RT.

RESULTS

Seventy-four patients were eligible for analysis (26 URT, 48 BRT). Median follow-up was 3.7 years (1.8-5.2 years). Sociodemographic, staging, and treatment variables were mostly balanced, with larger primaries observed in the BRT group. Four regional failures were reported (3 URT, 1 BRT), including one isolated contralateral regional failure in the URT cohort. Mean MDASI-RSS scores did not differ at 2 years (URT vs BRT, 1.1 vs 1.3; difference 0.1 [95% CI: -0.7 to 0.9], P = .75) or at any other time points for the MDASI-RSS, MDASI-SS, and MDASI-SI scores, except for worse MDASI-SI 1 week after treatment in the BRT group (4.7 vs 5.6). Fatigue (6.6 vs 5.4) at 1 week and dry mouth (3.5 vs 2.0) at 2 years were also worse in the BRT group. FACT-HN, HADS, RTW, PSS-HN, and CTCAE results were similar across the follow-up period.

CONCLUSIONS

In this favorable-risk cohort, treatment laterality resulted in fewer differences than anticipated in patient-reported or clinician-reported outcomes. Two years after treatment patients treated with BRT reported significantly worse dry mouth. Longer follow-up is needed to determine the impact of treatment laterality on late effects.

Long-term Locoregional Control With Unilateral Radiation for AJCC-7 T1-2N2b Tonsillar Cancer

OBJECTIVES

Unilateral radiation to cervical nodes has been used as a de-escalation strategy in well-lateralized tonsil cancers. The efficacy of this approach with multiple ipsilateral nodes is not established. The study hypothesis was that unilateral radiation for American Joint Committee on Cancer (AJCC)-7 T1-2N2b tonsillar cancer results in a low rate of contralateral nodal failure.

MATERIALS AND METHODS

This study was a retrospective chart review of patients with AJCC-7 T1-2N2b tonsillar cancer from 2 academic institutions who were treated with unilateral radiation. The primary endpoint was the contralateral nodal failure rate. Locoregional control, overall survival, and the need for gastrostomy tube placement were additional endpoints.

RESULTS

The study cohort included 66 patients treated between 2005 and 2016. The median follow-up time was 80.9 months; contralateral nodal failure occurred in 2/66 (3.0%) patients at 4.1 and 20.9 months, respectively. Both patients underwent salvage treatment with long-term subsequent survival. Overall locoregional control at both 2 and 5 years was 93.9% and the median duration of control was not reached. Overall survival at 5 years was 92.4%.

CONCLUSIONS

The use of unilateral radiation for AJCC-7 T1-2N2b tonsillar cancer resulted in low rates of contralateral nodal failure. This outcome demonstrates the safety of considering unilateral radiation treatment in patients with a relatively high ipsilateral nodal burden.

Swallowing After Primary TORS and Unilateral or Bilateral Radiation for Low- to Intermediate-Risk Tonsil Cancer

OBJECTIVE

The primary course of treatment for patients with low- to intermediate-risk tonsil cancer has evolved with a shift toward primary transoral robotic surgery (TORS) or radiation therapy (RT). While favorable outcomes have been reported after deintensification via unilateral TORS or RT (uniRT), comparisons of functional outcomes between these treatments are lacking. We compared clinical outcomes (Dynamic Imaging Grade of Swallowing Toxicity [DIGEST] and feeding tube [FT]) and patient-reported swallowing outcomes (MD Anderson Dysphagia Inventory [MDADI]) based on primary treatment strategy: TORS, uniRT, or bilateral RT (biRT).

STUDY DESIGN

Secondary analysis of prospective cohort.

SETTING

Single institution.

METHODS

The study sample comprised 135 patients with HPV/p16+ T1-T3, N0-2b (American Joint Committee on Cancer, seventh edition), N0-1 (eighth edition) squamous cell carcinoma of the tonsil were sampled from a prospective registry. Modified barium swallow studies graded per DIGEST, FT placement and duration, and MDADI were collected.

RESULTS

Baseline DIGEST grade significantly differed among treatment groups, with higher dysphagia prevalence in the TORS group (34%) vs the biRT group (12%, P = .04). No significant group differences were found in DIGEST grade or dysphagia prevalence at subacute and longitudinal time points (P = .41). Mean MDADI scores were similar among groups at baseline (TORS, 92; uniRT, 93; biRT, 93; P = .90), subacute (TORS, 83; uniRT, 88; biRT, 82; P = .38) and late time points (TORS, 86; uniRT, 86; biRT, 87; P = .99). FT placement and duration significantly differed among primary treatment groups (FT [median days]: TORS, 89% [3]; uniRT, 8% [82]; biRT, 37% [104]; P < .001).

CONCLUSION

While TORS and uniRT offer optimal functional outcomes related to dysphagia, results suggest that no measurable clinician-graded or patient-reported differences in swallow outcomes exist among these primary treatment strategies and biRT. Aside from baseline differences that drive treatment selection, differences in FT rate and duration by primary treatment strategy likely reflect diverse toxicities beyond dysphagia.

Contralateral nodal failures in oropharyngeal cancers after TORS and unilateral neck management: a retrospective study

Background

Report the incidence of contralateral nodal failure rates in well-lateralized oropharyngeal carcinoma treated with upfront surgery and unilateral neck management.

Methods

Lateralized oropharyngeal carcinomas treated with upfront surgery using transoral robotic surgery (TORS) and unilateral neck management (unilateral neck dissection ± unilateral radiation treatment) were identified. Primary endpoint was contralateral regional control (CRC). Secondary endpoints were local control (LC), and overall survival (OS).

Results

Thirty-two patients were included. Pathologic T categories included 66% pT1, 31% pT2 and 3% pT3. Nodal diseases comprised 41% N0 and 47% N1 (AJCC 8th). Twenty-three (72%) patients had HPV related tumors. 3-years CRC, LC and OS were 100%, 96% (89–100) and 96% (CI 89–100). One patient developed a second primary with contralateral nodal disease. Only one patient died from another primary cancer.

Conclusion

In selected patients with lateralized oropharyngeal cancer, treatment with TORS and ipsilateral management of the neck may be oncologically safe without significant risk of contralateral failure.

Level of evidence: Level 2.

Graphical abstract

Efficacy of Postoperative Unilateral Neck Irradiation in Patients with Buccal Mucosa Squamous Carcinoma with Extranodal Extension: A Propensity Score Analysis

Unilateral radiotherapy (RT) as a postoperative treatment for multiple ipsilateral lymph node (LN) metastases remains controversial. We investigated the efficacy of postoperative unilateral RT for buccal mucosa squamous cell carcinoma (BMSCC) with extranodal extensions (ENEs). We retrospectively reviewed the clinical records of 186 patients with ENE+ BMSCC who received postoperative RT during 1997-2016. Propensity score matching was used to establish comparable cohorts. The endpoints were contralateral nodal control (CLNC), overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS), local control (LC), and regional control (RC). After matching, 123 patients were selected for analysis; 45 (36.6%) and 78 (63.4%) patients underwent unilateral and bilateral RT, respectively. The median follow-up was 36.27 months. The survival outcomes in the unilateral and bilateral RT groups were similar: 3-year CLNC (85.6% vs. 89.1%, p = 0.748), OS (53.2% vs. 57.4%, p = 0.229), DFS (46.5% vs. 48.6%, p = 0.515), DMFS (70.7% vs. 72.0%, p = 0.499), LC (78.0% vs. 75.6%, p = 0.692), and RC (79.9% vs. 76.2%, p = 0.465). On multivariable Cox regression analysis, unilateral and bilateral RT showed comparable outcomes; the number of ENEs ≥ 4 was the only significant prognostic factor for all clinical outcomes. Using decision tree analysis, we classified our patients to have a low, intermediate, or high risk of contralateral failure based on three factors: number of ENEs, margin status, and tumor stage. In conclusion, postoperative unilateral RT did not worsen outcomes in patients with ENE+ BMSCC in this cohort. The decision tree model may assist physicians in optimizing and tailoring radiation fields.

Unilateral versus bilateral nodal irradiation: Current evidence in the treatment of squamous cell carcinoma of the head and neck

Cancers of the head and neck region often present with nodal involvement. There is a long-standing convention within the community of head and neck radiation oncology to irradiate both sides of the neck electively in almost all cases to include both macroscopic and microscopic disease extension (so called elective nodal volume). International guidelines for the selection and delineation of the elective lymph nodes were published in the early 2000s and were updated recently. However, diagnostic imaging techniques have improved the accuracy and reliability of nodal staging and as a result, small metastases that used to remain undetected and were thus in the past included in the elective nodal volume, will now be included in high-dose volumes. Furthermore, the elective nodal areas are situated close to the parotid glands, the submandibular glands and the swallowing muscles. Therefore, irradiation of a smaller, more selected volume of the elective nodes could reduce treatment-related toxicity. Several researchers consider the current bilateral elective neck irradiation strategies an overtreatment and show growing interest in a unilateral nodal irradiation in selected patients. The aim of this article is to give an overview of the current evidence about the indications and benefits of unilateral nodal irradiation and the use of SPECT/CT-guided nodal irradiation in squamous cell carcinomas of the head and neck.

Ipsilateral radiation for squamous cell carcinoma of the tonsil: American Radium Society appropriate use criteria executive summary

BACKGROUND

We conducted the current systemic review to provide up-to-date literature summary and optimal evidence-based recommendations for ipsilateral radiation for squamous cell carcinoma of the tonsil.

METHODS

We performed literature search of peer-reviewed journals through PubMed. The search strategy and subject-specific keywords were developed based on the expert panel's consensus. Articles published from January 2000 to May 2020 with full text available on PubMed and restricted to the English language and human subjects were included. Several prespecified search terms were used to identify relevant publications and additional evidence published since the initial American College of Radiology Appropriateness Criteria Ipsilateral Tonsil Radiation recommendation was finalized in 2012. The full bibliographies of identified articles were reviewed and irrelevant studies were removed.

RESULTS

The initial search and review returned 46 citations. The authors added three citations from bibliographies, websites, or books not found in the literature search. Of the 49 citations, 30 citations were retained for further detailed review, and 14 of them were added to the evidence table. Articles were removed from the bibliography if they were not relevant or generalizable to the topic, or focused on unknown primary disease. Several commonly encountered clinical case variants were created and panelists anonymously rated each treatment recommendation. The results were reviewed and disagreements discussed.

CONCLUSIONS

The panel provided updated evidence and recommendations for ipsilateral radiation for squamous cell carcinoma of the tonsil in the setting of primary radiation-based therapy and postoperative adjuvant radiotherapy. This committee did not reach agreements for some case variants due to a lack of strong evidence supporting specific treatment decisions, indicating a further need for research in these topics.

Early T1-T2 stage p16+ oropharyngeal tumours. Role of upfront transoral robotic surgery in de-escalation treatment strategies. A review of the current literature

Human papillomavirus is responsible of approximately 70% oropharyngeal tumours and is related with more favourable outcomes. It has led to an increasing interest for de-escalation treatment strategies such as Trans Oral Robotic Surgery (TORS). A literature review was performed searching for the role of TORS as de-escalation modality of treatment in patients with p16 positive oropharyngeal squamous cell carcinoma (OPSCC). Special attention was paid to the potential advantage offered by TORS in reducing adjuvant radiation therapy. Six questions were formulated. 67 studies were selected. Several trials analysing the role of upfront TORS to treat early stage p16+ OPSCC and the possibility of reducing the adjuvant radiotherapy were founded. A lot of studies based on the experience of single centres show promising results. Nevertheless to date no definitive data can be extrapolated. The continued investigation of this line of de-escalation therapy with randomized prospective clinical trials is needed.

Volume de-escalation in radiation therapy: state of the art and new perspectives

PURPOSE

New RT techniques and data emerging from follow-up for several tumor sites suggest that treatment volume de-escalation may permit to minimize therapy-related side effects and/or obtain better clinical outcomes. Here, we summarize the main evidence about volume de-escalation in RT.

METHOD

The relevant literature from PubMed was reviewed in this article. The ClinicalTrials.gov database was searched for clinical trials related to the specific topic.

RESULTS

In Lymphoma, large-volume techniques (extended- and involved-field RT) are being successfully replaced by involved-site RT and involved-node RT. In head and neck carcinoma, spare a part of elective neck is controversial. In early breast cancer, partial breast irradiation has been established as a treatment option in low-risk patients. In pancreatic cancer stereotactic body radiotherapy may be used to dose escalation. Stereotactic radiosurgery should be the treatment choice for patients with oligometastatic brain disease and a life expectancy of more than 3 months, and it should be considered an alternative to WBRT for patients with multiple brain metastases.

CONCLUSION

Further clinical trials are necessary to improve the identification of suitable patient cohorts and the extent of possible volume de-escalation that does not compromise tumor control.

Patient-reported quality of life and toxicity in unilateral and bilateral radiotherapy for early-stage human papillomavirus associated tonsillar carcinoma

Purpose

The purpose of this study was to compare self-reported health-related quality of life (QoL) and symptom burden in early stage tonsillar carcinoma patients treated with unilateral (URT) and bilateral radiotherapy (BRT).

Methods and materials

This is a secondary analysis of a larger study assessing patient reported outcomes in human papillomavirus (HPV) oropharyngeal cancer (OPC) patients. Recruited patients were ≥12 months from completion of radiotherapy. This analysis included only patients with T1-2, N1-2b tonsil cancer and excluded patients with base of tongue involvement or recurrent disease. QoL and patient reported toxicity was measured using the EORTC QLQ-C30 module and the MDASI-HN.

Results

Patients were enrolled from November 2018 to May 2019. Of the 136 patients recruited to the main study, 43 were eligible for this substudy (22 URT, 21 BRT), with a median age and follow up of 58.2 and 3.0 years respectively. The two groups were balanced with respect to patient, tumor and treatment factors with the exception of higher rates of T2 disease (27% v 71%, p = 0.006) and more extensive GTV nodal volumes (11.0 v 25.5cc, p = 0.006) in the BRT group.BRT patients had lower global health status/QoL (84 v 69, p = 0.0005) and social functioning scores (93 vs 78, p = 0.033) on the EORTC QLQ-C30, and higher symptom severity (0.6 vs. 2.0, p = 0.001) and symptom interference scores (0.8 vs. 2.0, p = 0.010) on the MDASI-HN. Four of the six largest differences observed on MDASI-HN items were attributable to radiotherapy technique (dry mouth, mucous, difficulty swallowing/chewing and taste), with corresponding dose differences to the respective organs (contralateral parotid, oral cavity and pharyngeal constrictors). In every instance, severity of symptoms was worse on average for patients treated with BRT.

Conclusions

In the highly conformal radiotherapy era, BRT in early HPV tonsillar cancer survivors has an enduring impact on long-term QoL and toxicity.

Risk of post-operative, pre-radiotherapy contralateral neck recurrence in patients treated with surgery followed by adjuvant radiotherapy for human papilloma virus-associated tonsil cancer

OBJECTIVE

One approach to reduce treatment-related morbidity for human papilloma virus (HPV)-associated tonsil cancer is omitting radiotherapy to the contralateral neck. Pathologic risk factors for early contralateral neck disease, however, are poorly understood. We report on the risk contralateral neck failures from the time of pre-operative diagnostic imaging to time of planning for adjuvant radiation in a single institution series of HPV-associated tonsillar cancer patients undergoing surgery followed by radiotherapy (RT).

METHODS

Retrospective analysis of 123 patients with T1-T3 HPV-positive tonsillar squamous cell carcinoma treated between 2010 and 2016 with transoral robotic surgery and selective ipsilateral neck dissection followed by adjuvant RT. Contralateral neck recurrence was classified as the detection of a pathologic node in the contralateral neck prior to initiation of adjuvant RT.

RESULTS

Seven patients (5.7%) developed contralateral neck disease/failure between the time of pre-operative diagnostic neck imaging and time of planning of adjuvant radiation. Increased ratio of positive/resected nodes [odds ratio (OR) 1.073, p = 0.005] was significantly associated with increased risk of contralateral neck recurrence, with a trend found for close/positive margins (OR 5.355, p = 0.06), tumor size (OR 2.046, p = 0.09), and total number of nodes positive (OR 1.179, p = 0.062).

CONCLUSIONS

Patients who develop very early contralateral neck disease, between completion of ipsilateral neck dissection and the initiation of radiotherapy, have a higher ratio of positive nodes to total nodes resected in the ipsilateral neck. These findings suggest that proper selection of patients for omission of treatment of the contralateral, node-negative neck should be made with this in mind, with future studies needed to document the impact on toxicity and disease outcomes from such an approach.

ADVANCES IN KNOWLEDGE

Pathologic risk factors in the dissected, ipsilateral neck in patients with tonsil cancer may inform the risk of contralateral neck failure. Patient selection for future, prospective efforts to examine sparing of the contralateral neck need to be based with these risk factors in mind.

Post-operative radiation effects on lymphopenia, neutrophil to lymphocyte ratio, and clinical outcomes in palatine tonsil cancers

OBJECTIVE

To evaluate radiation-induced lymphopenia associated with unilateral vs. bilateral neck radiation and to test post-treatment neutrophil to lymphocyte ratio (NLR) as a prognostic clinical biomarker.

METHODS

This was a single academic center retrospective review of palatine tonsil squamous cell cancer patients treated with post-operative intensity modulated radiation therapy (IMRT) from 1997 to 2013. Absolute lymphocyte count (ALC) and NLR were evaluated during and after radiation for up to a year. Correlations of lab values with loco-regional control (LRC), freedom from distant metastases (FFDM), and overall survival (OS) were assessed.

RESULTS

Ninety-nine patients with median follow up 5.8 years had ALC recorded at least at baseline and within one year of starting RT. Acute grade 3-4 lymphopenia (<10 weeks from RT start) occurred in 79% of bilateral neck RT patients (n = 70) and 58% of unilateral neck RT patients (n = 29), p = 0.03. There was no significant difference in late grade 3-4 (p = 0.12) lymphopenia. In a multivariable Cox regression model, acute NLR > 11.875 correlated with worse OS (HR = 4.4, 95% CI 1.2-16). Late NLR > 6.875 independently correlated with significantly worse FFDM (HR = 16, 95% CI 1.9-137) and OS (HR = 12, 95% CI 3.0-48).

CONCLUSIONS

Unilateral neck radiation may prevent acute iatrogenic immunosuppression. In exploratory analyses, elevated post-treatment NLR was associated with risk for distant metastases and death.

Comparison of the Clinical Outcomes of Patients with Squamous Cell Carcinoma of the Tonsil Receiving Postoperative Ipsilateral Versus Bilateral Neck Radiotherapy: A Propensity Score Matching Analysis (KROG 11-07)

Purpose

The impact of postoperative ipsilateral neck radiotherapy (INRT) versus bilateral neck radiotherapy (BNRT) on the clinical outcomes of patients with tonsillar squamous cell carcinoma was analyzed retrospectively.

Materials and Methods

Between October 2001 and June 2012, 241 patients with T1-2 and N0-N2b tonsillar carcinoma from 16 institutes underwent postoperative INRT (n=84) or BNRT (n=157) following a tonsillectomy. Seventy patients were identified from each group by propensity score matching and compared in terms of the overall survival (OS), disease-free survival (DFS), locoregional relapse-free survival (LRRFS), and distant metastasis-free survival (DMFS) rates calculated using the Kaplan-Meier method with a log-rank test.

Results

The median follow-up was 55 months (range, 3 to 133 months). The survival outcomes in the INRT and BNRT groups were similar: 5-year OS (92.8% vs. 94.0%, p=0.985), DFS (80.5% vs. 94.2%. p=0.085), LRRFS (88.1% vs. 97.1%, p=0.083), and DMFS (92.7% vs. 97.0%, p=0.370). Subgroup analysis revealed no contralateral neck recurrence in 61 patients with T1-2N0-2a regardless of the treatment groups. For 79 patients with N2b, contralateral neck recurrence was more common in the INRT group than in the BNRT group (7.9% vs. 0.0%), but the difference was not significant (p=0.107). The overall grade ≥ 2 toxicities were lower in the INRT group: acute (45.7% vs. 74.3%, p=0.001) and late (4.3% vs. 31.4%, p < 0.001), respectively.

Conclusion

INRT is an attractive strategy for patients with T1-2N0-2a tonsillar carcinoma compared to BNRT. For patients with N2b, there was a small risk of contralateral neck recurrence when treated with INRT, but its impact on the OS was limited with successful salvage treatment.