In-vivo lymphoscintigraphy of sinonasal tumors identifies retropharyngeal node and level I as predominant sentinel nodes

OBJECTIVE

To evaluate by in- vivo lymphoscintigraphy and SPECT-CT imaging, the lymphatic drainage patterns of para-nasal sinus(PNS) tumors. To confirm or refute the belief of the retropharyngeal lymph node (RPLN) being the significant draining lymph node for such tumors.

METHODS

Prospective cohort study conducted on previously untreated PNS tumors with no clinico-radiological evidence of lymph node metastasis. Lymphoscintigraphy undertaken by nasal endoscopic assisted peritumoral injection of 99mTc Sulfur colloid. Injections were classified as anterior or posterior as per a vertical line along the maxillary sinus ostium.

RESULTS

17 patients were included. Lymphoscintigraphy successfully identified 17 sentinel nodes in 15 patients and was unsuccessful (lymphoscintigraphy failure) in 2 patients. Predominant sites of sentinel lymphatic drainage were noted to be the RPLN (n = 8; 47%), and Level I (n = 7; 42%). Occasional drainage was identified at the peri-parotid node(n = 1) and at Level II (n = 1). Contralateral drainage was noted in 2 patients (level I-1 and RPLN-1). Anterior injections drained predominantly to Level I (6/8) and RPLN (2/8), while posterior injections drained predominantly to the RPLN ( 6/7). The relative risk of RPLN being identified as the sentinel node was significantly higher for posteriorly placed injections than for anteriorly placed injections (RR- 3.43; 95% CI-1.0-11.8, p = 0.05).

CONCLUSION

The RPLN is noted as a frequent draining node for sino-nasal tumours and merits routine attention in all sino-nasal tumors. The radio-colloid SPECT-CT technique described here offers an excellent in-vivo technique to further explore and validate the lymphatic drainage pathways of these tumours.

Prevalence and prognostic impact of retropharyngeal lymph nodes metastases in oropharyngeal squamous cell carcinoma: Meta-analysis of published literature

BACKGROUND

This systematic review and meta-analysis aims to estimate the prevalence and prognostic impact of retropharyngeal lymph node metastases (RLNMs) in oropharyngeal squamous cell carcinoma (OPSCC).

METHODS

This meta-analysis was conducted according to PRISMA guidelines.

INCLUSION CRITERIA

studies with more than 20 patients reporting the prevalence or prognostic impact of RLNMs in OPSCC. Whenever available, data on HPV status and subsites were extracted.

RESULTS

Twenty-two articles were included. The overall prevalence of RLNMs in OPSCC was 13%, with no significant differences depending on HPV status. The highest prevalence was observed for posterior pharyngeal wall SCC (24%), followed by soft palate (17%), palatine tonsil (15%), and base of tongue (8%). RLNMs were associated with a significantly higher risk of death (HR:2.54;IC95%1.89-3.41) and progression (HR:2.44;IC95%1.80-3.30).

CONCLUSIONS

The prevalence of RLNMs in OPSCC was 13%, being higher in tumors of the posterior pharyngeal wall. RLNMs were associated with unfavorable outcomes.

Novel Strategies for Managing Retropharyngeal Lymph Node Metastases in Head and Neck and Thyroid Cancer with Transoral Robotic Surgery (TORS)

Retropharyngeal metastases are encountered in a variety of head and neck malignancies, imposing significant surgical challenges owing to their distinct location and proximity to neurovascular structures. Radiotherapy is the recommended treatment in most cases owing to its oncological efficacy. However, retropharyngeal irradiation affects the superior pharyngeal constrictor muscles and parotid glands, with the potential for long-term dysphagia and xerostomia. A younger oropharyngeal and thyroid cancer patient demographic is trending, fueling interest in treatment de-escalation strategies. Consequently, reducing radiotoxicity and its long-term effects is of special relevance in modern head and neck oncology practice. Through its unique ability to safely extirpate these traditionally difficult-to-access retropharyngeal lymph nodes via a natural orifice, TransOral Robotic Surgery (TORS) can considerably lower the surgical morbidity of retropharyngeal lymph node dissection (RPLND), compared with current existing approaches. This review summarizes the latest developments in the field, exposing current research gaps and discusses specific clinical settings where TORS could enable treatment de-escalation. In early-stage node-negative oropharyngeal cancer, single-modality surgical treatment with TORS RPLND may improve risk stratification of metastasis and recurrence in this region. TORS RPLND is also a potentially viable treatment option in salvage of an isolated retropharyngeal node recurrence or in the primary setting of a thyroid malignancy with a single positive retropharyngeal node. In time, TORS RPLND may provide an alternative de-escalation strategy in these three scenarios. However, with the reported morbidities, further prospective trials with long-term follow-up data are required to prove oncological safety and functional benefits over existing strategies.

Oropharyngeal Carcinoma Treated with Surgery Alone: Outcomes and Predictors of Failure

OBJECTIVE

To analyze the oncologic outcomes and risk factors for recurrence in patients who underwent surgery for oropharyngeal squamous cell carcinoma (OPSCC), and in whom adjuvant therapy was not recommended or was declined.

METHODS

Retrospective cohort study of patients with OPSCC who were treated with transoral surgery only at a tertiary care academic medical center from April 2010 to March 2019.

RESULTS

Seventy-four patients met inclusion criteria. In 16, adjuvant therapy was recommended but declined. There were 8 recurrences, of which 6 had been given recommendations for adjuvant therapy. Of the 8 recurrences, 2 died, 2 are alive with disease, and 4 were successfully salvaged. Five patients died of unrelated causes. Lymphovascular invasion (LVI, P = .016) had a significant impact on recurrence, while other pathologic features of the primary tumor such as size, location, human papillomavirus (HPV) status, and margin status did not. Margins were classified as "positive" in 4 patients, "close" in 54, and "negative" in 16. There were 3 local recurrences (4.1%), each of whom had declined adjuvant therapy. Lymph node features such as N-stage (P = .0004), number of positive nodes (P = .0005), and presence of extra-nodal extension (ENE, P = .0042) had a statistically significant impact on relapse. Smoking history and surgical approach showed no significant impact on recurrence.

CONCLUSION

Patients who undergo surgery for HPV-positive OPSCC with negative margins, no PNI, no LVI, and ≤1 positive lymph node without ENE have low risk for recurrence. These patients can likely be safely treated with surgery alone. Patients with these risk factors who decline adjuvant therapy are at risk for recurrence, and should be monitored.

Is the retropharyngeal lymph node the first echelon node for carcinoma tonsil? Prospective evaluation and literature review

PURPOSE

Tonsil cancer being predominantly treated by non-surgical means, there is a paucity of data on lymph nodal drainage pathways and histo-pathologically confirmed metastatic rates. This study assesses the retropharyngeal lymph node (RPLN) in N0 squamous cell carcinoma tonsil as a possible first echelon node and a site for occult metastasis.

METHODS

Prospective study involving treatment naïve N0 carcinoma tonsil treated by primary surgery and adjuvant treatment from June 2017 to March 2019. In-vivo lymph nodal drainage patterns were assessed by sentinel node mapping by preoperative SPECT-CT and intra-operative hand-held Gamma probe. All patients had a subsequent Level I-III/IV sampling neck dissection supplemented with RPLN dissection. Histological evaluation of sentinel nodes and RPLN involved step-serial sectioning and pan-cytokeratin immunohistochemistry. A comprehensive literature review was performed with keywords "retropharyngeal lymph node", "oropharynx", "tonsil", "squamous cell carcinoma" to determine the incidence of RPLN positivity in previously published series.

RESULTS

Sentinel node was successfully identified by SPECT-CT in all 17 patients (ipsilateral level 2a-13/17, 2b-1/17, 3-1/17; bilateral 2a-1/17; isolated contralateral retropharyngeal node-1/17). 8/17 had occult neck metastasis. In no patient was an ipsilateral RPLN identified as the sentinel node. Histological sampling did not indicate metastatic tumor in the RPLN in any patient (0/17). A systematic literature review further confirmed that RPLN metastasis in oropharyngeal cancer is noted only in the presence of pN + disease at other neck levels, and isolated RPLN metastasis is extremely rare (1.2%).

CONCLUSION

The ipsilateral RPLN is not identified either as the first echelon node or as a site of occult metastatic disease in N0 tonsil cancer.

CTRI REGISTRATION

CTRI/2019/06/019551.

Transoral Robotic Retropharyngeal Lymph Node Dissection in Nasopharyngeal Carcinoma With Retropharyngeal Lymph Node Recurrence

OBJECTIVES

Nasopharyngeal carcinoma (NPC) patients with retropharyngeal lymph node (RPLN) recurrence typically undergo reirradiation and experience severe radiotoxicity. Salvage open surgery is challenging because gaining access to the retropharyngeal space is complex and risky. Thus, only several centers can perform this procedure, and complications are common. We applied transoral robotic surgery RPLN dissection (TORS-RPLND) to NPC patients with RPLN recurrence to address the problem with open surgery.

MATERIALS AND METHODS

From March 2017 to October 2020, 10 NPC patients with RPLN recurrence underwent TORS-RPLND using the da Vinci Si/Xi Surgical System. We applied the balloon occlusion test to protect the internal carotid artery, induction chemotherapy to shrink large tumors preoperatively, and ultrasound positioning to effectively locate unrecognizable RPLNs during surgery. Clinical characteristics, complications, and survival outcome data were retrospectively collected.

RESULTS

Of 10 patients, 8 underwent en bloc resection via TORS-RPLND, and the remaining 2 patients were converted to open surgery because we failed to identify the RPLN during TORS. After introducing intraoperative ultrasound positioning, no such failure occurred. The mean operative time and intraoperative blood loss were 297 ± 120 min and 40 ± 43 ml, respectively. All surgical margins were negative. TORS-related complications were mild, and the most severe one was grade 3 dysphagia in one patient who underwent conversion to open surgery (10%). With a median follow-up of 19 months, only 1 (10%) patient developed cervical recurrence.

CONCLUSIONS

TORS-RPLND is feasible, safe, and effective in the treatment of NPC patients with RPLN recurrence, especially with the help of intraoperative ultrasound positioning.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E1895-E1902, 2021.

Retropharyngeal Lymph Node Involvement in Oropharyngeal Carcinoma: Impact upon Risk of Distant Metastases and Survival Outcomes

The influence of retropharyngeal lymph node (RPLN) involvement on prognosis in oropharyngeal carcinoma remains poorly defined. The aim of this study was to assess the impact of RPLN involvement upon outcomes. A single-centre retrospective analysis of 402 patients with oropharyngeal carcinoma treated nonsurgically between 2010 and 2017 was performed. All had a baseline 2-[fluorine-18]-fluoro-2-deoxy-d-glucose (FDG) PET-CT and contrast-enhanced MRI and/or CT. RPLN status was determined by radiology review of cases with reported abnormal RPLN. Multivariate backwards logistic regression was used to examine impact on outcomes of factors. Abnormal RPLNs were identified in 40/402 (10%) of patients. Median follow up was 42.9 months. RPLN involvement was associated with inferior 3 year outcomes for overall survival (OS) (67.1% vs. 79.1%, p = 0.006) and distant metastases-free survival (DMFS) (73.9% versus 88.0%, p = 0.011), with no significant difference in local control (81.6% vs. 87.7%, p = 0.154) or regional control (80.7% vs. 85.4%, p = 0.252). On multivariate analysis abnormal RPLN, no concurrent chemotherapy and ongoing smoking were associated with inferior DMFS and OS, while advanced T stage was also associated with inferior OS. In summary, RPLN involvement, present in 10% of patients, was an independent prognostic factor for the development of distant disease failure translating into inferior OS. These findings need confirmation in future studies.

Incidence and patterns of retropharyngeal lymph node involvement in oropharyngeal carcinoma

INTRODUCTION

The aim was to evaluate in oropharyngeal carcinoma the: (1) incidence and predictors of retropharyngeal (RP) lymph node (LN) involvement, (2) pattern of ipsilateral/bilateral/contralateral-only RP LNs (3) location of RP LNs in relation to contouring guidelines.

METHODS

Single centre retrospective analysis of 402 patients with oropharyngeal carcinoma treated non-surgically between 2010 and 2017. All patients had a baseline FDG PET-CT and contrast-enhanced MRI and/or CT. All cases with reported abnormal RP LNs underwent radiology review.

RESULTS

Abnormal RP LNs were identified in 40/402 (10%) of patients. On multivariate analysis, RP LN involvement was associated with posterior pharyngeal wall/soft palate primaries (OR 10.13 (95% CI 2.29-19.08), p = 0.002) and contralateral cervical LN involvement (OR 2.26 (95% CI 1.05-4.86), p = 0.036). T stage, largest LN size, levels of ipsilateral LN level involvement, HPV and smoking status did not predict risk. 5/402 (1.2%) patients had bilateral RP involvement. 3/402 patients (0.7%) had contralateral-only RP LNs. All patients with contralateral RP LNs had contralateral neck nodes or primary cancers extending across midline. In 5/40 (12.5%) cases with involved RP LNs, the RP LNs were superior to hard palate/upper edge of body of C1 vertebra.

CONCLUSIONS

RP LNs were identified in 10% of oropharyngeal carcinoma patients, and were associated with contralateral neck disease and/or posterior pharyngeal wall/soft palate primary. Contralateral RP LN involvement was rare and associated with contralateral neck disease and/or primary crossing midline, suggesting potential for omission from target volumes for selected patients. Involvement of RP LNs close to the skull base highlights the need for generous elective outlining.

Radiographic retropharyngeal lymph node involvement in HPV-associated oropharyngeal carcinoma: Patterns of involvement and impact on patient outcomes

BACKGROUND

The objective of the current study was to characterize the incidence, pattern, and impact on oncologic outcomes of retropharyngeal lymph node (RPLN) involvement in HPV-associated oropharyngeal cancer (OPC).

METHODS

Data regarding patients with HPV-associated OPC who were treated at The University of Texas MD Anderson Cancer Center with intensity-modulated radiotherapy from 2004 through 2013 were analyzed retrospectively. RPLN status was determined by reviewing pretreatment imaging and/or reports. Outcomes analysis was restricted to patients with lymph node-positive (+) disease. Kaplan-Meier survival estimates were generated and survival curves were compared using the log-rank test. Bayesian information criterion assessed model performance changes with the addition of RPLN status to current American Joint Committee on Cancer staging. Competing risk analysis compared modes of disease recurrence.

RESULTS

The incidence of radiographic RPLN involvement was 9% (73 of 796 patients) and was found to vary by primary tumor site. The 5-year rates of freedom from distant metastases (FDM) and overall survival were lower in patients with RPLN(+) status compared with those with RPLN-negative (-) status (84% vs 93% [P = .0327] and 74% vs 87% [P = .0078], respectively). RPLN(+) status was not found to be associated with outcomes on multivariate analysis. Bayesian information criterion analysis demonstrated that current American Joint Committee on Cancer staging was not improved with the inclusion of RPLN. Locoregional and distant disease recurrence probabilities for those patients with RPLN(+) status were 8% and 13%, respectively, compared with 10% and 6%, respectively, for those with RPLN(-) status. RPLN(+) status portended worse 5-year FDM in the low-risk subgroup (smoking history of <10 pack-years) and among patients who received concurrent chemotherapy but not induction chemotherapy.

CONCLUSIONS

RPLN(+) status was associated with worse overall survival and FDM on univariate but not multivariate analysis. In subgroup analyses, RPLN(+) status was associated with poorer FDM in both patients with a smoking history of <10 pack-years and those who received concurrent chemotherapy, suggesting that RPLN(+) status could be considered an exclusion criteria in treatment deintensification efforts seeking to omit chemotherapy.

Omitting Elective Irradiation of the Contralateral Retropharyngeal Nodes in Oropharyngeal Squamous Cell Carcinoma Treated with Intensity-modulated Radiotherapy

Introduction: The use of intensity-modulated radiation therapy (IMRT) in head and neck cancers has allowed for selective sparing of low-risk or uninvolved lymph nodes. In oropharyngeal cancers, the benefits and risks of omitting contralateral retropharyngeal lymph nodes (RPLN) remain uncertain. This study examines the outcomes of elective coverage of contralateral RPLN in oropharyngeal cancer treated with definitive IMRT.

Methods: We analyzed 54 patients with newly diagnosed unilateral tonsil or base of tongue squamous cell carcinoma with at most unilateral neck involvement (cN0-N2b) and no RPLN involvement. These patients had no prior head and neck irradiation and were treated with definitive radiotherapy or chemoradiotherapy between 2012 and 2017. Cumulative incidences of local/regional/distant failure were estimated using competing risks methodology, and overall survival (OS) was estimated using the Kaplan-Meier method.

Results: All patients received elective nodal coverage to the ipsilateral RPLN, and 38 (62%) patients did not receive elective treatment of the contralateral RPLN. There were no significant differences in baseline characteristics. There were no contralateral RPLN failures observed. When comparing patients who received contralateral RP treatment with those who did not, there were no significant differences in two-year local failure (23% vs. 9%, p = 0.09), regional failure (18% vs. 4%, p = 0.12), or distant failure (15% vs. 9%, p = 0.62). Two-year OS was 89%. Mean parotid dose was not significantly lower after sparing vs. treating the contralateral RPLN (median 25.6 vs. 32.7 Gy, p = 0.15).

Conclusions: The omission of contralateral RPLN irradiation in tonsil or tongue base carcinomas with unilateral neck involvement is safe without compromising disease control.

The interplay of IMRT and transoral surgery in HPV-mediated oropharyngeal cancer: Getting the balance right

Transoral surgery (TOS) and IMRT represent two primary local ablative treatment modalities for oropharyngeal cancer (OPC). The choice of one over the other represents an interplay between the chance of cure vs risk of late sequelae. HPV-mediated (HPV+) OPC patients generally have excellent outcomes, especially in TNM-8 stage I disease. Controversies exist over which treatment has a more favorable toxicity profile and equal efficacy in the management of this population. Non-randomized retrospective data show comparable oncological and functional outcomes between TOS-based vs IMRT-based treatment for this disease. Several de-intensification concepts have been explored in this subset in both primary surgery-based vs primary radiotherapy-based trials. However, no robust mature trial data are available to convincingly guide treatment selection. TOS is often presented as one of the de-intensification options although the majority of series also describe the use of adjuvant treatments which inevitably result in non-negligible toxicities. Patient selection and surgeons' training are paramount. Understanding tumor biology and the prognostic value of traditional 'adverse' features will further guide trial design for refinement of risk tailored approach. In conclusion, comparative data suggests TOS and IMRT are both effective treatment for TNM-8 stage I HPV+ OPC with similar oncological and functional outcomes. TOS as a single modality has potential advantages in mitigating radiation included toxicities. TOS should be avoided in the presence of clinically overt extranodal extension or when negative margins are unlikely to be achieved. TOS is also less ideal for cases with radiological features predicting a high risk of distant metastasis.

Effectiveness of superselective intra-arterial chemoradiotherapy targeting retropharyngeal lymph node metastasis

We sought to evaluate the efficacy and feasibility of superselective intra-arterial infusion of high-dose cisplatin with concomitant radiotherapy (hereafter RADPLAT) for head and neck squamous cell cancer (hereafter HNSCC) patients with retropharyngeal lymph node (hereafter RPLN) metastasis. A retrospective case series review was conducted at University medical center in Japan. Ten HNSCC patients with RPLN metastasis treated by RADPLAT were analyzed. The ascending pharyngeal artery was targeted for the treatment of RPLN metastasis in 9 patients. The median total dose of cisplatin was 26.6 mg/m(2) (mean 31.5 mg/m(2), range 11.7-87.9 mg/m(2)). In the remaining patient, the RPLN was supplied by the ascending palatine artery. As grade 3 and 4 adverse effects, leukopenia was observed in three, mucositis in four and nausea in one patient. No neurological complications were observed in any patients. Metastatic RPLNs were evaluated as a complete response in all patients. There was no recurrence of RPLN metastasis in any patients. Four patients remain alive without any evidence of disease and six patients died of disease. The 5-year overall survival rate was 50 %. We have shown that superselective intra-arterial cisplatin infusion for RPLNs was a feasible and effective approach for HNSCC patients with RPLN metastasis.