Management of unknown primary head and neck cancer with radiation therapy in the era of human papillomavirus (HPV): No longer cutting down the tree to get an apple

PURPOSE

Given the central role that radiation has in the management of head and neck squamous cell carcinoma of unknown primary origin, it is imperative to review how treatment paradigms have been refined and continue to evolve in the modern era.

METHODS AND MATERIALS

This study was designed based on the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) statement. A literature search of peer-reviewed publications was undertaken to identify works pertaining to the use of radiation for squamous cell carcinoma of unknown primary origin presenting as cervical lymph node metastases. Articles published from January 2002 to January 2023 with full text available on PubMed and restricted to the English language and human subjects were included. The full bibliographies of identified articles were reviewed and irrelevant studies were removed.

RESULTS

While such breakthroughs as intensity-modulated radiotherapy, positron emission tomography, biomarker testing with immune-histochemistry, and minimally invasive surgical techniques such as transoral robotic surgery have fundamentally changed the approach to this disease in recent decades, controversies still exist with respect to the manner in which radiation is delivered. Although the incidence of head and neck unknown primary cancer is relatively low, questions regarding the necessity of comprehensive radiation using the age-old standard method of targeting the bilateral necks and entire pharyngeal axis to encompass all putative sites of mucosal disease persist.

CONCLUSIONS

Prospective evidence is lacking, and the available studies have been complicated by such factors as the relatively limited sample sizes, as well as the variability in work-up, treatment, inclusion criteria, and follow-up. Regardless, advances in science and technology have ushered in more precise approaches with a high degree of customization, particularly given the increased proportion of patients presenting with human papillomavirus-related disease.

Long-term results of radio(chemo)therapy in metastatic carcinoma to cervical lymph nodes from an unknown primary. Adult Comorbidity Evaluation 27 score as a predictor of survival

PURPOSE

To evaluate the effectiveness and toxicity of curative (chemo)radiotherapy in patients with metastatic carcinoma to cervical lymph nodes from an unknown primary.

METHODS

Retrospective study of 90 consecutive patients, treated with curative radiotherapy from 2003 to 2018 (median age 59 years; current/former smokers 76%) was conducted. The distribution of nodal staging was as follows: N1: 12%, N2a: 21%, N2b: 43%, N2c: 10%, N3: 13%. In 62% of patients, neck dissection was performed before radiotherapy. Concomitant chemotherapy was given to 64% of patients.

RESULTS

The median follow-up of surviving patients was 86 months. The median total radiotherapy dose achieved was 70 Gy. The 5‑ and 10-year locoregional control were 84% in both cases, while 5‑ and 10-year distant control were 90% and 89%, respectively. A primary tumor in the head and neck area was detected in only 2 patients. No patient had an initial failure in the pharyngeal axis or contralateral cervical nodes. The 5‑ and 10-year overall survival were 55% and 42%, respectively. Severe early toxicity occurred in 71%; severe late toxicity in 33% of patients. Multivariate analysis demonstrated N‑status (hazard ratio [HR] 2.424; 95% confidence interval [CI] 1.121-5.241; p = 0.024) and comorbidity scores assessed by ACE-27 (Adult Comorbidity Evaluation; HR 3.058; 95% CI 1.489-6.281; p = 0.002) as two independent prognostic factors for overall survival.

CONCLUSION

The results of our work study demonstrate the high effectiveness of curative (chemo)radiotherapy on the pharyngeal axis and bilateral cervical nodes with long-term locoregional and distant control in 3/4 of the treated patients. N‑status and comorbidity scores were shown as strong prognostic factors influencing overall survival.

The prognostic role of radiotherapy and radiotherapy target in cervical lymph node metastatic squamous cell carcinoma with unknown primary: a retrospective study

OBJECTIVES

Aim to analyze the effect of radiotherapy for cervical lymph node metastatic carcinoma with unknown primary (CCUP) and compare the survival benefits between Comprehensive radiotherapy and Involved Field radiotherapy.

MATERIALS AND METHODS

The patients diagnosed with CCUP between 2009 and 2019 in our institution were analyzed retrospectively. The categorical variables were tested by χ² test. Kaplan-Meier method was used for survival analysis. Log-rank test and Cox proportional hazards regression were performed with overall survival (OS) and disease-free survival (DFS) as the primary outcome variables.

RESULTS

Of 139 patients, 64.7% (90/139) of them received radiotherapy. Of the 90 patients who underwent radiotherapy, 45.6% (41/90) received Involved Field radiotherapy and the rest 49 patients received Comprehensive radiotherapy. The median follow-up of 139 patients is 69 months. The 1-year, 3-year, and 5-year OS rates are 87%, 62%, and 39%, respectively, and the DFS rates are 73%, 45%, and 29%, respectively. Multivariate analysis of 139 patients with CCUP shows that differentiation grade, N stage, radiotherapy, and the length of the largest lymph node (D_maxLN) are the independent prognostic factors for both OS and DFS. Subgroup analysis of 90 patients who received radiotherapy shows that the Comprehensive radiotherapy group has a better OS (P < 0.001) and DFS (P < 0.001) compared with Involved Field radiotherapy.

CONCLUSION

Radiotherapy is the independent prognostic factor for CCUP. Comprehensive radiotherapy may be superior to Involved Field radiotherapy in survival benefits.

Diagnosis and Management of Squamous Cell Carcinoma of Unknown Primary in the Head and Neck: ASCO Guideline

PURPOSE

To provide evidence-based recommendations to practicing physicians and other health care providers on the diagnosis and management of squamous cell carcinoma of unknown primary in the head and neck (SCCUP).

METHODS

The American Society of Clinical Oncology convened an Expert Panel of medical oncology, surgery, radiation oncology, radiology, pathology, and advocacy experts to conduct a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and prospective and retrospective comparative observational studies published from 2008 through 2019. Outcomes of interest included survival, local and regional disease control, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 100 relevant studies to inform the evidence base for this guideline. Four main clinical questions were addressed, which included subquestions on preoperative evaluations, surgical diagnostic and therapeutic procedures, appropriate pathology techniques, and adjuvant therapy.

RECOMMENDATIONS

Evidence-based recommendations were developed to address preoperative evaluation for patients with a neck mass, surgical diagnostic and therapeutic procedures, appropriate treatment options in unilateral versus bilateral SCCUP.Additional information is available at www.asco.org/head-neck-cancer-guidelines.

Evaluation of radiation treatment volumes for unknown primaries of the head and neck in the era of FDG PET

Objectives

Positron-emission tomography (PET) has improved identification of the primary tumor as well as occult nodal burden in cancer of the head and neck. Nevertheless, there are still patients where the primary tumor cannot be located. In these situations, the standard of care is comprehensive head and neck radiation therapy however it is unclear whether this is necessary. This study examines the effects of radiation treatment volume on outcomes among using data from two cancer centers in unknown primary carcinoma of the head and neck.

Methods

Patients received unilateral (n = 34), or bilateral radiation (n = 28). Patient factors such as age, gender, smoking history, and patterns of failure were compared using Mann Whitney U and Chi Square. Overall survival (OS) and disease free survival (DFS) trends were estimated using Kaplan-Meier survival curves. Effect of treatment volume on survival was examined using multivariate cox proportional hazard regression model.

Results

No significant differences were observed in the frequency of local (p = 0.32), regional (p = 0.50), or distant (p = 0.76) failures between unilateral and bilateral radiation therapy. By Kaplan-Meier estimates, OS (3-year OS bilateral = 71.67%, unilateral = 77.90%, p = 0.50) and DFS (3-year DFS bilateral = 77.92%, unilateral = 69.43%, p = 0.63) were similar between the two treatment approaches. Lastly, multivariate analysis did not demonstrate any significant differences in outcome by treatment volumes (OS: HR = 0.74, 95% CI: 0.31, 1.81, p = 0.51; DFS: HR: 0.68, 95% CI: 0.24, 1.93, p = 0.47).

Conclusions

Unilateral radiation therapy compared with bilateral produced similar survival.

Optimization of radiotherapy for neck carcinoma metastasis from unknown primary sites: a meta-analysis

This meta-analysis was designed to evaluate radiotherapy (RT) options preferable for neck cancer metastases from unknown primary sites (NCUP). Relevant articles published up through September 2015 were selected from EMBASE, Cochrane, PubMed and Web of Science. Thirty-three articles were identified, and relative risks (RRs) and 95% CIs for all pre-specified endpoints were calculated. Surgery plus RT showed an advantage for 5-year overall survival (OS) (RR 0.66, 95% CI 0.52-0.83, p = 0.0004) and neck recurrence (NR) (RR = 0.74, 95% CI 0.59-0.92, p = 0.008) compared to RT alone. The RRs for NR, primary tumor emergence (PTE), and 5-year disease free survival (DFS) for bilateral neck compared to ipsilateral neck irradiation were 0.61 (95% CI 0.41-0.91, p = 0.01), 0.44(95% CI 0.26-0.77, p = 0.004), and 0.81 (95% CI 0.64-1.03, p = 0.09), respectively. Irradiation of the neck plus potential primary tumor sites (PPTS) showed a benefit for 5-year DFS (RR 0.75, 95% CI 0.61-0.92, p = 0.005), NR (RR = 0.72, 95% CI 0.56-0.92, p = 0.009), and PTE (RR = 0.23, 95% CI 0.12-0.45, p < 0.0001) compared to neck-only irradiation. Adverse events occurred more frequently with bilateral neck plus PPTS irradiation. For NCUP, surgery plus RT of the bilateral neck and PPTS was associated with greater improvement of clinical outcomes.

Squamous cell carcinoma of unknown primary of the head and neck: Favorable prognostic factors comparable to those in oropharyngeal cancer

BACKGROUND

Treatment for squamous cell carcinoma (SCC) of unknown primary consists of radiotherapy (RT) +/- chemotherapy or neck dissection +/- adjuvant RT/chemoradiotherapy (CRT). We compared these strategies and identified prognostic factors.

METHODS

From 1993 to 2015, 75 patients with SCC of unknown primary had RT-based or surgery-based treatment. Primary endpoints were overall survival (OS) and disease-free survival (DFS). Event-time distributions were estimated using the Kaplan-Meier method.

RESULTS

Five-year OS and DFS for RT-based and surgery-based treatments were similar (OS 73% vs 68%, respectively; DFS 65% vs 64%, respectively). Among 38 patients with p16 data, 76% were p16 positive and showed improved 5-year DFS (90% vs 33%; P = .001) and OS (96% vs 33%; P < .001). Smoking history ≤10 pack-years conferred better 5-year DFS (88% vs 49%; P < .001) and OS (91% vs 59%; P < .001).

CONCLUSION

RT-based and surgery-based treatments produced similar outcomes. Patients with p16-positive disease with ≤10 pack-years of smoking history and limited nodal stage constitute a "low-risk" group in SCC of unknown primary similar to that in oropharyngeal cancer.

Cancer of unknown primary (CUP) of the head and neck: retrospective analysis of 81 patients

The treatment of patients with cervical lymph node metastases without detectable primary tumor remains an important challenge, until today, no standard therapy is available. The present study investigated the multimodal treatment of patients with head and neck CUP syndrome (HNCUP) and their follow-up retrospectively. 81 patients with cervical lymph node metastases without a primary tumor were treated at the Departments of Otorhinolaryngology as well as Radiotherapy and Radiation Oncology at the University of Saarland in Homburg, Germany in the period between 1991 and 2013. All patients received routine work-up consisting of CUP panendoscopy and imaging. Neck dissection was then performed in 77% of the patients. The most common histology was squamous cell carcinoma (80%). Ten percent of the patients had distant metastases. All patients underwent primary or adjuvant radiation therapy, or simultaneous radiochemotherapy. After a median follow-up of 3.5 years, the 5-year survival rate was 30%. There was a local recurrence that was known in 20/63 patients (31%) and distant metastases were documented in 19/61 M0 patients (31%). Higher grade late toxicity (grade 3-4) was observed in 12% of patients. Neck dissection and radiation therapy remains an integral part of HNCUP therapy, while the use of chemotherapy could be considered in selected cases. Prospective multicenter randomized trials would be necessary to identify the best target volume and to clarify the role of chemotherapy.

Neck lymph node metastases from unknown primary

Metastatic cervical carcinoma from unknown primary is a metastatic disease in the lymph nodes of the neck without any evidence of a primary tumour after appropriate investigation. The condition is rare and definite evidence is lacking for both diagnosis and treatment. In this review of the literature, we tried to draw some clinical indications based on the few available studies. We ultimately came to the following conclusions: (1) a thorough and accurate diagnostic work-up should be systematically offered. It includes accurate inspection with fibroscopy, CT or MRI, fine needle aspiration, panendoscopy and positron emission tomography, (2) Patients with low-volume neck disease, N1 and N2a stage and without extracapsular extension on histopathological examination should receive single modality treatment. Radiotherapy and surgery may be similarly effective but, if possible, surgery (excisional biopsy, neck dissection and tonsillectomy) should be favoured because it consents a more precise staging, (3) patients with more advanced conditions require combined treatment in the form of either resection followed by adjuvant radiation (±chemotherapy) or primary chemoradiation (±post-therapy neck dissection).

Patterns of failure in patients with head and neck carcinoma of unknown primary treated with radiation therapy

BACKGROUND

The purpose of this study was to examine patterns of failure and the relationship to radiation doses in patients with head and neck carcinoma of unknown primary (HNCUP).

METHODS

We reviewed 85 patients with HNCUP treated with curative-intent radiation therapy (RT) during 1995 to 2012.

RESULTS

There have been no failures in the pharyngeal axis. Relapse at initial neck sites of disease developed in 7 patients (8.2%). The median dose to these sites was 70 Gy (range, 63-70 Gy). Failure at neck sites without initial disease occurred in 4 patients (4.7%). The median dose was 54 Gy (range, 50-58.8 Gy). There were no contralateral failures in a small cohort of patients receiving unilateral treatment (n = 6). Percutaneous endoscopic gastrostomy (PEG) tube dependence at 12 months was 7.4%, and 2.5% at 3 years. Esophageal stricture developed in 5 patients (5.9%).

CONCLUSION

RT for HNCUP produces excellent locoregional control rates with acceptably low levels of late toxicity. Doses prescribed to sites of eventual failure did not vary significantly from those sites that were treated and remain in control. © 2015 Wiley Periodicals, Inc. Head Neck 38: E426-E431, 2016.

Cervical lymph node metastases from unknown primary cancer: a single-institution experience with intensity-modulated radiotherapy

PURPOSE

To determine the effectiveness and rate of complications of intensity-modulated radiotherapy (IMRT) in the treatment of cervical lymph node metastases from unknown primary cancer.

METHODS AND MATERIALS

Between February 2005 and November 2008, 25 patients with an unknown primary cancer underwent IMRT, with a median radiation dose of 70 Gy. The bilateral neck and ipsilateral putative pharyngeal mucosa were included in the target volume. All patients had squamous cell carcinoma, except for 1 patient who had adenosquamous differentiation. They were all treated with curative intent. Of the 25 included patients, 20 were men and 5 were women, with a median age of 54 years. Of these patients, 3 had Stage III, 18 had Stage IVa, and 4 had Stage IVb. Of the 25 patients, 18 (72%) received platinum-based chemotherapy in a combined-modality setting. Neck dissection was reserved for residual disease after definitive IMRT. Overall survival, disease-free survival, and locoregional control were calculated using the Kaplan-Meier method.

RESULTS

With a median follow-up of 38 months, the overall survival, disease-free survival, and locoregional control rates were all 100% at 3 years. No occurrence of primary cancer was observed during the follow-up period. The reported rates of xerostomia reduced with the interval from the completion of treatment. Nine patients (36%) reported Grade 2 or greater xerostomia at 6 months, and only 2 (8%) of them reported the same grade of salivary function toxicity after 24 months of follow-up.

CONCLUSION

In our institution, IMRT for unknown primary cancer has provided good overall and disease-free survival in all the patients with an acceptable rate of complications. IMRT allowed us to address the bilateral neck and ipsilateral putative pharyngeal mucosa with minimal late salivary function toxicity. The use of concurrent chemotherapy and IMRT for more advanced disease led to good clinical results with reasonable toxicities.