Peptide receptor radionuclide therapy (PRRT) in metastatic neuroendocrine tumors of unknown primary (CUP-NETs).

Rationale: Peptide receptor radionuclide therapy (PRRT) for the treatment of neuroendocrine tumors (NETs) has been explored for more than two decades, but there are only limited data on the treatment of NETs of unknown primary site (CUP-NETs). This study aimed to analyze the long-term outcome, efficacy, and safety of PRRT in patients with CUP-NETs. Methods: Patients with pathologically confirmed metastatic CUP-NET who received lutetium-177 (177Lu) and/or yttrium-90 (90Y) labeled somatostatin analogs between March 2001 and March 2019 were retrospectively reviewed; those patients were referred as cCUP-NETs (clinical CUP-NETs). Eighty-one patients had unknown primary tumors even after [68Ga]Ga-SSTR and [18F]FDG PET/CT and were classified as pCUP-NETs (PET CUP-NETs). Treatment response was assessed according to RECIST 1.1 and PERCIST. Progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan-Meier analysis, and adverse events were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE), version 5.0. Results: A total of 575 PRRT cycles were administered to 156 patients (76 men and 80 women) evaluable for analysis: these patients were monitored for a median period of 92.3 mo (range, 4.0-169.1 mo). The disease control rate was 41.4% (43.4%) by RECIST and 40.2% (40.8%) by PERCIST in cCUP-NENs (pCUP-NETs). The objective response rate (ORR) with PRRT was 29.4% and 32.2% in cCUP-NENs and pCUP-NETs, respectively. The median PFS and OS for the entire cohort were 17.4 mo (95% confidence interval [95% CI], 11.4-23.4) and 67.4 mo (95% CI, 47.2-87.2) for all patients, respectively. The median OS for G3 tumors was significantly lower (15 mo) than for patients with G1 NET (85.5 mo), G2 (71.7 mo), and for patients with unknown grade (63.3 mo) NETs (P = 0.186, HR: 10.6, 95% CI: 3.87, 28.97, P = 0.09). PRRT was well tolerated by all patients. During treatment and long-term follow-up, CTCAE grade 3 and grade 4 thrombocytopenia and leukocytopenia were observed in only 3 patients (1.9%); there was no evidence of renal or hepatic toxicity. Conclusion: In a large cohort of patients with advanced CUP-NETs treated with PRRT in a real-world scenario and followed up to 14 years after the commencement, PRRT has demonstrated favorable and clinically significant efficacy and survival with minimal and acceptable side effects. Our results indicate that PRRT is a well-tolerated and effective treatment option for patients with metastatic CUP-NETs expressing somatostatin receptors.

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.

Adjuvant Radiotherapy for Dissected Parotid Lymph Nodes Containing Merkel Cell Carcinoma from an Unknown Primary Skin Site: 2 Case Reports.

BACKGROUND Merkel cell carcinoma (MCC) is an aggressive neuroendocrine malignancy that has increased in incidence in recent decades. The management of MCC should involve multidisciplinary experts to achieve optimal patient outcomes. Radiotherapy is commonly used as adjuvant therapy. Our literature review of MCC indicates that aggressive adjuvant radiotherapy might have a positive impact on overall local control and survival. CASE REPORT The first case is a 75-year-old male patient who discovered a right preauricular mass 2 weeks prior. He underwent right parotidectomy with tumor removal on 2012/07/09, and pathology revealed MCC in 3 lymph nodes. The patient received postoperative adjuvant radiotherapy (61.2 Gy) to the remaining right parotid tumor bed and right neck lymph nodes. The patient refused adjuvant chemotherapy. During long-term follow-up, the patient remained disease free for 10 years. The other case is a 73-year-old female patient with metastatic MCC in a left parotid lymph node. She also underwent left parotidectomy with tumor removal, and pathological staging performed according to the 8th edition of the AJCC staging system showed pTxN1aMx, stage IIIA. After the operation, she received postoperative adjuvant radiotherapy (56 Gy) to the remaining left parotid and left neck lymph nodes. The patient remained disease free for 14 months. CONCLUSIONS Metastatic MCC of the parotid lymph nodes without a detectable primary skin tumor is very rare. Adjuvant radiotherapy to the tumor bed and regional nodal basin might be beneficial for preventing disease recurrence despite the absence of systemic medical therapy.

Radiotherapy-induced abscopal effect on the metastatic carcinoma of unknown primary origin: a case report and literature review.

OBJECTIVE: Abscopal effect of radiotherapy refers to a clinical phenomenon that is characterized by the eradication of distant metastatic tumors following localized irradiation. Reports on the abscopal effect following pure radiotherapy have been relatively rare. CASE REPORT: Herein, we reported a 70-year-old male patient, who has been subjected to swelling and pain in the left neck. Computed tomography examination presented a metastatic lymph node of the left cervical and an intra-abdominal mass which was located in hepatogastric space, upward of the pancreatic head. Histopathology of the left cervical lymph node further ensured a poorly-moderately differentiated form of squamous cell carcinoma. But the primary origin was not defined. This patient received radiotherapy on the metastatic lymph nodes of the left cervical (dose: 60 Gray in 30 fractions) only. After treatment, the pain in the left neck dramatically improved and the swelling of the radiation exposure site diminished gradually. Computed tomography examination also confirmed that the abdominal mass was significantly reduced. CONCLUSIONS: The abscopal effect, in this case, may help us to get a better understanding of the impact of radiotherapy.

Evaluation of risk-tailored individualized selection of radiation therapy target volume for head and neck carcinoma of unknown primary.

PURPOSE: Intensity-modulated radiation therapy (IMRT) has enabled risk-tailored approach to elective mucosal and nodal clinical target volumes (CTVs) in treatment of head and neck carcinoma of unknown primary (HNCUP). This study report outcomes following such approach. METHODS: HNCUP patients treated with definitive IMRT between 2005 and 2018 were reviewed. Local failure (LF), regional failure (RF), distant metastasis (DM), overall survival (OS) and grade ≥3 late toxicity (LT) were analyzed. Multivariable analysis (MVA) was used to identify OS predictors for entire cohort and cN2-3 subgroup. RESULTS: A total of 203 patients were eligible: cN1 (7%), cN2a (14%), cN2b (46%), cN2c (14%) and cN3 (19%). Among 118 patients with known HPV status (by p16 staining), 81 (68%) were positive. IMRT target volume spared contralateral tonsil (55%), bilateral or contralateral sides of hypopharynx (72%), nasopharynx (72%), larynx (87%) and contralateral uninvolved neck (21%). Median follow-up was 5 years. Five-year LF, RF, DM, OS, and LT were 3%, 14%, 10%, 79%, and 7% respectively. Four patients developed mucosal recurrence: 3 within and 1 at the margin of the elective mucosal CTV. None of ipsilateral neck irradiation patients failed in the contralateral uninvolved neck. MVA identified cN2c-N3, HPV-negative status and older age as predictors for inferior OS. Within cN2-3 subgroup (n = 189): cN2c-N3, HPV-negative status and older age predicted lower OS, while concurrent chemotherapy was associated with better OS. CONCLUSION: Definitive IMRT with risk-adaptive radiation volume de-escalation for HNCUP resulted in high probability of tumor control with acceptable rate of late toxicity.

Differential abscopal effect in extracranial and intracranial lesions after radiotherapy alone for vertebral bone metastasis of unknown primary: a case report.

BACKGROUND: The abscopal effect is a phenomenon in which a tumor located far from irradiated lesions regresses. We have experienced a case in which both intracranial and extracranial lesions showed an abscopal effect after radiotherapy for spinal metastases of unknown primary. We report the differential abscopal effect in extracranial and intracranial lesions. CASE PRESENTATION: A 57-year-old Japanese man was diagnosed with multiple lung nodules, bone metastases, and brain metastases. The results of pathological examination at the previous hospital he visited suggested adenocarcinoma of the lung. However, there was a possibility that the biopsy specimen was inadequate. Radiation therapy was performed on the ninth thoracic vertebra for a total dose of 39 Gy in 13 fractions because the lesion in the ninth thoracic vertebra was destructively extending. After thorough examination, the primary lesion could not be identified, and we made diagnosis of cancer of unknown primary. The patient did not want to receive systemic chemotherapy; however, all of the lesions except for the brain metastases had spontaneously shrunk 2 months after radiation therapy. Although the brain metastases had partially shrunk, whole-brain radiotherapy for a total dose of 36 Gy in 12 fractions was performed. Fifteen months after initial radiation therapy, the brain metastasis recurred, and Gamma Knife radiosurgery was additionally performed. The brain metastases disappeared after the radiosurgery. During a period of 30 months after radiation therapy for the ninth vertebra, the lesions of the trunk all maintained their shrinkage without systemic chemotherapy. Right cervical lymph node metastasis and brain metastases occurred 30 months after the initial radiation therapy. A biopsy of the right cervical lymph node led to the diagnosis of clear cell carcinoma. Although we considered additional radiation therapy or chemotherapy, the patient died 3 months after the progression of recurrence lesions. DISCUSSION AND CONCLUSIONS: We report a rare case in which radiotherapy alone for an extracranial metastatic lesion of a vertebra resulted in an abscopal effect on both extracranial and intracranial lesions. Notably, the abscopal effect in the intracranial lesions was weaker than that in the extracranial lesions.

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 (DmaxLN) 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.

Sparing the Larynx and Hypopharynx With Radiation Therapy for Squamous Cell Carcinoma of Unknown Primary Site and Predominant Adenopathy in Level IIA.

PURPOSE: There is controversy about the need to target the mucosa of the larynx and hypopharynx during radiation therapy (RT) for squamous cell carcinoma of an unknown primary site (SCCA-UP). By 1997, the policy in our department was to target only the oropharynx and nasopharynx in patients with SCCA-UP metastatic to the level II cervical nodes. The purpose of this study was to report the rate of cancer recurrence in the larynx or hypopharynx using an approach that excluded these areas from the RT target volumes. METHODS AND MATERIALS: The inclusion criteria for this study were RT in our department for SCCA-UP between January 1, 1997, and December 31, 2019; no history of surgery that could disrupt the cervical lymphatics; predominant adenopathy in level IIA; and neck stage N1-2c. We excluded N3 because the incidental dose to the larynx and hypopharynx is usually high in patients with a >6-cm nodal conglomerate. RESULTS: The study population was comprised of 50 patients with a median follow-up after RT of 7.1 years. No patient developed recurrent cancer in a mucosal site (0/50), 2% (1/50) developed a neck recurrence in a high-dose area with synchronous distant metastases, and 2% (1/50) developed distant metastases with no evidence of local or regional recurrence. CONCLUSIONS: When delivering RT for SCCA-UP metastatic predominantly to level IIA, it is not necessary to target the mucosa of the larynx or hypopharynx. The extent to which the incidental RT dose to these areas contributes to cancer control is not evaluated in this study.

Metástasis cervical con primario desconocido, cambios en los paradigmas: revisión sobre el enfrentamiento clínico, estudio y tratamiento / Cervical metastases from unknown primary tumor, paradigm changes: review on clinical confrontation, study and treatment

Resumen En adultos, una masa cervical detectada mediante examen físico o un estudio de imagen puede ser la única manifestación de un cáncer proveniente de cabeza y cuello. Un retraso en el diagnóstico repercute en el pronóstico de la enfermedad, por lo que debe haber un alto índice de sospecha. Las metástasis cervicales con primario desconocido (MCCPD) son tumores metastásicos en los que el estudio diagnóstico no logró identificar el sitio primario del cáncer, con una histología predominantemente de tipo escamosa. Según algunos estudios, el origen más frecuente resultó ser la orofaringe, incluyendo amígdala palatina y base de lengua. Factores de riesgo conocidos son edades avanzadas, consumo de tabaco y de alcohol. Actualmente, la infección por el virus del papiloma humano (VPH) está teniendo un rol cada vez más importante como factor de riesgo, formando parte de entre 20%-25% de los cánceres de cabeza y cuello. Al enfrentarse a un paciente con masa cervical es importante realizar una completa anamnesis y examen físico acucioso para detectar cualquier elemento sugerente de malignidad. Se debe complementar con nasofibroscopía para visualizar estructuras que no alcanzan a evaluarse en el examen habitual. También se puede orientar la búsqueda del primario desconocido en base a los patrones de drenaje linfático. Dentro del estudio complementario se puede comenzar con una tomografía computada (TC) y se puede considerar también el ultrasonido o un PET/TC. Si con esto aún no se logra definir el primario, continuar con una punción aspirativa con aguja fina (PAAF), luego biopsia core que consiste en tomar una muestra del centro de la lesión guiada por ecografía, si fuese necesario, incluyendo inmunohistoquímica para VPH; ambos estudios histológicos son preferibles en vez de una biopsia abierta debido al menor riesgo de diseminación y complicaciones. El siguiente paso incluye estudio endoscópico y biopsias bajo anestesia. El tratamiento de los pacientes con MCCPD, va a depender de factores relacionados con el estadio de la enfermedad: desde cirugía o radioterapia (RT) únicas, cirugía más RT, y en algunos casos quimioterapia. Se recomienda seguimiento clínico frecuente durante los primeros años y con imágenes dentro de los 6 primeros meses postratamiento.

Abstract In adults, a cervical mass detected by physical examination or an imaging study may be the only manifestation of cancer from the head and neck. A delay in the diagnosis affects the prognosis of the disease, so there must be a high index of suspicion. Cervical metastases from unknown primary tumor (CUP) are metastatic tumors in which the diagnostic study failed to identify the primary site of cancer, with predominantly squamous histology. According to some studies, the most frequent origin was the oropharynx, including palatine tonsil and tongue base. Known risk factors are advanced ages, tobacco and alcohol consumption. Currently, human papilloma virus (HPV) infection is playing an increasingly important role as a risk factor, being the cause of between 20-25% of cancers of the head and neck. When confronting a patient with cervical mass it is important to carry out a complete anamnesis and a thorough physical examination to detect any element suggestive of malignancy. Physical examination could be complemented with a flexible nasal endoscopic to evaluate structures that can not be evaluated in the habitual examination. The search for the unknown primary can also be oriented based on lymphatic drainage patterns. Within the complementary evaluations, one can start with a study of images such as computed tomography (CT) or magnetic resonance imaging (MRI) with contrast, and also could consider ultrasound or PET/CT. If the primary can not be defined yet, fine needle aspiration (FNAP) can be the next choice and then a core biopsy that consisting of taking a sample from the center of the ultrasound-guided lesion, if necessary, including immunohistochemistry for HPV; both histological studies are preferable to an open biopsy because of the lower risk of complications. The next step searching for the primary includes endoscopic study and biopsies under anesthesia. Regarding to the management of patients with CUP, it will depend on factors related to the stage of the disease: from surgery or radiotherapy (RT) only, surgery and RT, and in some cases chemotherapy. Frequent clinical follow-up is recommended during the first years and images within the first 6 months after treatment.

Comparative cohort study of volumetric modulated arc therapy for squamous cell cancer of unknown primary in the head and neck-Involved neck only versus mucosal irradiation.

OBJECTIVES: Target volumes for irradiation remain ill-defined for squamous cell cancer of unknown primary in the head and neck (SCCUP). The aim of this study was to compare involved neck only (INO) radiotherapy (RT) with irradiating involved neck plus potential mucosal primary sites and contralateral neck (MUC) in patients diagnosed and treated with modern diagnostics and techniques. DESIGN: This is a retrospective cohort study. Patients with a diagnosis of SCCUP with unilateral neck disease were included. RESULTS: Thirty patients were identified. All underwent FDG PET-CT. 47% of patients had HPV-positive SCC. 20 patients received RT to INO, 10 patients to MUC, all with volumetric modulated arc therapy (VMAT). A significantly lower dose for each organ at risk was delivered in INO-treated patients, with mean dose to contralateral parotid gland 57% less. The proportion of patients with late grade 2 or worse xerostomia was higher in MUC patients. The incidence of grade 2-3 mucositis (89% vs 45%) and grade 3 or worse dysphagia (50% vs 10%) was higher in MUC patients. Median follow-up was 31 months. No mucosal primaries emerged. Progression-free survival at 2 years was 74.7% for INO patients, 70% in the MUC group. Overall survival at 2 years was 79.7% in the INO group and 70% in the MUC patients. CONCLUSION: INO radiotherapy for patients with SCCUP of the head and neck is a safe treatment strategy resulting in clinically significant lower RT doses to OARS. Acute and late toxicities are reduced without detriment to patient survival.

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.

Tumor control of cervical lymph node metastases of unknown primary origin: the impact of the radiotherapy target volume.

PURPOSE: Debate on the extent of treatment of neck metastasis of cancer of unknown primary tumors (CUPs) is still ongoing. In two Dutch tertiary referral centers, the post-surgical radiation target volume changed from the bilateral neck including the pharyngeal axis to the unilateral neck only, in the course of the last decade. This study aims to investigate the outcome of patients with CUP before and after de-escalation of post-surgical radiotherapy. METHODS: Data of two Dutch tertiary referral centers were merged. Disease-free survival (DFS), overall survival (OS), and regional control rate (RCR) of 80 patients diagnosed with CUP (squamous cell and undifferentiated carcinomas) between 1990 and 2009 were retrospectively analyzed. RESULTS: Thirty patients received bilateral neck and pharyngeal axis radiotherapy and 42 patients ipsilateral radiotherapy only. In another eight patients, the postsurgical radiation target volume was expanded to the contralateral neck or to the pharyngeal axis, due to suspicious lesions on imaging. The 5-year DFS, OS and RCR were 60%, 51.2%, and 80%, respectively, in the total patient population. RCR did not differ in patients treated with ipsilateral as compared to bilateral radiotherapy nor did 5-year OS and DFS. No tumors occurred in the pharyngeal axis. CONCLUSION: In this study, omitting elective treatment of the contralateral neck and pharyngeal axis did not lead to a decrease in locoregional control or survival rates when treating patients with CUP.

Long-term results of elective mucosal irradiation for head and neck cancer of unknown primary in Chinese population: The EMICUP study.

OBJECTIVE: Controversy still exists regarding the volume of radiation for head and neck cancer of unknown primary (HNCUP). Theoretically, elective mucosal irradiation (EMI) should achieve a balance between survival and toxicity. This prospective study was conducted to evaluate the long-term benefit of EMI in Chinese HNCUP patients. METHODS: A phase II, single-arm trial was performed at two centers in China. HNCUP patients with pathologically confirmed metastatic squamous cell carcinoma or poorly differentiated carcinoma were enrolled. Patients with metastatic lymph nodes limited to level IV and/or the supraclavicular fossa were excluded. The EMI approach was specifically customized to Chinese patients by differentiating HNCUP as putative nasopharyngeal carcinoma (NPC) or non-putative NPC. The primary endpoint was 3-year mucosal recurrence-free survival (MRFS). RESULTS: A total of 48 patients were enrolled between 02/02/2010 and 08/01/2018; 46 patients were analyzed, including 24 putative NPC and 22 non-putative NPC patients. No primary recurrence was observed during a median follow-up period of 70 months, and only 1 patient experienced out of field recurrence in the contralateral neck. The 3-year MRFS was 90.6% (95%CI: 76.4%-96.4%). The 5-year MRFS, regional-recurrence free survival (RRFS) and overall survival (OS) were 90.6% (95%CI: 76.4%-96.4%), 86.0% (95%CI: 71.1%-93.7%), and 90.6% (95%CI: 76.4%-96.4%), respectively. No grade 4 acute or late toxicities occurred, and the most frequent grade 3 acute toxicity was oral mucositis (45.7%). CONCLUSION: To the best of our knowledge, this is the first prospective study to evaluate the long-term outcomes of EMI in Chinese HNCUP patients. Excellent MRFS and OS rates were observed. Further randomized studies are warranted.

Pharyngeal-sparing radiation for head and neck carcinoma of unknown primary following TORS assisted work-up.

OBJECTIVE: In patients with head and neck carcinoma of unknown primary (HNCUP;pT0) following TORS-assisted workup, we have adopted a pharyngeal-sparing radiation therapy (PSRT) approach targeting only the at-risk neck and omitting treatment of the pharynx. We report outcomes following PSRT, and compare to institutional historical control subjects who received pharyngeal-targeted RT (PRT). METHODS: Between 2009 and 2018, 172 patients underwent TORS-assisted endoscopy as part of their workup for HNCUP. Following TORS, 54 patients had pT0 disease, of which 45 received RT. Forty-nine percent received PSRT and 51% received PRT. RESULTS: No statistically significant differences existed between the PSRT and PRT groups with respect to overall nodal distribution, p16 positivity (55% vs. 43%, P = .12), neck dissection rates (77% vs. 65%, P = .51), and administration of chemotherapy (55% vs. 65%, P = .55). Median follow-up for PSRT and PRT groups were 24 and 28 months, respectively (P = .04). Two-year RFS was 86% and 74% for PSRT and PRT patients, respectively (log-rank P = .30). Three and six patients recurred after PSRT and PRT, respectively. Two-year OS for PSRT and PRT patients was 91% and 74%, respectively (log-rank P = .31). Compared to PRT, PSRT was associated with statistically significantly less: grade 2+ mucositis (18% vs. 91%, P < .01), new opioid requirement (27% vs. 91%, P < .01), mean weight loss during RT (6.2 lbs vs. 17.4 lbs, P < .01), feeding tube placement during RT (5% vs. 43%, P < .01), and treatment-related unplanned hospitalizations (9% vs. 39%, P = .04). CONCLUSION: Following TORS-assisted management of patients with pT0 HNCUP, we observed reduced toxicity following PSRT compared to PRT without apparent compromise of disease cure. LEVEL OF EVIDENCE: Level 3 evidence, retrospective review comparing cases and controls Laryngoscope, 130:691-697, 2020.

When Should we Irradiate the Primary in Metastatic Lung Cancer?

Metastatic lung cancer encompasses a heterogenous group of patients in terms of burdens of disease, ranging from patients with extensive metastases to those with a limited number of metastatic lesions (oligometastatic disease). Histopathological heterogeneity also exists within two broad categories, non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC), portraying different patterns and evolution of disease. Local consolidative therapy to the primary tumour and metastatic sites, including surgery and/or radical dose radiotherapy, is increasingly being used to improve survival outcomes, particularly in the context of oligometastatic disease, with or without the use of molecular targeted therapy and immunotherapy. Recently, randomised studies in oligometastatic NSCLC have shown that local consolidative therapy may confer a survival advantage. This review explores whether treating just the primary tumour with radiotherapy may similarly produce improved clinical outcomes. Such a treatment strategy may carry less potential toxicity than treating multiple sites upfront. The biological rationale behind the potential benefits of treating just the primary in metastatic malignancy is discussed. The clinical evidence of such an approach across tumour sites, such as breast and prostate cancer, is also explored. Then the review focuses on treating the primary in NSCLC and SCLC with radiotherapy, by first exploring patterns of failure in metastatic NSCLC and second exploring evidence on survival outcomes from studies in metastatic NSCLC and SCLC. It is challenging to draw conclusions on the clinical benefit of treating the primary cancer in isolation from the evidence available. This highlights the need to collect data within the ongoing clinical trials on the clinical outcome and toxicity of radiotherapy delivery to primary thoracic disease specifically. This challenge also identifies the need to design future clinical trials to produce randomised evidence for such an approach.

Unilateral or bilateral irradiation in cervical lymph node metastases of unknown primary? A retrospective cohort study.

INTRODUCTION: Patients with cervical lymphadenopathy of unknown primary carcinoma (CUP) usually undergo neck dissection and irradiation. There is an ongoing controversy regarding the extent of nodal and mucosal volumes to be irradiated. We assessed outcomes after bilateral or unilateral nodal irradiation. METHODS: This retrospective multicentre study included patients with CUP and squamous cellular carcinoma who underwent radiotherapy (RT) between 2000 and 2015. RESULTS: Of 350 patients, 74.5% had unilateral disease and 25.5% had bilateral disease. Of 297 patients with available data on disease and irradiation sides, 61 (20.5%) patients had unilateral disease and unilateral irradiation, 155 (52.2%), unilateral disease and bilateral irradiation and 81 (27.3%), bilateral disease and bilateral irradiation. Thirty-four (9.7%) and 217 (62.0%) patients received neoadjuvant and/or concomitant chemotherapy, respectively. Median follow-up was 37 months. Three-year local, regional, locoregional failure rates and CUP-specific survival were 5.6%, 11.7%, 15.0% and 84.7%, respectively. In patients with unilateral disease, the 3-year cumulative incidence of regional/local relapse was 7.7%/4.3% after bilateral irradiation versus 16.9%/11.1% after unilateral irradiation (hazard ratio = 0.56/0.61, p = 0.17/0.32). The cumulative incidence of CUP-specific deaths was 9.2% after bilateral irradiation and 15.5% after unilateral irradiation (p = 0.92). In multivariate analysis, mucosal irradiation was associated with better local control, whereas no neck dissection, ≥N2b and interruption of RT for more than 4 days were associated with poorer regional control. Toxicity was higher after bilateral irradiation (p < 0.05). No positron-emission tomography-computed tomography, largest node diameter, ≥N2b, neoadjuvant chemotherapy and interruption of RT were associated with poorer cause-specific survival. CONCLUSION: Bilateral nodal irradiation yielded non-significant better nodal and mucosal control rates but was associated with higher rates of severe toxicity.

Outcomes of Stage III NSCLC with occult primary vs. known primary lesions.

OBJECTIVES: Occult primary non-small cell lung cancer (OP-NSCLC) involving mediastinal lymph nodes without an identifiable primary tumor is a rare presentation, with little known about how outcomes compare to typical Stage III NSCLC. We reviewed our experience treating OP-NSCLC with definitive radiotherapy and compared outcomes to a contemporary cohort of stage III NSCLC patients. MATERIALS AND METHODS: We reviewed 605 patients with stage III NSCLC staged with PET-CT and treated with definitive radiotherapy between 1998 and 2013. Overall survival, intrathoracic control, and freedom from distant metastasis were computed using Kaplan-Meier method and logrank comparison. Cox hazard ratios were used to perform univariate and multivariate analyses. RESULTS: Twenty-one patients were identified with OP-NSCLC (3.5%). Patients with OP-NSCLC, as compared to known primary NSCLC, had significantly better 5-year rates of intrathoracic control (83.5% vs. 24.2%, P < 0.001), freedom from distant metastasis (59.0% vs. 26.3%, P = 0.003), and overall survival (61.6% vs. 15.2%, P < 0.001). Multivariate analyses confirmed occult primary as an independent prognostic factor associated with a 70% reduction in risk of intrathoracic failure, a 55% reduction in risk of distant metastasis, and a 70% reduction in risk of death. CONCLUSION: To our knowledge, this is the largest reported series of OP-NSCLC and the first to compare it to a contemporary cohort of Stage III NSCLC with known primary lesion. Definitive radiation therapy was associated with favorable locoregional control and survival, particularly compared with typical stage III NSCLC. This difference suggests that occult primary NSCLC may be a distinct entity with different biology than typical NSCLC.

Bilateral vs ipsilateral adjuvant radiotherapy in patients with cancer of unknown primary of the head and neck: An analysis of the clinical outcome and radiation-induced side effects.

BACKGROUND: The purpose of this study was to analyze and compare ipsilateral and bilateral adjuvant radiotherapy in patients with cancer of unknown primary (CUP) of the head and neck. METHODS: Overall survival, recurrence-free survival, and radiation-induced side effects were assessed in 76 patients with CUP who underwent ipsilateral (n = 29) or bilateral (n = 47) radiotherapy. RESULTS: At a median follow-up of 41 months, the 5-year overall survival and recurrence-free rate were 67.9% and 71.5%, respectively. No statistically significant difference between ipsilateral and bilateral radiotherapy could be found regarding 5-year overall survival, recurrence-free survival, occurrence of a primary tumor, and distant metastasis. The analysis of radiation-induced acute side effects showed a significant benefit of ipsilateral radiotherapy. CONCLUSION: As the main parameters of the study regarding the outcome and radiation-induced side effects showed no advantages of bilateral radiotherapy, the strategy of ipsilateral radiotherapy can be recommended for the adjuvant treatment of CUP patients.

Finding/identifying primaries with neck disease (FIND) clinical trial protocol: a study integrating transoral robotic surgery, histopathological localisation and tailored deintensification of radiotherapy for unknown primary and small oropharyngeal head and neck squamous cell carcinoma.

INTRODUCTION: Carcinomas of unknown primary site (CUP) of the head and neck have historically been worked up and managed heterogeneously. Failure to identify a primary site may result in large radiotherapy mucosal volumes. Transoral approaches such as Transoral Robotic Surgery (TORS) may improve the yield of identifying hidden primaries. We aim to assess the oncological and functional outcomes of a combined treatment approach with TORS and tailored radiotherapy. METHODS AND ANALYSIS: Twenty-five patients with metastatic squamous cell carcinoma to the neck without clinical or radiographic evidence of a primary site will be enrolled in a phase II trial. Patients will undergo a diagnostic or therapeutic approach with TORS based on specific algorithms incorporating tailored radiotherapy according to the location and laterality of the primary tumour. The primary outcome is to evaluate the out-of-field failure rate over a 2-year period. Secondary outcomes include identification rates, survival outcomes, patient reported outcomes and functional swallowing outcomes. ETHICS AND DISSEMINATION: The University Health Network Research Ethics Board approved this study (ID 15-9767). The results will be published in an open access journal. TRIAL REGISTRATION NUMBER: NCT03281499.