A Review of the Evolving Role of Radiotherapy in the Treatment of Neuroendocrine Neoplasms

BACKGROUND

Neuroendocrine neoplasms (NENs) are rare tumours that develop from neuroendocrine cells in various parts of the body. The management of this disease poses a significant challenge because of the heterogeneous clinical presentation and varying degrees of aggressiveness. A multidisciplinary approach is often required in complex clinical situations. Radiotherapy (RT) plays a key role in managing NETs in both curative and palliative settings.

SUMMARY

In this review, we summarize and discuss recent developments in the field of advanced RT in early-stage, locally advanced, and metastatic NENs. We highlight limitations in current approaches and discuss future potential treatment strategies for patients with NENs.

The receptive field for visceral pain referred orofacially by the vagus nerves

BACKGROUND

The nociceptive receptive field of the vagus nerves in animals includes virtually the entire thoracic, abdominal and laryngopharyngeal regions. However, the role of the vagus nerves in the transmission of visceral pain in humans, with the exception of pain from coronary artery diseases, is believed to be insignificant.

AIM

The purpose of this report is to map out the clinical visceral pain receptive field of the vagus nerves relative to its nociceptive counterpart in animals.

MATERIALS AND METHODS

The PubMed database and PMC were searched for case reports of patients with orofacial pain believed by the author(s) of the article to be referred from underlying non-cardiac thoracic, laryngopharyngeal or abdominal diseases. Reports of diseases for which non-neural explanations for the orofacial spread of pain were suggested were excluded.

RESULTS

A total of 52 case reports of jaw pain and/or otalgia referred from laryngopharyngeal and noncardiac thoracic sources were discovered. In addition, a multicenter prospective study found that 25.8% of more than 3,000 patients with thoracic aortic dissection experienced pain in the head and neck region. In stark contrast, no case reports of orofacially referred pain from abdominal diseases were found.

DISCUSSION

The results indicate that the laryngopharyngeal and thoracic portions of the vagal receptive field are capable of referring pain orofacially while the abdominal portion is not. The roles of the somatotopic organization of the trigeminal sub nucleus caudalis and neuromodulation in this referral of pain were discussed.

CONCLUSION

Referred orofacial pain can lead to delayed diagnosis and poorer outcome in visceral diseases.

Clinical recommendations on the treatment of neuroendocrine carcinoma of the larynx: A meta-analysis of 436 reported cases

BACKGROUND

Current recommendations on the treatment of neuroendocrine carcinoma of the larynx (NCL) are based on anecdotal evidence. With this meta-analysis, our purpose was to provide clinicians with more substantiated guidelines in order to improve the treatment outcome of the patients affected with NCL.

METHODS

A structured literature search for all research concerning NCL was performed against the MEDLINE and EMBASE databases. Available data was normalized, pooled, and statistically analyzed.

RESULTS

Four hundred thirty-six cases of NCL were extracted from 182 studies, of which 23 were typical carcinoid, 163 were atypical carcinoid, 183 were small-cell neuroendocrine carcinoma, 29 were large-cell neuroendocrine carcinoma, and 38 were unspecified carcinoid tumors. The 5-year disease-specific survival (DSS) was 100% for typical carcinoid, 53% for atypical carcinoid, 19% for small-cell neuroendocrine carcinoma, and 15% for large-cell neuroendocrine carcinoma (p < .001). Patients with an atypical carcinoid treated with surgery had better DSS than those treated with radiotherapy (60% vs 54%; p = .035). Postoperative radiotherapy did not result in better DSS in atypical carcinoid. Patients with an atypical carcinoid, not undergoing surgical treatment of the neck, developed isolated regional recurrence in 30% of cases (p = .001). Radiochemotherapy yielded the best DSS for small-cell neuroendocrine carcinoma compared to other modalities (31% vs 13%; p = .001).

CONCLUSION

Typical carcinoid can be treated by local excision alone. Atypical carcinoids do not seem to respond well to radiotherapy and are best managed through radical surgical excision in combination with elective neck dissection. Patients with small-cell neuroendocrine carcinoma or large-cell neuroendocrine carcinoma seem to benefit most from chemoradiotherapy.

A case of typical carcinoid of the larynx

We report herein a rare case of typical carcinoid occurring primarily in the epiglottis. The patient was a 70-year-old man. On initial examination, a polypoid lesion with irregular surface near the center right-hand side of the laryngeal surface of the epiglottis was observed, and a biopsy was performed. Pathological examination of the specimen suggested the possibility of adenocarcinoma. Surgical excision was performed by means of laryngomicrosurgery. A Weerda-type laryngoscope was used to open the larynx, supplemented by rigid nasal sinus surgery endoscopes, and the right-hand half of the epiglottis were excised was ensured using a CO₂ laser. Postoperative pathological diagnosis was negative for adenocarcinoma and squamous cell cancer; typical carcinoid was diagnosed according to the World Health Organization criteria. Aspiration occurred postoperatively, swallowing training was therefore provided, and the patient was discharged from hospital 2 months after surgery when he was able to eat normally. As of 4 years after surgery, the patient remains under follow-up observation by means of PET-CT and neck, thoracic, and abdominal CT administered at appropriate intervals, but no findings indicating obvious recurrence or metastasis have been observed, and the patient displays good swallowing function.

Neuroendocrine neoplasms of the larynx: Advances in identification, understanding, and management

While 85-90% of laryngeal malignancies prove to be squamous carcinomas, the second most common tumour type found in the laryngeal region will prove to be a member of the family of neuroendocrine tumours. Laryngeal carcinoid tumours have a capacity for metastasis, and so are more aggressive tumours than their light microscopic features might imply--5-year survival rates are in the vicinity of 50%. Laryngeal atypical carcinoid tumours are lesions with a well-recognized capacity for local recurrence as well as metastasis, with a 5-year survival of just under 50%. Laryngeal small cell neuroendocrine carcinomas are particularly aggressive tumours, with a 5-year survival of no more than 5-10%. Laryngeal paragangliomas are lesions without any real capacity for metastasizing. Surgical excision is the mainstay of treatment of carcinoid tumours, atypical carcinoid tumours, and paragangliomas. Small cell neuroendocrine carcinomas are chiefly treated by way of radiation and chemotherapy; the role of adjuvant therapy in the treatment of atypical carcinoid tumours remains to be established.

An analysis of rare carcinoid tumors: clarifying these clinical conundrums

Carcinoid tumors are distinct neuroendocrine neoplasms with characteristic histological, clinical, and biological properties. Though commonly associated with the gastrointestinal tract and bronchopulmonary system, a substantial number of these tumors originate in less common anatomical sites and can range from indolent, unrecognized entities to highly active, metastatic secretory tumors. Their presentation within unfamiliar locations often results in clinical confusion, and they persist as unrecognized lesions, subjecting patients to delayed, inappropriate, or ineffective treatment. The authors reviewed 13,715 carcinoid tumors identified by three consecutive registries of the National Cancer Institute (NCI) from 1950 to 1999, focusing on the anatomic sites accounting for less than one percent of all carcinoids. In addition, data from the world's literature published on carcinoid tumors within these particular anatomic locations were then analyzed with respect to incidence, clinical presentation, symptoms, diagnostic evaluation, microscopic and immunohistochemical findings, treatment strategies, and prognosis. The primary organs in which carcinoids are most commonly mistaken for some of the more conspicuous endemic tumors include the esophagus, pancreas, liver, biliary tract, gallbladder, and Meckel's diverticulum, as well as within the pelvic and otolaryngeal organs and the breast. In general, the highest proportion of "rare" carcinoids was identified in the gastrointestinal (GI) tract, with the ovary as the single most affected extra-GI site. Tumors with the worst prognosis were those that involved the pancreas (37.5%: 5-year survival) and those in the cervix (12-33%: 3-year survival). While gastrointestinal carcinoids have become a more recognized entity and thus more amenable to identification, similar lesions are often not considered in other sites and have often either been overlooked or misdiagnosed. Widespread reports of their occurrence in rare locations warrants attention. The diminution of the likelihood of inadvertently neglecting these often benign, indolent neoplasms that are well known to metastasize if unaddressed would represent an important advance. Familiarity with such unusual sites of origin will facilitate appropriate recognition and characterization of such tumors, allowing for timely intervention.