Improvement of oral ingestion in patients with inoperable esophageal cancer treated with radiotherapy, chemotherapy and insertion of a self-expanding nitinol stent

Neoplasia avançada de esôfago: diagnóstico ainda muito tardio

RACIONAL: A neoplasia de esôfago está entre as 10 mais incidentes no Brasil. O diagnóstico é geralmente tardio e a sobrevida média é de 4 a 6 meses, independente da terapêutica. O alívio da disfagia e a melhora da qualidade de vida são os objetivos principais da terapêutica paliativa. OBJETIVO: Avaliar a qualidade de vida e a paliação da disfagia obtida com diferentes tipos de tratamento oferecidos aos pacientes com neoplasia avançada de esôfago. PACIENTES E MÉTODO: Avaliação prospectiva de 38 pacientes com neoplasia avançada de esôfago, com disfagia, sem possibilidade de tratamento curativo, entre setembro de 2001 a junho de 2005. Os pacientes foram alocados aleatoriamente, de acordo com a disponibilidade da terapia ou preferência do paciente ou do médico responsável, sendo 14 tratados com colocação de prótese (9 metálicas auto-expansíveis, 4 plásticas e 1 plástica auto-expansível), 4 com cirurgia paliativa, 8 com gastrostomia (7 cirúrgicas e 1 endoscópica) e 12 com sonda nasoenteral. RESULTADOS: Houve melhora do índice médio de disfagia em 30 dias em todos os grupos, exceto no da gastrostomia. A colocação da prótese de esôfago melhorou a disfagia de forma estatisticamente significante em relação às outras terapias paliativas. A qualidade de vida avaliada pela mediana do índice de Karnofsky não apresentou melhora em nenhum grupo de pacientes. O número de internações necessárias não foi diferente entre os grupos. A duração média das internações foi maior no grupo de tratamento cirúrgico (42 dias), embora sem diferença significativa. Não houve diferença na sobrevida média dos pacientes, independente do tipo de tratamento. CONCLUSÃO: A paliação ideal para todos os casos não existe. O método deve ser individualizado para cada paciente. O tratamento cirúrgico paliativo é o mais oneroso, devido ao prolongado tempo médio de internação desses pacientes. Infelizmente, o diagnóstico de tumor de esôfago em nosso meio ainda é muito tardio, limitando o benefício que poderia advir dos métodos de ponta de paliação endoscópica.

Clinical evaluation of radiotherapy for advanced esophageal cancer after metallic stent placement

AIM: To evaluate the therapeutic effect of radiotherapy for esophageal cancer after expandable metallic stent placement.

METHODS: Ten cases of advanced esophageal cancer were evaluated, 7 having complete obstruction and 3 with digestive-respiratory fistula. Ten nitinol stents were placed at the site of stenosis. Patients were treated with a total dose of 1200 cGy divided into 3 fractions of 400 cGy 4-7 d after stents placement.

RESULTS: All the 10 stents were placed successfully at one time. After radiotherapy for advanced esophageal cancer, the survival period of the cases ranged from 14 to 22 mo, with a mean survival of 17 mo. No re-stenosis occurred among all the 10 cases.

CONCLUSION: Stent placement combined with radiotherapy for esophageal cancer is helpful to prolong patients’ survival and reduce occurrence of re-stenosis.

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Radiotherapy dose perturbation of metallic esophageal stents

PURPOSE

Metallic esophageal stents frequently present during the treatment of esophageal cancer while using either external beam radiotherapy or brachytherapy. The dosimetric effects due to these metallic stents have not been reported. This work investigates these dose effects for various stent models presented during a radiotherapy procedure.

METHODS AND MATERIALS

Two types of representative stent models, shell and ring stents, with various designs (e.g., composition and shell thickness or ring spacing), were studied. Three Monte Carlo code systems (EGS4/BEAM, EGSnrc/DOSRZnrc, and MCNP) were used to calculate the dose distributions for 6- and 15-MV external photon beams and for a (192)Ir brachytherapy source with and without a metallic esophageal stent in place.

RESULTS

For a single external beam, a dose enhancement is generally observed in front of the stent (upstream) in the region within 4-mm distance of the stent surface. The enhancement at 0.5-mm distance from the stent surface can be as high as 20%. The dose behind the stent (downstream) is generally reduced. For a parallel-opposed pair (POP), a dose enhancement is always observed in the region within 3-mm distance of the stent surface. The enhancement at 0.5-mm distance from the stent surface can be as high as 10% for the 15-MV POP and 8% for the 6-MV POP. The dose effects depend on stent design (e.g., composition, thickness of shell stent, or ring spacing in ring stents). This dependence is reduced for a POP. In the case of the (192)Ir brachytherapy source, a dose enhancement is observed in the region within 1-mm distance from the stent surface. The dose enhancement is approximately 5% at 0.5-mm distance from the stent surface.

CONCLUSION

The dose perturbations due to the presence of a metallic esophageal stent during the treatment of esophageal cancer while using either external beam radiotherapy or brachytherapy should be recognized. These perturbations result in an overdose in esophageal mucosa. The overdose is within 5%-10% at a depth of 0.5 mm in the esophageal wall.

Best palliation in esophageal cancer: surgery, stenting, radiation, or what?

Palliation of patients with obstructing or fistulizing esophageal cancer is not easy. Median survival cannot be expected to be longer than 3-6 months, regardless of which therapy is carried out. Self-expandable metal stents have revolutionized the treatment of these patients because of easy insertion, relatively low complication rates and reasonably good functional results. Plastic tubes are mainly indicated in situations in which removal may be needed. The palliative effect of external beam radiation is well established, endoesophageal brachytherapy having the advantage of delivering a high dose in a short time. More recently, there has been increasing interest in locally destructive therapies, mostly in combination with palliative radiation or radiochemotherapy. Obviously, a single best palliation for every situation does not exist. The most appropriate method to alleviate symptoms must be worked out for each individual patient depending on the specific patient situation and the specific expertise of the physician.