Radiation Therapy in Extensive Stage Small Cell Lung Cancer

Abstract

Lung cancer is the major cancer killer in the Western world, with the small cell lung cancer (SCLC) representing around 15–20% of all lung cancers. Extensive disease small cell lung cancer (ED SCLC) is found in approximately two-thirds of all cases, composed of both metastatic (M1) and non-metastatic (but presumably with tumor burden too large for locoregional-only approach) variant. Standard treatment options involve chemotherapy (CHT) over the past several decades. Radiation therapy (RT) had mostly been used in palliation of locoregional and/or metastatic disease. In contrast to its established role in treating metastatic disease, thoracic RT (TRT) had never been established as important part of the treatment aspects in this setting. In the past two decades, thoracic oncologists have witnessed wide introduction of modern RT and CHT aspects in ED SCLC, which led to more frequent use of RT and rise in the number of clinical studies. Since the pivotal study of Jeremic et al., who were the first to show importance of TRT in ED SCLC, a number of single-institutional studies have reconfirmed this observation, while recent prospective randomized trials (CREST and RTOG 0937) brought more substance to this issue. Similarly, the issue of prophylactic cranial irradiation was investigated in EORTC and the Japanese study, respectively, bringing somewhat conflicting results and calling for additional research in this setting. Future studies in ED SCLC could incorporate questions of RT dose and fractionation as well as the number of CHT cycles and type of combined Rt-CHT (sequential vs concurrent).

Radiotherapy improves the survival of patients with extensive-disease small-cell lung cancer: a propensity score matched analysis of Surveillance, Epidemiology, and End Results database

“…We defined ED-SCLC polymetastases as more than or equal to two organ metastases and oligometastases as less than one organ metastasis. This SCLC categorization method was also described recently by Jeremic et al and Luo et al 3 , 20 …”

“…Because RT was mostly used in the palliation of thoracic lesions for ED-SCLC, the doses used were also usually palliative. It was also indicated 6 and suggested 3 , 32 that a higher TRT dose was associated with better survival for ED-SCLC. High-dose radiation was found to be safe even in the 2D-RT era.…”

“…Therefore, the metastatic tumor burden should be considered because patients with ≥2 metastases had a significantly worse outcome. 3 , 12 , 32 …”

“… 2 Although it is highly sensitive to chemotherapy, relapse of ED-SCLC is almost a rule. 1 , 3 Among the consequences of relapse, thoracic tumor progression is a major cause of morbidity in ED-SCLC. Even after chemotherapy, 75%–90% of patients have residual intrathoracic disease or develop intrathoracic progression during the first year after diagnosis.…”

Hypofractionated radiotherapy in nine dogs with unresectable solitary lung adenocarcinoma

“…In humans, thoracic radiotherapy plays a well-established and indispensable role in the treatment of advanced small cell lung cancer, aiding in the palliation of locoregional and/or metastatic disease and improving the overall survival of patients when combined with chemotherapy. 9,10 Similarly, with regard to nonsmall cell lung cancer, radiotherapy has been suggested to prolong the survival of medically inoperable patients or patients refusing surgery, including those with stage I/II disease; furthermore, a survival advantage with the addition of surgery to chemoradiotherapy has been reported. 11,12 To our knowledge, however, no published studies have evaluated the efficacy and side effects of radiotherapy in dogs with lung tumors.…”