lung cancer is the leading cause of cancer - related death worldwide . small - cell lung cancer ( sclc ) accounts for approximately 15% of all lung cancers , and it is characterized by rapid tumor growth and early metastasis to multiple organs . response to initial chemotherapy is generally good ; however , the majority of patients develop recurrence and the prognosis of such patients remains poor . recently , a strategy of maintenance chemotherapy has been established for non - small - cell lung cancer ( nsclc ) and is currently recommended as a standard treatment in clinical guidelines [ 4 , 5 ] ; however , cumulative data have indicated that this maintenance strategy is not effective for sclc . a 58-year - old japanese man was referred to our hospital due to a dry cough continuing for over 3 weeks . computed tomography ( ct ) of the chest revealed left pleural effusion and a large tumor of about 120 mm invading the aorta and main pulmonary artery directly ( fig . the serum concentration of neuron - specific enolase had increased to 24.8 ng / ml , and pro - gastrin - releasing peptide had also increased to 987.5 pg / ml . abdominal ct , whole - body bone scintigraphy and brain magnetic resonance imaging did not reveal any distant metastasis . therefore , the clinical stage of his disease was determined as t4n2m1a , stage iv . four cycles of chemotherapy , consisting of cisplatin and irinotecan , were performed and a partial response was achieved ( fig . 2 ) . neuron - specific enolase and pro - gastrin - releasing peptide levels decreased to the normal range . subsequently , 2 years and 6 months after the initial diagnosis , f - fluorodeoxyglucose positron emission tomography showed no positive sign of disease ; the main tumor , lymph nodes , and pleural effusion had completely disappeared and the response was defined as a complete response ( fig . currently ( 3 years since the initial diagnosis ) , disease relapse has not been documented and the patient is still alive without any complaints . recent meta - analyses have shown that thoracic radiotherapy with concurrent chemotherapy resulted in a 5-year survival rate of 2030% in patients with limited disease ; however , long - term survivors with extensive disease are extremely rare . consequently , the majority of sclc patients inevitably develop recurrence . currently , topotecan is the only drug approved by the us food and drug administration for relapsed sclc , and is considered the standard second - line chemotherapy in many countries . more recently , amrubicin has also shown promising antitumor activity in this setting [ 8 , 9 ] ; however , the prognosis of such patients remains dismal . although maintenance chemotherapy has been extensively investigated for nsclc and is currently recommended as a standard treatment in clinical guidelines [ 4 , 5 ] , the strategy has not been established for sclc . however , previous studies tested only old agents , and newer agents such as irinotecan and amrubicin have not been investigated in the maintenance setting . considering that the maintenance strategy succeeded in nsclc using newer agents , such as pemetrexed and erlotinib , which are more effective and less toxic than older agents , newer agents for sclc , such as irinotecan , topotecan , and amrubicin , should also be investigated in the maintenance setting for sclc . to our knowledge , only one study has investigated the efficacy of irinotecan as maintenance chemotherapy in sclc . although the results of the study were negative , our successful case indicates that maintenance strategy may merit further investigation for patients with sclc . no author has a financial relationship with a commercial entity that has an interest in the topic of this paper .
lung cancer is the leading cause of cancer - related death worldwide . small - cell lung cancer ( sclc ) accounts for approximately 15% of all lung cancers . 
 it is characterized by rapid tumor growth and early metastasis to multiple organs . 
 response to initial chemotherapy is generally good ; however , the majority of patients develop recurrence and the prognosis of such patients is reportedly 24 months . 
 evolution of the treatment for sclc has stagnated , and cisplatin + etoposide has been the standard chemotherapy for decades . 
 meanwhile , the combination of cisplatin + irinotecan has demonstrated equivalent efficacy to cisplatin + etoposide . 
 recently , maintenance chemotherapy has been extensively investigated in non - small - cell lung cancer ( nsclc ) , and is currently recommended as a standard treatment in clinical guidelines . on the contrary , a maintenance strategy has not been established for sclc . here 
 , we describe an sclc patient who received maintenance chemotherapy with irinotecan for more than 2 years after induction chemotherapy with cisplatin + irinotecan , and survived long term with no recurrence .