Hello there! i am sorry for your trouble , Small cell carcinoma AKA oat c ell carcinoma is notoriously fast and aggressive 70 % diagnosed at high levels. You didnot mention the nodal status that is inolvement of your lymph nodes. But As Your doctor started you on 6 doses of chemo i would adivise combination of radio too. I beliee you have extensive small cell lung carcinoma. Lets pray chemo gets effective, But as you said it is a relapse confirmed by PET scan Odds are Not good only 20 percent chances to respond to chemo.lets hope you do. every human being should be realistic and should face troubles like a man and fight them,. i must be sincere that only 7 months is the average surival time after diagnosis of the disiease. Only 2 % MAke it up to 5 years, I am sure you are that 2 %. I would advise some more things first of all i recommend prophylactic cranial irradiation if the first dose showed a little response even. i would prefer addition of topotecan and etoposides to replace your current meds if the response is not good. I adise Serum LDH levels and Full blood count before every cycle as their levels show the response level of the chemo. so LDH before every cycle. I would recommend to consult a dietrician for you diet modifications as Your electrolytes will derange sodium will decrease, potassium and uric acid wil rise, phosphates will increase, calcium levels will come down. We call it as TUMOR LYSIS SYNDROME it is a good thing as it shows resonse of chemo which is a good omen I would strongly recommend DEMECLOCYCLIN added to your regimen IF SIADH syndrome of inapproprpiate anti di uretic hormone is an issue . a problem body retains excessive of water and kidney dont excrete it a problme associated with small cell cancer called Para neoplastic syndrome. I would also advise to stay active and increase activity to give a tough time to LAMBART EATON syndrome an autoimmune disease more or less like myesthenia also a complication of SCLC. And One more thing stop smoking cause 98 percent of the people get SCLC because of smoking tobacco. Only 2 unlucky people are non smokers exposed to some other reason like argon or uranium etc. I pray for your getting well soon. and i will be here for you if you need me. Regards Dr Shafi Ullah Khan My Patient is My family