in stage 4 is not curable but chemotherapy
is given for two purpose : first to prolong the survival by few weeks to months and secondly to palliate the symptoms.
Because of immunosuppression
by tumour and to some extent by chemothery pneumonia is not unusual, but since WBC is in normal range it seems bone marrow
is working properly so there is nothing to worry......has the WBC specially neutrophil has gone down, then probably GM-CSF infusion was needed, but not now....
complete the full cycle of chemotherapy and pray to god