Usually chemical or drug therapy is used after surgery has removed most or "all" of the tumor; this is called chemotherapy. Of course, if truly all the cancer cells were removed, no more therapy would be necessary, but experience with many cancers including PPB has shown that it is very unlikely that surgery has removed literally all of the disease. Chemotherapy gets to the tumor through the blood supply. Usually several drugs are used in a carefully scheduled sequence called a "regimen" or "course" or "protocol" of chemotherapy.

Chemotherapy is based on the principle that certain chemicals (the chemotherapy drugs) can damage tumor cells such that they cannot recover from the damage and die. The rationale for chemotherapy is that drugs get to virtually every tumor cell in the body because every tumor cell has a blood supply. Unfortunately, every normal cell also has a blood supply and is exposed to the drugs as well. But normal cells can recover better from the damage and do not die. The “side-effects” of chemotherapy are due to the drugs’ effects on normal tissue. Such side-effects are not discussed here, but caregivers will discuss side-effects with families before beginning the treatments.

There is much experience with many drugs for treating childhood cancers. Even children as young as newborns can be safely treated for life-threatening cancers with chemotherapy. In pediatric cancer research, hundreds of patients are needed to ”prove” one drug’s effectiveness and hundreds of PPB patients have not yet been studied. Thus there are not proven regimens of chemotherapy for PPB. For PPB, physicians chose the overall best drugs (which often are effective for many different cancers) and chose drugs shown to be effective for cancers that look like or seem closest to PPB. Most importantly, the children with PPB who have been cured and evaluated are a guide to physicians for what to use for subsequent patients. On this website, we review what is known about chemotherapy for PPB and make recommendations for treatment. It must be understood that such recommendations are “educated guesses”. In cancer treatment, there is no technique for testing a particular child’s cancer to be sure the treatments selected will work (see For Health Professionals].

Occasionally, chemotherapy drugs have been injected directly into the chest cavity of PPB patients to bathe remaining tumor cells in a drug in order to kill them. This is called “intracavitary chemotherapy” and has been used fairly widely in certain adult diseases. It would be an uncommon approach to PPB, and there is not nearly enough data to document its usefulness, but just as with chemotherapy discussed above, it could be reasonable for physicians comfortable with its use to recommend it for specific patients.

For Type I PPB, chemotherapy may not be necessary, but there have been recurrences after using surgery as the only therapy. There is not a consensus on the best approach. Types II and III PPB have a sufficiently poor outcome with surgery as the only approach that most physicians would recommend using chemotherapy and/or radiation therapy after surgery.At this time The PPB Registry does not have sufficient data to comment on the role of chemotherapy for the prevention of progression in Type Ir PPB in children up to 6.5 years of age, but believes Type Ir in older children and adults does not require chemotherapy.