Pleuropulmonary blastoma PPB is an extremely rare type of lung cancer that affects children. It is the only type of cancer in children that starts in the lungs and is very different from lung cancer in adults.

PPB should not be confused with pulmonary blastoma, a type of cancer that affects adults.

PPB tends mainly to affect infants and children up to 5 years of age but it can occasionally occur in older children and teenagers.

It is not known what causes PPB. In some children PPB develops in cysts in the lungs. (Lungs cysts are larger than normal air spaces in the lungs). But, many children who have lung cysts never develop PPB.

About 1 in 4 families with a child who has PPB also have other children with cancer or medical problems. Because of this, there is research looking into whether some children with PPB have inherited a faulty gene that increases their risk of cancer and other medical problems.

The most common symptoms of PPB are:

• cough
• breathlessness
• high temperature (fever)
• pain in the chest.

Because it is such a rare cancer most doctors won't have seen a child with PPB. So it may not be diagnosed immediately. It is not unusual for children with PPB to first be diagnosed as having a chest infection. But, when the child's symptoms don't get better with antibiotics more tests are done and PPB is diagnosed.

There are three types of PPB.

• Type 1 This tends to affect younger children of about 10 months old on average. It causes growths in the lungs that are mainly made up of cyst like tissue with lots of air spaces and only a small amount of cancer in the wall of the cyst. This seems to be the slowest growing type of PPB with the highest success rate for treatment. It may need less intensive treatment than other types of PPB.

• Type 2 The average age of children with this type of PPB is 2 to 3 years of age. The growths in the lungs are a mixture of cysts and more solid cancer tissue. Stronger treatment is needed than for Type 1 PPB.

• Type 3 The average age of children is between 3 and 4 years of age. The growths are made up of solid cancer tissue only. Stronger treatment is needed that for Type 1 PPB.

Treatment for PPB may include surgery, chemotherapy and radiotherapy. A team of specialists will usually be involved in making decisions about treatment.

An operation to remove as much as possible of the cancer is usually the main treatment for PPB within the lungs.

Chemotherapy is sometimes given before surgery to shrink the cancer and make the operation easier. This is called neo-adjuvant chemotherapy. Or, chemotherapy may be given after the operation. This is called adjuvant chemotherapy. It is used to reduce the risk of cancer coming back. Cancer can come back because of tiny cancer cells, which can't be seen by the naked eye, being left behind after surgery.

Radiotherapy can also be given after an operation to try to kill any cancer cells that remain.

Chemotherapy and radiotherapy may also be given if PPB spreads outside of the lungs to other parts of the body. Sometimes in this situation high dose chemotherapy followed by stem cell transplant may be considered. Your child's specialist will be able to talk over the possible treatment options for your child.

References:

• Priest J et al 2006. Type I Pleuropulmonary Blastoma: A report from the International Pleuropulmonary Blastoma Registry. Journal of Clinical Oncology, 24(27): 4492-4498.
• Indolfi P et al 2005 Type II Pleuropulmonary Blastoma responsive to multimodal therapy. Pediatric Hematology and Oncology, 22:71-76.