Growth and puberty after childhood cancer treatment

It can, but many children grow and go through puberty normally after treatment. During chemotherapy, growth often slows because of illness, poor appetite, steroids and the stress of treatment. For many children, growth catches up once treatment ends and eating and activity return to normal. Some treatments, however, carry a higher risk of lasting effects on growth or puberty. Radiotherapy to the brain can reduce growth hormone and other hormones made by the pituitary gland, the small gland at the base of the brain that controls growth and puberty. Radiotherapy to the spine can limit spinal growth, reducing sitting height. Total body irradiation and high-dose chemotherapy before stem cell transplant can affect growth, thyroid and sex hormones. Long courses of steroids can slow growth and weaken bones.

Puberty can be affected in different ways. Some children, especially girls who had brain radiotherapy, may start puberty earlier than usual, which can shorten final height because growth stops sooner. Others may have delayed or incomplete puberty because the ovaries or testes were affected by alkylating medicines such as cyclophosphamide, busulfan or ifosfamide, or by radiotherapy to the pelvis or abdomen, or because the pituitary gland does not send the right signals. Signs include no breast development, no periods, or no voice deepening and body changes at the expected age. Thyroid problems after neck or brain radiotherapy can also slow growth.

Regular monitoring helps catch problems early, when treatment is most effective. Children's height, weight and pubertal development are usually measured at each follow-up visit and plotted on growth charts. If growth slows or puberty does not progress as expected, a children's hormone specialist, called a paediatric endocrinologist, may do blood tests, a hand X-ray to estimate bone age, and sometimes tests of growth hormone. Treatments such as growth hormone, thyroid hormone or sex hormones to start or support puberty can help many children, and are decided by the specialist. This page explains the general picture; your child's team will assess their growth and development.

Many children catch up

Growth often recovers after treatment ends.

Some treatments carry higher risk

Brain or spinal radiotherapy, transplant and some medicines matter most.

Hormone treatment can help

Specialists can support growth and puberty when needed.

It cannot tell you whether your child's growth or puberty will be affected, or what their adult height will be. That depends on their treatment and development, and specialists can assess this.

It also cannot advise on hormone treatments. These are decided by a children's hormone specialist.

Growth hormone treatment

If growth hormone is low, daily injections prescribed by a specialist can improve growth. Specialists consider timing after cancer treatment and monitor carefully. Parents can ask about benefits, risks and practical aspects.

Early puberty

If puberty starts too early, medicines can pause it to allow more time for growth. This is decided by a specialist.

Delayed puberty and fertility

If the ovaries or testes do not produce enough hormones, sex hormone treatment can start and maintain puberty, supporting bone and emotional development. Fertility may also be affected, so discussions about fertility become important as the child grows.

Emotional impact

Being shorter than friends or going through puberty at a different time can affect confidence and body image. Counselling, peer support and open conversations help.

Nutrition and activity

Balanced meals with enough protein, calcium and vitamin D, and regular physical activity, support growth and bone health.

Keeping growth records

Keep a record of height measurements over time, as this helps doctors see trends, especially if you change hospitals.

Sitting height and spinal growth

After radiotherapy to the spine, the spine may grow less than the legs. Doctors may measure sitting height as well as standing height to track this. Spinal changes can also affect posture, so physiotherapy may help.

Growth charts explained

Growth charts show how a child's height compares with others of the same age and sex. What matters most is whether a child continues to grow along their usual line. Crossing down lines over time may prompt assessment.

Bone age X-rays

A hand and wrist X-ray shows how mature the bones are. If bone age is behind actual age, more growth may still be possible; if ahead, growth may finish sooner. This helps specialists plan treatment.

Thyroid and growth

An underactive thyroid can slow growth and cause tiredness, constipation and weight gain. It is easily detected with a blood test and treated with thyroid tablets prescribed by a doctor.

Weight after treatment

Some children gain weight after treatment, especially after brain radiotherapy or long steroid use, while others remain underweight. Both can affect growth and health. A dietitian can help families plan balanced meals.

Talking to your child about height

Children who are shorter than friends may feel self-conscious. Focusing on their strengths, involving them in decisions about treatment and connecting them with other survivors can build confidence.

Periods and fertility in girls

Irregular periods or periods that stop in teenage girls after treatment can signal ovarian changes and should be checked. Hormone treatment protects bones and supports development, and fertility can be discussed as they grow.

Testosterone and fertility in boys

Boys may have normal testosterone and puberty but reduced sperm production after some treatments. Fertility testing in adulthood helps plan families.

Coordination between specialists

Growth and puberty care often involves the oncologist, endocrinologist, paediatrician and sometimes a gynaecologist or urologist. Keeping everyone informed helps.

Moving to adult hormone care

Young people receiving hormone treatment need a planned move to adult hormone specialists so treatment continues without gaps.

What to do next

Ensure growth and puberty are measured at follow-up, keep growth records, report slowed growth or unusual puberty timing, ask about a paediatric endocrinologist, support nutrition and activity, and offer emotional support.