Cancer is not something that we expect to be associated with height. However, it is surprising to note that even the risk of cancer is modified by the height of a person.
It has been found that taller people are more likely to have a higher risk of cancers of different organs than shorter people.
This can be explained with the help of a theory that takes into account the patient’s age as one of the criteria influencing the height. For most forms of cancers including cancers of the breast, colon, prostate, and thyroid, the risk increases with advancing age dramatically.
The number of cells in the body
The incidence of cancers of different organs is the lowest in children and young adults less than 30 years of age, with blood cancers being an exception to this. Researchers are trying to find whether the risk of cancer increases with age due to the more number of cells being produced in the body.
Since the body of a fully grown adult has a larger number of cells than the body of children and younger people, the tendency for the abnormal growth and multiplication of cells might also increase with age.
The same theory can also be applied to taller people and shorter people. The body of taller people has more number of cells across all organs and tissues. So, the chances of some of these cells getting exposed to carcinogenic agents (elements responsible for triggering cancer like bacteria, viruses, pollutants, toxins, and radiation) and developing abnormal changes increase proportionately as height increases.
In short, the more the number of cells in your body, the more will be the chances of some of them turning cancerous and so, more would be the risk of cancer.
What does research say?
An evolutionary biologist who assessed the data from 5 large-scale surveillance projects on nearly 23 cancer categories has confirmed this theory.
Cancer research studies have established that taller people might have an increased possibility of developing cancer, with the risk rising by nearly 10% for an increase in the height by 10 centimeters (or 4 inches) each.
The independent role of nutrition, health, and social conditions
Other researchers have also proposed that some factors such as nutrition, health, and social conditions can create an influence on the body’s functioning in early life. These factors may influence the person’s growth as well as the cancer risk, though independently.
In other words, the factors that affect the person’s growth and development during childhood can also play a role in determining the risk of cancer thus creating an indirect correlation between height and cancer risk.
The risk might vary for different forms of cancers.
Thyroid and skin cancers
For example; a comparison of the effect of height on the risks of cancers in both women and men has revealed that taller people are more likely to develop cancer of the thyroid and skin. In women, being taller led to an increased risk of thyroid cancer, while, in men, it led to the risk of skin cancer. 
The risk of melanoma
Further studies have shown that among all forms of skin cancers, it is the melanoma that has shown a very strong correlation with height.
Melanoma is a type of skin cancer that occurs when the melanin pigments responsible for giving a darker color to the skin multiply and grow uninhibited. The increased risk of melanoma in taller men could be attributed to the higher production of a hormone called IGF-1 in them.
IGF-1 is a growth factor, which plays a key role in early development. IGF-1 might also contribute to the rate of cell division.
This means, the increased IGF-1 in taller men can make the cells in the skin and other organs to divide and form new cells at a faster rate due to which the likelihood of them developing into cancerous cells can increase. 
The risk of colorectal cancer
Also, the incidence of most cancers including colon and rectum is more in men than in women. This relation can also be attributed to the higher average height of men compared to that of women.
However, height has been found to influence the chances of developing only some forms of cancers. No significant correlation could be found in the risk of cancers of pancreas, stomach, esophagus, and mouth and the height in both men and women.