The Covid-19 pandemic is having a "catastrophic" impact on cancer treatment, the World Health Organization's European branch warned on Thursday, with cancer services disrupted in a third of countries in the region.

"The impact of the pandemic on cancer in the region is nothing short of catastrophic," WHO Europe director Hans Kluge warned on World Cancer Day. 

Among the 53 member states in the UN agency's European region, which includes several in central Asia, one in three countries has experienced partially or completely disrupted cancer services because of the strain Covid-19 has put on health systems and travel restrictions.

"Some countries have experienced shortages of cancer drugs, and many have seen a significant drop in new cancer diagnoses -- even the most resource-rich countries," Kluge said in a statement.

He added that pre-existing inequalities were also growing because of the economic crisis, making it harder for many to adopt healthy behaviours or have access to prevention and care services.

In the Netherlands and Belgium during the first lockdown of 2020, the number of cancers diagnosed dropped by 30–40 percent, while at the Kyrgyzstan National Center of Oncology the number fell 90 percent.

Delayed diagnosis and treatment in the United Kingdom are expected to result in an increase in the number of deaths from colorectal cancer by 15 percent, and by nine percent for breast cancer over the next five years.

In a normal year, non-communicable diseases such as cancer, chronic respiratory diseases and diabetes are the leading causes of death and disability in the WHO European region, accounting for more than 80 percent of fatalities, the agency said.

The WHO said it plans to mobilise authorities with a cancer initiative focused primarily on prevention, early detection and access for all to diagnosis and treatment.