Less than three-fifths of women in Kensington and Chelsea are being screened for breast cancer, one of the worst rates in England.
Just 57.4% of eligible women in the area were up to date with screening at the end March 2016, according to NHS data.
However, this did represent a small increase from 57.3% in 2015.
Neighbouring Hammersmith and Fulham saw one of the biggest improvements in England, with 62.8% screened in 2016, up from 61.1% in 2015, but still had some of the worst coverage rates in the country, as did Westminster (60%) and Brent (65.8%).
In Harrow, the borough saw one of the biggest drops in the country from 74.4% to 72.9%, although this was still the best coverage rate in west London.
Coverage is defined as the percentage of women in the population who are eligible for screening at a particular point in time, who have had a test with a recorded result within the last three years.
Women between the ages of 50 and 70 are invited for regular breast screening every three years under a national programme.
Across the country coverage of women aged 53-70 was 75.5% in March 2016, compared with 75.4% at the same point in 2015 - representing a first increase in five years, but still some distance from a peak of 77.2% in 2011.
Keep up to date with the latest news in west London via the free getwestlondon app.
You can even set it to receive push notifications for all the breaking news in your area.