The NHS' provision of services to patients is beginning to struggle to meet targets beyond A&E, a briefing from the Nuffield Trust has warned.
While targets for treating 90% of inpatients and 95% of outpatients within 18 weeks have been met, performance has deteriorated over the past year.
Diagnostic testing was found to have seen a similar decline.
The rate of deterioration varied between the top and bottom hospitals, however with the bottom hospitals seeing more of a decline.
While the NHS has seen improvements on cancer targets in recent years, the report warned that the bottom end of hospitals were seeing declines in targets met.
The NHS missed one of the cancer waiting time targets in the last three months of 2014.
The majority of hospitals breached targets on one or two measures, and no hospital breached five or more targets, only six trusts breached four targets.
The briefing questioned whether as hospitals are asked to treat more patients the access to care deteriorates with 240,000 more diagnostic tests and 45,000 urgent cancer referrals with "little impact" on target performance.
Ian Blunt, co-author of the briefing and senior research analyst at the Nuffield Trust, said: "While looking at a narrow set of targets can only tell us so much about the quality of care, this analysis does suggest that some of the recent reductions in performance are systemic.
"The response to declining performance must be dictated by a deeper understanding of its causes, and political leaders should be aware of their system-wide nature.
"There are no quick fixes for growing waiting times and we need to be prepared to see further breaches of targets in the future."
Holly Dorning, co-author of the briefing and research analyst at the Nuffield Trust, said: "The vast majority of patients are still receiving care within the target times, but our analysis shows that deteriorating access to services is starting to affect patients attending even the best-performing hospitals.
"We've known that hospitals have been struggling to meet the four-hour A&E target for a while. But the fact that we are starting to see problems in other areas, like access to planned treatment, is a real concern."
