Health bosses have vowed to employ more consultants in a bid to treat cancer patients on time.
Latest figures for July to September show that NHS Forth Valley missed the target of treating patients urgently referred with a suspicion of cancer within 62 days.
Guidelines state that 95 per cent of people should be seen in this timeline but the local health authority only achieved it in 86 per cent of cases.
Only two Scottish health boards met the 62 day standard with the national average 87.1 per cent.
MSP Alison Harris has said the figures are “worrying” and urged for more to be done.
She said: “Fourteen per cent of my constituents suspected of having cancer or waiting for treatment for cancer are waiting longer then they need to and longer than they were promised by the Scottish Government.
“This year cancer patients have been refused access to several drugs and now we find out that cancer patients are being let down with waiting times.
“Time is crucial in saving people’s lives.”
NHS Forth Valley did meet the target for patients waiting no more than 31 days from decision to treat to first cancer treatment with 98.4 per cent achieved.
However, it has indicated a rising demand in colorectal cases leading to capacity issues.
In the latest report of cancer waits across Scotland, the health board noted: “The colorectal cancer team are reviewing their vetting practice and reprioritising referrals. Extra theatres are sometimes available, however, due to consultant’s other clinical commitments, it is not always possible to match consultant availability with the theatres available.
“NHS Forth Valley continue to review and redesign pathways to improve the efficient utilisation of available capacity.”
A spokeswoman for the health authority said: “Over the last few months our performance in relation to the 62-day target has improved and we continue to meet or exceed the 31-day target.
“The vast majority of patients with cancer in Forth Valley are seen and treated very quickly, however we are seeing a number of more complex cases where patients may require a number of additional specialist tests and investigations.
“We are planning to recruit a number of additional consultants to help increase local capacity and meet these important targets on a consistent basis.”
Earlier this month the drug Perjeta, used to treat breast cancer, was rejected for use within NHS Scotland, while another, Kadclya, also used to treat this kind of cancer has been deemed too expensive at £90,000 per patient per year, despite both being available in England.