Minister for Health Mary Harney will be urged to retain a successful regional cancer network in the west at a protest march planned for Mayo this weekend.
Up to 250,000 people will be affected if the existing treatment network in Donegal, Sligo, Mayo and Galway is dismantled, according to the organisers of the march, which takes place in Castlebar on Sunday.
A similar protest march is to take place in Sligo today.
The new national cancer control programme has identified eight specialist cancer centres, based in each of the four Health Service Executive (HSE) areas, to provide an integrated treatment service for all forms of cancer, including diagnostic, surgical, medical and radiation oncology services.
Some 13 regional centres have been asked to discontinue breast cancer surgery immediately and others, including Mayo General Hospital and Sligo General Hospital, have been asked to do so on a phased basis.
However, Letterkenny General Hospital in Donegal has been granted a "linkage" to University College Hospital, Galway (UCHG), which is one of the eight named centres of excellence and one of two for the west, along with Limerick Regional Hospital.
Fine Gael leader Enda Kenny said last week he had information that the changes were to take place in Mayo General Hospital "inside three months", but this was contradicted by Independent TD Beverley Flynn. Mr Kenny, who denied that he was scaremongering, said he was seeking further clarification from the HSE.
Several cancer patient support groups say that while they have no difficulties with development of specialist centres, the concept is more applicable to densely populated areas in Europe than to sparsely populated areas with poor infrastructure, such as the west of Ireland.
Earlier this week Minister of State for Health and Sligo TD Dr Jimmy Devins said he was "absolutely outraged" at the decision to discontinue breast cancer surgery in Sligo. He said that UCHG did not have the capacity to deal with extra patients.
UCHG has one of the largest public waiting lists in the State.
Campaign groups point out that a managed clinical network for treatment of cancer was developed at Mayo General Hospital with Department of Health support, in response to an outcry seven years ago over an earlier report on a national strategy by Prof Niall O'Higgins.
As part of the response, Mayo General Hospital's status was confirmed, and it was given approval for the appointment of a designated surgeon, working with a minimum of 50 cases a year.
The "satellite" arrangement with UCHG involves a multidisciplinary approach to cases, plans for video-conferencing, and referral of some specialist cases, such as breast reconstruction, to Galway.
Kevin Barry, consultant surgeon at Mayo General Hospital since 1999, said the clinical network in the west worked very well, recognising poor infrastructure and geographical considerations.
The symbiotic relationship with UCHG provided for excellent survival rates and a sharing of skills and expertise, he said. This year, some 79 cases of breast cancer involved operations at Mayo General Hospital.