Consent, Capacity and Communication in Cancer Care

Consent, capacity and communication in cancer care: who decides, and who gets told

Cancer decisions are different from most medical decisions, and the difference matters for anybody thinking about capacity.

Screening decisions are relatively low-stakes and reversible. Cancer treatment decisions are not. They involve trade-offs between length of life and quality of life, between aggressive treatment and comfort, between side effects now and possible benefit later. They are often made under time pressure. They are frequently irreversible. And the right answer depends entirely on what the person values — which means nobody else can work it out for them from the outside.

This is exactly the territory where people with cognitive or communication disability get written out of their own decisions. Not maliciously. It happens because the conversation is complicated, the clinician has twenty minutes, the family is frightened, and there is a support worker in the room who can answer questions faster than the person can.

The National Centre of Excellence in Intellectual Disability Health’s State of Play in Intellectual Disability Health, published in March 2025, lists among the core problems in healthcare for people with intellectual disability: miscommunication, the absence of the person’s usual support people from consultations, and poor supported decision-making. Cancer Council Australia’s own policy material notes that oncology nurses report being less comfortable communicating with people with intellectual or cognitive disability, and cites a sample of general practice nurses in which around 16.5 per cent had no professional or personal experience with people with disability at all.

This is written by a disability provider operating in New South Wales. We are not lawyers and nothing in this guide is legal advice — the law on medical consent is state-specific and the stakes here are high enough that you should get proper advice for a real situation. What we can set out is how this is supposed to work and where it reliably goes wrong.

Start here: the presumption of capacity

Every adult is presumed to have capacity to make their own decisions, including medical decisions. That presumption is the starting point and it is not displaced by a diagnosis.

Three things follow that get forgotten constantly.

Capacity is decision-specific. Somebody may lack capacity to manage a share portfolio and have full capacity to decide whether they want surgery. The two questions are unrelated. The existence of a financial management order says nothing about medical decision-making.

Capacity is time-specific and context-specific. A person may have capacity in the morning and not in the evening, or with support and not without it, or about a simple decision and not a complex one. Capacity assessed once is not capacity settled forever.

Lacking capacity is not the same as needing support. This is the distinction that does the most work. A person who needs information in Easy Read, needs an hour instead of fifteen minutes, needs three conversations instead of one, and needs a trusted person present, may have full capacity. They need support to exercise it. Treating need-for-support as absence-of-capacity is the most common error in this field and it is the one that removes people from their own decisions.

Supported decision-making, and what it actually looks like

Australia is a party to the UN Convention on the Rights of Persons with Disabilities, whose Article 12 requires support to exercise legal capacity rather than substitution of another person’s decision. The Royal Commission into Violence, Abuse, Neglect and Exploitation of People with Disability examined supported decision-making extensively and found substantial gaps between the principle and the practice.

In a cancer context, supported decision-making is not a philosophy. It is a set of concrete things:

Information in a format the person can use. Easy Read material about the diagnosis and the treatment options. Pictures. Plain language. Written down so it can be gone back to. One idea per page. Cancer Council produces accessible material and the treating team can often source condition-specific Easy Read resources.

Time, and more than one conversation. A cancer consultation delivers an enormous amount of information at once, under emotional conditions that reduce anybody’s processing. For a person with cognitive disability it is unusable in a single sitting. Three shorter conversations over a fortnight — where that is clinically possible — produce a far better-informed decision than one long one.

A trusted person present, chosen by the person. Not whoever is on shift. The NCEIDH report names the absence of the person’s usual support people from consultations as a specific problem. Continuity matters: somebody who has known the person for years can tell when they have not understood, and can translate.

Checking understanding rather than checking agreement. Ask the person to explain back what is going to happen and what the choices are. Nodding is not comprehension. This single technique catches most of the cases where somebody has apparently consented to something they do not understand.

Decision aids and concrete framing. Abstract probabilities are hard for everybody and harder with cognitive disability. “This treatment means coming to hospital every three weeks for six months, and you will feel sick for about a week each time” is usable information. “A 23 per cent improvement in five-year disease-free survival” is not.

Separating the decisions. A cancer treatment plan is not one decision. It is a sequence: have a biopsy, have surgery, have chemotherapy, continue chemotherapy, have radiotherapy, stop treatment. Presenting it as a single yes-or-no is both harder to understand and less accurate. Breaking it up gives the person real decisions they can actually make.

Recording the person’s values, not just their answer. What matters to them. Whether they would rather feel well for a shorter time or accept feeling awful for a chance at longer. Whether being in hospital frightens them more than the disease does. This is the information that makes later decisions possible if capacity declines, and almost nobody writes it down.

The question families ask most: should we tell them?

This comes up constantly and it deserves a direct answer.

Families frequently want to withhold a cancer diagnosis from a relative with intellectual disability, out of genuine love and a wish to protect them from fear. The reasoning is usually some version of: they will not understand it, it will only frighten them, there is nothing they can do about it.

The position in both ethics and practice is that the person should be told, with support, in a way they can understand.

The reasons are practical as well as principled:

They will know something is wrong. People notice hospital visits, hushed conversations, tears, changes in how they are treated. Being frightened without being told why is worse than being frightened with an explanation. In our experience this is the thing families most consistently underestimate.

They cannot consent to treatment they have not been told the reason for. Consent requires information. A person agreeing to “some medicine that will make you tired” has not consented to chemotherapy.

They cannot say what they want if they do not know what is happening. Treatment decisions involve trade-offs about their own body and their own remaining time. Excluding them from the information excludes them from the choice.

It is their information. The diagnosis belongs to them, not to the family.

Withholding it rarely holds. Someone eventually says something. Finding out by accident, late, having realised everybody knew, is a betrayal that damages trust in everyone involved.

How to do it well: in several short conversations rather than one. In plain language with concrete words — cancer, a lump, medicine that is strong, going to hospital. With pictures or Easy Read where that helps. With a trusted person present. With honest answers to the questions they ask and no answers to the questions they do not. With time afterwards, and with willingness to go over it again, repeatedly, because people process information about their own mortality slowly and in pieces.

What this does not mean is delivering a prognosis in statistical form to somebody who has not asked for it. Being told the truth and being told everything at once are different things. Follow the person’s lead on what they want to know.

When the person genuinely cannot decide

Sometimes, even with full support, a person cannot make a particular treatment decision. At that point substitute decision-making applies, and the law is state-specific.

In New South Wales, medical and dental treatment consent for adults who cannot consent for themselves is governed by the Guardianship Act 1987. The key features:

There is a “person responsible” hierarchy. In broad terms: a guardian with a health or medical function if one has been appointed; otherwise the person’s spouse or de facto partner; otherwise the person who has care of them on an unpaid basis; otherwise a close relative or friend who has a continuing relationship with them.

A paid carer is not the person responsible. This is the most important practical point in this whole section and it is the one most often got wrong. A support worker, a house manager, a SIL provider or anybody paid to provide support cannot consent to medical treatment. We say this plainly because we are a provider and we are sometimes asked to: we cannot, and a hospital that accepts a support worker’s consent has made an error.

Some treatment requires the Tribunal. Certain categories of treatment cannot be consented to by a person responsible and require NSW Civil and Administrative Tribunal involvement. Where there is a dispute, where there is no person responsible, or where the treatment falls into a restricted category, NCAT is the pathway.

Decisions must be made in the person’s interests, taking into account their wishes and views as far as these can be ascertained, including wishes expressed when they had capacity.

Urgent treatment can proceed without consent where it is necessary to save life or prevent serious damage to health. Nobody should be left untreated in an emergency because the consent question is unresolved.

Two things worth adding. First, the detail here matters and it changes — if you are facing a real decision, get advice from the NSW Public Guardian, from NCAT, or from a solicitor, not from a guide on a provider’s website. Second, the same decision in Victoria, Queensland or Western Australia follows different legislation with different terminology, so interstate advice can mislead.

Communication access is a legal obligation, not a courtesy

Under the Disability Discrimination Act 1992, health services have obligations to make reasonable adjustments. In a cancer context that includes communication.

Auslan interpreters. A Deaf person has a right to an interpreter for a consultation where significant information is being conveyed or significant decisions made. A family member interpreting is not adequate for a cancer consultation — it is unreliable and it puts the family member in an impossible position. Hospitals can book accredited interpreters and should.

Interpreters for people from non-English-speaking backgrounds. The Translating and Interpreting Service is available to medical practices, and hospitals have interpreter services. Using a relative, including a child, to interpret a cancer discussion is poor practice and produces unreliable information.

Augmentative and alternative communication. If the person uses a communication device, board or system, it must come to the appointment, be charged and set up, and the clinician must be told how it works and given time for it. A person with a device who is not given time to use it has been silenced by the clock.

Speech pathology involvement. For somebody with significant communication impairment facing major treatment decisions, a speech pathologist can advise on how to present information and how to verify understanding. This is an under-used referral.

Cancer Council’s policy work identifies that reasonable adjustments in cancer care often depend on being requested in advance. Which means somebody has to ask, early, and ask specifically.

Advance care planning, and why it belongs here

Cancer is one of the few situations where a person’s future decision-making capacity can be predicted to decline. Brain tumours in particular, and advanced disease generally, mean that the person who can make decisions today may not be able to in six months.

That makes advance care planning more important here than almost anywhere, and it is systematically not done for people with disability.

What it involves:

• A conversation about what the person wants, while they can tell you, recorded in writing.
• An advance care directive where the person has capacity to make one, setting out treatment they would want or refuse.
• Appointment of an enduring guardian — which in NSW a person with capacity can do, choosing who will make health and lifestyle decisions for them if they lose capacity. This is enormously better than the default hierarchy, because the person chooses.
• Recording values and preferences even where a formal directive is not possible — what matters to them, what frightens them, what they have said about hospitals, pain, and being at home.

For a person who already has limited capacity, formal advance care planning may not be possible, but recording their expressed wishes and values is still worth doing and still carries weight in later decision-making.

This connects directly to palliative care, which has its own guide in this library and its own unresolved boundary problems.

The failure modes, named

Four patterns account for most of what goes wrong. They are worth being able to recognise.

Paralysis. The clinician is uncertain whether the person can consent, nobody resolves it, and the decision gets deferred. In screening this means a test never happens. In cancer treatment it means delay, and delay in cancer is measured in stages.

Proceeding on the wrong person’s word. A support worker or a family member who is not the person responsible gives what everybody treats as consent. Common, legally wrong, and it means the actual decision-maker was never consulted and the person was never involved.

The person in the room who is not spoken to. The clinician addresses the support worker. Questions about the person’s body, symptoms and preferences are asked of somebody else. The person sits there. This is the most common of the four and the most corrosive, because it teaches the person that medical settings are places where they do not count — which is how the avoidance documented in the discrimination data begins.

Over-reading refusal. A person pulls away, says no, becomes distressed, and it gets recorded as a refusal of treatment. Sometimes that is exactly what it is and it should be respected. Often it is a response to not understanding, to pain, to fear, or to being handled without warning. Those need completely different responses and they look identical in a file.

A practical sequence for a major cancer decision

1. Establish who the decision-maker is, in writing, before the consultation. Presume the person. If there is a guardian or person responsible, identify them by name and confirm it with the hospital.
2. Book a longer appointment. For people with intellectual disability, Medicare funds a prolonged health assessment annually under item 707, and longer consultations under items 36 and 44. Ask for the time.
3. Request adjustments in advance — interpreter, quiet room, extra time, accessible information, the person’s communication device accommodated.
4. Bring the right support person, chosen by the person, who knows them well.
5. Get the information in accessible format before the appointment where possible, so the person has already begun processing it.
6. Split the decision into its component parts.
7. Check understanding by asking for it back, not by asking whether they understand.
8. Record the person’s values, not only their answer.
9. Allow a second conversation before anything irreversible, where clinically possible.
10. Document what was explained, how, and what the person said — including what they were uncertain about.
11. Ask for a case conference if the situation is complex. Medicare funds multidisciplinary case conferences through items 735, 739 and 743 for a GP organising, coordinating or participating, and items 747, 750 and 758 where the GP and at least two other health professionals are involved. For a decision this consequential it gets everybody into one conversation.
12. Consider advance care planning at the same time, while the person can participate.

Who to contact when it is stuck

• NSW Public Guardian — advice on guardianship and medical consent in NSW.
• NSW Civil and Administrative Tribunal (NCAT) — Guardianship Division, for guardianship applications, disputes and restricted treatment categories.
• Translating and Interpreting Service, and hospital interpreter services, for language access.
• Deaf Connect and state Deaf organisations for Auslan interpreting.
• Cancer Council 13 11 20 — free, staffed by cancer nurses, and able to talk through treatment information and decision-making.
• Advance Care Planning Australia — 1300 208 582 — for advance care directives and enduring guardianship information.
• Disability advocacy organisations funded under the National Disability Advocacy Programme.
• Hospital social worker — frequently the most effective person in the building for sorting out a stuck consent situation.