Cancer Awareness: When Rare Complications Become a Family’s Reality

October is Breast Cancer Awareness Month, a time when we see pink ribbons, hear stories of survival, and recognize the importance of cancer research, early detection, and advances in treatment.

But this October, cancer awareness has taken on a particularly personal meaning for me. Both of my parents are receiving treatment for metastatic cancer. And while neither is currently being treated for breast cancer, their experiences have reminded me that cancer affects not only the person diagnosed but also the family and loved ones navigating the experience alongside them.

My parents’ recent experiences have reinforced this reality: A medication can be life-changing for one person while another faces serious complications that may be related to their treatment. And while we often celebrate medical breakthroughs, we don’t always give the same attention to what happens when patients experience those complications.

My dad is undergoing immunotherapy for metastatic melanoma, and his response has been encouraging. His cancer appears to be shrinking, and he’s experiencing few, if any, side effects.

My mom’s experience has been different.

Years ago, she survived stage IV non-Hodgkin lymphoma after receiving the R-CHOP cancer treatment regimen. We’re profoundly grateful for the treatment that gave her more years of life — years that allowed her to travel, celebrate her grandchildren’s weddings, and welcome many great-grandchildren into the family.

Now, at 85 years old, she’s facing a new metastatic cancer diagnosis and once again navigating the complexities of cancer treatment.

But this time, one of those complexities has been the sudden development of severe diabetes with insulin deficiency — a recognized but uncommon potential complication of the immunotherapy she received.

I want to be clear about something from the beginning. I’m not sharing this story to discourage anyone from pursuing cancer treatment. I’ve witnessed firsthand what these treatments can accomplish, even when they carry the possibility of serious complications.

My concern is something different.

What happens when a known but uncommon complication actually occurs, and the healthcare system struggles to provide the coordinated care needed to manage it?

When a Rare Side Effect Becomes Reality

We are living in an extraordinary time in medicine. Treatments that once seemed unimaginable are extending lives and offering hope to people facing serious illnesses.

We sometimes hear medications described as “miracle drugs.” Immunotherapies and GLP-1 medications are both examples of treatments that have generated tremendous enthusiasm for their potential to improve health outcomes.

But enthusiasm for a medication’s benefits should never overshadow our responsibility to educate, recognize, and respond to its potential harms. Whether an adverse effect is common or rare, patients can be left without adequate evaluation, support, or treatment when their concerns about possible side effects are minimized or dismissed, or their symptoms are attributed too quickly to other causes.

The challenge isn’t to diminish the remarkable benefits these medications may offer. It’s to recognize that a treatment can be highly effective for many people while creating significant difficulties for others.

Immunotherapy medications include a class of cancer treatments known as “immune checkpoint inhibitors” that work by helping the immune system recognize and attack cancer cells.

One rare but well-documented complication of these treatments is the development of insulin-deficient diabetes, which can occur suddenly and sometimes present with life-threatening diabetic ketoacidosis (DKA).

Research suggests that checkpoint inhibitor–associated diabetes occurs in approximately 0.2% to 1.4% of treated patients, depending on the population studied and how the condition is defined. [1]

These are small percentages. But what do those numbers mean to the person who experiences this side effect? For my mom, it meant arriving at the emergency department with severe diabetic ketoacidosis.

Thankfully, the emergency team recognized the seriousness of her condition, initiated appropriate treatment, and admitted her for further care.

The inpatient team considered the possibility of immune checkpoint inhibitor–associated diabetes or steroid-related hyperglycemia. During her hospitalization, the treatment plan included long-acting and rapid-acting insulin, along with education about managing her blood glucose.

Given the severity of her presentation, we understood that she would be going home with an insulin regimen.

But shortly before discharge, that plan changed.

Recognizing a Complication Is Only the Beginning

At discharge, the physician changed my mom’s treatment to metformin alone. My parents didn’t receive a clear explanation for the change, and we couldn’t find a rationale in the discharge documentation.

Concerned about the discharge plan, I asked my mom to check her blood glucose the following day. Her reading was significantly elevated, prompting another visit to the ER. Despite the elevated glucose, my parents’ concerns were minimized with the explanation that metformin had not yet had enough time to work. The treatment plan was adjusted to include long-acting insulin alongside metformin, but no mealtime insulin, with the stated rationale of reducing the risk of hypoglycemia.

Still concerned that her treatment plan did not adequately address her insulin needs, I encouraged my mom to follow up with her primary care clinician the next day, who recognized that additional treatment was needed and provided instructions for adding rapid-acting insulin using a correction scale.

Each encounter brought another adjustment, but without a clearly communicated, coordinated plan that accounted for the larger clinical picture. To say that my parents were overwhelmed and confused is an understatement.

But there were important clinical findings that didn’t seem to be reflected in the decisions about her ongoing diabetes treatment.

My mom’s evaluation included several findings that raised concern about the sudden onset of insulin-deficient diabetes. Her blood glucose had been checked approximately every three weeks during cancer treatment, with consistently normal results.

When she presented with severe hyperglycemia and diabetic ketoacidosis, her A1C was 7.6%, further suggesting that the marked elevation in blood glucose was relatively recent rather than longstanding.

Another important finding was a very low C-peptide level measured alongside significant hyperglycemia. C-peptide is released when the pancreas produces insulin, and measuring it alongside blood glucose helps clinicians assess the body’s own insulin production.

When blood glucose is substantially elevated, the pancreas would ordinarily be expected to increase insulin secretion. A very low C-peptide in that setting raises concern that the body is not producing sufficient insulin. For dietitians and other healthcare professionals more familiar with managing type 2 diabetes, this distinction matters.

Immune checkpoint inhibitor–associated diabetes is thought to involve immune-mediated damage to the insulin-producing beta cells of the pancreas, often resulting in rapid and substantial insulin deficiency. [1, 2] Although insulin resistance and insulin deficiency can coexist, significant insulin deficiency requires insulin replacement. Medications such as metformin, which primarily improve insulin sensitivity, cannot replace insulin the body is unable to produce.

Clinical guidelines from the American Society of Clinical Oncology recommend insulin treatment when checkpoint inhibitor–associated diabetes is suspected, even when the diagnosis remains uncertain, and endocrinology consultation for concerning presentations. [3]

In my mom’s case, the combination of severe DKA, evidence suggesting substantial insulin deficiency, and recent immunotherapy exposure warranted careful consideration and a coordinated plan for ongoing evaluation and treatment. Given these circumstances, any decision to discontinue insulin following hospitalization should have been accompanied by a clearly documented clinical rationale, careful discharge planning, and communication to ensure that she and our family understood how the new treatment plan would address the risk of recurrent severe hyperglycemia or ketoacidosis.

This is not about expecting every clinician to have all the answers. It’s about ensuring that important clinical findings, suspected diagnoses, and unresolved questions are communicated across the treatment team.

When Multiple Treatments Complicate the Picture

The challenges didn’t end with her discharge.

My mom is now receiving another cancer treatment that includes dexamethasone, a corticosteroid used to help manage treatment-related side effects. Corticosteroids can substantially increase blood glucose levels and insulin requirements, creating additional challenges for someone already experiencing significant insulin deficiency.

This isn’t an obscure physiological interaction. Steroid-induced hyperglycemia is well recognized, and diabetes care guidelines emphasize the importance of considering the type, dose, and duration of glucocorticoid therapy when planning treatment. [3]

Yet we found ourselves navigating dramatic glucose fluctuations without a clear, proactive plan for how her insulin needs might change during the days surrounding treatment.

As a healthcare professional, I understand that insulin dosing requires individualization and that glucose responses can be unpredictable. As a daughter, however, I also understand the anxiety of watching a glucose monitor display dangerously elevated readings while trying to determine what to do next.

There is a difference between the unavoidable uncertainty of a medical condition and the additional uncertainty created when patients and families don’t have adequate guidance.

When Food Becomes the Focus Instead of the Physiology

As a registered dietitian, one of the most troubling aspects of this experience has been watching the conversation shift toward what my mom is eating.

When her blood glucose remained persistently elevated, the advice she received through clinical triage focused on nutrition. At one point, ordinary foods she had eaten became the culprit in the conversation, creating additional anxiety, confusion, and fear about foods she had previously enjoyed without concern.

Certainly, carbohydrate intake influences blood glucose. Nutrition is an important component of diabetes care. But in someone who has recently experienced diabetic ketoacidosis, may have substantial insulin deficiency, and is receiving medications known to increase blood glucose, food is only one part of a much more complex physiological picture. Without adequate insulin, dietary changes cannot correct severe insulin deficiency.

What concerns me is the message that gets communicated when we focus disproportionately on food.

My mom is 85 years old. She has generally enjoyed food without the fear and scrutiny that so often accompany diabetes management. Now, while undergoing treatment for metastatic cancer, she is beginning to question whether ordinary meals are responsible for dangerously elevated blood glucose.

And that’s heartbreaking to watch.

Nutrition education should help people feel informed and supported, not leave them fearful of eating or feeling responsible for metabolic changes that require medical treatment. This is particularly important during cancer treatment, when maintaining adequate nourishment, strength, and quality of life already presents challenges.

The Hidden Burden of Fragmented Care

One of the lessons I’ve taken from this experience is that the consequences of a serious side effect extend well beyond the diagnosis itself.

For my mom, the challenges of living with metastatic cancer now include managing an entirely new medical condition: diabetes. Each comes with its own treatment demands, uncertainties, and emotional burdens. And managing both simultaneously adds another layer of complexity to an already overwhelming experience.

Throughout their cancer treatment, my parents have been informed about potential risks and side effects. The challenge hasn’t been a lack of information about what could happen, but rather what happens when a serious complication actually occurs. That’s when communication and coordination across the healthcare team become especially important.

There are new medications to learn, blood glucose readings to interpret, appointments to coordinate, and decisions to make about when symptoms or test results require urgent attention.

For patients and families, these responsibilities can be overwhelming, especially when they are already navigating a serious illness. And when the guidance they receive changes from one clinician to another, uncertainty can quickly turn into anxiety.

I have the benefit of a healthcare background. I understand nutrition, glucose metabolism, and the importance of asking questions. Even so, helping my parents navigate this experience has been challenging.

Which adds another dimension to this experience that I think deserves attention.

It’s important to recognize that questioning medical decisions isn’t always easy for patients and families. When someone is navigating a serious illness, they often place tremendous trust in their healthcare professionals. And even when questions or concerns arise, they may hesitate to speak up for fear of being perceived as difficult or challenging.

This raises an important question: How many patients leave appointments with unanswered questions, not because they aren’t engaged in their care, but because they don’t feel comfortable questioning someone they perceive as having greater authority?

We often encourage patients to advocate for themselves. But healthcare professionals also have a responsibility to invite questions, explain clinical reasoning, and ensure that important findings are followed up, even when patients don’t know what questions to ask.

Patients and families shouldn’t need a healthcare background to recognize when additional evaluation may be warranted. And they shouldn’t have to choose between maintaining a trusting relationship with their clinicians and feeling confident that their medical concerns are being addressed.

Patient advocacy shouldn’t be a prerequisite for receiving appropriate care.

The American Diabetes Association emphasizes the importance of individualized inpatient diabetes management, proactive discharge planning, and timely follow-up to support safe transitions from hospital to home. [4]

These aren’t simply administrative details. They are essential components of patient care.

What Can We Learn From This?

I don’t believe every complication can be prevented, and I don’t expect healthcare professionals to have all the answers in every situation.

Medicine is complex. Clinicians make decisions under pressure, often with incomplete information. And coordinating care across oncology, emergency medicine, endocrinology, and primary care isn’t always straightforward.

But complexity shouldn’t prevent us from examining where care can improve.

For me, several lessons stand out.

First, informed consent should involve more than explaining how frequently a side effect occurs. Patients and families also need to understand what to watch for and what to do if a serious complication develops.

Second, recognizing a complication is only the beginning. Appropriate treatment, documentation, discharge planning, communication, and follow-up are equally important. When a diagnosis remains uncertain, that uncertainty — and its implications for treatment — should be clearly communicated.

Third, when multiple treatments and medical conditions intersect, someone needs to take responsibility for coordinating the plan. Patients should know whom to contact, what changes to anticipate, and when to seek urgent care.

Fourth, we need to be thoughtful about the messages we communicate to patients. When we oversimplify complex medical problems or focus on individual behaviors without considering the underlying physiology, we can unintentionally create confusion, anxiety, and even shame.

And finally, we need to consider whether our healthcare systems create an environment where patients feel comfortable asking questions and seeking clarification, without placing the burden on them to recognize gaps in their own care.

These concerns are not unique to cancer care. As medical treatments evolve, so must our systems for recognizing adverse effects, sharing information across specialties, and supporting patients when complications occur.

None of these observations are intended to diminish the dedication of the healthcare professionals who care for people with cancer every day. Nor do they diminish my gratitude for the treatments that have helped both of my parents.

Rather, they are an invitation to consider how we can do better.

Cancer Awareness Is About More Than the Cancer

As we recognize Breast Cancer Awareness Month, I hope we can also make room for conversations about the broader realities of living with cancer, regardless of the diagnosis.

We should celebrate advances in treatment. We should recognize the researchers and clinicians whose work continues to improve survival and quality of life. And we should remain hopeful about what the future of cancer care may bring.

But we also need to acknowledge the experiences that don’t fit neatly into the stories of treatment breakthroughs and successful outcomes.

These include the challenges of managing serious complications, navigating transitions between healthcare settings, and coping with the emotional burden on patients and families, as well as recognizing opportunities to improve care when things don’t go as expected.

When I asked my parents about sharing their story, they generously gave their permission, hoping that their experiences might help others. I’m grateful for their willingness to share something so personal.

My mom’s diabetes may be related to a treatment intended to help her fight cancer, and the complication itself may not have been preventable. But the confusion, fear, and uncertainty that followed should not simply be accepted as inevitable.

We don’t have to choose between celebrating medical breakthroughs and taking their complications seriously. Good healthcare requires us to do both.

Bottom line: Rare side effects are real, and cancer awareness should be about more than recognizing the disease and celebrating advances in treatment. It should also mean ensuring that when complications occur, patients and families can trust that the healthcare system is prepared to respond with thoughtful, coordinated, and compassionate care.

References

1. Wu L, Tsang V, Menzies AM, et al. Risk Factors and Characteristics of Checkpoint Inhibitor-Associated Autoimmune Diabetes Mellitus (CIADM): A Systematic Review and Delineation From Type 1 Diabetes. Diabetes Care. 2023 Jun 1;46(6):1292-1299. doi: 10.2337/dc22-2202. PMID: 37220262.
2. Nagy S, Demory Beckler M, Hussein A, Kesselman MM. The Development of Diabetes and Diabetic Ketoacidosis Following Immunotherapy Treatment: A Systematic Review of Case Reports. Cureus. 2024 Apr 9;16(4):e57894. doi: 10.7759/cureus.57894. PMID: 38606021; PMCID: PMC11007471.
3. Schneider BJ, Naidoo J, Santomasso BD, et al. Management of Immune-Related Adverse Events in Patients Treated With Immune Checkpoint Inhibitor Therapy: ASCO Guideline Update. J Clin Oncol. 2021 Dec 20;39(36):4073-4126. doi: 10.1200/JCO.21.01440. Epub 2021 Nov 1. Erratum in: J Clin Oncol. 2022 Jan 20;40(3):315. doi: 10.1200/JCO.21.02786. PMID: 34724392.
4. American Diabetes Association Professional Practice Committee for Diabetes*. 16. Diabetes Care in the Hospital: Standards of Care in Diabetes-2026. Diabetes Care. 2026 Jan 1;49(Supplement_1):S339-S355. doi: 10.2337/dc26-S016. PMID: 41358892; PMCID: PMC12690180.