Rare Cancer Misdiagnosed as Weight Loss Jab Side Effect
Becki Ward, a 33-year-old trainee health practitioner from Great Yarmouth, found herself in a distressing situation, initially attributing her health concerns to the popular weight loss medication Mounjaro. Like millions of other adults in the UK, Becki began taking Mounjaro in October 2024, hoping to manage her lifelong struggles with weight.
“At first it was working well, and suppressing my appetite, but then I realised I wasn’t losing weight as fast as everybody else,” Becki explained. She observed others shedding significant weight, sometimes half a stone per week, while her own progress was a mere one or two pounds in the same timeframe. This disparity led her to believe the issue was personal, perhaps due to her age, perceived laziness, or overeating.
However, the truth was far more serious. Unbeknownst to Becki, a colossal 12kg cancerous tumour was growing within her abdomen. This was caused by an extremely rare form of cancer known as Pseudomyxoma Peritonei (PMP), a condition so uncommon that only two hospitals in the UK are equipped to treat it. PMP affects approximately 400 new patients annually in Britain. It typically originates as a small polyp in the appendix, but can, in rarer instances, begin in the bowel or ovaries.
After several months of self-blame for the perceived ineffectiveness of the weight loss injections, Becki started experiencing alarming new symptoms. “I assumed it wasn’t working because I’m in my 30s, I was lazy, or I was overeating,” she recalled. Her concerns escalated when she began suffering from severe night sweats and persistent stomach pains. Having read about potential side effects of Mounjaro, including pancreatitis, Becki became increasingly anxious, fearing she might be experiencing this serious complication.
It’s worth noting that Mounjaro manufacturer Eli Lilly does list acute pancreatitis as an ‘uncommon’ side effect, potentially affecting up to 1 in 100 people. The manufacturer updated its information leaflet regarding this risk on October 31, 2025.
The Shocking Diagnosis: Pseudomyxoma Peritonei
Driven by her worsening symptoms, Becki sought medical attention for blood tests and organ checks. The results delivered a profound shock: tumour markers flagged up. Initially, doctors suspected ovarian cancer and conducted further investigations to confirm the diagnosis.
Understanding Pseudomyxoma Peritonei (PMP):
- PMP is a rare cancer that typically grows slowly.
- It can spread throughout the abdomen, including the peritoneum, the lining of the abdominal cavity.
- Cancer cells in PMP produce a mucus, known as mucin, which accumulates in the abdomen as a jelly-like fluid. This characteristic has earned the cancer the nickname “jelly belly.”
- Unlike many other cancers, PMP does not typically spread to distant parts of the body but remains confined within the abdominal cavity.
- It is more prevalent in women than men and can be mistaken for ovarian cancer due to the similar symptom of abdominal swelling.
Common Symptoms of PMP:
- Pain in the abdomen or pelvis.
- Infertility.
- Significant swelling and bloating of the abdomen.
- Alterations in bowel habits.
- Hernias (bulges in the abdominal wall or groin).
- Loss of appetite.
- A persistent feeling of fullness.
The primary treatments for PMP involve surgery and chemotherapy.
After extensive testing, doctors identified a 22cm cyst on Becki’s left ovary. However, it took a further five months for her to receive the definitive diagnosis of pseudomyxoma peritonei. “I was so shocked when I got the diagnosis; the thing I’ve always been most terrified of is getting cancer,” Becki confessed. “I just wasn’t expecting it, and I immediately thought the worst.”
Doctors estimated that Becki might have harboured the cancer for as long as five years, given the severity of her symptoms. This led to her being scheduled for an extensive eight-hour surgery in August 2025.
A Gruelling Surgery and Life-Altering Changes
By the days leading up to her surgery, Becki’s abdomen had distended dramatically. “My stomach continued to grow, and days before the surgery, I looked like I was about to give birth to twins,” she recounted. The tumour, when finally removed, was immense, weighing a staggering 12kg.
The surgery, initially planned for eight hours, stretched to an unprecedented 11 hours as the extent of the cancer’s spread became evident. Surgeons worked diligently to remove all visible cancerous tissue. This involved the removal of Becki’s spleen, appendix, gall bladder, omentum (a fold of fatty tissue in the abdomen), and peritoneum. Furthermore, a total hysterectomy was performed.
The consequences of the surgery were immediate and profound. “I was plunged into early menopause,” Becki shared. While hormone replacement therapy (HRT) provided some relief, she highlighted the significant challenges in finding adequate support and information for women experiencing menopause at such a young age.
The surgery also meant that Becki would never be able to have children. Fortunately, she and her husband, Ed, 36, had already made the decision not to pursue parenthood before her diagnosis. “I can imagine it would be devastating for a lot of people though, as 33 is the age when so many people want to have a baby,” she acknowledged.
Following the surgical intervention, Becki underwent heated chemotherapy circulated directly within her abdomen. This was a crucial step to eliminate any microscopic cancer cells that might have remained undetected during the procedure.
After a five-day stay in intensive care and a total of two weeks in hospital, Becki was discharged. She is now in the process of a slow recovery, managing residual fatigue and limitations in lifting heavy objects.
Doctors are optimistic, believing Becki to be cancer-free. However, the threat of recurrence remains, with a 30% chance of the cancer returning. This necessitates regular check-ups for the next two decades. For now, Becki is focused on her recovery and looking forward to a future free from the immediate danger of cancer.
