‘No surgery, no chemo’: new cancer trial shows 100% remission with immunotherapy

What if your body’s own immune system could be taught to wipe out tumours — and do it so effectively that no further treatment was needed?

That is the potential of immunotherapy, a treatment that harnesses and enhances the body’s immune response to target and destroy cancer cells. While it has typically been reserved for later stages of treatment, new clinical research is beginning to challenge that timeline.

In cases where tumours carry a mutation known as mismatch repair deficiency (dMMR) — which causes a higher number of mutations in cancer cells — immunotherapy has shown the ability to completely eliminate tumours without the need for surgery or traditional therapies. This approach is now being explored in early-stage cancers across multiple organs, offering patients the possibility of effective treatment with fewer long-term side effects.

A promising trial: Immunotherapy as a first-line treatment

At Memorial Sloan Kettering Cancer Center in New York, researchers conducted a Phase 2 clinical trial exploring the use of immunotherapy as a primary treatment for cancers with mismatch repair deficiency (dMMR).

This genetic mutation, which prevents cells from fixing errors during DNA replication, leads to a high number of mutations in tumours. These mutations, in turn, make the tumours more recognisable and vulnerable to the immune system when supported by immunotherapy.

In the study, participants received the immunotherapy drug dostarlimab (sold under the brand name Jemperli) every three weeks for six months. The trial included patients with a range of early-stage cancers — such as rectal, gastroesophageal, endometrial, and bile duct cancers — all with confirmed dMMR mutations.

The results were striking. Among 49 rectal cancer patients, 100% had a complete response: their tumours disappeared, and none needed further treatment. Of the 54 patients with other types of dMMR-positive cancers, 61% had a complete response, meaning no evidence of cancer remained after immunotherapy alone.

These findings build on an earlier study where 12 rectal cancer patients also achieved complete remission with immunotherapy — results that earned the drug an FDA “Breakthrough Therapy” designation.

Maureen’s experience: A life changed by immunotherapy

For Maureen Sideris, the signs of cancer first appeared during a road trip. While driving to Maine for a wedding in August 2022, the 71-year-old found herself unable to swallow her sandwich — a symptom that soon led to a diagnosis of gastroesophageal cancer. The tumour had obstructed part of her oesophagus, making it difficult to eat.

Traditionally, treatment for this type of cancer involves chemotherapy and radiation, followed by invasive surgery to remove part of the oesophagus and stomach. But Maureen’s case was different. Thanks to her eligibility for the trial, she received only immunotherapy — bypassing the need for surgery or chemo entirely.

The treatment was straightforward: a 45-minute IV infusion every three weeks over six months. Two years later, she remains in remission.

While the treatment spared her from the harsh side effects of chemotherapy and surgery, it did come with challenges. Maureen developed adrenal insufficiency, a known side effect of the drug, and now takes medication to manage it. Still, she describes the experience as “like winning the lottery.”

What this means for the future of cancer care

After early success with rectal cancer, researchers expanded the use of dostarlimab to treat other dMMR cancers — including those in the oesophagus, uterus, bile ducts, and kidneys. The results were encouraging: 61% of patients saw their tumours vanish completely after just six months of immunotherapy, without needing surgery or chemotherapy.

Immunotherapy represents a major breakthrough in cancer care, offering a less invasive and more targeted alternative to traditional treatments. Its success, particularly in patients with mismatch repair-deficient (dMMR) tumours, points to a future where surgery, chemotherapy, and radiation may no longer be the only options.

However, challenges remain: the treatment is effective only for cancers with specific mutations, can cause hormonal side effects, and remains financially out of reach for many. In India — where the drug is available but often used alongside traditional treatments — a single dose can cost up to $11,000, limiting accessibility.

Still, the growing success of immunotherapy offers real hope for a new, more humane chapter in cancer treatment.

(Compiled by Vismaya Vijayan)