Immunotherapy, which engages the body’s immune system to identify and destroy malignant (cancer) cells, has advanced far enough to offer a therapeutic option that, in a growing number of cases, negates the need for conventional chemotherapy, radiation, or surgery. As more researchers confirm its efficacy and its use expands in clinical settings, evidence shows that the treatment improves long-term quality of life while achieving favorable outcomes.
Immunotherapy and dMMR Tumors
Mismatch repair deficiency (dMMR) is a “flaw” in the cellular mechanism that normally corrects DNA replication errors. Tumors with this abnormality can have several mutations, making them more visible to the immune system. This heightened immunogenicity helps immune checkpoint inhibitors target and eradicate these tumors.
For example, dostarlimab, marketed under the brand name Jemperli, belongs to a class of drugs known as PD-1 inhibitors. These agents block a protein that malignant cells exploit to evade immune detection. By disabling this mechanism, the immune system can mount a direct attack on tumor cells.
Recent Clinical Trial and Its Findings
A 2025 study published in the New England Journal of Medicine followed 117 participants, each diagnosed with either advanced rectal cancer or other solid tumors such as those found in the stomach, bladder, prostate, or colon. All individuals had tumors identified as mismatch repair-deficient. Of those enrolled, 103 completed the full six-month course of treatment with dostarlimab.
The treatment protocol was as follows:
- Patients received 30-minute intravenous infusions of dostarlimab every three weeks.
- The complete treatment cycle spanned six months.
- Monitoring continued for two years following treatment completion.
The primary outcome was the rate of complete clinical response, defined as the total absence of detectable cancer following treatment. Among rectal cancer patients, all participants achieved complete response with no recurrence observed in nearly five years for most. In the broader cohort, at least 80% of those treated did not require additional therapies, including surgery, radiation, or chemotherapy.
Case Insight: A Young Mother Recovers Without Conventional Approaches
One of the trial participants, a 28-year-old woman diagnosed with stage III rectal cancer, was originally planning to undergo chemotherapy, radiation, and surgical intervention, including the possibility of a permanent colostomy. After entering the clinical trial, her tumor had diminished by half after four treatments. Much to her surprise, imaging confirmed the tumor had vanished by the ninth dose. Her physicians declared her cancer-free, saving her from needing surgery and radiation.
Her story is proof of not only the clinical effectiveness of immune checkpoint inhibitors but also their potential to preserve fertility and prevent life-altering surgical outcomes.
More About How Immunotherapy Is Improving Cancer Care
This study strengthens the growing evidence that immune-based therapies are a powerful ally against tumors across anatomical sites. As researchers continue to observe long-term efficacy in patients with rectal cancer, this approach may also prove beneficial against cancers with the same genetic features identified through tumor sequencing.
Dr. Luis Diaz, a co-author, emphasized that the responses observed have persisted for several years and restored patients to normal life without toxic side effects. According to the researchers, three patients treated for rectal cancer were later able to conceive and deliver healthy children, a feat typically unattainable following standard treatment.
Side Effects and Safety
Of those who received at least one dose of the immunotherapy agent, about 65% reported some form of adverse reaction. These events were mild in most cases and included symptoms such as fatigue, skin rash, localized irritation at the infusion site, or pruritus. No deaths occurred among study participants during the trial. Related article: Immunotherapy Side Effects and How to Manage Them
Limitations and Eligibility Considerations
While the study’s results are promising, they apply only to patients with confirmed mismatch repair-deficient tumors. Genetic sequencing is necessary prior to any decision regarding immunotherapy. Testing allows clinicians to identify the specific mutations driving the cancer and determine whether immune-based treatments are viable.
Dr. Stacey Cohen of Fred Hutchinson Cancer Center, not involved in the study, stressed the need for caution. Not all patients, even those with the appropriate biomarker, will achieve a complete response. Additional research is a must to learn more about tumor behaviors and resistance mechanisms.
Genetic Sequencing at Diagnosis
The potential of immune-based therapy reinforces the importance of genomic testing at the time of cancer diagnosis. Tumor sequencing can reveal mutations that make immunotherapy a feasible treatment option. In some cases, this approach may replace traditional modalities entirely. In others, it may be a preliminary treatment before considering additional interventions.
According to Dr. William Dahut of the American Cancer Society, a tumor’s mutational burden can influence its response to checkpoint inhibitors. The higher the number of genetic abnormalities, the more probable the immune system will recognize and attack the cancer with the help of immunotherapy agents.
Future Directions in Cancer Treatment
While the clinical trial presented encouraging results, larger studies are necessary to confirm the reproducibility and durability of this approach across different tumor types. Researchers are now pursuing additional investigations to assess the potency of dostarlimab and similar agents in other genetic subtypes and cancer stages.
This progress also raises the likelihood of immunotherapy replacing conventional treatments for a subset of patients. The avoidance of radiation, surgery, and chemotherapy, especially when achieved without sacrificing disease control, is a momentous advancement in care strategy.
The Bottom Line: Immunotherapy Is the Present and Future of Cancer Care
Immunotherapy with agents such as dostarlimab demonstrates the possibility of complete and lasting tumor regression without the physical and mental burden associated with traditional treatments. The featured study above suggests that immune-based treatments could be the most effective and least invasive path to recovery for certain genetically defined malignant diseases.
In fact, immunotherapy is no longer limited to experimental settings. At New Hope Unlimited, we have adopted immunotherapy and other precision oncology methods based on validated clinical evidence and evolving treatment standards. Genetic sequencing and biomarker testing now inform treatment decisions at our facility, ensuring that patients receive options suited to the biology of their specific tumor. If you or someone you know has received a cancer diagnosis, we encourage you to consult our team. We will evaluate your case thoroughly, including molecular profiling where indicated, to determine the safest and most effective cancer treatment. Please reach out to us to set an appointment or request additional information.
