The concept of oligoprogression sits within a broader revolution in how clinicians understand metastatic cancer. For most of the twentieth century, spread beyond the primary tumour was treated as a uniformly systemic disease, best managed with drugs rather than directed local therapy. That binary view began to crumble in 1995, when Samuel Hellman and Ralph Weichselbaum described oligometastasis, an intermediate state in which the metastatic burden is limited enough that aggressive local treatment might genuinely alter the disease course. Oligoprogression refines this idea further: the patient’s overall disease is broadly controlled, often by targeted drugs or immunotherapy, but a small number of lesions, defined in this study as five or fewer, begin to grow while everything else stays stable. These resistant clones represent a unique clinical window, because eliminating them locally could preserve the effectiveness of a systemic regimen that is still suppressing the rest of the disease.

Until now, the dominant local therapy for oligoprogressive disease has been stereotactic body radiotherapy, or SBRT, which delivers precisely focused, high-dose radiation to individual lesions. Clinical trials, including a randomised phase 2 study published in The Lancet in 2024, have shown that adding SBRT to standard systemic therapy can delay disease progression in patients with oligoprogressive breast and lung cancers. But radiation has inherent limits. Cumulative dose constraints restrict how often a region can be retreated, previously irradiated tissue may be off-limits entirely, and tumours sitting close to the bowel, nerves, or other sensitive structures can be difficult to treat safely. The literature on non-radiation ablative alternatives for soft-tissue metastases in this setting has been, until this study, essentially nonexistent.

Cryoablation offers a fundamentally different physical approach. Thin cryoprobes, ranging from 14 to 17 gauge in this study, are inserted into or alongside the target tumour under CT guidance, sometimes supplemented by ultrasound. Argon-based gas expansion drops the probe tip temperature to levels that freeze the tissue, forming an ice ball whose edges are visible in real time on the CT images. This visibility is one of the technique’s greatest assets: the interventional radiologist can watch the frozen zone expand and confirm that it envelops the tumour with a safety margin, in this case 5 millimetres beyond the lesion boundary, before declaring technical success. The standard protocol used at Royal Marsden consisted of two 10-minute freezing cycles separated by a 9-minute passive thaw and a 1-minute active thaw, a freeze-thaw-freeze sequence that maximises cellular destruction through a combination of direct ice-crystal injury and vascular compromise.

One of the study’s most technically interesting features is its systematic use of thermoprotective manoeuvres. Because many soft-tissue metastases lie near the gastrointestinal tract, major nerves, or blood vessels, the team frequently created physical buffers between the ice ball and vulnerable structures. Hydrodissection, injecting fluid to push organs away, was used in 19 cases, while carbodissection, insufflating carbon dioxide to achieve the same separation, was used in 6, with 2 cases combining both and 3 relying on a thermocouple device. Warm saline compresses and subcutaneous saline injections protected overlying skin. These techniques, refined at the centre over years, were instrumental in keeping the overall complication rate to 13 percent across 46 sessions, with the six complications comprising two pneumothoraces, two transient nerve palsies affecting the femoral and obturator nerves, and two skin injuries, all of which resolved without long-term sequelae.

The oncologic results are equally noteworthy. Of the 52 treated tumours, which had a median diameter of 20 millimetres and arose from primary cancers including colorectal tumours, sarcomas, breast, cholangiocarcinoma, and lung cancer, 41 were ablated with curative-intent local control in mind, while 11 were treated purely for symptom palliation and excluded from the survival analysis. Among the 41 lesions treated for control, only three showed residual unablated tumour at first follow-up imaging, and two of those were successfully retreated, yielding a primary technique efficacy of 93 percent and a secondary efficacy of 98 percent. Local tumour progression occurred in 20 percent of lesions during a median follow-up of 11.3 months, producing an estimated two-year local tumour progression-free survival of 76 percent, a figure that aligns with or exceeds outcomes reported for SBRT and surgery in comparable cohorts.

Perhaps the most clinically meaningful number, however, is the divergence between local and systemic outcomes. While local control at two years stood at 76 percent, progression-free survival across the whole body was just 27 percent at two years, with a median of 5.8 months. This gap is not a failure of the technique; it is a window into the biology of oligoprogression itself. Freezing a lesion eliminates the resistant clone at that site, but the underlying systemic disease continues to evolve under the pressure of ongoing therapy. The value of ablation lies in buying time: by removing the progressing foci, clinicians can keep a patient on a systemic regimen that is otherwise working, rather than switching to a next-line drug with its own toxicity profile and uncertain benefit. Notably, the authors report that nearly one-third of patients avoided a change in systemic therapy or remained on a treatment break for at least two years after the procedure, a substantial gain in treatment-free interval and quality of life.

Cryoablation also carries practical advantages over radiotherapy that could reshape multidisciplinary decision-making. There is no cumulative radiation dose to worry about, so previously irradiated sites can be treated and retreatment is possible if a lesion recurs. The ice ball can be monitored continuously, giving immediate visual confirmation of coverage. Crucially, patients do not need to interrupt their systemic therapy around the procedure, which means the pharmaceutical control of the wider disease is never suspended. The team even exploited the percutaneous approach diagnostically: in 10 patients, an image-guided biopsy was performed immediately before ablation in the same session, allowing molecular characterisation of the progressing clone that could inform subsequent lines of systemic treatment. Most procedures were performed under general anaesthesia, took a median of 88 minutes, and required a median hospital stay of just 27 hours, with superficial lesions managed entirely on an outpatient basis.

The authors are candid about the limitations of their work. The study was retrospective and single-centre, with the selection biases that implies, and the heterogeneity of tumour histologies and sizes complicates interpretation of the survival data. Follow-up imaging varied between CT, PET-CT, and MRI depending on the clinical scenario. Yet even with these caveats, the consistency of the safety profile and the strength of the local control figures give the findings considerable weight, particularly as the first reported application of cryoablation to non-visceral, non-nodal soft-tissue metastases in the oligoprogressive setting. The research was supported by the National Institute for Health Research Biomedical Research Centre at The Royal Marsden and the Institute of Cancer Research, and the underlying data are available on request.

What comes next could be decisive. The team argues that prospective controlled trials comparing cryoablation directly with SBRT and surgical resection are now warranted to define where freezing fits within the evolving treatment paradigm for limited disease progression. If those trials confirm the London results, interventional oncology may gain a new pillar in the management of metastatic cancer, one in which a handful of needles, a CT scanner, and precisely controlled cold can hold resistant tumour clones at bay while the drugs that keep the rest of the disease in check continue to do their work. For patients caught in the narrow but consequential gap between remission and widespread progression, that could translate into months or years of continued benefit from their existing therapy, without the burden of yet another drug switch.

Subject of Research: Image-guided percutaneous cryoablation of soft-tissue metastases in patients with oligoprogressive cancer

Article Title: Image-guided cryoablation of soft-tissue metastases in patients with oligoprogressive disease: analysis of feasibility, safety, and efficacy

Article References: Fotiadis, N., Ahmed, N., Johnston, E. W., Starling, N., Jones, R., Hayes, A., Popat, S., Cunningham, D., & Tekkis, P. (2025). Image-guided cryoablation of soft-tissue metastases in patients with oligoprogressive disease: analysis of feasibility, safety, and efficacy. CVIR Oncology, 1(1), Article 20. https://doi.org/10.1007/s44343-025-00019-x

Image Credits: AI Generated

DOI: 10.1007/s44343-025-00019-x

Keywords: cryoablation, oligoprogressive disease, soft-tissue metastases, interventional oncology, local ablative therapy, stereotactic body radiotherapy, oligometastasis, local tumour control, progression-free survival, minimally invasive surgery, cancer treatment, Royal Marsden Hospital