Dormant cells and minimal residual disease

CEPHEUS extends the quadruplet standard to patients who are not going to transplant, closing the gap between transplant-eligible and ineligible populations. It is also one of the first phase 3 trials to be designed around MRD-negativity as the primary endpoint, which could shorten future myeloma trials by years. Frailer patients still need dose-adapted approaches.

After bladder removal, a blood test can now tell who needs immunotherapy and who can safely be spared it. This is the model for MRD-guided adjuvant therapy across cancers: treat the blood-positive, watch the blood-negative.

E1910 changed the standard of care for adult B-ALL: immunotherapy is now part of front-line consolidation even for patients with no detectable leukaemia, because MRD-negative by flow cytometry does not mean cured. It also demonstrated that a T-cell engager can improve overall survival in a curative setting. Chemotherapy-light or chemotherapy-free regimens built on blinatumomab and inotuzumab are the next step.

Ribociclib is a second adjuvant CDK4/6 option, and the only one with data in node-negative stage II disease. Roughly 3 in 100 patients avoid a relapse or death at three years, so the decision depends heavily on individual risk, tolerance of a three-year oral drug, and cost. Whether the benefit persists after treatment ends, as it did with abemaciclib, needs longer follow-up.

Patients fit enough for cisplatin whose bladder cancer has invaded the muscle wall should now be offered durvalumab with their pre-operative chemotherapy and for about a year after surgery, which improves the chance of cure without compromising the operation. The trial cannot say whether the adjuvant phase is necessary, or how to treat cisplatin-ineligible patients, for whom other trials are ongoing.

PERSEUS, with the earlier GRIFFIN and CASSIOPEIA trials, made a four-drug daratumumab quadruplet the standard for fit patients heading to transplant. It also introduced MRD-directed stopping of the antibody, a step towards treatment that is deep but not indefinite. Whether transplant itself remains necessary on top of a quadruplet is now the open question.

The blood test stratifies risk far better than stage or pathology. It supports treating ctDNA-positive patients and suggests ctDNA-negative patients gain little from chemotherapy, but because treatment was not randomised the de-escalation claim needs the randomised trials that are now under way.

Relapse after surgery is driven by particular subclones that can be identified in the primary tumour and tracked in blood, which argues for evolution-aware adjuvant strategies. The pollution finding reframes carcinogenesis: some agents promote already-mutant cells rather than causing mutations.

Patients with operable stage II-III lung cancer without EGFR or ALK alterations should have chemo-immunotherapy discussed before surgery rather than only afterwards. Three pre-operative cycles do not compromise the operation and improve cure rates. Whether to continue immunotherapy after surgery, as the perioperative trials do, and whether patients with pCR need any further treatment, remain open questions.

For stage II colon cancer, where most patients are cured by surgery alone, a blood test can identify the minority who benefit from chemotherapy and spare everyone else its side effects. It does not yet prove that treating ctDNA-positive patients improves survival compared with not treating them.

For stage II-III triple-negative breast cancer, chemotherapy plus pembrolizumab before surgery and pembrolizumab alone afterwards is now the standard approach worldwide, and the survival gain is real, not just a surrogate. It does not apply to stage I disease or to hormone-receptor-positive or HER2-positive cancers. The price is a year of immunotherapy with a meaningful chance of a permanent endocrine side effect such as hypothyroidism or adrenal insufficiency.

Patients whose kidney cancer has been removed but who are at high risk of recurrence (large or high-grade tumours, node involvement, or resected metastases) can now be offered a year of pembrolizumab, which increases the chance of being alive and cancer-free several years later. Roughly nine patients need treatment to prevent one recurrence at two years, and some will have permanent side effects, so shared decision-making matters. Why pembrolizumab succeeded where similar drugs failed is not fully understood.

Everyone with HER2-negative early breast cancer that meets high-risk criteria should be offered germline BRCA testing, because a positive result now changes treatment: a year of olaparib after chemotherapy reduces relapse and death. It does not apply to low-risk tumours, HER2-positive disease, or somatic-only BRCA mutations.

Every resected non-squamous lung cancer should be tested for EGFR mutations, because patients who carry one live longer if they take osimertinib for three years after surgery. The trial does not tell us whether adjuvant chemotherapy can be omitted, nor what happens on relapse after osimertinib, and the three-year duration was chosen empirically.

Women with hormone-receptor-positive, HER2-negative breast cancer that has spread to lymph nodes and has other high-risk features can now be offered two years of abemaciclib alongside their hormone therapy, with a durable reduction in relapse. It does not apply to node-negative or low-risk disease, and the diarrhoea and cost are real trade-offs to discuss.

CLL14 established the first chemotherapy-free, fixed-duration regimen for front-line CLL and made MRD-guided thinking mainstream in the disease. Patients get a year of treatment and then a treatment-free period rather than indefinite therapy. The choice today is between fixed-duration venetoclax combinations and continuous BTK inhibitors, with no proven survival difference.

HER2-positive breast cancer is now routinely treated before surgery so that the pathology result can guide what comes after: patients with no residual cancer continue trastuzumab (with or without pertuzumab), while those with residual disease switch to T-DM1. This model of using the tumour's response as a test has since been copied in triple-negative and other cancers.

Women with newly diagnosed advanced ovarian cancer should have their tumour tested for BRCA mutations and homologous recombination deficiency, because those who are HRD-positive gain years of additional disease control and better survival from adding olaparib to bevacizumab maintenance. Those who are HRD-negative gain nothing from olaparib in this combination and should not be exposed to its toxicity and cost. HRD testing has become a routine part of ovarian cancer care as a result.

MURANO made fixed-duration venetoclax the standard for relapsed CLL and showed that stopping therapy after a deep response is safe for most patients. It also established MRD at end of treatment as a practical guide to who is likely to stay in remission. Retreatment with venetoclax at relapse appears feasible.

Every woman diagnosed with advanced high-grade ovarian cancer should be tested for BRCA mutations at diagnosis, because those who carry one should receive two years of olaparib after chemotherapy, which greatly extends the time in remission and improves long-term survival. The plateau in the survival curves suggests some patients are cured by this approach. Toxicity is mostly anaemia, fatigue and nausea, and the two-year limit appears sufficient.

Lung cancers keep evolving after they form, and it is ongoing chromosomal instability rather than the number of mutations that best predicts who will relapse. This gives a rationale for targeting the earliest (clonal) drivers and neoantigens and for tracking evolution in blood after surgery.