Most people arrive at this page holding a single number and a discouraging sentence. That number is where the assessment starts, not where it ends. Four measurements decide together, and the answer runs in both directions: some patients told they were unfit are found to have the reserve for an operation, and some patients with reassuring breathing tests are found not to. Dr Lawrence Okiror assesses patients with borderline lung function privately at London Bridge Hospital and The Lister Chelsea, within 2–3 working days. Self-referrals welcome.
Last reviewed: August 2026 · Dr Lawrence Okiror FRCS(CTh) FRCSEd(CTh) · GMC 6150382
FEV1 opens the assessment. Predicted post-operative function, transfer factor, exercise capacity and regional imaging decide it. Severely reduced spirometry does not by itself rule an operation out, and near-normal spirometry does not by itself make one safe.
A full workup is not a route to surgery. It corrects the initial impression in whichever direction the physiology points — including withdrawing an operation that had already been listed. Four ways it turns out →
Reserve alone does not settle it. Where the tumour sits determines whether a smaller operation is available at all — and a centrally placed nodule can close the door that good physiology would otherwise open.
Borderline lung function is not a diagnosis. It is a description of a position in an assessment — the point at which the standard breathing test no longer answers the question on its own, and further testing is required before anyone can say whether an operation is safe.
Four measurements contribute. FEV1 is the volume of air moved in the first second of a forced breath out. Transfer factor (TLCO, sometimes written DLCO) measures how efficiently oxygen crosses from the air sacs into the blood, and is often the more sensitive of the two in emphysema. Predicted post-operative function — ppoFEV1 and ppoTLCO — estimates what those figures would become after the planned resection. Cardiopulmonary exercise testing measures how the heart, lungs and muscles perform together under load, which none of the resting tests can show.
Where those four disagree with each other, the disagreement is the finding. It is the reason a decision made on spirometry alone is worth revisiting. For the wider fitness picture — cardiac risk, frailty and prehabilitation — see Am I Fit for Lung Surgery? →
Spirometry cannot say which part of which lung the number is coming from, whether the area to be removed contributes 5% of function or 25%, or whether the limit on exertion is cardiac rather than respiratory. Those are separate questions with separate tests.
There is no single FEV1 cut-off below which lung cancer surgery stops. UK national guidance (NICE NG122, last updated March 2024) works from the predicted post-operative figure and from exercise capacity, not from the raw breathing test. The thresholds below are the ones used at every major UK thoracic centre. Patients are often surprised by how permissive they are.
| Category | Thresholds & operation type |
|---|---|
| Lobectomy usually suitable | Predicted post-operative FEV1 and transfer factor above 30%. Peak VO2 above 15 mL/kg/min on CPET, or shuttle walk above 400 m. |
| Smaller operation preferred | Peak VO2 between 10 and 15 mL/kg/min. Lobectomy carries higher risk in this range, so a segmentectomy or wedge resection is considered instead — provided the tumour position allows one. |
| Surgery offered with informed consent | Predicted post-operative FEV1 or transfer factor below 30%. NICE 2024 is explicit that surgery with curative intent should still be offered if the patient accepts the risks of breathlessness and complications. The 30% figure is a threshold for a conversation, not an exclusion. |
| Other approaches usually considered | Peak VO2 below 10 mL/kg/min, or several thresholds crossed together with significant frailty or cardiac impairment. Stereotactic radiotherapy, ablation or systemic therapy are usually the appropriate routes. |
ppoFEV1 is the predicted post-operative FEV1 — an estimate of the breathing test after the planned resection rather than before it. It is calculated from the current FEV1 and the share of function contributed by the part of the lung that would be removed. That share can be estimated by counting bronchopulmonary segments, or measured directly on a quantitative VQ SPECT scan. The two methods can differ substantially where the lung is unevenly damaged, and in emphysema the segment count usually understates what will be left behind.
A full functional workup is not a mechanism for converting refusals into operations. It is a mechanism for replacing an impression formed from one test with a decision informed by four. Sometimes that opens a door. Sometimes it closes one that had already been opened — including for patients who were on the operating list. The four patterns below are the ones that recur.
Spirometry and transfer factor, read alone, would not support a lobectomy. Exercise testing shows that the heart and lungs working together deliver more reserve than the resting figures imply. The operation proceeds, with the increased perioperative risk set out and accepted rather than glossed over. This is the pattern that makes a decision taken on spirometry alone worth revisiting.
Surgery remains possible but a lobectomy does not. Reserve sits in the range where a smaller anatomical resection carries acceptable risk and a larger one does not, and the tumour is positioned such that a smaller operation can still clear it. The workup here is not deciding whether to operate but which operation preserves the most functioning lung while achieving complete excision.
Spirometry looks acceptable, but the patient is limited far out of proportion to it. Exercise testing quantifies the gap the breathing test concealed. Where the tumour also sits centrally, so that no resection smaller than a lobectomy is technically available, the surgical route closes despite reassuring numbers and radiotherapy becomes the appropriate recommendation.
A patient is listed provisionally while the workup completes, and the workup returns a result that makes the operation unsafe. The listing is cancelled and the patient redirected to oncology. This is why testing is completed before a date is treated as fixed, and why the limiting factor is not always the lungs — cardiac impairment, arrhythmia and frailty all reduce operative reserve independently of the breathing test.
A lung function result is a measurement, and measurements have failure modes. Treating a number as a fixed property of the patient rather than as the output of a test performed on a particular day is one of the commonest reasons a fitness decision needs revisiting.
In a current smoker, the transfer factor can be depressed by carboxyhaemoglobin — carbon monoxide already bound to haemoglobin from smoking competes with the test gas, so the result understates true gas exchange. A patient who cannot perform the technique reliably, or cannot hold their breath for the required interval, may have no valid transfer factor or lung volume measurement at all. And an exercise test can end early for reasons that have nothing to do with cardiopulmonary limitation — leg fatigue, back pain, or a heart rate response blunted by beta-blockade — producing a peak VO2 that is submaximal rather than maximal.
None of this makes the tests unreliable. It makes their interpretation a clinical task rather than an arithmetic one. Reading the test quality is part of reading the test. For the full clinician-facing account of respiratory physiology and pre-operative testing, see Lung Function Testing for Thoracic Surgery →
Stopping before surgery lowers complication rates. It also changes what the transfer factor measures, which can alter the assessment itself. Both reasons are given at the consultation. See Smoking and Lung Health →
Two patients with the same lung function can receive different recommendations, and the reason is usually anatomical. A peripheral nodule sitting in the outer lung can often be removed by wedge resection — the smallest operation, and the one that costs least breathing capacity. A nodule sitting deep within the centre of a lobe cannot: there is no way to reach it and clear it without taking the lobe. For a patient with marginal reserve, that difference decides whether any surgical option exists at all.
This is why the assessment runs on two axes at once. Reserve determines how much lung can safely be given up. Position determines the smallest operation capable of clearing the cancer. Where the two are compatible, surgery proceeds. Where good physiology meets a central tumour, or preserved anatomy meets poor reserve, the answer changes.
Stereotactic radiotherapy (SABR, also called SBRT) is a genuine curative-intent treatment, and for some patients it is the correct recommendation rather than a consolation. It requires no anaesthetic, no chest incision and no loss of lung tissue, and it is the standard route where the risks of an operation are not justified.
For patients who can safely undergo an operation, surgical resection generally offers the better prognosis, and it carries one advantage radiotherapy cannot reproduce: it produces a specimen. The specimen establishes the true pathological stage rather than the stage estimated from imaging, and it provides tissue for biomarker testing where a small biopsy has yielded too little. That distinction matters most in exactly the patients this page is about, because a nodule in poorly functioning lung is often the hardest to biopsy adequately in the first place.
Both options are put side by side at the consultation, with the trade-offs stated plainly. Where the honest answer is that surgery is not safe, that is the answer given.
A quantitative ventilation-perfusion SPECT scan combines three pieces of information: which parts of the lung are receiving air, which are receiving blood, and a CT image showing the anatomy underneath. Together they express each region as a percentage of total lung function — which is what converts a segment count into a measured ppoFEV1.
In emphysema this matters more than anywhere else. Damage is rarely uniform, and destroyed lung is hyperinflated: it occupies space without contributing useful gas exchange. Where a cancer sits within that destroyed lung, removing it costs less function than the overall numbers suggest, and the resection can deliver a lung volume reduction effect alongside cancer clearance. Patients told that radiotherapy is their only remaining option on the basis of resting lung function alone are among those for whom this measurement most often changes the assessment.
Selection for that combined approach rests on high-resolution CT and quantitative VQ SPECT, not on spirometry. More on the emphysema side of the practice: Emphysema Surgery in 2026 →
The scan is painless, takes around 30–45 minutes, needs no preparation, and carries a radiation dose comparable to a standard CT of the chest.
Where a sublobar resection is planned in a patient with limited reserve, indocyanine green dye and the robotic infrared camera are used during the operation to confirm that the lung being preserved is genuinely perfused before the plane is divided. When every millilitre of functioning lung counts, the preserved lung is verified rather than assumed. Robotic Lung Surgery →
Patients with borderline lung function rarely arrive through a cancer pathway that was looking for cancer. They arrive because a scan taken for something else found one — and because their lungs were already compromised before anybody mentioned an operation.
A patient under review for COPD or emphysema has chest imaging as part of that care, and a nodule or mass is found. The cancer is often caught earlier than it would otherwise have been — and the reduced lung function is already documented before the surgical question is even asked.
Imaging after an accident, before another operation, or during investigation of an unrelated symptom shows a lung mass in someone who has never been assessed for surgery. See Shadow on a Lung Scan →
A decision has been made on the basis of lung function, and the patient wants it reviewed by someone who assesses this group routinely. Specialist Second Opinion →
Fitness after chemoimmunotherapy, or before a second operation, is not the fitness recorded beforehand. Previous treatment alters regional function in ways spirometry does not show. Surgery after chemoimmunotherapy →
At Guy's and St Thomas' NHS Foundation Trust, lung cancers identified in the COPD and emphysema clinics are discussed at the chest multidisciplinary team meeting and referred onward to Dr Okiror, who leads the Trust's lung-cancer-in-emphysema pathway. Quantitative VQ SPECT has been the planning instrument across more than 100 emphysema interventions there since 2019.
Thoracic surgical outcomes at the Trust are reported annually to the SCTS National Thoracic Surgery Audit. The 2024–25 audit reports an operative survival rate of 99.59% at Guy's and St Thomas', against a national benchmark of 98.5%. Private patients are seen at London Bridge Hospital and The Lister Hospital Chelsea; where a quantitative VQ SPECT is required, it is arranged through an established private patient pathway covered by medical insurance or self-pay.
If a decision about your fitness for lung cancer surgery was made on the breathing test alone, an independent review is reasonable — whichever way it turns out. Most patients are seen within 2–3 working days.
Book a Consultation →Or call Jo Mitchelson, PA:
020 7952 2882
If a decision was made on spirometry alone, a full functional assessment is reasonable — and it is worth having whichever way it points. Private appointments at London Bridge Hospital and The Lister Chelsea within 2–3 working days, or by video consultation for patients outside London. Bring your scans, lung function results and previous letters. Self-referrals welcome.
Jo Mitchelson, PA · 020 7952 2882 · pa@lungsurgeon.co.uk
St Thomas’ Hospital #1 UK · Guy’s Hospital #2 UK · London Bridge Hospital #10 UK · Newsweek World’s Best Hospitals 2026
This page describes Dr Lawrence Okiror's clinical practice in the assessment of patients with borderline lung function being considered for lung cancer surgery. It is patient information, not medical advice for any individual case. Decisions about fitness for surgery are made case by case after clinical evaluation and multidisciplinary review. Dr Okiror is a Consultant Thoracic and Robotic Surgeon at Guy's and St Thomas' NHS Foundation Trust, with private practising privileges at London Bridge Hospital and The Lister Hospital Chelsea.
The wider fitness framework — cardiac risk, frailty, prehabilitation and what happens at consultation.
Lung Function Testing for Thoracic SurgeryThe clinician-facing reference on respiratory physiology, DLCO, CPET and the assessment frameworks.
BreathlessnessWhen breathlessness has a thoracic cause, and what a surgical assessment covers.
Robotic SegmentectomyLung-sparing resection — the smaller operation the assessment often selects.
Emphysema Surgery in 2026EBV and LVRS — where cancer sits in destroyed lung, and the combined operation.
Lung Cancer Surgery in 2026Stage-by-stage pathway from diagnosis to surgery to systemic therapy.
Journal: “Unfit for surgery” is not a planCommentary on what the phrase leaves undecided, and who it leaves untreated.
Specialist Second OpinionIndependent review of imaging, fitness assessment and treatment plan within 2–3 working days.
Smoking and Lung HealthWhy stopping changes both the operative risk and the transfer factor itself.