Old cavity, new cancer - is it time to re-think?

This case report re-visits the long debated ‘scar theory’ as a proposed risk factor for lung cancer.

Case report

A 73-year-old woman initially presented 3 years ago with a three-month history of cough with purulent sputum, anorexia and weight loss. She had retired as a driving instructor and had a 50-pack/year smoking history. Chest radiograph and computed tomography (CT) demonstrated a thick-walled cavity with an air fluid level in the right upper lobe (Figure 1a). Sputum culture grew a fully sensitive Streptococcus milleri.

Figure 1

Frontal chest radiographs at the time of initial presentation (a) showing a large right apical cavity (arrow) which resolved after appropriate treatment (b) only to be replaced by a malignant mass (c) three years later

Subsequent bronchoscopy (three days into treatment with antibiotics) was macroscopically normal and the washings were negative for acid-fast bacilli, bacteria and fungi. Cytology showed benign inflammation with no malignant cells. She was discharged home on oral antibiotics after clinical and biochemical improvement following a week of intravenous antibiotics.

Two weeks later she represented with acute worsening of breathlessness. CT pulmonary angiogram showed no emboli but the cavity had decreased in size with resolution of fluid content (Figure 2a). On this occasion she was treated for likely exacerbation of chronic obstructive pulmonary disease and discharged. At her outpatient follow-up all her symptoms had resolved and the chest radiograph showed further resolution of the right upper lobe abscess (Figure 1b). She unfortunately did not attend any further follow-up appointments.

Figure 2

CT images in axial plane showing a large cavity in the right upper lobe (a), which was replaced by a malignant growth (star) three years later (b)

Three years later she again presented with anorexia, weight loss and purulent sputum. On this occasion she also had back pain and mild hypercalcaemia. Over the last six months she was empirically treated for infection with little improvement in her symptoms. Chest radiograph showed a soft tissue mass at the right apex and right hilar lymphadenopathy (Figure 1c). CT confirmed a right cavitating mass (at the site of previous abscess cavity) with local rib invasion, bilateral adrenal and widespread bony metastases (Figure 2b). Features were consistent with a disseminated lung cancer (T4 N2 M1b). Histological confirmation was not sought as the result would not have affected the palliative treatment approach chosen in view of poor performance status and advanced chronic lung disease. She died peacefully at home two weeks after discharge.

Discussion

Lung cancer arising in damaged pulmonary tissue has been long recognized. Specifically there have been reports of cancer forming within a previous cavity. This is thought to be due to chronic inflammation particularly with peripheral scarring due to possible malignant transformation during the reparative hyperplasia of the small bronchioles.[1] Prospective data have shown an increase in risk of ipsilateral lung cancer in patients with asymptomatic pulmonary scarring.[2]

Lifelong surveillance of all patients with a pulmonary cavity is neither desirable nor feasible to detect potential malignant transformation but with increasing life expectation of patients with chronic lung disease there may well be a case for clinical and/or radiological follow-up in selected cases. Selected cases may have to include those with a heavy smoking history and patients where the cavity wall remains thick. Additional prospective research is necessary to formulate any potential guidelines. Until then selected patients with pulmonary cavities should be considered for clinical monitoring at intervals and early CT imaging and investigation where change occurs.

DECLARATIONS

Competing interests

None declared

Funding

None

Ethical approval

Written informed consent to publication has been obtained from the patient or next of kin

Guarantor

SK

Contributorship

All authors contributed equally

Acknowledgements

None

Reviewer

Howard Branley