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Worth Attention lung toxicity

Treatment interruptions were associated with poorer early outcomes during lung cancer radiotherapy

Unplanned radiotherapy interruptions occurred in 35% and were associated with lower response, more toxicity and markedly worse six-month survival.

RadOncToday · ·1 min read

KEY POINTS

  • This single-center retrospective cohort included 226 patients with lung cancer treated from 2020–2022; 195 had NSCLC and 31 had SCLC. An unplanned interruption was defined as a treatment pause of at least one day, excluding scheduled breaks; 79 patients (35.0%) experienced at least one interruption.
  • Interruptions lasted a median of 5 days and occurred most often during the middle third of the radiation course (60.8%). Treatment-related toxicity caused 49.4% of interruptions, including grade ≥3 esophagitis in 22.8%, pneumonitis in 13.9% and myelosuppression in 8.9% of interrupted patients; patient-related factors accounted for another 27.8%.
  • Patients who interrupted treatment already had substantially less favorable baseline characteristics: stage III–IV disease was present in 86.1% versus 64.6%, ECOG 2–3 in 59.5% versus 23.1%, and mean tumor volume was 59.1 versus 41.5 cm³. Palliative treatment and concurrent chemoradiotherapy were also more frequent in the interrupted group.
  • After multivariable analysis, stage III–IV disease, tumor volume ≥50 cm³ and ECOG 2–3 remained independently associated with longer interruption duration. Dose completion averaged 81.9% in interrupted versus 95.0% in non-interrupted patients (p<0.001).
  • Early tumor response was poorer among interrupted patients: overall response was 55.7% versus 76.2%, disease control 77.2% versus 93.9%, and grade ≥3 acute toxicity 44.3% versus 19.7%. Because toxicity itself was the most common reason for stopping treatment, the toxicity association is especially vulnerable to reverse causality.
  • Six-month progression-free survival was 22.8% versus 89.8%, and six-month overall survival 26.6% versus 91.2%. Interruption remained associated with progression after adjustment (HR 2.99, 95% CI 1.82–4.90) and death (HR 3.22, 95% CI 1.96–5.28), but the observational design, very short follow-up, heterogeneous disease and treatment intent, and major baseline differences preclude a causal conclusion.

CLINICAL TAKEAWAY

Unplanned treatment breaks identify a particularly vulnerable lung cancer population and reinforce the value of early toxicity management and logistical support to maintain treatment continuity. The approximately threefold adjusted hazards should not be interpreted as proof that the interruptions themselves caused the survival disadvantage, because toxicity, progression and worse baseline disease also drove interruptions.

SOURCE

Frontiers in Oncology