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Worth Attention cutaneous-squamous-cell Retrospective

Radiotherapy may offset the survival disadvantage of perineural invasion in cutaneous head and neck cancer

PNI-positive patients without radiotherapy had worse survival, while those receiving radiotherapy had outcomes comparable to patients without PNI.

RadOncToday · ·1 min read

KEY POINTS

  • This National Cancer Database analysis included 929 adults with surgically treated cutaneous squamous-cell carcinoma of the head and neck diagnosed between 2018 and 2021. 276 patients had perineural invasion, while 653 did not.
  • Radiotherapy use differed markedly by PNI status: 49.6% of PNI-positive patients received RT versus only 11.3% of PNI-negative patients (p<0.001). Among PNI-positive patients, 137 received RT and 139 did not.
  • PNI alone was not significantly associated with overall survival after adjustment (HR 1.38, 95% CI 0.98–1.96; p=0.066), and RT alone was likewise not independently associated with survival in the entire cohort.
  • The key finding was a significant PNI × RT interaction (multivariable p=0.016), indicating that the relationship between PNI and survival differed depending on whether radiotherapy was delivered.
  • Among patients who did not receive RT, PNI was associated with an 80% higher adjusted risk of death compared with PNI-negative patients (HR 1.80, 95% CI 1.18–2.76).
  • In contrast, PNI-positive patients who received RT had survival comparable to the PNI-negative, untreated reference group (HR 1.05, 95% CI 0.64–1.71 in the reported group comparison). The Kaplan-Meier curves on page 5 show the PNI-positive/no-RT group separating downward while the PNI-positive/RT curve tracks much closer to the reference population.
  • The study cannot establish that radiotherapy caused the survival difference. NCDB lacked reliable information on PNI caliber, named-nerve involvement, disease stage, comorbidity, RT dose/fractionation, recurrence and cause-specific mortality, and even treatment sequence could not be reliably established.

CLINICAL TAKEAWAY

For surgically treated head and neck cutaneous squamous-cell carcinoma, PNI appeared prognostically adverse primarily when radiotherapy was not given. The finding fits current risk-adapted use of postoperative RT, but because treatment selection and key tumor characteristics were incompletely captured, this should be viewed as supportive observational evidence rather than proof of a survival benefit.

SOURCE

Head & Neck