Act now and your tumor gets a pregame pep talk, a halftime adjustment, and an encore from immunotherapy - because apparently even head and neck cancer treatment has entered its deluxe box-set era.

Under the sales pitch, though, sits a serious question. A 2026 Journal of Clinical Oncology commentary with the wonderfully shady title Notably Off Key asks whether the applause around the phase 3 KEYNOTE-689 trial might be a little too loud.[1] Translation: yes, perioperative pembrolizumab helped on paper, but are we hearing a real clinical symphony here, or just one very dramatic cymbal crash?

The Main Melody

Head and neck squamous cell carcinoma, or HNSCC, is the category that covers many cancers of the mouth, throat, larynx, and nearby real estate. Standard treatment for resectable, locally advanced disease is already no picnic: surgery first, then radiation, sometimes with cisplatin if the pathology looks especially rude. Even after all that, recurrence still likes to crash the party.[2]

Pembrolizumab is a PD-1 blocker, which is science-speak for "stop the tumor from putting immune cells in bureaucratic timeout." Tumors often wave PD-L1 around like a fake backstage pass, telling T cells to calm down and go home. Pembrolizumab yanks that pass.[3]

KEYNOTE-689 tested whether giving pembrolizumab before surgery and then again after surgery could improve outcomes. The trial enrolled 714 patients with resectable stage III to IVA HNSCC. Patients either got standard care alone or two cycles of pembrolizumab before surgery, followed by more pembrolizumab during and after postoperative radiation, with cisplatin added when pathology showed high-risk features.[2]

And the trial did hit its main endpoint. In patients whose tumors had PD-L1 combined positive score, or CPS, at least 1, median event-free survival was 59.7 months with pembrolizumab versus 29.6 months with standard care alone. At 36 months, event-free survival was 58.2% versus 44.9%.[2] That is not nothing. That is a real note, played loudly.

Why the JCO Commentary Is Side-Eyeing the Encore

Here is where Notably Off Key walks onto the stage wearing the expression of a jazz critic who just heard a seven-minute drum solo and wants to discuss restraint.[1]

First, KEYNOTE-689 improved event-free survival, not yet overall survival. Those are related, but they are not identical twins. Event-free survival asks whether the cancer progressed, recurred, blocked surgery, or the patient died. Overall survival asks the blunt question your aunt would ask over fries: "Did people actually live longer?" At the interim analysis, overall survival was still immature.[2]

Second, the treatment package is a bundle deal. Patients got pembrolizumab before surgery, during postoperative radiation, and after that. The trial was not designed to tell us which part did the heavy lifting.[2] Was the magic in the pre-op window, the long adjuvant tail, or the whole combo like a medical power trio? We do not know yet.

Third, "works for everyone" is not the vibe. The FDA approval in the United States, issued on June 12, 2025, was for tumors with PD-L1 CPS at least 1.[2] Exploratory subgroup analyses also raised eyebrows. Patients with hypopharyngeal tumors did not look like obvious winners in the pembrolizumab arm, and older patients may benefit less, though that needs more study.[2,4]

Fourth, real life is not a neat Kaplan-Meier curve. Surgery still happened in about 88% of patients in both arms, but delays were more common with neoadjuvant pembrolizumab.[5] Add in the need for rapid PD-L1 testing, insurance approval, infusion scheduling, and one more specialist visit, and suddenly this regimen starts sounding less like a clean melody and more like a band trying to load gear through a side door at midnight.[4]

And then there is toxicity. Pembrolizumab did not invent misery here, because radiation to the head and neck already has a long criminal record, but it added its own signature. Common side effects included stomatitis, fatigue, rash, diarrhea, and hypothyroidism.[2] Useful therapy, yes. Free lunch, absolutely not.

So Is This a Key Change or Just a Fancy Intro?

Probably both.

KEYNOTE-689 matters because it shows the immune system might help earlier in treatment, not just after cancer comes back or spreads. That is a meaningful shift.[5,6] Earlier studies and newer neoadjuvant trials also support the idea that the pre-surgery window can generate real tumor responses and teach us which patients are actually responding.[6,7]

But the JCO commentary is doing its job by asking for better standards than "the curve moved, everybody clap."[1] If this approach is going to become routine, doctors need cleaner answers about overall survival, quality of life, who benefits most, and whether the full perioperative marathon is necessary for every patient.

Cancer biology is weird enough without pretending every positive trial is a standing ovation. Sometimes it is a promising riff that still needs the rest of the band.

References

1. Awan M, Caudell J, Wong S, et al. Notably Off Key: Questioning the Clinical Benefit of Perioperative Immunotherapy for Resectable Head and Neck Squamous Cell Carcinoma After KEYNOTE-689. J Clin Oncol. 2026. DOI: https://doi.org/10.1200/JCO-25-01990

2. Uppaluri R, Haddad RI, Tao YG, et al. Neoadjuvant and Adjuvant Pembrolizumab in Locally Advanced Head and Neck Cancer. N Engl J Med. 2025;393(1):37-50. DOI: https://doi.org/10.1056/NEJMoa2415434

3. Johnson DE, Burtness B, Leemans CR, et al. Head and neck squamous cell carcinoma. Nat Rev Dis Primers. 2020;6:92. DOI: https://doi.org/10.1038/s41572-020-00224-3

4. Brammer B, Gross JH, Boyce BJ, Schmitt NC. Implementing perioperative immunotherapy for head and neck cancer after KEYNOTE-689: questions and challenges. Transl Cancer Res. 2025;14(12):8221-8227. DOI: https://doi.org/10.21037/tcr-2025-2042

5. FDA. FDA approves neoadjuvant and adjuvant pembrolizumab for resectable locally advanced head and neck squamous cell carcinoma. June 12, 2025. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-neoadjuvant-and-adjuvant-pembrolizumab-resectable-locally-advanced-head-and-neck

6. Wise-Draper TM, Gulati S, Palackdharry S, et al. Phase II Clinical Trial of Neoadjuvant and Adjuvant Pembrolizumab in Resectable Local-Regionally Advanced Head and Neck Squamous Cell Carcinoma. Clin Cancer Res. 2022;28(7):1345-1352. DOI: https://doi.org/10.1158/1078-0432.CCR-21-3351

7. Liu Z, Wang D, Li G, et al. Neoadjuvant with low-dose radiotherapy, tislelizumab, albumin-bound paclitaxel, and cisplatin for resectable locally advanced head and neck squamous cell carcinoma: phase II single-arm trial. Nat Commun. 2025;16:4608. DOI: https://doi.org/10.1038/s41467-025-59865-1

Disclaimer: The image accompanying this article is for illustrative purposes only and does not depict actual experimental results, data, or biological mechanisms.