Adjuvant Mitotane After Low-Risk Adrenocortical Carcinoma Resection: What ADIUVO Actually Showed
A single patient in the exact population the only randomized trial of adjuvant mitotane ever studied, where the trial's own null result sits against real, ongoing treatment toxicity.
Simone D., a 44-year-old accountant, had a stage II adrenocortical carcinoma removed six weeks ago with clean margins and a Ki-67 proliferation index of 8% — precisely the low-to-intermediate-risk profile the ADIUVO trial was built to study, the first and only randomized trial ever conducted on whether adjuvant mitotane actually helps a patient in her exact situation. She has spent the weeks since surgery reading everything she can find about a disease so rare that most of what exists online is either outdated or written for a very different, higher-risk patient than she is, printing out pages and highlighting them the same methodical way she reconciles a client's ledger, and arrives at this visit having already decided, tentatively, that she wants "the treatment that gives the best odds" — a phrase that turns out to be genuinely harder to answer than she expects.
ADIUVO randomized ninety-one patients meeting her exact risk profile — R0 resection, stage I through III, Ki-67 at or below 10% — to adjuvant mitotane or observation alone, and found five-year recurrence-free survival of 79% with mitotane against 75% with observation, a difference that did not reach statistical significance. Four percentage points of absolute difference is a number needed to treat of roughly 25, and that figure is itself drawn from a point estimate the trial could not separate from no effect at all. The trial's own investigators were explicit that patients in this specific risk category have a substantially better prognosis than historically assumed for adrenocortical carcinoma generally, and do not clearly benefit from a drug whose real toxicity — adrenal insufficiency requiring lifelong hydrocortisone and fludrocortisone replacement even after a curative resection, real gastrointestinal and neurocognitive side effects, and months of slow dose titration guided by therapeutic drug monitoring — is neither small nor hypothetical.
Post-resection visit, adjuvant therapy discussion
ADIUVO's own point estimate still favored mitotane — 79% versus 75% five-year recurrence-free survival — it just didn't reach statistical significance in a trial that accrued far more slowly than planned because this disease is so rare. A small, possibly underpowered negative trial isn't the same as proof mitotane doesn't help. I'd recommend it, given it's still the only agent with any evidence behind it in this disease.
I'd weigh the toxicity side of that trade more heavily than I think it's being weighed. Her adrenal function is normal right now — mitotane would very likely make her permanently dependent on hydrocortisone and fludrocortisone, on top of real gastrointestinal and neurocognitive side effects, for a benefit the actual randomized trial in her exact risk category couldn't demonstrate. That's a real, certain cost against an uncertain one.
I take the underpowering concern seriously — I'm not claiming ADIUVO proves no effect exists — I'm saying "might be underpowered" isn't the same as "probably works," and the toxicity she'd accept is not hypothetical either way.
I don't think either of you should be the one who decides this for her. Show her the actual ADIUVO numbers plainly — what the trial's own four-point difference really means — a number needed to treat of roughly twenty-five, so about twenty-four of every twenty-five patients who take mitotane get no recurrence benefit from it but do get its real side effects — alongside what those side effects concretely look like day to day, including for someone doing detail-focused work. Given genuine equipoise in the evidence, her own read of that trade is the actual right basis for this decision, not ours.
Agreed: present Simone the ADIUVO trial's actual numbers and mitotane's real toxicity directly, and let her own preference decide between adjuvant mitotane and observation, with standard surveillance imaging continuing regardless of her choice.
Not agreed: what the team should do if she remains genuinely torn after hearing the full picture. The oncologist would lean toward gently recommending mitotane in that case, given the disease's overall severity outside this specific favorable subgroup; the endocrinologist would consider genuine ambivalence itself a reason to favor observation, given that accepting real, certain toxicity requires more conviction than accepting an uncertain risk of recurrence.