Chemotherapy given together with radiation to treat anal cancer without surgery. Blood counts drop later than usual (around week 4), and the radiation causes skin soreness and bowel changes in the treated area.
Mitomycin + continuous-infusion 5-FU given WITH radiation (chemoradiation, Nigro-type protocol) for anal cancer. Two features stand out: mitomycin's blood-count drop is DELAYED (nadir around 4 weeks), and radiation adds skin and bowel effects in the treated area.
Get help straight away — this is true on any regimen, on any day.
A temperature of 100.4°F (38°C) or higher during treatment can mean a
serious infection while your blood counts are low. Call your team or go to the ER — do not
wait it out.
Also urgent: trouble breathing or chest pain · swelling of the face, lips or throat ·
new confusion or fainting · shaking chills · not being able to keep fluids down.
This is standing guidance shown to everyone. Nothing on this page is based on anything
about you, and nobody is monitoring you.
Timed to the cycle
Day 1 is the day of your infusion. These are the effects a retrievable
document ties to a day range for this regimen — not a prediction about you.
Myelosuppression (delayed nadir)
Typically around days 9–56
Drops in white cells and platelets that come LATER than with most chemo — the low point is often around 4 weeks and can be prolonged. Your team checks counts well beyond the treatment days.
Call your team urgently: A temperature of 100.4°F (38.0°C) or higher — an emergency.
reported by about ~60% of people; severe in ~25-40% · Timing from the manufacturer’s prescribing information · from Mitomycin, Fluorouracil
Not tied to a cycle day
These build with the number of doses, or are measured from when treatment started, so a cycle day would be the wrong shape for them. Each keeps the timing its own source states.
Radiation dermatitis (treated area)
builds through radiation; peaks near/after the end
The skin around the anus/groin can become red, sore, and peel during and shortly after radiation — chemo makes it more intense. Gentle skin care as directed helps; it heals over weeks after radiation ends.
Call your team: Open, weeping, or infected-looking skin, or pain that isn't controlled.
reported by about ~70% of people; severe in ~30-45% · from Radiation
Diarrhea / bowel irritation
builds through radiation
Radiation to the pelvis plus 5-FU commonly causes diarrhea, urgency, and cramping. Anti-diarrheal medicine, hydration, and diet changes help; tell your team if it's severe.
Call your team: More than 6 stools above normal in a day, or any with dizziness/fever.
reported by about ~50% of people; severe in ~10-20% · from Radiation, Fluorouracil
Nausea
Sickness in the first 24 hours is the "acute" phase and usually peaks 2-3 hours in; anything from 24 to 120 hours is the "delayed" phase.
Usually mild-moderate and controlled with anti-nausea medicine.
reported by about ~40% of people · Timing from a clinical guideline · from Fluorouracil, Mitomycin
Where this comes from
S1. Mitomycin FDA prescribing information — FDA label
S3. Fluorouracil (5-FU) FDA prescribing information — FDA label
Timing windows on this page rest on:
Fluorouracil injection prescribing information — “The nadir in neutrophil counts commonly occurs between 9 and 14 days after Fluorouracil administration” source
A window appears here only where a retrievable document ties it to a drug in
this regimen. Where nothing could be found, the window was removed rather than estimated —
so a missing time is an honest gap, not an oversight.