The 10 year survival rate for stage 0 melanoma (in situ) is 99 percent. So what happens with that one percent? Do they die from their melanoma in situ?
• How does anyone die from melanoma in situ?
• Shouldn’t the survival rate be 100 percent?
• In situ melanoma is confined to the top most layer of the skin, the epidermis.
• Stage 0 melanoma has grown in horizontal width (superficial spread) before it has burrowed into the next layer of skin, the dermis.
What happens to that 1 percent
of stage 0 melanoma patients
who don’t survive after 10 years?
One out of 100 melanoma in situ patients will not be alive 10 years after diagnosis. In fact, the 99 percent survival rate is also given for the five year mark.
There is no way to know just how many of those one-percenters, out of, for instance, 10,000 stage 0 melanoma cases, actually died from their original stage 0 melanoma.
We just know that five to 10 years later, a hundred out of those 10,000 will be dead.
Medical oncologist Daniel Vorobiof, MD, says that this mortality figure can, in part, be explained by study participants not being available for future follow-ups or dying from an unrelated condition.
But there’s more to it than these two explanations, because as the melanoma gets deeper, the five to 10 year mortality rate goes up. (Same with any cancer.)
So though we can say that out of those 100 death cases from the 10,000 in situ diagnoses — perhaps 20 percent perished from a heart attack and five percent died in car accidents, and maybe four were murdered and 10 more succumbed to stroke, food poisoning, shark attacks and rock climbing falls — this line of logic disintegrates as the stage of cancer gets more advanced.
Can People Die from
Melanoma In Situ?
“When a lesion is removed and diagnosed, especially if it is a melanoma, we cannot be sure that it hasn’t sent some cells before, and years later we might see the appearance of a metastasis,” says Dr. Vorobiof, former medical oncology director of The Sandton Oncology Centre in Johannesburg, South Africa.
Having authored more than 100 peer reviewed articles in international medical journals. Dr. Vorobiof also runs the “Ask the Oncologist” forum in Belong.Life, the world’s largest social network for cancer patients.
“It is not uncommon to see in melanoma that there is regression (complete or partial) of a mole, and years later it appears somewhere else, and nobody has realized that there was an early lesion which disappears or is very small and without any specific characteristics,” explains Dr. Vorobiof.
“So it is not what the lesion does from today, but what it did beforehand, and we can’t measure that in time and we can’t visualize it or identify it later.
“That is why the risk of developing a metastases from a stage 0 (which is the lay term; we call it ‘in situ’) is very small, but nothing is impossible in the human body.”
When statistics are determined for cancer survival rates, there are limitations that can in part explain why there’s a mortality rate for melanoma in situ (or DCIS breast cancer, for that matter, which also has a 99 percent survival rate out to 10 years).
The first limitation is that elderly people have shorter survival times than younger patients, regardless of cancer stage.
The presence of elderly people in the stage 0 melanoma pool will affect the calculation for the survival rate.
Second, those with weakened immune systems from an unrelated condition like HIV infection will have a lower survival rate when compared to healthy people with the same stage of cancer.
So these are two more variables that account for the mortality of one percent in stage 0 melanoma.
But can melanoma in situ
actually be fatal?
Literally, it can’t be, because by definition, it is confined to its starting point: the top-most layer of skin. “In situ” is Latin for “in place.”
However, it’s not impossible for the excision of the lesion to leave behind one malignant cell, which goes undetected – and multiplies – and over time becomes invasive.
If melanoma in situ ever became fatal, it would not be at stage 0 by the time it becomes untreatable. If such an early cancer goes untreated, of course it will eventually become invasive with a poor survival rate.
In medicine, nothing is ever 100 percent. “There are only two certainties in life that are 100 percent — birth and death,” says Dr. Vorobiof.